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          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VesselsOperatingExpenses" xlink:label="loc_CISS_VesselsOperatingExpenses" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_CISS_VesselsOperatingExpenses" use="optional" order="12" weight="1" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VesselsOperatingExpensesRelatedParty" xlink:label="loc_CISS_VesselsOperatingExpensesRelatedParty" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="loc_CISS_VesselsOperatingExpensesRelatedParty" use="optional" order="13" weight="1" />
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          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="loc_us-gaap_NonoperatingIncomeExpense" use="optional" order="14" weight="1" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDebtExpense" xlink:label="loc_us-gaap_InterestAndDebtExpense" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_InterestAndDebtExpense" use="optional" order="15" weight="-1" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_InvestmentIncomeInterest" use="optional" order="16" weight="1" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" use="optional" order="17" weight="1" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_InterestAndDebtExpensesRelatedParty" xlink:label="loc_CISS_InterestAndDebtExpensesRelatedParty" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_CISS_InterestAndDebtExpensesRelatedParty" use="optional" order="18" weight="-1" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants" use="optional" order="19" weight="-1" />
        </link:calculationLink>
        <link:calculationLink xlink:type="extended" xlink:role="http://www.c3is.com/role/AccruedAndOtherLiabilitiesSummaryOfAccompanyingConsolidatedBalanceSheetsOfAccruedAndOtherLiabilitiesDetail" >
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AdministrationExpensesPayableCurrent" xlink:label="loc_CISS_AdministrationExpensesPayableCurrent" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:to="loc_CISS_AdministrationExpensesPayableCurrent" use="optional" order="1" weight="1" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AccruedVesselOperatingAndVoyageExpenses" xlink:label="loc_CISS_AccruedVesselOperatingAndVoyageExpenses" />
          <link:calculationArc xlink:type="arc" xlink:arcrole="https://xbrl.org/2023/arcrole/summation-item" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:to="loc_CISS_AccruedVesselOperatingAndVoyageExpenses" use="optional" order="2" weight="1" />
        </link:calculationLink>
        <link:labelLink xlink:type="extended" xlink:role="http://www.xbrl.org/2003/role/link" >
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CoverAbstract" xlink:label="loc_dei_CoverAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_CoverAbstract" xml:lang="en-US">Cover [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CoverAbstract" xlink:to="lab_dei_CoverAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationTable" xlink:label="loc_dei_DocumentInformationTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentInformationTable" xml:lang="en-US">Document Information [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentInformationTable" xlink:to="lab_dei_DocumentInformationTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementClassOfStockAxis" xml:lang="en-US">Class of Stock [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementClassOfStockAxis" xlink:to="lab_us-gaap_StatementClassOfStockAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfStockDomain" xml:lang="en-US">Class of Stock [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfStockDomain" xlink:to="lab_us-gaap_ClassOfStockDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityAddressesAddressTypeAxis" xlink:label="loc_dei_EntityAddressesAddressTypeAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_EntityAddressesAddressTypeAxis" xml:lang="en-US">Entity Addresses, Address Type [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressesAddressTypeAxis" xlink:to="lab_dei_EntityAddressesAddressTypeAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AddressTypeDomain" xlink:label="loc_dei_AddressTypeDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_AddressTypeDomain" xml:lang="en-US">Address Type [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AddressTypeDomain" xlink:to="lab_dei_AddressTypeDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentInformationLineItems" xlink:label="loc_dei_DocumentInformationLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentInformationLineItems" xml:lang="en-US">Document Information [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentInformationLineItems" xlink:to="lab_dei_DocumentInformationLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentType" xml:lang="en-US">Document Type</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentType" xlink:to="lab_dei_DocumentType" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_EntityRegistrantName" xml:lang="en-US">Entity Registrant Name</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityRegistrantName" xlink:to="lab_dei_EntityRegistrantName" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_EntityCentralIndexKey" xml:lang="en-US">Entity Central Index Key</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCentralIndexKey" xlink:to="lab_dei_EntityCentralIndexKey" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentPeriodEndDate" xml:lang="en-US">Document Period End Date</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_AmendmentFlag" xml:lang="en-US">Amendment Flag</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AmendmentFlag" xlink:to="lab_dei_AmendmentFlag" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_CurrentFiscalYearEndDate" xml:lang="en-US">Current Fiscal Year End Date</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_CurrentFiscalYearEndDate" xlink:to="lab_dei_CurrentFiscalYearEndDate" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentFiscalYearFocus" xml:lang="en-US">Document Fiscal Year Focus</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalYearFocus" xlink:to="lab_dei_DocumentFiscalYearFocus" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_DocumentFiscalPeriodFocus" xml:lang="en-US">Document Fiscal Period Focus</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentFiscalPeriodFocus" xlink:to="lab_dei_DocumentFiscalPeriodFocus" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract" xlink:to="lab_us-gaap_StatementOfFinancialPositionAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementTable" xml:lang="en-US">Statement [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementTable" xlink:to="lab_us-gaap_StatementTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="loc_srt_ConsolidatedEntitiesAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_srt_ConsolidatedEntitiesAxis" xml:lang="en-US">Consolidated Entities [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesAxis" xlink:to="lab_srt_ConsolidatedEntitiesAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="loc_srt_ConsolidatedEntitiesDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_srt_ConsolidatedEntitiesDomain" xml:lang="en-US">Consolidated Entities [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesDomain" xlink:to="lab_srt_ConsolidatedEntitiesDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesAPreferredStockMember" xlink:label="loc_us-gaap_SeriesAPreferredStockMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SeriesAPreferredStockMember" xml:lang="en-US">Series A Preferred Stock [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_SeriesAPreferredStockMember" xml:lang="en-US">Series A Preferred Stock [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/presentationGuidance" xlink:label="lab_us-gaap_SeriesAPreferredStockMember" xml:lang="en-US">Series A Perpetual Convertible Preferred Shares [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SeriesAPreferredStockMember" xlink:to="lab_us-gaap_SeriesAPreferredStockMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementLineItems" xml:lang="en-US">Statement [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementLineItems" xlink:to="lab_us-gaap_StatementLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract" xlink:label="loc_us-gaap_AssetsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsAbstract" xml:lang="en-US">Assets [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AssetsAbstract" xml:lang="en-US">Assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="lab_us-gaap_AssetsAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="loc_us-gaap_AssetsCurrentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xml:lang="en-US">Assets, Current [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AssetsCurrentAbstract" xml:lang="en-US">Current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrentAbstract" xlink:to="lab_us-gaap_AssetsCurrentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xml:lang="en-US">Cash and Cash Equivalents, at Carrying Value</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" xml:lang="en-US">Cash and cash equivalents</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="lab_us-gaap_CashAndCashEquivalentsAtCarryingValue" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_TimeDepositsCurrent" xlink:label="loc_ciss_TimeDepositsCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_TimeDepositsCurrent" xml:lang="en-US">Time Deposits Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_TimeDepositsCurrent" xml:lang="en-US">Time deposits</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_TimeDepositsCurrent" xlink:to="lab_ciss_TimeDepositsCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_TimeDepositsCurrent" xml:lang="en-US">Time deposits current.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsAndOtherReceivablesNetCurrent" xlink:label="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent" xml:lang="en-US">Accounts and Other Receivables, Net, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent" xml:lang="en-US">Trade and other receivables</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsAndOtherReceivablesNetCurrent" xlink:to="lab_us-gaap_AccountsAndOtherReceivablesNetCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaap_OtherAssetsCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OtherAssetsCurrent" xml:lang="en-US">Other Assets, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_OtherAssetsCurrent" xml:lang="en-US">Other current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherAssetsCurrent" xlink:to="lab_us-gaap_OtherAssetsCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xml:lang="en-US">Prepaid Expense and Other Assets, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xml:lang="en-US">Advances and prepayments</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:to="lab_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaap_InventoryNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InventoryNet" xml:lang="en-US">Inventory, Net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InventoryNet" xml:lang="en-US">Inventories</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryNet" xlink:to="lab_us-gaap_InventoryNet" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaap_AssetsCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsCurrent" xml:lang="en-US">Assets, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_AssetsCurrent" xml:lang="en-US">Total current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsCurrent" xlink:to="lab_us-gaap_AssetsCurrent" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_OperatingLeaseRightOfUseAssetCurrent" xlink:label="loc_ciss_OperatingLeaseRightOfUseAssetCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_OperatingLeaseRightOfUseAssetCurrent" xml:lang="en-US">Operating Lease Right Of Use Asset Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_OperatingLeaseRightOfUseAssetCurrent" xml:lang="en-US">Operating lease right-of-use assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_OperatingLeaseRightOfUseAssetCurrent" xlink:to="lab_ciss_OperatingLeaseRightOfUseAssetCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_OperatingLeaseRightOfUseAssetCurrent" xml:lang="en-US">Operating lease right of use asset current.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrentAbstract" xlink:label="loc_us-gaap_AssetsNoncurrentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsNoncurrentAbstract" xml:lang="en-US">Assets, Noncurrent [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AssetsNoncurrentAbstract" xml:lang="en-US">Non current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsNoncurrentAbstract" xlink:to="lab_us-gaap_AssetsNoncurrentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xml:lang="en-US">Property, Plant and Equipment, Net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xml:lang="en-US">Vessels, net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xml:lang="en-US">Beginning Balance, Net Book Value</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentNet" xml:lang="en-US">Ending Balance, Net Book Value</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentNet" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaap_AssetsNoncurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsNoncurrent" xml:lang="en-US">Assets, Noncurrent</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_AssetsNoncurrent" xml:lang="en-US">Total non current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsNoncurrent" xlink:to="lab_us-gaap_AssetsNoncurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_Assets" xml:lang="en-US">Assets</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_Assets" xml:lang="en-US">Total assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xml:lang="en-US">Liabilities and Stockholders' Equity</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract" xml:lang="en-US">Liabilities, Current [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_LiabilitiesCurrentAbstract" xml:lang="en-US">Current liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="lab_us-gaap_LiabilitiesCurrentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableTradeCurrent" xlink:label="loc_us-gaap_AccountsPayableTradeCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccountsPayableTradeCurrent" xml:lang="en-US">Accounts Payable, Trade, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AccountsPayableTradeCurrent" xml:lang="en-US">Trade accounts payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableTradeCurrent" xlink:to="lab_us-gaap_AccountsPayableTradeCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xml:lang="en-US">Other Liabilities, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xml:lang="en-US">Payable to related parties</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent" xml:lang="en-US">Related party liability</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesCurrent" xlink:to="lab_us-gaap_OtherLiabilitiesCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xml:lang="en-US">Accrued Liabilities, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xml:lang="en-US">Accrued and other liabilities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrent" xml:lang="en-US">Total</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:to="lab_us-gaap_AccruedLiabilitiesCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeCurrent" xlink:label="loc_us-gaap_DeferredIncomeCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DeferredIncomeCurrent" xml:lang="en-US">Deferred Income, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_DeferredIncomeCurrent" xml:lang="en-US">Deferred income</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeCurrent" xlink:to="lab_us-gaap_DeferredIncomeCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaap_LiabilitiesCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesCurrent" xml:lang="en-US">Liabilities, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_LiabilitiesCurrent" xml:lang="en-US">Total current liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesCurrent" xlink:to="lab_us-gaap_LiabilitiesCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xml:lang="en-US">Operating Lease, Liability, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_OperatingLeaseLiabilityCurrent" xml:lang="en-US">Operating lease liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseLiabilityCurrent" xlink:to="lab_us-gaap_OperatingLeaseLiabilityCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaap_Liabilities" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_Liabilities" xml:lang="en-US">Liabilities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_Liabilities" xml:lang="en-US">Total liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Liabilities" xlink:to="lab_us-gaap_Liabilities" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrentAbstract" xlink:label="loc_us-gaap_LiabilitiesNoncurrentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesNoncurrentAbstract" xml:lang="en-US">Liabilities, Noncurrent [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_LiabilitiesNoncurrentAbstract" xml:lang="en-US">Non current liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesNoncurrentAbstract" xlink:to="lab_us-gaap_LiabilitiesNoncurrentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilitiesNoncurrent" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DerivativeLiabilitiesNoncurrent" xml:lang="en-US">Derivative Liability, Noncurrent</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_DerivativeLiabilitiesNoncurrent" xml:lang="en-US">Warrant liability</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeLiabilitiesNoncurrent" xlink:to="lab_us-gaap_DerivativeLiabilitiesNoncurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaap_LiabilitiesNoncurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesNoncurrent" xml:lang="en-US">Liabilities, Noncurrent</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_LiabilitiesNoncurrent" xml:lang="en-US">Total non current liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesNoncurrent" xlink:to="lab_us-gaap_LiabilitiesNoncurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaap_CommitmentsAndContingencies" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xml:lang="en-US">Commitments and Contingencies</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommitmentsAndContingencies" xml:lang="en-US">Commitments and contingencies</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommitmentsAndContingencies" xlink:to="lab_us-gaap_CommitmentsAndContingencies" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaap_CommonStockValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockValue" xml:lang="en-US">Common Stock, Value, Issued</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockValue" xml:lang="en-US">Capital stock, $0.01 par value, 2,000,000,000 shares authorized at December&#160;31, 2025 and June&#160;30, 2026, 2,356 and 38,690 issued and outstanding at December&#160;31, 2025 and June&#160;30, 2026, respectively (Note 8)</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockValue" xlink:to="lab_us-gaap_CommonStockValue" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockValue" xml:lang="en-US">Preferred Stock, Value, Issued</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockValue" xml:lang="en-US">Preferred Stock, 200,000,000 shares authorized Preferred stock, Series A, $0.01 par value, 600,000 shares issued and outstanding as of December&#160;31, 2025 and June&#160;30, 2026</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockValue" xlink:to="lab_us-gaap_PreferredStockValue" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AdditionalPaidInCapital" xml:lang="en-US">Additional Paid in Capital</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AdditionalPaidInCapital" xml:lang="en-US">Additional paid-in capital</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapital" xlink:to="lab_us-gaap_AdditionalPaidInCapital" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xml:lang="en-US">Retained Earnings (Accumulated Deficit)</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RetainedEarningsAccumulatedDeficit" xml:lang="en-US">Retained earnings</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="lab_us-gaap_RetainedEarningsAccumulatedDeficit" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StockholdersEquity" xml:lang="en-US">Equity, Attributable to Parent</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_StockholdersEquity" xml:lang="en-US">Total stockholders' equity</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_us-gaap_StockholdersEquity" xml:lang="en-US">Beginning balance, value</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_us-gaap_StockholdersEquity" xml:lang="en-US">Ending balance, value</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquity" xlink:to="lab_us-gaap_StockholdersEquity" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xml:lang="en-US">Liabilities and Equity</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xml:lang="en-US">Total liabilities and stockholders' equity</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionAxis" xml:lang="en-US">Related Party Transaction [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionDomain" xml:lang="en-US">Related Party Transaction [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain" xlink:to="lab_us-gaap_RelatedPartyTransactionDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember" xlink:label="loc_us-gaap_RelatedPartyMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyMember" xml:lang="en-US">Related Party [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RelatedPartyMember" xml:lang="en-US">Related Party [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyMember" xlink:to="lab_us-gaap_RelatedPartyMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xml:lang="en-US">Common Stock, Par or Stated Value Per Share</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockParOrStatedValuePerShare" xml:lang="en-US">Common stock par or stated value per share</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_CommonStockParOrStatedValuePerShare" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xml:lang="en-US">Common Stock, Shares Authorized</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xml:lang="en-US">Common stock shares authorized</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesAuthorized" xlink:to="lab_us-gaap_CommonStockSharesAuthorized" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockSharesIssued" xml:lang="en-US">Common Stock, Shares, Issued</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockSharesIssued" xml:lang="en-US">Common stock shares issued</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesIssued" xlink:to="lab_us-gaap_CommonStockSharesIssued" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xml:lang="en-US">Common Stock, Shares, Outstanding</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockSharesOutstanding" xml:lang="en-US">Common stock shares outstanding</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesOutstanding" xlink:to="lab_us-gaap_CommonStockSharesOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockSharesAuthorized" xml:lang="en-US">Preferred Stock, Shares Authorized</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockSharesAuthorized" xml:lang="en-US">Preferred stock shares authorized</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesAuthorized" xlink:to="lab_us-gaap_PreferredStockSharesAuthorized" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xml:lang="en-US">Preferred Stock, Par or Stated Value Per Share</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xml:lang="en-US">Preferred stock par or stated value per share</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:to="lab_us-gaap_PreferredStockParOrStatedValuePerShare" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaap_PreferredStockSharesIssued" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockSharesIssued" xml:lang="en-US">Preferred Stock, Shares Issued</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockSharesIssued" xml:lang="en-US">Preferred stock shares issued</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesIssued" xlink:to="lab_us-gaap_PreferredStockSharesIssued" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xml:lang="en-US">Preferred Stock, Shares Outstanding</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xml:lang="en-US">Preferred stock shares outstanding</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesOutstanding" xlink:to="lab_us-gaap_PreferredStockSharesOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementAbstract" xlink:label="loc_us-gaap_IncomeStatementAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncomeStatementAbstract" xml:lang="en-US">Income Statement [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="lab_us-gaap_IncomeStatementAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract" xlink:label="loc_us-gaap_RevenuesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RevenuesAbstract" xml:lang="en-US">Revenues [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RevenuesAbstract" xml:lang="en-US">Revenues</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesAbstract" xlink:to="lab_us-gaap_RevenuesAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_Revenues" xml:lang="en-US">Revenues</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_Revenues" xml:lang="en-US">Total revenues</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_Revenues" xml:lang="en-US">Revenues</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Revenues" xlink:to="lab_us-gaap_Revenues" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xml:lang="en-US">Revenue from Contract with Customer, Including Assessed Tax</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xml:lang="en-US">Revenues</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:to="lab_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="loc_us-gaap_OperatingExpensesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xml:lang="en-US">Operating Expenses [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_OperatingExpensesAbstract" xml:lang="en-US">Expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpensesAbstract" xlink:to="lab_us-gaap_OperatingExpensesAbstract" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VoyageExpenses" xlink:label="loc_ciss_VoyageExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_VoyageExpenses" xml:lang="en-US">Voyage Expenses</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_VoyageExpenses" xml:lang="en-US">Voyage expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_VoyageExpenses" xlink:to="lab_ciss_VoyageExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_VoyageExpenses" xml:lang="en-US">Voyage expenses.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DryDockingCosts" xlink:label="loc_ciss_DryDockingCosts" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DryDockingCosts" xml:lang="en-US">Dry Docking Costs</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_DryDockingCosts" xml:lang="en-US">Drydocking costs</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DryDockingCosts" xlink:to="lab_ciss_DryDockingCosts" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DryDockingCosts" xml:lang="en-US">Dry docking costs.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DepreciationNetOffWriteBacks" xlink:label="loc_ciss_DepreciationNetOffWriteBacks" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DepreciationNetOffWriteBacks" xml:lang="en-US">Depreciation Net Off Write Backs</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DepreciationNetOffWriteBacks" xml:lang="en-US">Depreciation</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DepreciationNetOffWriteBacks" xlink:to="lab_ciss_DepreciationNetOffWriteBacks" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DepreciationNetOffWriteBacks" xml:lang="en-US">Depreciation net off write backs.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ManagementFees" xlink:label="loc_ciss_ManagementFees" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ManagementFees" xml:lang="en-US">Management Fees</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ManagementFees" xml:lang="en-US">Management fees &#8211; related party</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ManagementFees" xlink:to="lab_ciss_ManagementFees" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ManagementFees" xml:lang="en-US">Management fees.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" xlink:label="loc_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" xml:lang="en-US">General And Administration Expenses Net Off Write Backs</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" xml:lang="en-US">General and administrative expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" xlink:to="lab_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" xml:lang="en-US">General and administration expenses net off write backs.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaap_OperatingExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OperatingExpenses" xml:lang="en-US">Operating Expenses</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_OperatingExpenses" xml:lang="en-US">Total expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingExpenses" xlink:to="lab_us-gaap_OperatingExpenses" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OperatingIncomeLoss" xml:lang="en-US">Operating Income (Loss)</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_OperatingIncomeLoss" xml:lang="en-US">Income from operations</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingIncomeLoss" xlink:to="lab_us-gaap_OperatingIncomeLoss" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VoyageExpensesRelatedParty" xlink:label="loc_ciss_VoyageExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_VoyageExpensesRelatedParty" xml:lang="en-US">Voyage Expenses Related Party</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_VoyageExpensesRelatedParty" xml:lang="en-US">Voyage expenses &#8211; related party</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_VoyageExpensesRelatedParty" xlink:to="lab_ciss_VoyageExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_VoyageExpensesRelatedParty" xml:lang="en-US">Voyage expenses related party.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_GeneralAndAdministrativeExpenseRelatedParty" xlink:label="loc_ciss_GeneralAndAdministrativeExpenseRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_GeneralAndAdministrativeExpenseRelatedParty" xml:lang="en-US">General and Administrative Expense Related Party</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_GeneralAndAdministrativeExpenseRelatedParty" xml:lang="en-US">General and administrative expenses &#8211; related party</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_GeneralAndAdministrativeExpenseRelatedParty" xlink:to="lab_ciss_GeneralAndAdministrativeExpenseRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_GeneralAndAdministrativeExpenseRelatedParty" xml:lang="en-US">General and administrative expense related party.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VesselsOperatingExpenses" xlink:label="loc_ciss_VesselsOperatingExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_VesselsOperatingExpenses" xml:lang="en-US">Vessels Operating Expenses</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_VesselsOperatingExpenses" xml:lang="en-US">Vessels' operating expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_VesselsOperatingExpenses" xlink:to="lab_ciss_VesselsOperatingExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_VesselsOperatingExpenses" xml:lang="en-US">Vessels operating expenses.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VesselsOperatingExpensesRelatedParty" xlink:label="loc_ciss_VesselsOperatingExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_VesselsOperatingExpensesRelatedParty" xml:lang="en-US">Vessels Operating Expenses Related Party</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_VesselsOperatingExpensesRelatedParty" xml:lang="en-US">Vessels' operating expenses &#8211; related party</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_VesselsOperatingExpensesRelatedParty" xlink:to="lab_ciss_VesselsOperatingExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_VesselsOperatingExpensesRelatedParty" xml:lang="en-US">Vessels operating expenses related party.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xml:lang="en-US">Nonoperating Income (Expense) [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_NonoperatingIncomeExpenseAbstract" xml:lang="en-US">Other (expenses)/income</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract" xlink:to="lab_us-gaap_NonoperatingIncomeExpenseAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestAndDebtExpense" xlink:label="loc_us-gaap_InterestAndDebtExpense" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InterestAndDebtExpense" xml:lang="en-US">Interest and Debt Expense</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_InterestAndDebtExpense" xml:lang="en-US">Interest and finance costs</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestAndDebtExpense" xlink:to="lab_us-gaap_InterestAndDebtExpense" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="loc_us-gaap_InvestmentIncomeInterest" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InvestmentIncomeInterest" xml:lang="en-US">Investment Income, Interest</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InvestmentIncomeInterest" xml:lang="en-US">Interest income</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentIncomeInterest" xlink:to="lab_us-gaap_InvestmentIncomeInterest" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xml:lang="en-US">Gain (Loss), Foreign Currency Transaction, before Tax</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xml:lang="en-US">Foreign exchange loss</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:to="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="loc_us-gaap_NonoperatingIncomeExpense" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NonoperatingIncomeExpense" xml:lang="en-US">Nonoperating Income (Expense)</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_NonoperatingIncomeExpense" xml:lang="en-US">Other income/(expenses), net</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NonoperatingIncomeExpense" xlink:to="lab_us-gaap_NonoperatingIncomeExpense" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetIncomeLoss" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_NetIncomeLoss" xml:lang="en-US">Net income</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/definitionGuidance" xlink:label="lab_us-gaap_NetIncomeLoss" xml:lang="en-US">Net Income</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_NetIncomeLoss" xml:lang="en-US">Net income for the period</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_NetIncomeLoss" xml:lang="en-US">Net income</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss" xlink:to="lab_us-gaap_NetIncomeLoss" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_InterestAndDebtExpensesRelatedParty" xlink:label="loc_ciss_InterestAndDebtExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_InterestAndDebtExpensesRelatedParty" xml:lang="en-US">Interest And Debt Expenses Related Party</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_ciss_InterestAndDebtExpensesRelatedParty" xml:lang="en-US">Interest and finance costs &#8211; related parties</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_InterestAndDebtExpensesRelatedParty" xlink:to="lab_ciss_InterestAndDebtExpensesRelatedParty" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_InterestAndDebtExpensesRelatedParty" xml:lang="en-US">Interest And Debt Expenses Related Party.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FairValueAdjustmentOfWarrants" xml:lang="en-US">Fair Value Adjustment of Warrants</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_FairValueAdjustmentOfWarrants" xml:lang="en-US">Gain/(loss) on warrants</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_FairValueAdjustmentOfWarrants" xml:lang="en-US">(Gain)/loss on warrants</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_FairValueAdjustmentOfWarrants" xml:lang="en-US">Adjustment to fair value of warrant liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAdjustmentOfWarrants" xlink:to="lab_us-gaap_FairValueAdjustmentOfWarrants" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_EarningsPerShareAbstract" xml:lang="en-US">Earnings/(loss) per share (Note 9)</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareAbstract" xlink:to="lab_us-gaap_EarningsPerShareAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_EarningsPerShareBasic" xml:lang="en-US">Earnings Per Share, Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_EarningsPerShareBasic" xml:lang="en-US">-Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_EarningsPerShareBasic" xml:lang="en-US">Earnings/(loss) per share, basic</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasic" xlink:to="lab_us-gaap_EarningsPerShareBasic" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xml:lang="en-US">Earnings Per Share, Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xml:lang="en-US">-Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xml:lang="en-US">Earnings/(loss) per share, diluted</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareDiluted" xlink:to="lab_us-gaap_EarningsPerShareDiluted" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_WeightedAverageNumberOfSharesAbstract" xlink:label="loc_ciss_WeightedAverageNumberOfSharesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_WeightedAverageNumberOfSharesAbstract" xml:lang="en-US">Weighted Average Number Of Shares [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_WeightedAverageNumberOfSharesAbstract" xml:lang="en-US">Weighted average number of shares (Note 9)</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_WeightedAverageNumberOfSharesAbstract" xlink:to="lab_ciss_WeightedAverageNumberOfSharesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_WeightedAverageNumberOfSharesAbstract" xml:lang="en-US">Weighted average number of shares.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xml:lang="en-US">-Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xml:lang="en-US">Weighted average number of shares outstanding, diluted</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xml:lang="en-US">-Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xml:lang="en-US">Weighted average number of shares outstanding, basic</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementOfStockholdersEquityAbstract" xml:lang="en-US">Statement of Stockholders' Equity [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="lab_us-gaap_StatementOfStockholdersEquityAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaap_SharesOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SharesOutstanding" xml:lang="en-US">Shares, Outstanding</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_us-gaap_SharesOutstanding" xml:lang="en-US">Beginning balance, shares</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_us-gaap_SharesOutstanding" xml:lang="en-US">Ending balance, shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SharesOutstanding" xlink:to="lab_us-gaap_SharesOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xml:lang="en-US">Stock Issued During Period, Shares, New Issues</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xml:lang="en-US">Issuance of common stock, net of issuance costs, shares</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xml:lang="en-US">Exercise of warrants share</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/presentationGuidance" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xml:lang="en-US">Common stock shares issued</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/definitionGuidance" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xml:lang="en-US">Common stock shares issued</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesNewIssues" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xml:lang="en-US">Stock Issued During Period, Value, New Issues</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" xml:lang="en-US">Issuance of common stock, net of issuance costs, value</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueNewIssues" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xml:lang="en-US">Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xml:lang="en-US">Dividends declared on Series A preferred shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DownRoundDeemedDividendsPreferredStock" xlink:label="loc_ciss_DownRoundDeemedDividendsPreferredStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DownRoundDeemedDividendsPreferredStock" xml:lang="en-US">Down Round Deemed Dividends Preferred Stock</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DownRoundDeemedDividendsPreferredStock" xml:lang="en-US">Down round deemed dividend on Series A preferred shares</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_DownRoundDeemedDividendsPreferredStock" xml:lang="en-US">Adjusted down round deemed dividends preferred stock</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DownRoundDeemedDividendsPreferredStock" xlink:to="lab_ciss_DownRoundDeemedDividendsPreferredStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DownRoundDeemedDividendsPreferredStock" xml:lang="en-US">Down Round Deemed Dividends Preferred Stock.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xml:lang="en-US">APIC, Share-Based Payment Arrangement, Increase for Cost Recognition</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xml:lang="en-US">Stock-based compensation</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ExerciseOfWarrantsValue" xlink:label="loc_ciss_ExerciseOfWarrantsValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ExerciseOfWarrantsValue" xml:lang="en-US">Exercise Of Warrants Value</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ExerciseOfWarrantsValue" xml:lang="en-US">Exercise of warrants value</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ExerciseOfWarrantsValue" xlink:to="lab_ciss_ExerciseOfWarrantsValue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ExerciseOfWarrantsValue" xml:lang="en-US">Exercise of warrants value.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementEquityComponentsAxis" xml:lang="en-US">Equity Components [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementEquityComponentsAxis" xlink:to="lab_us-gaap_StatementEquityComponentsAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_EquityComponentDomain" xml:lang="en-US">Equity Component [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonStockMember" xml:lang="en-US">Common Stock [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CommonStockMember" xml:lang="en-US">Capital stock [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockMember" xml:lang="en-US">Preferred Stock [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_PreferredStockMember" xml:lang="en-US">Preferred stock [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockMember" xlink:to="lab_us-gaap_PreferredStockMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xml:lang="en-US">Additional Paid-in Capital [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AdditionalPaidInCapitalMember" xml:lang="en-US">Additional Paid-in Capital [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionalPaidInCapitalMember" xlink:to="lab_us-gaap_AdditionalPaidInCapitalMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RetainedEarningsMember" xml:lang="en-US">Retained Earnings [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RetainedEarningsMember" xml:lang="en-US">Retained Earnings [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetainedEarningsMember" xlink:to="lab_us-gaap_RetainedEarningsMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xml:lang="en-US">Related and Nonrelated Parties [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="lab_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaap_RelatedPartyDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyDomain" xml:lang="en-US">Related and Nonrelated Parties [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyDomain" xlink:to="lab_us-gaap_RelatedPartyDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_EventAxis" xlink:label="loc_ciss_EventAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_EventAxis" xml:lang="en-US">Event [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_EventAxis" xlink:to="lab_ciss_EventAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_EventAxis" xml:lang="en-US">Event axis.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_EventDomain" xlink:label="loc_ciss_EventDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_EventDomain" xml:lang="en-US">Event [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_EventDomain" xlink:to="lab_ciss_EventDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_EventDomain" xml:lang="en-US">Event domain.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ExcerciseOfWarrantsMember" xlink:label="loc_ciss_ExcerciseOfWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ExcerciseOfWarrantsMember" xml:lang="en-US">Excercise Of Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ExcerciseOfWarrantsMember" xlink:to="lab_ciss_ExcerciseOfWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ExcerciseOfWarrantsMember" xml:lang="en-US">Excercise of warrants member.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareDeclared" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockDividendsPerShareDeclared" xml:lang="en-US">Preferred Stock, Dividends Per Share, Declared</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockDividendsPerShareDeclared" xml:lang="en-US">Preferred stock dividends per share</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:to="lab_us-gaap_PreferredStockDividendsPerShareDeclared" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" xlink:label="loc_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" xml:lang="en-US">Preferred Stock Down Round Deemed Dividends Per Share Declared</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" xml:lang="en-US">Preferred stock down round deemed dividends per share</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" xlink:to="lab_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" xml:lang="en-US">preferred stock down round deemed dividends per share declared.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xml:lang="en-US">Cash flows from operating activities:</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xml:lang="en-US">Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xml:lang="en-US">Adjustments to reconcile net income to net cash provided by operating activities:</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="lab_us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_Depreciation" xml:lang="en-US">Depreciation</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_Depreciation" xml:lang="en-US">Depreciation</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_Depreciation" xml:lang="en-US">Depreciation for the period</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Depreciation" xlink:to="lab_us-gaap_Depreciation" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ShareBasedCompensation" xml:lang="en-US">Share-Based Payment Arrangement, Noncash Expense</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ShareBasedCompensation" xml:lang="en-US">Share based compensation</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensation" xlink:to="lab_us-gaap_ShareBasedCompensation" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xml:lang="en-US">Increase (Decrease) in Operating Capital [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xml:lang="en-US">Changes in operating assets and liabilities:</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xml:lang="en-US">Increase (Decrease) in Accounts Receivable</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" xml:lang="en-US">(Increase)/decrease in Trade and other receivables</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsReceivable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherCurrentAssets" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherCurrentAssets" xml:lang="en-US">Increase (Decrease) in Other Current Assets</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInOtherCurrentAssets" xml:lang="en-US">(Increase)/decrease in Other current assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:to="lab_us-gaap_IncreaseDecreaseInOtherCurrentAssets" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xml:lang="en-US">Increase (Decrease) in Prepaid Expense and Other Assets</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xml:lang="en-US">(Increase)/decrease in Advances and prepayments</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:to="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInInventories" xml:lang="en-US">Increase (Decrease) in Inventories</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInInventories" xml:lang="en-US">(Increase)/decrease in Inventories</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInInventories" xlink:to="lab_us-gaap_IncreaseDecreaseInInventories" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayableTrade" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableTrade" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableTrade" xml:lang="en-US">Increase (Decrease) in Accounts Payable, Trade</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsPayableTrade" xml:lang="en-US">Increase/(Decrease) in Trade accounts payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsPayableTrade" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsPayableTrade" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xlink:label="loc_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xml:lang="en-US">Increase (Decrease) in Due to Related Parties, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xml:lang="en-US">Increase/(Decrease) in Payable to related parties</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" xlink:to="lab_us-gaap_IncreaseDecreaseInDueToRelatedPartiesCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInAccruedLiabilities" xml:lang="en-US">Increase (Decrease) in Accrued Liabilities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInAccruedLiabilities" xml:lang="en-US">Increase/(Decrease) in Accrued liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:to="lab_us-gaap_IncreaseDecreaseInAccruedLiabilities" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInDeferredRevenue" xml:lang="en-US">Increase (Decrease) in Deferred Revenue</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInDeferredRevenue" xml:lang="en-US">Increase/(Decrease) in Deferred income</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:to="lab_us-gaap_IncreaseDecreaseInDeferredRevenue" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xml:lang="en-US">Increase (Decrease) in Operating Lease Liability</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xml:lang="en-US">Increase/(Decrease) in Changes in operating lease liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingLeaseLiability" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ForeignCurrencyTransactionGainLossUnrealized" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossUnrealized" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossUnrealized" xml:lang="en-US">Unrealized Gain (Loss), Foreign Currency Transaction, before Tax</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossUnrealized" xml:lang="en-US">Unrealized foreign exchange loss on time deposits</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyTransactionGainLossUnrealized" xlink:to="lab_us-gaap_ForeignCurrencyTransactionGainLossUnrealized" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xml:lang="en-US">Operating Lease, Right-of-Use Asset, Periodic Reduction</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xml:lang="en-US">Non-cash lease expense</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xlink:to="lab_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xml:lang="en-US">Net cash provided by operating activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xml:lang="en-US">Cash flows from investing activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IncreaseInBankTimeDeposits" xlink:label="loc_ciss_IncreaseInBankTimeDeposits" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IncreaseInBankTimeDeposits" xml:lang="en-US">Increase In Bank Time Deposits</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="lab_ciss_IncreaseInBankTimeDeposits" xml:lang="en-US">Increase in bank time deposits</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IncreaseInBankTimeDeposits" xlink:to="lab_ciss_IncreaseInBankTimeDeposits" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IncreaseInBankTimeDeposits" xml:lang="en-US">Increase in bank time deposits.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" xml:lang="en-US">Net cash provided by/(used in) investing activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xml:lang="en-US">Proceeds from Sale and Maturity of Other Investments</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xml:lang="en-US">Maturity of bank time deposits</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" xlink:to="lab_us-gaap_ProceedsFromSaleAndMaturityOfOtherInvestments" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForCapitalImprovements" xlink:label="loc_us-gaap_PaymentsForCapitalImprovements" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PaymentsForCapitalImprovements" xml:lang="en-US">Payments for Capital Improvements</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_PaymentsForCapitalImprovements" xml:lang="en-US">Payments for acquisition and capitalized expenses of vessel</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForCapitalImprovements" xlink:to="lab_us-gaap_PaymentsForCapitalImprovements" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xml:lang="en-US">Cash flows from financing activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfStockIssuanceCosts" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PaymentsOfStockIssuanceCosts" xml:lang="en-US">Payments of Stock Issuance Costs</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_PaymentsOfStockIssuanceCosts" xml:lang="en-US">Stock issuance costs</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfStockIssuanceCosts" xlink:to="lab_us-gaap_PaymentsOfStockIssuanceCosts" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xlink:label="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xml:lang="en-US">Payments of Ordinary Dividends, Preferred Stock and Preference Stock</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xml:lang="en-US">Dividends paid on preferred shares</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xml:lang="en-US">Payments of ordinary dividends preferred stock and preference stock</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" xlink:to="lab_us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xml:lang="en-US">Net cash (used in)/provided by financing activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromWarrantExercises" xlink:label="loc_us-gaap_ProceedsFromWarrantExercises" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ProceedsFromWarrantExercises" xml:lang="en-US">Proceeds from Warrant Exercises</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_ProceedsFromWarrantExercises" xml:lang="en-US">Proceeds from exercise of warrants</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ProceedsFromWarrantExercises" xml:lang="en-US">Proceeds from exercise of warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromWarrantExercises" xlink:to="lab_us-gaap_ProceedsFromWarrantExercises" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfLongtermLoansFromVendors" xlink:label="loc_us-gaap_RepaymentsOfLongtermLoansFromVendors" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RepaymentsOfLongtermLoansFromVendors" xml:lang="en-US">Repayments of Long-Term Loans from Vendors</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="lab_us-gaap_RepaymentsOfLongtermLoansFromVendors" xml:lang="en-US">Repayment of seller financing</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RepaymentsOfLongtermLoansFromVendors" xlink:to="lab_us-gaap_RepaymentsOfLongtermLoansFromVendors" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ProceedsFromIssuanceInitialPublicOffering" xml:lang="en-US">Proceeds from Issuance Initial Public Offering</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ProceedsFromIssuanceInitialPublicOffering" xml:lang="en-US">Proceeds from equity offering</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:to="lab_us-gaap_ProceedsFromIssuanceInitialPublicOffering" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xml:lang="en-US">Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xml:lang="en-US">Net (decrease)/increase in cash and cash equivalents</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xml:lang="en-US">Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xml:lang="en-US">Cash and cash equivalents at beginning of period</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xml:lang="en-US">Cash and cash equivalents at end of period</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="lab_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplementalCashFlowElementsAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowElementsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SupplementalCashFlowElementsAbstract" xml:lang="en-US">Supplemental Cash Flow Elements [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_SupplementalCashFlowElementsAbstract" xml:lang="en-US">Supplemental Cash Flow Information</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowElementsAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowElementsAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xml:lang="en-US">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xml:lang="en-US">Non-cash Financing Activities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueOfAssetsAcquired" xlink:label="loc_us-gaap_FairValueOfAssetsAcquired" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FairValueOfAssetsAcquired" xml:lang="en-US">Fair Value of Assets Acquired</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_FairValueOfAssetsAcquired" xml:lang="en-US">Non cash investing activity - Vessel acquisition included in payable to related parties</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueOfAssetsAcquired" xlink:to="lab_us-gaap_FairValueOfAssetsAcquired" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" xml:lang="en-US">Dividends Payable</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/presentationGuidance" xlink:label="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" xml:lang="en-US">Non cash financing activity - Dividends on preferred shares Series A included in payable to related parties</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:to="lab_us-gaap_DividendsPayableCurrentAndNoncurrent" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CashlessExerciseofWarrants" xlink:label="loc_ciss_CashlessExerciseofWarrants" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CashlessExerciseofWarrants" xml:lang="en-US">Cashless Exercise of Warrants</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_CashlessExerciseofWarrants" xml:lang="en-US">Non cash financing activity - Cashless exercise of Class&#160;B2 and Class&#160;C2 warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CashlessExerciseofWarrants" xlink:to="lab_ciss_CashlessExerciseofWarrants" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CashlessExerciseofWarrants" xml:lang="en-US">Cashless exercise of warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPaidNet" xlink:label="loc_us-gaap_InterestPaidNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InterestPaidNet" xml:lang="en-US">Interest Paid, Excluding Capitalized Interest, Operating Activities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InterestPaidNet" xml:lang="en-US">Cash paid for interest in relation to seller financing</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet" xlink:to="lab_us-gaap_InterestPaidNet" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xml:lang="en-US">Basis of Presentation and General Information</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:to="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SignificantAccountingPoliciesTextBlock" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xml:lang="en-US">Significant Accounting Policies [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xml:lang="en-US">Significant Accounting Policies</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:to="lab_us-gaap_SignificantAccountingPoliciesTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsAbstract" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionsAbstract" xml:lang="en-US">Related Party Transactions [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract" xlink:to="lab_us-gaap_RelatedPartyTransactionsAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:label="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xml:lang="en-US">Related Party Transactions Disclosure [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xml:lang="en-US">Transactions with Related Parties</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:to="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryDisclosureAbstract" xlink:label="loc_us-gaap_InventoryDisclosureAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InventoryDisclosureAbstract" xml:lang="en-US">Inventory Disclosure [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryDisclosureAbstract" xlink:to="lab_us-gaap_InventoryDisclosureAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryDisclosureTextBlock" xlink:label="loc_us-gaap_InventoryDisclosureTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock" xml:lang="en-US">Inventory Disclosure [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InventoryDisclosureTextBlock" xml:lang="en-US">Inventories</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryDisclosureTextBlock" xlink:to="lab_us-gaap_InventoryDisclosureTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAbstract" xml:lang="en-US">Property, Plant and Equipment [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xml:lang="en-US">Property, Plant and Equipment Disclosure [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xml:lang="en-US">Vessels, Net</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAbstract" xml:lang="en-US">Accounts Payable and Accrued Liabilities, Current [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAbstract" xlink:to="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xlink:label="loc_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xml:lang="en-US">Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xml:lang="en-US">Accrued and Other Liabilities</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xlink:to="lab_us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FairValueDisclosuresAbstract" xml:lang="en-US">Fair Value Disclosures [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract" xlink:to="lab_us-gaap_FairValueDisclosuresAbstract" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosuresTextBlock" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock" />
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          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xml:lang="en-US">Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:to="lab_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_ParentEntityLegalName" xlink:label="loc_dei_ParentEntityLegalName" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_ParentEntityLegalName" xml:lang="en-US">Parent Entity Legal Name</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_dei_ParentEntityLegalName" xml:lang="en-US">Name of the parent company</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_ParentEntityLegalName" xlink:to="lab_dei_ParentEntityLegalName" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_EntityFormationDateOfFormation" xlink:label="loc_ciss_EntityFormationDateOfFormation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_EntityFormationDateOfFormation" xml:lang="en-US">Entity Formation Date Of Formation</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_EntityFormationDateOfFormation" xml:lang="en-US">Date of the formation of entity</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_EntityFormationDateOfFormation" xlink:to="lab_ciss_EntityFormationDateOfFormation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_EntityFormationDateOfFormation" xml:lang="en-US">Entity formation date of formation.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Cash" xlink:label="loc_us-gaap_Cash" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_Cash" xml:lang="en-US">Cash</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_Cash" xml:lang="en-US">Cash distributed by parent company</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Cash" xlink:to="lab_us-gaap_Cash" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendRatePercentage" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockDividendRatePercentage" xml:lang="en-US">Preferred Stock, Dividend Rate, Percentage</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockDividendRatePercentage" xml:lang="en-US">Dividend rate of the preferred shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockDividendRatePercentage" xlink:to="lab_us-gaap_PreferredStockDividendRatePercentage" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ParentCompanyMember" xlink:label="loc_srt_ParentCompanyMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_srt_ParentCompanyMember" xml:lang="en-US">Parent Company [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ParentCompanyMember" xlink:to="lab_srt_ParentCompanyMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightAxis" xml:lang="en-US">Class of Warrant or Right [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis" xlink:to="lab_us-gaap_ClassOfWarrantOrRightAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightDomain" xml:lang="en-US">Class of Warrant or Right [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain" xlink:to="lab_us-gaap_ClassOfWarrantOrRightDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsequentEventTypeAxis" xml:lang="en-US">Subsequent Event Type [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTypeAxis" xlink:to="lab_us-gaap_SubsequentEventTypeAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsequentEventTypeDomain" xml:lang="en-US">Subsequent Event Type [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTypeDomain" xlink:to="lab_us-gaap_SubsequentEventTypeDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityIncorporationDateOfIncorporation" xlink:label="loc_dei_EntityIncorporationDateOfIncorporation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_dei_EntityIncorporationDateOfIncorporation" xml:lang="en-US">Entity Incorporation, Date of Incorporation</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_dei_EntityIncorporationDateOfIncorporation" xml:lang="en-US">Date of Incorporation</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityIncorporationDateOfIncorporation" xlink:to="lab_dei_EntityIncorporationDateOfIncorporation" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DeadWeightTonnage" xlink:label="loc_ciss_DeadWeightTonnage" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DeadWeightTonnage" xml:lang="en-US">Dead weight tonnage</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DeadWeightTonnage" xml:lang="en-US">Dead Weight Tonnage ("dwt")</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DeadWeightTonnage" xlink:to="lab_ciss_DeadWeightTonnage" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DeadWeightTonnage" xml:lang="en-US">Dead weight tonnage.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" xlink:label="loc_us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" xml:lang="en-US">Asset Acquisition, Effective Date of Acquisition</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" xml:lang="en-US">Acquisition Date</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" xlink:to="lab_us-gaap_AssetAcquisitionEffectiveDateOfAcquisition" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_NameOfTheVesselOwnedBySubsidiary" xlink:label="loc_ciss_NameOfTheVesselOwnedBySubsidiary" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_NameOfTheVesselOwnedBySubsidiary" xml:lang="en-US">Name Of The Vessel Owned By Subsidiary</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_NameOfTheVesselOwnedBySubsidiary" xml:lang="en-US">Name of Vessel Owned by Subsidiary</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_NameOfTheVesselOwnedBySubsidiary" xlink:to="lab_ciss_NameOfTheVesselOwnedBySubsidiary" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_NameOfTheVesselOwnedBySubsidiary" xml:lang="en-US">Name of the vessel owned by subsidiary.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionAxis" xlink:label="loc_us-gaap_AssetAcquisitionAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetAcquisitionAxis" xml:lang="en-US">Asset Acquisition [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetAcquisitionAxis" xlink:to="lab_us-gaap_AssetAcquisitionAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetAcquisitionDomain" xlink:label="loc_us-gaap_AssetAcquisitionDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetAcquisitionDomain" xml:lang="en-US">Asset Acquisition [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetAcquisitionDomain" xlink:to="lab_us-gaap_AssetAcquisitionDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DrybulkInternationalTradingAndShippingIncMember" xlink:label="loc_ciss_DrybulkInternationalTradingAndShippingIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DrybulkInternationalTradingAndShippingIncMember" xml:lang="en-US">Drybulk International Trading and Shipping Inc [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DrybulkInternationalTradingAndShippingIncMember" xml:lang="en-US">Drybulk International Trading and Shipping Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DrybulkInternationalTradingAndShippingIncMember" xlink:to="lab_ciss_DrybulkInternationalTradingAndShippingIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DrybulkInternationalTradingAndShippingIncMember" xml:lang="en-US">Drybulk international trading and shipping inc.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RawCommoditiesAndExportsIncMember" xlink:label="loc_ciss_RawCommoditiesAndExportsIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RawCommoditiesAndExportsIncMember" xml:lang="en-US">Raw Commodities and Exports Inc [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_RawCommoditiesAndExportsIncMember" xml:lang="en-US">Raw Commodities Exports Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RawCommoditiesAndExportsIncMember" xlink:to="lab_ciss_RawCommoditiesAndExportsIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RawCommoditiesAndExportsIncMember" xml:lang="en-US">Raw commodities and exports inc.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CrudeOilServicesInternationalIncMember" xlink:label="loc_ciss_CrudeOilServicesInternationalIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CrudeOilServicesInternationalIncMember" xml:lang="en-US">Crude Oil Services International Inc [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_CrudeOilServicesInternationalIncMember" xml:lang="en-US">Crude Oil Services International Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CrudeOilServicesInternationalIncMember" xlink:to="lab_ciss_CrudeOilServicesInternationalIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CrudeOilServicesInternationalIncMember" xml:lang="en-US">Crude oil services international inc.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_SpitfireDragonTransportIncMember" xlink:label="loc_ciss_SpitfireDragonTransportIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_SpitfireDragonTransportIncMember" xml:lang="en-US">Spitfire Dragon Transport Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_SpitfireDragonTransportIncMember" xlink:to="lab_ciss_SpitfireDragonTransportIncMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FuriousPetroleumTransportIncMember" xlink:label="loc_ciss_FuriousPetroleumTransportIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FuriousPetroleumTransportIncMember" xml:lang="en-US">Furious Petroleum Transport Inc. [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FuriousPetroleumTransportIncMember" xlink:to="lab_ciss_FuriousPetroleumTransportIncMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_MagnificentHydrocarbonsIncMember" xlink:label="loc_ciss_MagnificentHydrocarbonsIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_MagnificentHydrocarbonsIncMember" xml:lang="en-US">Magnificent Hydrocarbons Inc. [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_MagnificentHydrocarbonsIncMember" xlink:to="lab_ciss_MagnificentHydrocarbonsIncMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xml:lang="en-US">Schedule of Related Party Transactions, by Related Party [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="lab_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionLineItems" xml:lang="en-US">Related Party Transaction [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems" xlink:to="lab_us-gaap_RelatedPartyTransactionLineItems" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RelatedPartyBrokerageCommissionPerVessel" xlink:label="loc_ciss_RelatedPartyBrokerageCommissionPerVessel" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RelatedPartyBrokerageCommissionPerVessel" xml:lang="en-US">Related Party Brokerage Commission Per vessel</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_RelatedPartyBrokerageCommissionPerVessel" xml:lang="en-US">Brokerage commission</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RelatedPartyBrokerageCommissionPerVessel" xlink:to="lab_ciss_RelatedPartyBrokerageCommissionPerVessel" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RelatedPartyBrokerageCommissionPerVessel" xml:lang="en-US">Related party brokerage commission per vessel.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_InitialConsiderationPaidOnAssetAcquisition" xlink:label="loc_ciss_InitialConsiderationPaidOnAssetAcquisition" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_InitialConsiderationPaidOnAssetAcquisition" xml:lang="en-US">Initial Consideration Paid On Asset Acquisition</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_InitialConsiderationPaidOnAssetAcquisition" xml:lang="en-US">Consideration paid</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_InitialConsiderationPaidOnAssetAcquisition" xlink:to="lab_ciss_InitialConsiderationPaidOnAssetAcquisition" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_InitialConsiderationPaidOnAssetAcquisition" xml:lang="en-US">Initial consideration paid on asset acquisition.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RemainingConsiderationToBePaid" xlink:label="loc_ciss_RemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RemainingConsiderationToBePaid" xml:lang="en-US">Remaining Consideration To Be Paid</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_RemainingConsiderationToBePaid" xml:lang="en-US">Consideration payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RemainingConsiderationToBePaid" xlink:to="lab_ciss_RemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RemainingConsiderationToBePaid" xml:lang="en-US">Remaining consideration to be paid.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xml:lang="en-US">Fair value of asset acquired</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosure" xlink:to="lab_us-gaap_AssetsFairValueDisclosure" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CommissionAsAPercentageOfSalePriceOfVehicles" xlink:label="loc_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" xml:lang="en-US">Commission As A Percentage Of Sale Price Of Vehicles</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" xml:lang="en-US">Commission as a percentage of sale price of vessels</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" xlink:to="lab_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CommissionAsAPercentageOfSalePriceOfVehicles" xml:lang="en-US">Commission as a percentage of sale price of vehicles.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xml:lang="en-US">Related Party Transaction, Amounts of Transaction</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xml:lang="en-US">Related party fee</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xml:lang="en-US">Related parties transaction, amounts of transaction</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:to="lab_us-gaap_RelatedPartyTransactionAmountsOfTransaction" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireProductiveAssets" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PaymentsToAcquireProductiveAssets" xml:lang="en-US">Payments to Acquire Productive Assets</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PaymentsToAcquireProductiveAssets" xml:lang="en-US">Payments to acquire productive assets</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireProductiveAssets" xlink:to="lab_us-gaap_PaymentsToAcquireProductiveAssets" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_InitialPercentageOfConsiderationPaid" xlink:label="loc_ciss_InitialPercentageOfConsiderationPaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_InitialPercentageOfConsiderationPaid" xml:lang="en-US">Initial Percentage Of Consideration Paid</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_InitialPercentageOfConsiderationPaid" xml:lang="en-US">Initial percentage of consideration paid</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_InitialPercentageOfConsiderationPaid" xlink:to="lab_ciss_InitialPercentageOfConsiderationPaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_InitialPercentageOfConsiderationPaid" xml:lang="en-US">Initial percentage of consideration paid.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RemainingPurchasePrice" xlink:label="loc_ciss_RemainingPurchasePrice" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RemainingPurchasePrice" xml:lang="en-US">Remaining Purchase Price</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_RemainingPurchasePrice" xml:lang="en-US">Remaining purchase price</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RemainingPurchasePrice" xlink:to="lab_ciss_RemainingPurchasePrice" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RemainingPurchasePrice" xml:lang="en-US">Remaining purchase price.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestReceivable" xlink:label="loc_us-gaap_InterestReceivable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InterestReceivable" xml:lang="en-US">Interest Receivable</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InterestReceivable" xml:lang="en-US">Interest receivable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestReceivable" xlink:to="lab_us-gaap_InterestReceivable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InterestPayableCurrentAndNoncurrent" xml:lang="en-US">Interest Payable</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_InterestPayableCurrentAndNoncurrent" xml:lang="en-US">Interest payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPayableCurrentAndNoncurrent" xlink:to="lab_us-gaap_InterestPayableCurrentAndNoncurrent" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FinancialComponentAccountingOnAssetAcquisition" xlink:label="loc_ciss_FinancialComponentAccountingOnAssetAcquisition" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FinancialComponentAccountingOnAssetAcquisition" xml:lang="en-US">Financial Component Accounting On Asset Acquisition</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_FinancialComponentAccountingOnAssetAcquisition" xml:lang="en-US">Financial component accounting on asset acquisition</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FinancialComponentAccountingOnAssetAcquisition" xlink:to="lab_ciss_FinancialComponentAccountingOnAssetAcquisition" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_FinancialComponentAccountingOnAssetAcquisition" xml:lang="en-US">Financial component accounting on asset acquisition.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DescriptionOfRemainingConsiderationToBePaid" xlink:label="loc_ciss_DescriptionOfRemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DescriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Description Of Remaining Consideration To Be Paid</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DescriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Description of remining consideration payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DescriptionOfRemainingConsiderationToBePaid" xlink:to="lab_ciss_DescriptionOfRemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DescriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Description of remaining consideration to be paid.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DiscriptionOfRemainingConsiderationToBePaid" xlink:label="loc_ciss_DiscriptionOfRemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DiscriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Discription Of Remaining Consideration To Be Paid</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DiscriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Discription of remining consideration payable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DiscriptionOfRemainingConsiderationToBePaid" xlink:to="lab_ciss_DiscriptionOfRemainingConsiderationToBePaid" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DiscriptionOfRemainingConsiderationToBePaid" xml:lang="en-US">Discription of remaining consideration to be paid.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CrewManagementFeesMember" xlink:label="loc_ciss_CrewManagementFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CrewManagementFeesMember" xml:lang="en-US">Crew Management Fees [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_CrewManagementFeesMember" xml:lang="en-US">Crew Management Fees [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CrewManagementFeesMember" xlink:to="lab_ciss_CrewManagementFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CrewManagementFeesMember" xml:lang="en-US">Crew management fees.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FuriozaTradingDeskOverseasIncMember" xlink:label="loc_ciss_FuriozaTradingDeskOverseasIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FuriozaTradingDeskOverseasIncMember" xml:lang="en-US">Furioza Trading Desk Overseas Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FuriozaTradingDeskOverseasIncMember" xlink:to="lab_ciss_FuriozaTradingDeskOverseasIncMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ImperialPetroleumIncMember" xlink:label="loc_ciss_ImperialPetroleumIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ImperialPetroleumIncMember" xml:lang="en-US">Imperial Petroleum Inc [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_ImperialPetroleumIncMember" xml:lang="en-US">Imperial Petroleum Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ImperialPetroleumIncMember" xlink:to="lab_ciss_ImperialPetroleumIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ImperialPetroleumIncMember" xml:lang="en-US">Imperial petroleum inc.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_HellenicManningOverseasIncMember" xlink:label="loc_ciss_HellenicManningOverseasIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_HellenicManningOverseasIncMember" xml:lang="en-US">Hellenic Manning Overseas Inc [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_HellenicManningOverseasIncMember" xlink:to="lab_ciss_HellenicManningOverseasIncMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_HellenicManningOverseasIncMember" xml:lang="en-US">Hellenic manning overseas Inc.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ManagementFeeMember" xlink:label="loc_ciss_ManagementFeeMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ManagementFeeMember" xml:lang="en-US">Management Fee [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ManagementFeeMember" xlink:to="lab_ciss_ManagementFeeMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ManagerMember" xlink:label="loc_ciss_ManagerMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ManagerMember" xml:lang="en-US">Manager [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ManagerMember" xlink:to="lab_ciss_ManagerMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AfrapearlIiMember" xlink:label="loc_ciss_AfrapearlIiMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AfrapearlIiMember" xml:lang="en-US">Afrapearl II [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_AfrapearlIiMember" xml:lang="en-US">Afrapearl II [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AfrapearlIiMember" xlink:to="lab_ciss_AfrapearlIiMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AfrapearlIiMember" xml:lang="en-US">Afrapearl II.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_EcoSpitfireMember" xlink:label="loc_ciss_EcoSpitfireMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_EcoSpitfireMember" xml:lang="en-US">Eco Spitfire [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_EcoSpitfireMember" xlink:to="lab_ciss_EcoSpitfireMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_SanRemoMember" xlink:label="loc_ciss_SanRemoMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_SanRemoMember" xml:lang="en-US">San Remo [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_SanRemoMember" xlink:to="lab_ciss_SanRemoMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CleanFuryMember" xlink:label="loc_ciss_CleanFuryMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CleanFuryMember" xml:lang="en-US">Clean Fury [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CleanFuryMember" xlink:to="lab_ciss_CleanFuryMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementOfIncomeLocationBalanceAxis" xml:lang="en-US">Location, Statement of Income, Balance [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfIncomeLocationBalanceAxis" xlink:to="lab_us-gaap_StatementOfIncomeLocationBalanceAxis" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ManagementFeesMember" xlink:label="loc_ciss_ManagementFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ManagementFeesMember" xml:lang="en-US">Management Fees [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ManagementFeesMember" xlink:to="lab_ciss_ManagementFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ManagementFeesMember" xml:lang="en-US">Management Fees [Member].</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_BrokerageCommissionsMember" xlink:label="loc_ciss_BrokerageCommissionsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_BrokerageCommissionsMember" xml:lang="en-US">Brokerage Commissions [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_BrokerageCommissionsMember" xlink:to="lab_ciss_BrokerageCommissionsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_BrokerageCommissionsMember" xml:lang="en-US">Brokerage commissions.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_SuperintendentFeesMember" xlink:label="loc_ciss_SuperintendentFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_SuperintendentFeesMember" xml:lang="en-US">Superintendent Fees [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_SuperintendentFeesMember" xlink:to="lab_ciss_SuperintendentFeesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_SuperintendentFeesMember" xml:lang="en-US">Superintendent fees.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ExecutiveCompensationMember" xlink:label="loc_ciss_ExecutiveCompensationMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ExecutiveCompensationMember" xml:lang="en-US">Executive Compensation [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ExecutiveCompensationMember" xlink:to="lab_ciss_ExecutiveCompensationMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ExecutiveCompensationMember" xml:lang="en-US">Executive compensation.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RentalExpenseMember" xlink:label="loc_ciss_RentalExpenseMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RentalExpenseMember" xml:lang="en-US">Rental Expense [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RentalExpenseMember" xlink:to="lab_ciss_RentalExpenseMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RentalExpenseMember" xml:lang="en-US">Rental expense.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CommissionVesselPurchasedMember" xlink:label="loc_ciss_CommissionVesselPurchasedMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CommissionVesselPurchasedMember" xml:lang="en-US">Commission Vessel Purchased [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CommissionVesselPurchasedMember" xlink:to="lab_ciss_CommissionVesselPurchasedMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CommissionVesselPurchasedMember" xml:lang="en-US">Commission &#8211; vessel purchased.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_InterestAndFinanceExpenseMember" xlink:label="loc_ciss_InterestAndFinanceExpenseMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_InterestAndFinanceExpenseMember" xml:lang="en-US">Interest and Finance Expense [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_InterestAndFinanceExpenseMember" xml:lang="en-US">Interest Expense [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_InterestAndFinanceExpenseMember" xlink:to="lab_ciss_InterestAndFinanceExpenseMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_InterestAndFinanceExpenseMember" xml:lang="en-US">Interest and finance expense.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SfpLocationActivityCapitalizationAxis" xlink:label="loc_us-gaap_SfpLocationActivityCapitalizationAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SfpLocationActivityCapitalizationAxis" xml:lang="en-US">Location, Statement of Financial Position, Activity, Capitalization [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SfpLocationActivityCapitalizationAxis" xlink:to="lab_us-gaap_SfpLocationActivityCapitalizationAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryCurrentTable" xlink:label="loc_us-gaap_InventoryCurrentTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InventoryCurrentTable" xml:lang="en-US">Inventory, Current [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryCurrentTable" xlink:to="lab_us-gaap_InventoryCurrentTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryAxis" xlink:label="loc_us-gaap_PublicUtilitiesInventoryAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PublicUtilitiesInventoryAxis" xml:lang="en-US">Inventory [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PublicUtilitiesInventoryAxis" xlink:to="lab_us-gaap_PublicUtilitiesInventoryAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PublicUtilitiesInventoryTypeDomain" xlink:label="loc_us-gaap_PublicUtilitiesInventoryTypeDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PublicUtilitiesInventoryTypeDomain" xml:lang="en-US">Inventory [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PublicUtilitiesInventoryTypeDomain" xlink:to="lab_us-gaap_PublicUtilitiesInventoryTypeDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_BunkersMember" xlink:label="loc_ciss_BunkersMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_BunkersMember" xml:lang="en-US">Bunkers [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_BunkersMember" xlink:to="lab_ciss_BunkersMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_BunkersMember" xml:lang="en-US">Bunkers.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_LubricantsMember" xlink:label="loc_ciss_LubricantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_LubricantsMember" xml:lang="en-US">Lubricants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_LubricantsMember" xlink:to="lab_ciss_LubricantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_LubricantsMember" xml:lang="en-US">Lubricants.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryLineItems" xlink:label="loc_us-gaap_InventoryLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_InventoryLineItems" xml:lang="en-US">Inventory [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InventoryLineItems" xlink:to="lab_us-gaap_InventoryLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xml:lang="en-US">Property, Plant and Equipment [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xml:lang="en-US">Property, Plant and Equipment, Gross</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xml:lang="en-US">Beginning Balance, Vessel cost</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentGross" xml:lang="en-US">Ending Balance, Vessel cost</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentGross" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentGross" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentAdditions" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAdditions" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAdditions" xml:lang="en-US">Property, Plant and Equipment, Additions</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentAdditions" xml:lang="en-US">Acquisition and improvements</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAdditions" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentAdditions" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xml:lang="en-US">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodStartLabel" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xml:lang="en-US">Beginning Balance, Accumulated Depreciation</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedPeriodEndLabel" xlink:label="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xml:lang="en-US">Ending Balance, Accumulated Depreciation</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="lab_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AcquisitionsAndImprovementsOfVesselNet" xlink:label="loc_ciss_AcquisitionsAndImprovementsOfVesselNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AcquisitionsAndImprovementsOfVesselNet" xml:lang="en-US">Acquisitions And Improvements Of Vessel Net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_AcquisitionsAndImprovementsOfVesselNet" xml:lang="en-US">Acquisition and improvements</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AcquisitionsAndImprovementsOfVesselNet" xlink:to="lab_ciss_AcquisitionsAndImprovementsOfVesselNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AcquisitionsAndImprovementsOfVesselNet" xml:lang="en-US">Acquisitions and improvements of vessel net.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_DepreciationNet" xlink:label="loc_ciss_DepreciationNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_DepreciationNet" xml:lang="en-US">Depreciation Net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_DepreciationNet" xml:lang="en-US">Depreciation for the period</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_DepreciationNet" xlink:to="lab_ciss_DepreciationNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_DepreciationNet" xml:lang="en-US">Depreciation net.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PayablesAndAccrualsAbstract" xlink:label="loc_us-gaap_PayablesAndAccrualsAbstract" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PayablesAndAccrualsAbstract" xml:lang="en-US">Payables and Accruals [Abstract]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PayablesAndAccrualsAbstract" xlink:to="lab_us-gaap_PayablesAndAccrualsAbstract" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AdministrationExpensesPayableCurrent" xlink:label="loc_ciss_AdministrationExpensesPayableCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AdministrationExpensesPayableCurrent" xml:lang="en-US">Administration Expenses Payable Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_AdministrationExpensesPayableCurrent" xml:lang="en-US">Administrative expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AdministrationExpensesPayableCurrent" xlink:to="lab_ciss_AdministrationExpensesPayableCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AdministrationExpensesPayableCurrent" xml:lang="en-US">Administration expenses payable current.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AccruedVesselOperatingAndVoyageExpenses" xlink:label="loc_ciss_AccruedVesselOperatingAndVoyageExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AccruedVesselOperatingAndVoyageExpenses" xml:lang="en-US">Accrued Vessel Operating And Voyage Expenses</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_AccruedVesselOperatingAndVoyageExpenses" xml:lang="en-US">Vessel operating and voyage expenses</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AccruedVesselOperatingAndVoyageExpenses" xlink:to="lab_ciss_AccruedVesselOperatingAndVoyageExpenses" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AccruedVesselOperatingAndVoyageExpenses" xml:lang="en-US">Accrued vessel operating and voyage expenses.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ScheduleOfStockByClassTable" xml:lang="en-US">Stock, Class of Stock [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable" xlink:to="lab_us-gaap_ScheduleOfStockByClassTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaap_ClassOfStockLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfStockLineItems" xml:lang="en-US">Class of Stock [Line Items]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ClassOfStockLineItems" xml:lang="en-US">Increase The Number of Share Issuable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfStockLineItems" xlink:to="lab_us-gaap_ClassOfStockLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xml:lang="en-US">Class of Warrant or Right, Exercise Price of Warrants or Rights</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xml:lang="en-US">Class of warrant or right exercise price of warrants or rights</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xml:lang="en-US">Class of warrants or rights exercise price</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:to="lab_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_WarrantsAndRightsOutstanding" xml:lang="en-US">Warrants and Rights Outstanding</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_WarrantsAndRightsOutstanding" xml:lang="en-US">Warrants and rights outstanding</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WarrantsAndRightsOutstanding" xlink:to="lab_us-gaap_WarrantsAndRightsOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConvertibleConversionPrice" xlink:label="loc_us-gaap_PreferredStockConvertibleConversionPrice" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockConvertibleConversionPrice" xml:lang="en-US">Preferred Stock, Convertible, Conversion Price</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockConvertibleConversionPrice" xml:lang="en-US">Preferred stock, convertible, conversion price</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockConvertibleConversionPrice" xlink:to="lab_us-gaap_PreferredStockConvertibleConversionPrice" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_WarrantsAndRightsExercised" xlink:label="loc_ciss_WarrantsAndRightsExercised" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_WarrantsAndRightsExercised" xml:lang="en-US">Warrants And Rights Exercised</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_WarrantsAndRightsExercised" xml:lang="en-US">Class A warrants exercised</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_WarrantsAndRightsExercised" xlink:to="lab_ciss_WarrantsAndRightsExercised" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_WarrantsAndRightsExercised" xml:lang="en-US">Warrants and rights exercised.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FairValueWarrantOfShareIssue" xlink:label="loc_ciss_FairValueWarrantOfShareIssue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FairValueWarrantOfShareIssue" xml:lang="en-US">Fair Value Warrant Of Share Issue</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_FairValueWarrantOfShareIssue" xml:lang="en-US">Fair Value Warrant Of Share Issue</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FairValueWarrantOfShareIssue" xlink:to="lab_ciss_FairValueWarrantOfShareIssue" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_FairValueWarrantOfShareIssue" xml:lang="en-US">Fair value warrant of share issue.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" xlink:label="loc_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" xml:lang="en-US">Fair Value Measurements Of Warrant Expected Volatility Rate</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" xml:lang="en-US">Fair Value Measurements Of Warrant Expected Volatility Rate</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" xlink:to="lab_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" xml:lang="en-US">Fair value measurements of warrant expected volatility rate.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" xlink:label="loc_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" xml:lang="en-US">Fair Value Measurements Of Warrant Risk Free Interest Rate</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" xml:lang="en-US">Fair Value Measurements Of Warrant Risk Free Interest Rate</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" xlink:to="lab_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" xml:lang="en-US">Fair value measurements of warrant risk free interest rate.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_MarketValueOfCommonStock" xlink:label="loc_ciss_MarketValueOfCommonStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_MarketValueOfCommonStock" xml:lang="en-US">Market Value Of Common Stock</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_MarketValueOfCommonStock" xml:lang="en-US">Market Value Of Common Stock</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_MarketValueOfCommonStock" xlink:to="lab_ciss_MarketValueOfCommonStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_MarketValueOfCommonStock" xml:lang="en-US">Market value of common stock.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CommonStockRegisteredForSaleAmount" xlink:label="loc_ciss_CommonStockRegisteredForSaleAmount" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CommonStockRegisteredForSaleAmount" xml:lang="en-US">Common Stock Registered For Sale Amount</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_CommonStockRegisteredForSaleAmount" xml:lang="en-US">Common stock registered for sale amount</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CommonStockRegisteredForSaleAmount" xlink:to="lab_ciss_CommonStockRegisteredForSaleAmount" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CommonStockRegisteredForSaleAmount" xml:lang="en-US">Common stock registered for sale amount.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xml:lang="en-US">Proceeds from Issuance of Common Stock</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" xml:lang="en-US">Proceeds from issuance of common stock</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:to="lab_us-gaap_ProceedsFromIssuanceOfCommonStock" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_SeriesAPreferredSharesMember" xlink:label="loc_ciss_SeriesAPreferredSharesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_SeriesAPreferredSharesMember" xml:lang="en-US">Series A Preferred Shares [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_SeriesAPreferredSharesMember" xml:lang="en-US">Series A Preferred Shares [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_SeriesAPreferredSharesMember" xlink:to="lab_ciss_SeriesAPreferredSharesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_SeriesAPreferredSharesMember" xml:lang="en-US">Series A Preferred Shares.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredClassAMember" xlink:label="loc_us-gaap_PreferredClassAMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredClassAMember" xml:lang="en-US">Preferred Class A [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredClassAMember" xml:lang="en-US">Preferred Class A [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredClassAMember" xlink:to="lab_us-gaap_PreferredClassAMember" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AllExchangesAxis" xlink:label="loc_ciss_AllExchangesAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AllExchangesAxis" xml:lang="en-US">All Exchanges [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AllExchangesAxis" xlink:to="lab_ciss_AllExchangesAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AllExchangesAxis" xml:lang="en-US">All exchanges.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/exch/2026/exch-2026.xsd#exch_AllExchangesDomain" xlink:label="loc_exch_AllExchangesDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_exch_AllExchangesDomain" xml:lang="en-US">All Exchanges [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_exch_AllExchangesDomain" xlink:to="lab_exch_AllExchangesDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassB2WarrantMember" xlink:label="loc_ciss_ClassB2WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassB2WarrantMember" xml:lang="en-US">Class B2 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_ClassB2WarrantMember" xml:lang="en-US">Class B2 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ClassB2WarrantMember" xml:lang="en-US">Class B2 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassB2WarrantMember" xlink:to="lab_ciss_ClassB2WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassB2WarrantMember" xml:lang="en-US">Class B2 warrant.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassC2WarrantMember" xlink:label="loc_ciss_ClassC2WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassC2WarrantMember" xml:lang="en-US">Class C2 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_ClassC2WarrantMember" xml:lang="en-US">Class C2 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ClassC2WarrantMember" xml:lang="en-US">Class C2 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassC2WarrantMember" xlink:to="lab_ciss_ClassC2WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassC2WarrantMember" xml:lang="en-US">Class C2 warrant.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassB1B2C1AndC2WarrantsMember" xlink:label="loc_ciss_ClassB1B2C1AndC2WarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassB1B2C1AndC2WarrantsMember" xml:lang="en-US">Class B1 B2 C1 And C2 Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassB1B2C1AndC2WarrantsMember" xlink:to="lab_ciss_ClassB1B2C1AndC2WarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassB1B2C1AndC2WarrantsMember" xml:lang="en-US">Class B1 B2 C1 and C2 warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassEWarrantsMember" xlink:label="loc_ciss_ClassEWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassEWarrantsMember" xml:lang="en-US">Class E Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassEWarrantsMember" xlink:to="lab_ciss_ClassEWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassEWarrantsMember" xml:lang="en-US">Class E warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassDWarrantsMember" xlink:label="loc_ciss_ClassDWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassDWarrantsMember" xml:lang="en-US">Class D Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassDWarrantsMember" xlink:to="lab_ciss_ClassDWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassDWarrantsMember" xml:lang="en-US">Class&#160;D warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PlanNameAxis" xml:lang="en-US">Plan Name [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameAxis" xlink:to="lab_us-gaap_PlanNameAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PlanNameDomain" xml:lang="en-US">Plan Name [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VestingAxis" xlink:label="loc_us-gaap_VestingAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_VestingAxis" xml:lang="en-US">Vesting [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VestingAxis" xlink:to="lab_us-gaap_VestingAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VestingDomain" xlink:label="loc_us-gaap_VestingDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_VestingDomain" xml:lang="en-US">Vesting [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VestingDomain" xlink:to="lab_us-gaap_VestingDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="loc_us-gaap_FinancialInstrumentAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xml:lang="en-US">Financial Instrument [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentAxis" xlink:to="lab_us-gaap_FinancialInstrumentAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xml:lang="en-US">Financial Instruments [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="lab_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassesOfShareCapitalAxis" xlink:label="loc_ciss_ClassesOfShareCapitalAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassesOfShareCapitalAxis" xml:lang="en-US">Classes Of Share Capital [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassesOfShareCapitalAxis" xlink:to="lab_ciss_ClassesOfShareCapitalAxis" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassesOfShareCapitalDomain" xlink:label="loc_ciss_ClassesOfShareCapitalDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassesOfShareCapitalDomain" xml:lang="en-US">Classes Of Share Capital [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassesOfShareCapitalDomain" xlink:to="lab_ciss_ClassesOfShareCapitalDomain" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" xml:lang="en-US">Fair Value Hierarchy and NAV [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="lab_us-gaap_FairValueByFairValueHierarchyLevelAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xml:lang="en-US">Fair Value Hierarchy and NAV [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="lab_us-gaap_FairValueMeasurementsFairValueHierarchyDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IssuancesOfEquitySecuritiesAxis" xlink:label="loc_ciss_IssuancesOfEquitySecuritiesAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IssuancesOfEquitySecuritiesAxis" xml:lang="en-US">Issuances Of Equity Securities [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IssuancesOfEquitySecuritiesAxis" xlink:to="lab_ciss_IssuancesOfEquitySecuritiesAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IssuancesOfEquitySecuritiesAxis" xml:lang="en-US">Issuances of equity securities.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IssuancesOfEquitySecuritiesDomain" xlink:label="loc_ciss_IssuancesOfEquitySecuritiesDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IssuancesOfEquitySecuritiesDomain" xml:lang="en-US">Issuances Of Equity Securities [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IssuancesOfEquitySecuritiesDomain" xlink:to="lab_ciss_IssuancesOfEquitySecuritiesDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IssuancesOfEquitySecuritiesDomain" xml:lang="en-US">Issuances of equity securities.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AtTheMarketOfferingMember" xlink:label="loc_ciss_AtTheMarketOfferingMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AtTheMarketOfferingMember" xml:lang="en-US">At The Market Offering [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AtTheMarketOfferingMember" xlink:to="lab_ciss_AtTheMarketOfferingMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AtTheMarketOfferingMember" xml:lang="en-US">At the market offering.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IssuanceTypeAxis" xlink:label="loc_ciss_IssuanceTypeAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IssuanceTypeAxis" xml:lang="en-US">Issuance Type [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IssuanceTypeAxis" xlink:to="lab_ciss_IssuanceTypeAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IssuanceTypeAxis" xml:lang="en-US">Issuance type.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IssuanceTypeDomain" xlink:label="loc_ciss_IssuanceTypeDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IssuanceTypeDomain" xml:lang="en-US">Issuance Type [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IssuanceTypeDomain" xlink:to="lab_ciss_IssuanceTypeDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IssuanceTypeDomain" xml:lang="en-US">Issuance type.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CashExerciseOfWarrantsMember" xlink:label="loc_ciss_CashExerciseOfWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CashExerciseOfWarrantsMember" xml:lang="en-US">Cash Exercise Of Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CashExerciseOfWarrantsMember" xlink:to="lab_ciss_CashExerciseOfWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_CashExerciseOfWarrantsMember" xml:lang="en-US">Cash exercise of warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CashlessExerciseOfWarrantsMember" xlink:label="loc_ciss_CashlessExerciseOfWarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CashlessExerciseOfWarrantsMember" xml:lang="en-US">Cashless Exercise Of Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CashlessExerciseOfWarrantsMember" xlink:to="lab_ciss_CashlessExerciseOfWarrantsMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightTable" xml:lang="en-US">Class of Warrant or Right [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable" xlink:to="lab_us-gaap_ClassOfWarrantOrRightTable" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassB1WarrantMember" xlink:label="loc_ciss_ClassB1WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassB1WarrantMember" xml:lang="en-US">Class B1 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ClassB1WarrantMember" xml:lang="en-US">Class B1 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassB1WarrantMember" xlink:to="lab_ciss_ClassB1WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassB1WarrantMember" xml:lang="en-US">Class B1.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassC1WarrantMember" xlink:label="loc_ciss_ClassC1WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassC1WarrantMember" xml:lang="en-US">Class C1 Warrant [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_ciss_ClassC1WarrantMember" xml:lang="en-US">Class C1 [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassC1WarrantMember" xlink:to="lab_ciss_ClassC1WarrantMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ClassC1WarrantMember" xml:lang="en-US">Class C1.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightLineItems" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightLineItems" xml:lang="en-US">Class of Warrant or Right [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems" xlink:to="lab_us-gaap_ClassOfWarrantOrRightLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xml:lang="en-US">Class of Warrant or Right, Number of Securities Called by Warrants or Rights</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xml:lang="en-US">Shares to be issued upon exercise of remaining warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:to="lab_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_WarrantLiabilityOpeningBalance" xlink:label="loc_ciss_WarrantLiabilityOpeningBalance" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_WarrantLiabilityOpeningBalance" xml:lang="en-US">Warrant Liability Opening Balance</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="lab_ciss_WarrantLiabilityOpeningBalance" xml:lang="en-US">Balance as of December&#160;31, 2025</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_WarrantLiabilityOpeningBalance" xlink:to="lab_ciss_WarrantLiabilityOpeningBalance" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_WarrantLiabilityOpeningBalance" xml:lang="en-US">Warrant liability opening balance.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ChangeInFairValueOfWarrant" xlink:label="loc_ciss_ChangeInFairValueOfWarrant" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ChangeInFairValueOfWarrant" xml:lang="en-US">Change In Fair Value Of Warrant</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_ChangeInFairValueOfWarrant" xml:lang="en-US">Change in fair value of warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ChangeInFairValueOfWarrant" xlink:to="lab_ciss_ChangeInFairValueOfWarrant" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ChangeInFairValueOfWarrant" xml:lang="en-US">Change in fair value of warrant.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ExerciseOfWarrant" xlink:label="loc_ciss_ExerciseOfWarrant" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ExerciseOfWarrant" xml:lang="en-US">Exercise Of Warrant</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_ExerciseOfWarrant" xml:lang="en-US">Exercise of warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ExerciseOfWarrant" xlink:to="lab_ciss_ExerciseOfWarrant" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_ExerciseOfWarrant" xml:lang="en-US">Exercise of warrant.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_WarrantLiabilityClosingBalance" xlink:label="loc_ciss_WarrantLiabilityClosingBalance" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_WarrantLiabilityClosingBalance" xml:lang="en-US">Warrant Liability Closing Balance</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="lab_ciss_WarrantLiabilityClosingBalance" xml:lang="en-US">Balance as of June&#160;30, 2026</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_WarrantLiabilityClosingBalance" xlink:to="lab_ciss_WarrantLiabilityClosingBalance" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_WarrantLiabilityClosingBalance" xml:lang="en-US">Warrant liability closing balance.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" xml:lang="en-US">Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" xlink:to="lab_us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasicLineItems" xlink:label="loc_us-gaap_EarningsPerShareBasicLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_EarningsPerShareBasicLineItems" xml:lang="en-US">Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasicLineItems" xlink:to="lab_us-gaap_EarningsPerShareBasicLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xml:lang="en-US">Net income/(loss) attributable to common shareholders, basic</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Diluted, Total</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xml:lang="en-US">Net income/(loss) attributable to common shareholders, diluted</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:to="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" xlink:label="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" xml:lang="en-US">Undistributed Earnings (Loss) Allocated to Participating Securities, Basic</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" xml:lang="en-US">Less: Undistributed earnings allocated to non-vested shares, basic</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" xlink:to="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_PreferredStockDownRoundDeemedDividendsAdjustment" xlink:label="loc_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" xml:lang="en-US">Preferred Stock Down Round Deemed Dividends Adjustment</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" xml:lang="en-US">Less: Down round deemed dividend on Series A Perpetual Convertible Preferred Shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" xlink:to="lab_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_PreferredStockDownRoundDeemedDividendsAdjustment" xml:lang="en-US">Preferred stock down round deemed dividends adjustment.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendsAndOtherAdjustments" xlink:label="loc_us-gaap_PreferredStockDividendsAndOtherAdjustments" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockDividendsAndOtherAdjustments" xml:lang="en-US">Preferred Stock Dividends and Other Adjustments</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockDividendsAndOtherAdjustments" xml:lang="en-US">Less: Cumulative dividends on Series A Perpetual Convertible Preferred Shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockDividendsAndOtherAdjustments" xlink:to="lab_us-gaap_PreferredStockDividendsAndOtherAdjustments" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" xlink:label="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" xml:lang="en-US">Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" xml:lang="en-US">Weighted average number of shares outstanding, diluted</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" xlink:to="lab_us-gaap_NetIncomeLossFromContinuingOperationsAvailableToCommonShareholdersDiluted" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" xlink:label="loc_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" xml:lang="en-US">Increase Decrease In Fair Value Of Warrants Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/definitionGuidance" xlink:label="lab_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" xml:lang="en-US">Change in fair value of warrants</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" xlink:to="lab_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" xml:lang="en-US">Increase decrease in fair value of warrants diluted.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" xlink:label="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" xml:lang="en-US">Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" xml:lang="en-US">Effect of dilutive shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" xlink:to="lab_us-gaap_DilutiveSecuritiesEffectOnBasicEarningsPerShareOther" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_PerpetualConvertiblePreferredSharesDiluted" xlink:label="loc_ciss_PerpetualConvertiblePreferredSharesDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_PerpetualConvertiblePreferredSharesDiluted" xml:lang="en-US">Perpetual Convertible Preferred Shares Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_PerpetualConvertiblePreferredSharesDiluted" xml:lang="en-US">Series A Perpetual Convertible Preferred Shares (Note 8)</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_PerpetualConvertiblePreferredSharesDiluted" xlink:to="lab_ciss_PerpetualConvertiblePreferredSharesDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_PerpetualConvertiblePreferredSharesDiluted" xml:lang="en-US">Perpetual ConvertiblePreferredSharesDiluted</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" xlink:label="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" xml:lang="en-US">Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" xml:lang="en-US">Less: Undistributed earnings allocated to non-vested shares, diluted</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" xlink:to="lab_us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_WarrantsSharesDiluted" xlink:label="loc_ciss_WarrantsSharesDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_WarrantsSharesDiluted" xml:lang="en-US">Warrants Shares Diluted</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_WarrantsSharesDiluted" xml:lang="en-US">Warrants (Note 8)</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_WarrantsSharesDiluted" xlink:to="lab_ciss_WarrantsSharesDiluted" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_WarrantsSharesDiluted" xml:lang="en-US">WarrantsSharesDiluted</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConversionsInducements" xlink:label="loc_us-gaap_PreferredStockConversionsInducements" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockConversionsInducements" xml:lang="en-US">Preferred Stock Conversions, Inducements</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_PreferredStockConversionsInducements" xml:lang="en-US">Series A Perpetual Convertible Preferred Shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockConversionsInducements" xlink:to="lab_us-gaap_PreferredStockConversionsInducements" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_RepresentativepurchasewarrantsMember" xlink:label="loc_ciss_RepresentativepurchasewarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_RepresentativepurchasewarrantsMember" xml:lang="en-US">Representative Purchase Warrants [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_RepresentativepurchasewarrantsMember" xml:lang="en-US">Representative Purchase Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_RepresentativepurchasewarrantsMember" xlink:to="lab_ciss_RepresentativepurchasewarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_RepresentativepurchasewarrantsMember" xml:lang="en-US">Representative Purchase Warrants.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonClassAMember" xlink:label="loc_us-gaap_CommonClassAMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CommonClassAMember" xml:lang="en-US">Common Class A [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonClassAMember" xlink:to="lab_us-gaap_CommonClassAMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ClassOfWarrantOrRightOutstanding" xml:lang="en-US">Class of Warrant or Right, Outstanding</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ClassOfWarrantOrRightOutstanding" xml:lang="en-US">Class of warrant or right, outstanding</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClassOfWarrantOrRightOutstanding" xlink:to="lab_us-gaap_ClassOfWarrantOrRightOutstanding" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesRestrictedStock" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesRestrictedStock" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesRestrictedStock" xml:lang="en-US">Weighted Average Number of Shares, Restricted Stock</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesRestrictedStock" xml:lang="en-US">Weighted average number of shares restricted stock</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesRestrictedStock" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesRestrictedStock" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockConvertibleSharesIssuable" xlink:label="loc_us-gaap_PreferredStockConvertibleSharesIssuable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_PreferredStockConvertibleSharesIssuable" xml:lang="en-US">Preferred Stock, Convertible, Shares Issuable</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="lab_us-gaap_PreferredStockConvertibleSharesIssuable" xml:lang="en-US">Preferred Stock, Convertible, Shares Issuable</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockConvertibleSharesIssuable" xlink:to="lab_us-gaap_PreferredStockConvertibleSharesIssuable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonShares" xlink:label="loc_us-gaap_TreasuryStockCommonShares" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_TreasuryStockCommonShares" xml:lang="en-US">Treasury Stock, Common, Shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockCommonShares" xlink:to="lab_us-gaap_TreasuryStockCommonShares" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AggregateNumberOfOptionsToPurchaseCommonShares" xlink:label="loc_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" xml:lang="en-US">Aggregate Number Of Options To Purchase Common Shares</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" xml:lang="en-US">Aggregate number of options to purchase common shares</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" xlink:to="lab_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_AggregateNumberOfOptionsToPurchaseCommonShares" xml:lang="en-US">Aggregate number of options to purchase common shares.</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockByUniqueDescriptionAxis" xlink:label="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ConversionOfStockByUniqueDescriptionAxis" xml:lang="en-US">Stock Conversion Description [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis" xlink:to="lab_us-gaap_ConversionOfStockByUniqueDescriptionAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockNameDomain" xlink:label="loc_us-gaap_ConversionOfStockNameDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ConversionOfStockNameDomain" xml:lang="en-US">Conversion of Stock, Name [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConversionOfStockNameDomain" xlink:to="lab_us-gaap_ConversionOfStockNameDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_IfConvertedMethodMember" xlink:label="loc_ciss_IfConvertedMethodMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_IfConvertedMethodMember" xml:lang="en-US">If Converted Method [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_IfConvertedMethodMember" xlink:to="lab_ciss_IfConvertedMethodMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_IfConvertedMethodMember" xml:lang="en-US">If converted method.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_ClassB2C2WarrantsMember" xlink:label="loc_ciss_ClassB2C2WarrantsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_ClassB2C2WarrantsMember" xml:lang="en-US">Class B2 C2 Warrants [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_ClassB2C2WarrantsMember" xlink:to="lab_ciss_ClassB2C2WarrantsMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DisaggregationOfRevenueTable" xml:lang="en-US">Disaggregation of Revenue [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable" xlink:to="lab_us-gaap_DisaggregationOfRevenueTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_srt_ProductOrServiceAxis" xml:lang="en-US">Product and Service [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductOrServiceAxis" xlink:to="lab_srt_ProductOrServiceAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_srt_ProductsAndServicesDomain" xml:lang="en-US">Product and Service [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_TimeCharterRevenuesMember" xlink:label="loc_ciss_TimeCharterRevenuesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_TimeCharterRevenuesMember" xml:lang="en-US">Time Charter Revenues [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_TimeCharterRevenuesMember" xml:lang="en-US">Time charter revenues [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_TimeCharterRevenuesMember" xlink:to="lab_ciss_TimeCharterRevenuesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_TimeCharterRevenuesMember" xml:lang="en-US">Time charter revenues.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_VoyageCharterRevenuesMember" xlink:label="loc_ciss_VoyageCharterRevenuesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_VoyageCharterRevenuesMember" xml:lang="en-US">Voyage Charter Revenues [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_VoyageCharterRevenuesMember" xml:lang="en-US">Voyage charter revenues [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_VoyageCharterRevenuesMember" xlink:to="lab_ciss_VoyageCharterRevenuesMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_VoyageCharterRevenuesMember" xml:lang="en-US">Voyage charter revenues.</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_OtherOperatingIncomeMember" xlink:label="loc_ciss_OtherOperatingIncomeMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_OtherOperatingIncomeMember" xml:lang="en-US">Other Operating Income [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_OtherOperatingIncomeMember" xml:lang="en-US">Other Operating Income [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_OtherOperatingIncomeMember" xlink:to="lab_ciss_OtherOperatingIncomeMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_OtherOperatingIncomeMember" xml:lang="en-US">Other operating income</link:label>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DisaggregationOfRevenueLineItems" xml:lang="en-US">Disaggregation of Revenue [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems" xlink:to="lab_us-gaap_DisaggregationOfRevenueLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="loc_us-gaap_ReceivablesNetCurrent" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_ReceivablesNetCurrent" xml:lang="en-US">Receivables, Net, Current</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_ReceivablesNetCurrent" xml:lang="en-US">Receivables, net, current</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReceivablesNetCurrent" xlink:to="lab_us-gaap_ReceivablesNetCurrent" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalizedContractCostNet" xlink:label="loc_us-gaap_CapitalizedContractCostNet" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_CapitalizedContractCostNet" xml:lang="en-US">Capitalized Contract Cost, Net</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_CapitalizedContractCostNet" xml:lang="en-US">Capitalized contract cost, net</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CapitalizedContractCostNet" xlink:to="lab_us-gaap_CapitalizedContractCostNet" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueRemainingPerformanceObligation" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation" xml:lang="en-US">Revenue, Remaining Performance Obligation, Amount</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_RevenueRemainingPerformanceObligation" xml:lang="en-US">Revenue remaining performance obligation amount</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligation" xlink:to="lab_us-gaap_RevenueRemainingPerformanceObligation" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfFinancialPositionLocationBalanceAxis" xlink:label="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StatementOfFinancialPositionLocationBalanceAxis" xml:lang="en-US">Location, Statement of Financial Position, Balance [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfFinancialPositionLocationBalanceAxis" xlink:to="lab_us-gaap_StatementOfFinancialPositionLocationBalanceAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesTable" xlink:label="loc_us-gaap_LossContingenciesTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LossContingenciesTable" xml:lang="en-US">Loss Contingencies [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesTable" xlink:to="lab_us-gaap_LossContingenciesTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingenciesLineItems" xlink:label="loc_us-gaap_LossContingenciesLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_LossContingenciesLineItems" xml:lang="en-US">Loss Contingencies [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LossContingenciesLineItems" xlink:to="lab_us-gaap_LossContingenciesLineItems" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" xlink:label="loc_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" xml:lang="en-US">Future Minimum Payments Due Future Minimum Sublease Rentals For Next Twelve Months</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" xml:lang="en-US">Future minimum charter revenues next twelve months</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" xlink:to="lab_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="lab_ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" xml:lang="en-US">Future minimum payments due future minimum sublease rentals for next twelve months</link:label>
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_CleanReaperMember" xlink:label="loc_ciss_CleanReaperMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_CleanReaperMember" xml:lang="en-US">Clean Reaper [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_CleanReaperMember" xlink:to="lab_ciss_CleanReaperMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable" xlink:label="loc_us-gaap_SubsequentEventTable" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsequentEventTable" xml:lang="en-US">Subsequent Event [Table]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventTable" xlink:to="lab_us-gaap_SubsequentEventTable" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsequentEventLineItems" xml:lang="en-US">Subsequent Event [Line Items]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventLineItems" xlink:to="lab_us-gaap_SubsequentEventLineItems" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPreferredStockCash" xlink:label="loc_us-gaap_DividendsPreferredStockCash" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_DividendsPreferredStockCash" xml:lang="en-US">Dividends, Preferred Stock, Cash</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_DividendsPreferredStockCash" xml:lang="en-US">Company paid dividends</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DividendsPreferredStockCash" xlink:to="lab_us-gaap_DividendsPreferredStockCash" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityReverseStockSplit" xlink:label="loc_us-gaap_StockholdersEquityReverseStockSplit" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_StockholdersEquityReverseStockSplit" xml:lang="en-US">Stockholders' Equity, Reverse Stock Split</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockholdersEquityReverseStockSplit" xlink:to="lab_us-gaap_StockholdersEquityReverseStockSplit" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaap_SubsequentEventMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsequentEventMember" xml:lang="en-US">Subsequent Event [Member]</link:label>
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="lab_us-gaap_SubsequentEventMember" xml:lang="en-US">Subsequent Event [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventMember" xlink:to="lab_us-gaap_SubsequentEventMember" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SubsidiarySaleOfStockAxis" xml:lang="en-US">Sale of Stock [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis" xlink:to="lab_us-gaap_SubsidiarySaleOfStockAxis" />
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_us-gaap_SaleOfStockNameOfTransactionDomain" xml:lang="en-US">Sale of Stock [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain" xlink:to="lab_us-gaap_SaleOfStockNameOfTransactionDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AssetAcquisitionOneAxis" xlink:label="loc_ciss_AssetAcquisitionOneAxis" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AssetAcquisitionOneAxis" xml:lang="en-US">Asset Acquisition One [Axis]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AssetAcquisitionOneAxis" xlink:to="lab_ciss_AssetAcquisitionOneAxis" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_AssetAcquisitionOneDomain" xlink:label="loc_ciss_AssetAcquisitionOneDomain" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_AssetAcquisitionOneDomain" xml:lang="en-US">Asset Acquisition One [Domain]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_AssetAcquisitionOneDomain" xlink:to="lab_ciss_AssetAcquisitionOneDomain" />
          <link:loc xlink:type="locator" xlink:href="ciss-20260630.xsd#ciss_UnitsMember" xlink:label="loc_ciss_UnitsMember" />
          <link:label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="lab_ciss_UnitsMember" xml:lang="en-US">Units [Member]</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ciss_UnitsMember" xlink:to="lab_ciss_UnitsMember" />
        </link:labelLink>
      </link:linkbase>
    </appinfo>
  </annotation>
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <import namespace="http://xbrl.org/2020/extensible-enumerations-2.0" schemaLocation="https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd" />
  <import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd" />
  <import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <import namespace="http://www.xbrl.org/2006/ref" schemaLocation="http://www.xbrl.org/2006/ref-2006-02-27.xsd" />
  <import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/currency/2026" schemaLocation="https://xbrl.sec.gov/currency/2026/currency-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/exch/2026" schemaLocation="https://xbrl.sec.gov/exch/2026/exch-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/stpr/2026" schemaLocation="https://xbrl.sec.gov/stpr/2026/stpr-2026.xsd" />
  <import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" />
  <import namespace="http://www.xbrl.org/2003/XLink" schemaLocation="http://www.xbrl.org/2003/xl-2003-12-31.xsd" />
  <import namespace="http://www.w3.org/1999/xlink" schemaLocation="http://www.xbrl.org/2003/xlink-2003-12-31.xsd" />
  <import namespace="http://fasb.org/srt-types/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-types-2026.xsd" />
  <import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/naics/2026" schemaLocation="https://xbrl.sec.gov/naics/2026/naics-2026.xsd" />
  <import namespace="http://xbrl.sec.gov/sic/2026" schemaLocation="https://xbrl.sec.gov/sic/2026/sic-2026.xsd" />
  <import namespace="http://fasb.org/us-types/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-types-2026.xsd" />
  <element name="TimeDepositsCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_TimeDepositsCurrent" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="OperatingLeaseRightOfUseAssetCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_OperatingLeaseRightOfUseAssetCurrent" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="VoyageExpenses" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_VoyageExpenses" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="DryDockingCosts" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DryDockingCosts" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="DepreciationNetOffWriteBacks" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DepreciationNetOffWriteBacks" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="ManagementFees" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_ManagementFees" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="GeneralAndAdministrationExpensesNetOffWriteBacks" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_GeneralAndAdministrationExpensesNetOffWriteBacks" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="VoyageExpensesRelatedParty" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_VoyageExpensesRelatedParty" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="GeneralAndAdministrativeExpenseRelatedParty" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_GeneralAndAdministrativeExpenseRelatedParty" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="VesselsOperatingExpenses" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_VesselsOperatingExpenses" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="VesselsOperatingExpensesRelatedParty" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_VesselsOperatingExpensesRelatedParty" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="InterestAndDebtExpensesRelatedParty" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_InterestAndDebtExpensesRelatedParty" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="WeightedAverageNumberOfSharesAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_WeightedAverageNumberOfSharesAbstract" substitutionGroup="xbrli:item" />
  <element name="DownRoundDeemedDividendsPreferredStock" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DownRoundDeemedDividendsPreferredStock" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="ExerciseOfWarrantsValue" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_ExerciseOfWarrantsValue" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="EventAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_EventAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="EventDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_EventDomain" substitutionGroup="xbrli:item" />
  <element name="ExcerciseOfWarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ExcerciseOfWarrantsMember" substitutionGroup="xbrli:item" />
  <element name="PreferredStockDownRoundDeemedDividendsPerShareDeclared" type="dtr-types:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_PreferredStockDownRoundDeemedDividendsPerShareDeclared" substitutionGroup="xbrli:item" />
  <element name="IncreaseInBankTimeDeposits" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_IncreaseInBankTimeDeposits" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="CashlessExerciseofWarrants" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_CashlessExerciseofWarrants" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="DisclosureInTabularFormOfCompaniesSubsidiariesIncludedInTheConsolidatedFinancialStatementsTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DisclosureInTabularFormOfCompaniesSubsidiariesIncludedInTheConsolidatedFinancialStatementsTableTextBlock" substitutionGroup="xbrli:item" />
  <element name="ScheduleOfChangesInWarrantLiabilityTableTextBlock" type="dtr-types:textBlockItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_ScheduleOfChangesInWarrantLiabilityTableTextBlock" substitutionGroup="xbrli:item" />
  <element name="EntityFormationDateOfFormation" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_EntityFormationDateOfFormation" substitutionGroup="xbrli:item" />
  <element name="DeadWeightTonnage" type="dtr-types:massItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DeadWeightTonnage" substitutionGroup="xbrli:item" />
  <element name="NameOfTheVesselOwnedBySubsidiary" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_NameOfTheVesselOwnedBySubsidiary" substitutionGroup="xbrli:item" />
  <element name="DrybulkInternationalTradingAndShippingIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_DrybulkInternationalTradingAndShippingIncMember" substitutionGroup="xbrli:item" />
  <element name="RawCommoditiesAndExportsIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_RawCommoditiesAndExportsIncMember" substitutionGroup="xbrli:item" />
  <element name="CrudeOilServicesInternationalIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CrudeOilServicesInternationalIncMember" substitutionGroup="xbrli:item" />
  <element name="SpitfireDragonTransportIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_SpitfireDragonTransportIncMember" substitutionGroup="xbrli:item" />
  <element name="FuriousPetroleumTransportIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_FuriousPetroleumTransportIncMember" substitutionGroup="xbrli:item" />
  <element name="MagnificentHydrocarbonsIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_MagnificentHydrocarbonsIncMember" substitutionGroup="xbrli:item" />
  <element name="RelatedPartyBrokerageCommissionPerVessel" type="dtr-types:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_RelatedPartyBrokerageCommissionPerVessel" substitutionGroup="xbrli:item" />
  <element name="InitialConsiderationPaidOnAssetAcquisition" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_InitialConsiderationPaidOnAssetAcquisition" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="RemainingConsiderationToBePaid" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_RemainingConsiderationToBePaid" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="CommissionAsAPercentageOfSalePriceOfVehicles" type="dtr-types:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_CommissionAsAPercentageOfSalePriceOfVehicles" substitutionGroup="xbrli:item" />
  <element name="InitialPercentageOfConsiderationPaid" type="dtr-types:percentItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_InitialPercentageOfConsiderationPaid" substitutionGroup="xbrli:item" />
  <element name="RemainingPurchasePrice" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_RemainingPurchasePrice" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="FinancialComponentAccountingOnAssetAcquisition" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_FinancialComponentAccountingOnAssetAcquisition" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="DescriptionOfRemainingConsiderationToBePaid" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DescriptionOfRemainingConsiderationToBePaid" substitutionGroup="xbrli:item" />
  <element name="DiscriptionOfRemainingConsiderationToBePaid" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DiscriptionOfRemainingConsiderationToBePaid" substitutionGroup="xbrli:item" />
  <element name="CrewManagementFeesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CrewManagementFeesMember" substitutionGroup="xbrli:item" />
  <element name="FuriozaTradingDeskOverseasIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_FuriozaTradingDeskOverseasIncMember" substitutionGroup="xbrli:item" />
  <element name="ImperialPetroleumIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ImperialPetroleumIncMember" substitutionGroup="xbrli:item" />
  <element name="HellenicManningOverseasIncMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_HellenicManningOverseasIncMember" substitutionGroup="xbrli:item" />
  <element name="ManagementFeeMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ManagementFeeMember" substitutionGroup="xbrli:item" />
  <element name="ManagerMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ManagerMember" substitutionGroup="xbrli:item" />
  <element name="AfrapearlIiMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_AfrapearlIiMember" substitutionGroup="xbrli:item" />
  <element name="EcoSpitfireMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_EcoSpitfireMember" substitutionGroup="xbrli:item" />
  <element name="SanRemoMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_SanRemoMember" substitutionGroup="xbrli:item" />
  <element name="CleanFuryMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CleanFuryMember" substitutionGroup="xbrli:item" />
  <element name="ManagementFeesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ManagementFeesMember" substitutionGroup="xbrli:item" />
  <element name="BrokerageCommissionsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_BrokerageCommissionsMember" substitutionGroup="xbrli:item" />
  <element name="SuperintendentFeesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_SuperintendentFeesMember" substitutionGroup="xbrli:item" />
  <element name="ExecutiveCompensationMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ExecutiveCompensationMember" substitutionGroup="xbrli:item" />
  <element name="RentalExpenseMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_RentalExpenseMember" substitutionGroup="xbrli:item" />
  <element name="CommissionVesselPurchasedMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CommissionVesselPurchasedMember" substitutionGroup="xbrli:item" />
  <element name="InterestAndFinanceExpenseMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_InterestAndFinanceExpenseMember" substitutionGroup="xbrli:item" />
  <element name="BunkersMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_BunkersMember" substitutionGroup="xbrli:item" />
  <element name="LubricantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_LubricantsMember" substitutionGroup="xbrli:item" />
  <element name="AcquisitionsAndImprovementsOfVesselNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_AcquisitionsAndImprovementsOfVesselNet" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="DepreciationNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_DepreciationNet" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="AdministrationExpensesPayableCurrent" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_AdministrationExpensesPayableCurrent" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="AccruedVesselOperatingAndVoyageExpenses" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_AccruedVesselOperatingAndVoyageExpenses" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="WarrantsAndRightsExercised" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_WarrantsAndRightsExercised" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="FairValueWarrantOfShareIssue" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_FairValueWarrantOfShareIssue" substitutionGroup="xbrli:item" />
  <element name="FairValueMeasurementsOfWarrantExpectedVolatilityRate" type="dtr-types:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_FairValueMeasurementsOfWarrantExpectedVolatilityRate" substitutionGroup="xbrli:item" />
  <element name="FairValueMeasurementsOfWarrantRiskFreeInterestRate" type="dtr-types:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_FairValueMeasurementsOfWarrantRiskFreeInterestRate" substitutionGroup="xbrli:item" />
  <element name="MarketValueOfCommonStock" type="dtr-types:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_MarketValueOfCommonStock" substitutionGroup="xbrli:item" />
  <element name="CommonStockRegisteredForSaleAmount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_CommonStockRegisteredForSaleAmount" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="SeriesAPreferredSharesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_SeriesAPreferredSharesMember" substitutionGroup="xbrli:item" />
  <element name="AllExchangesAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_AllExchangesAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="ClassB2WarrantMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassB2WarrantMember" substitutionGroup="xbrli:item" />
  <element name="ClassC2WarrantMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassC2WarrantMember" substitutionGroup="xbrli:item" />
  <element name="ClassB1B2C1AndC2WarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassB1B2C1AndC2WarrantsMember" substitutionGroup="xbrli:item" />
  <element name="ClassEWarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassEWarrantsMember" substitutionGroup="xbrli:item" />
  <element name="ClassDWarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassDWarrantsMember" substitutionGroup="xbrli:item" />
  <element name="ClassesOfShareCapitalAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassesOfShareCapitalAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="ClassesOfShareCapitalDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassesOfShareCapitalDomain" substitutionGroup="xbrli:item" />
  <element name="IssuancesOfEquitySecuritiesAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_IssuancesOfEquitySecuritiesAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="IssuancesOfEquitySecuritiesDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_IssuancesOfEquitySecuritiesDomain" substitutionGroup="xbrli:item" />
  <element name="AtTheMarketOfferingMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_AtTheMarketOfferingMember" substitutionGroup="xbrli:item" />
  <element name="IssuanceTypeAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_IssuanceTypeAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="IssuanceTypeDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_IssuanceTypeDomain" substitutionGroup="xbrli:item" />
  <element name="CashExerciseOfWarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CashExerciseOfWarrantsMember" substitutionGroup="xbrli:item" />
  <element name="CashlessExerciseOfWarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CashlessExerciseOfWarrantsMember" substitutionGroup="xbrli:item" />
  <element name="ClassB1WarrantMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassB1WarrantMember" substitutionGroup="xbrli:item" />
  <element name="ClassC1WarrantMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassC1WarrantMember" substitutionGroup="xbrli:item" />
  <element name="WarrantLiabilityOpeningBalance" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_WarrantLiabilityOpeningBalance" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="ChangeInFairValueOfWarrant" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_ChangeInFairValueOfWarrant" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="ExerciseOfWarrant" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_ExerciseOfWarrant" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="WarrantLiabilityClosingBalance" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_WarrantLiabilityClosingBalance" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="PreferredStockDownRoundDeemedDividendsAdjustment" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_PreferredStockDownRoundDeemedDividendsAdjustment" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="IncreaseDecreaseInFairValueOfWarrantsDiluted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_IncreaseDecreaseInFairValueOfWarrantsDiluted" substitutionGroup="xbrli:item" xbrli:balance="debit" />
  <element name="PerpetualConvertiblePreferredSharesDiluted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_PerpetualConvertiblePreferredSharesDiluted" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="WarrantsSharesDiluted" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" id="ciss_WarrantsSharesDiluted" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="RepresentativepurchasewarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_RepresentativepurchasewarrantsMember" substitutionGroup="xbrli:item" />
  <element name="AggregateNumberOfOptionsToPurchaseCommonShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_AggregateNumberOfOptionsToPurchaseCommonShares" substitutionGroup="xbrli:item" />
  <element name="IfConvertedMethodMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_IfConvertedMethodMember" substitutionGroup="xbrli:item" />
  <element name="ClassB2C2WarrantsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_ClassB2C2WarrantsMember" substitutionGroup="xbrli:item" />
  <element name="TimeCharterRevenuesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_TimeCharterRevenuesMember" substitutionGroup="xbrli:item" />
  <element name="VoyageCharterRevenuesMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_VoyageCharterRevenuesMember" substitutionGroup="xbrli:item" />
  <element name="OtherOperatingIncomeMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_OtherOperatingIncomeMember" substitutionGroup="xbrli:item" />
  <element name="FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" nillable="true" id="ciss_FutureMinimumPaymentsDueFutureMinimumSubleaseRentalsForNextTwelveMonths" substitutionGroup="xbrli:item" xbrli:balance="credit" />
  <element name="CleanReaperMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_CleanReaperMember" substitutionGroup="xbrli:item" />
  <element name="AssetAcquisitionOneAxis" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_AssetAcquisitionOneAxis" substitutionGroup="xbrldt:dimensionItem" />
  <element name="AssetAcquisitionOneDomain" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_AssetAcquisitionOneDomain" substitutionGroup="xbrli:item" />
  <element name="UnitsMember" type="dtr-types:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" id="ciss_UnitsMember" substitutionGroup="xbrli:item" />
</schema>
