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<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2020-03-04T19:41:21.4382285+00:00 -->
<!-- Version            : 5.0.1.321 -->
<!-- Package ID         : 2d94a7670ffe4eb6a44a72f93a162579 -->
<!-- Copyright (c) 2020 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
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  <xsd:element id="smhi_NatureOfOperationAndAccountingPoliciesAbstract" name="NatureOfOperationAndAccountingPoliciesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_WarrantsAndRightsTextBlock" name="WarrantsAndRightsTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DeferredGainsPolicyTextBlock" name="DeferredGainsPolicyTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_RecentlyAdoptedAccountingStandardsPolicyTextBlock" name="RecentlyAdoptedAccountingStandardsPolicyTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleOfCashCashEquivalentsAndRestrictedCashTableTextBlock" name="ScheduleOfCashCashEquivalentsAndRestrictedCashTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_PropertyPlantAndEquipmentEstimatedUsefulLifeTableTextBlock" name="PropertyPlantAndEquipmentEstimatedUsefulLifeTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleOfDeferredGainTableTextBlock" name="ScheduleOfDeferredGainTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleOfCumulativeRestructuringAndReorganizationCostIncurredToDateEstimatedRemainingAndToBeIncurredTableTextBlock" name="ScheduleOfCumulativeRestructuringAndReorganizationCostIncurredToDateEstimatedRemainingAndToBeIncurredTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_SheduleOfVesselAcquiredAndDisposedOfTableTextBlock" name="SheduleOfVesselAcquiredAndDisposedOfTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleOfOtherInformationRelatedToOperatingLeasesTableTextBlock" name="ScheduleOfOtherInformationRelatedToOperatingLeasesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleOfNoncontrollingInterestTableTextBlock" name="ScheduleOfNoncontrollingInterestTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ScheduleIIValuationAndQualifyingAccountsTableTextBlock" name="ScheduleIIValuationAndQualifyingAccountsTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NatureOfOperationsAndAccountingPoliciesLineItems" name="NatureOfOperationsAndAccountingPoliciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NatureOfOperationsAndAccountingPoliciesTable" name="NatureOfOperationsAndAccountingPoliciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MexMarMember" name="MexMarMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORMarineInternationalLLCMember" name="SEACORMarineInternationalLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MEXMAROffshoreMember" name="MEXMAROffshoreMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SeaCoscoOffshoreLLCMember" name="SeaCoscoOffshoreLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_CMEMember" name="CMEMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORMarineForeignHoldingsMember" name="SEACORMarineForeignHoldingsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PrepaidVesselManagementFeesMember" name="PrepaidVesselManagementFeesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ChangeInAccountingPrincipleForEquipmentOfficeAndLandLeasesMember" name="ChangeInAccountingPrincipleForEquipmentOfficeAndLandLeasesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ChangeInAccountingPrincipleForUnamortizedDeferredGainsMember" name="ChangeInAccountingPrincipleForUnamortizedDeferredGainsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfVessels" name="NumberOfVessels" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfVesselsOwned" name="NumberOfVesselsOwned" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfVesselsJointVentured" name="NumberOfVesselsJointVentured" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfNonWindFarmVessels" name="NumberOfNonWindFarmVessels" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_CrewTransferVesselsMember" name="CrewTransferVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_AllOtherOffshoreSupportVesselsMember" name="AllOtherOffshoreSupportVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OffshoreSupportVesselsAnchorHandlingTowingSupplyMember" name="OffshoreSupportVesselsAnchorHandlingTowingSupplyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FastSupportVesselsMember" name="FastSupportVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OffshoreSupportVesselsSupplyMember" name="OffshoreSupportVesselsSupplyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OffshoreSupportVesselsSpecialtyMember" name="OffshoreSupportVesselsSpecialtyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OffshoreSupportVesselsLiftboatsMember" name="OffshoreSupportVesselsLiftboatsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_GeneralMachineryAndSparesMember" name="GeneralMachineryAndSparesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ReclassOfGainToRetainedEarnings" name="ReclassOfGainToRetainedEarnings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_AmortizationOfDeferredGainsIncludedInGainsOnAssetDispositionsAndImpairmentsNet" name="AmortizationOfDeferredGainsIncludedInGainsOnAssetDispositionsAndImpairmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_DeferredGainOnSaleOfPropertyOtherAdjustments" name="DeferredGainOnSaleOfPropertyOtherAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_SaleLeasebackAndFinancedEquipmentSalesMember" name="SaleLeasebackAndFinancedEquipmentSalesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_VesselSalesToFiftyPercentOrLessOwnedSubsidiariesMember" name="VesselSalesToFiftyPercentOrLessOwnedSubsidiariesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TransformationPlanMember" name="TransformationPlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MiddleEastAndAsiaMember" name="MiddleEastAndAsiaMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_RestructuringLiability" name="RestructuringLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_ProfessionalAndOtherMember" name="ProfessionalAndOtherMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_JointVentureTotalCapital" name="JointVentureTotalCapital" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_JointVentureContributionFromPreviousJointVenture" name="JointVentureContributionFromPreviousJointVenture" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_JointVentureContributionFromNoncontrollingInterest" name="JointVentureContributionFromNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_NoteToFinancialStatementDetailsTextual" name="NoteToFinancialStatementDetailsTextual" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalHoldingMember" name="FalconGlobalHoldingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLessNoncontrollingInterest" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLessNoncontrollingInterest" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_CapitalExpendituresAndPaymentsOnEquipment" name="CapitalExpendituresAndPaymentsOnEquipment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_VesselsMember" name="VesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_VesselUnderConstructionMember" name="VesselUnderConstructionMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_AnchorHandlingTowingSupplyMember" name="AnchorHandlingTowingSupplyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SpecialtyVesselMember" name="SpecialtyVesselMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_AnchorHandlingTowingSupplyVesselAndOtherEquipmentMember" name="AnchorHandlingTowingSupplyVesselAndOtherEquipmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LiftBoatsMember" name="LiftBoatsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PlatformSupplyVesselsMember" name="PlatformSupplyVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfEquipmentAcquired" name="NumberOfEquipmentAcquired" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfEquipmentAcquiredExcludedFromDeliveriesOfOffshoreSupportVessels" name="NumberOfEquipmentAcquiredExcludedFromDeliveriesOfOffshoreSupportVessels" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfEquipmentSoldUponCompletion" name="NumberOfEquipmentSoldUponCompletion" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_EmergencyResponseAndRescueVesselMember" name="EmergencyResponseAndRescueVesselMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_WindcatOffshoreLogisticsMember" name="WindcatOffshoreLogisticsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OffshoreVesselHoldingsMember" name="OffshoreVesselHoldingsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_EmergencyResponseAndRescueVesselFromDiscontinuedOperationsMember" name="EmergencyResponseAndRescueVesselFromDiscontinuedOperationsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfEquipmentSold" name="NumberOfEquipmentSold" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationMaximumAdditionalConsideration" name="DisposalGroupIncludingDiscontinuedOperationMaximumAdditionalConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ProceedsFromPropertyPlantAndEquipmentIncludingDepositsAndGainOnSale" name="ProceedsFromPropertyPlantAndEquipmentIncludingDepositsAndGainOnSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ProceedsFromDeposits" name="ProceedsFromDeposits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ProceedsFromSaleOfPropertyPlantAndEquipmentIncludingDeposits" name="ProceedsFromSaleOfPropertyPlantAndEquipmentIncludingDeposits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ProceedsFromSaleOfPropertyPlantAndEquipmentExcludingDepositsForFutureVesselSales" name="ProceedsFromSaleOfPropertyPlantAndEquipmentExcludingDepositsForFutureVesselSales" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_NumberOfEquipmentRemovedFromService" name="NumberOfEquipmentRemovedFromService" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfEquipmentRemovedFromServiceExcludesFromMajorEquipmentDispositions" name="NumberOfEquipmentRemovedFromServiceExcludesFromMajorEquipmentDispositions" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_OSVPartnersMember" name="OSVPartnersMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORMarlinLLCMember" name="SEACORMarlinLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DynamicOffshoreMember" name="DynamicOffshoreMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NauticalPowerMember" name="NauticalPowerMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherOffshoreMarineServicesJointVenturesMember" name="OtherOffshoreMarineServicesJointVenturesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_AllOtherExcludingMexMarFalconGlobalSeaCatCrewzerAndSeaCatCrewzerIIMember" name="AllOtherExcludingMexMarFalconGlobalSeaCatCrewzerAndSeaCatCrewzerIIMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_EquityMethodInvestmentSummarizedFinancialInformationOperatingAndAdministrative" name="EquityMethodInvestmentSummarizedFinancialInformationOperatingAndAdministrative" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_EquityMethodInvestmentSummarizedFinancialInformationDepreciation" name="EquityMethodInvestmentSummarizedFinancialInformationDepreciation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_EquityMethodInvestmentSummarizedFinancialInformationOperatingCostsAndExpenses" name="EquityMethodInvestmentSummarizedFinancialInformationOperatingCostsAndExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_EquityMethodInvestmentSummarizedFinancialInformationIncomeLossOnAssetDispositionsAndImpairmentsNet" name="EquityMethodInvestmentSummarizedFinancialInformationIncomeLossOnAssetDispositionsAndImpairmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_OffshoreSupportVesselsMember" name="OffshoreSupportVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACOROffshoreAsiaMember" name="SEACOROffshoreAsiaMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ChinaShippingFanTaiLimitedAndChinaShippingIndustryHongKongCoLimitedMember" name="ChinaShippingFanTaiLimitedAndChinaShippingIndustryHongKongCoLimitedMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MemorandumOfUnderstandingMember" name="MemorandumOfUnderstandingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MexmarOffshoreInternationalMember" name="MexmarOffshoreInternationalMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_JackUpDrillingsMember" name="JackUpDrillingsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FSVOffshoreSupportVesselsMember" name="FSVOffshoreSupportVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalInternationalTermLoanFacilityMember" name="FalconGlobalInternationalTermLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SeaCatCrewzerIIMember" name="SeaCatCrewzerIIMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SeacatCrewzerMember" name="SeacatCrewzerMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfEquipmentOperated" name="NumberOfEquipmentOperated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfVesselsDeliveredToCompany" name="NumberOfVesselsDeliveredToCompany" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_AgreementStandstillDate" name="AgreementStandstillDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_LoansReceivableInterestRateStatedPercentage" name="LoansReceivableInterestRateStatedPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_ShareholderLoansInRespectOfWorkingCapital" name="ShareholderLoansInRespectOfWorkingCapital" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_InterestIncomeRecognizedOnShareholderLoansInRespectOfWorkingCapital" name="InterestIncomeRecognizedOnShareholderLoansInRespectOfWorkingCapital" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_NumberOfVesselsAcquired" name="NumberOfVesselsAcquired" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_PartnersCapitalAccountAdvancedContributions" name="PartnersCapitalAccountAdvancedContributions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_InvestmentInAffiliatesAmountOfPreferredEquityOffereingParticipated" name="InvestmentInAffiliatesAmountOfPreferredEquityOffereingParticipated" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_CommitmentToInvestAdditionalFundsIfCallByGeneralPartner" name="CommitmentToInvestAdditionalFundsIfCallByGeneralPartner" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_EquityMethodInvestmentOwnershipPercentSold" name="EquityMethodInvestmentOwnershipPercentSold" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_FinancingAgreement" name="FinancingAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ReturnOfCapitalEquityMethodInvestment" name="ReturnOfCapitalEquityMethodInvestment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ConstructionReserveFundsCommitmentPeriod" name="ConstructionReserveFundsCommitmentPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfExtensionPeriod" name="NumberOfExtensionPeriod" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ConstructionReserveFundsExtensionPeriod" name="ConstructionReserveFundsExtensionPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ConstructionReserveFundWithdrawals" name="ConstructionReserveFundWithdrawals" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_ConstructionReserveFundDeposits" name="ConstructionReserveFundDeposits" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ConstructionReserveFundActivityNet" name="ConstructionReserveFundActivityNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_OtherEquipmentMember" name="OtherEquipmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfOperatingLeasesOnEquipment" name="NumberOfOperatingLeasesOnEquipment" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfOperatingLeasesImpaired" name="NumberOfOperatingLeasesImpaired" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ConvertibleSeniorNotesMember" name="ConvertibleSeniorNotesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORMarineForeignHoldingsLoanFacilityMember" name="SEACORMarineForeignHoldingsLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalUSATermLoanFacilityMember" name="FalconGlobalUSATermLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SeaCatCrewzerIIITermLoanFacilityMember" name="SeaCatCrewzerIIITermLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_WindcatWorkboatsFacilitiesMember" name="WindcatWorkboatsFacilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalUSARevolverMember" name="FalconGlobalUSARevolverMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACOR88888TermLoanMember" name="SEACOR88888TermLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORAlpsMember" name="SEACORAlpsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_BNDESEquipmentConstructionFinanceNotesMember" name="BNDESEquipmentConstructionFinanceNotesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DebtInstrumentMaturityPeriod" name="DebtInstrumentMaturityPeriod" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DebtInstrumentPercentageOfFinancingOnTotalPurchasePrice" name="DebtInstrumentPercentageOfFinancingOnTotalPurchasePrice" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_LoanFacilityWithDNBBankASAMember" name="LoanFacilityWithDNBBankASAMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherDNBCreditFacilitiesMember" name="OtherDNBCreditFacilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ConvertibleSeniorNotes375PercentMember" name="ConvertibleSeniorNotes375PercentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_CarlyleWarrantsMember" name="CarlyleWarrantsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ThreePointSevenFivePercentageConvertibleNotesMember" name="ThreePointSevenFivePercentageConvertibleNotesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ConvertibleSeniorNotesConvertedToWarrantsMember" name="ConvertibleSeniorNotesConvertedToWarrantsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_CarlyleGroupMember" name="CarlyleGroupMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalUSALLCMember" name="FalconGlobalUSALLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FGUSACreditFacilityMember" name="FGUSACreditFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TermLoanMember" name="TermLoanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_EuroDebtMember" name="EuroDebtMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PoundSterlingDebtMember" name="PoundSterlingDebtMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ConversionRevolvingCreditFacilityFromWindcatWorkboatsMember" name="ConversionRevolvingCreditFacilityFromWindcatWorkboatsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TermLoanToAcquireTwoVesselsMember" name="TermLoanToAcquireTwoVesselsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FalconGlobalMember" name="FalconGlobalMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TrancheAMember" name="TrancheAMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TrancheBMember" name="TrancheBMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LongtermDebtObligationMember" name="LongtermDebtObligationMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PaymentsForDebtorInPossessionObligations" name="PaymentsForDebtorInPossessionObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DebtAgreementMaximumBorrowingCapacity" name="DebtAgreementMaximumBorrowingCapacity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DebtInstrumentMaturityYear" name="DebtInstrumentMaturityYear" type="xbrli:gYearItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ClaimsRecoverableUnderBorrowingsPercentageOfObligationsOutstanding" name="ClaimsRecoverableUnderBorrowingsPercentageOfObligationsOutstanding" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_ClaimsRecoverableAmountUnderBorrowings" name="ClaimsRecoverableAmountUnderBorrowings" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_NumberOfForeignFlagLiftboatsToBeConstructedUnderTermLoan" name="NumberOfForeignFlagLiftboatsToBeConstructedUnderTermLoan" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_NumberOfTranches" name="NumberOfTranches" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DebtInstrumentRepaymentTerm" name="DebtInstrumentRepaymentTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DebtInstrumentFinalBaloonPayment" name="DebtInstrumentFinalBaloonPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_IncomeTaxesLineItems" name="IncomeTaxesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_IncomeTaxesTable" name="IncomeTaxesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_EliminationsMember" name="EliminationsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_IncreaseDecreaseInTransitionTaxLiability" name="IncreaseDecreaseInTransitionTaxLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_CurrentIncomeTaxExpenseBenefitNonqualifiedWithdrwalOfFundsFromCapitalConstructionFund" name="CurrentIncomeTaxExpenseBenefitNonqualifiedWithdrwalOfFundsFromCapitalConstructionFund" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_EffectiveIncomeTaxRateReconciliationReturnToProvision" name="EffectiveIncomeTaxRateReconciliationReturnToProvision" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_InterestExpenseSuspended" name="InterestExpenseSuspended" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_InterestExpenseSuspendedLimitationPercentage" name="InterestExpenseSuspendedLimitationPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_OperatingLossCarryforwardsPercentageOfTaxableIncomeUtilizationLimitation" name="OperatingLossCarryforwardsPercentageOfTaxableIncomeUtilizationLimitation" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_OperatingLossCarryforwardsExpirationPeriod" name="OperatingLossCarryforwardsExpirationPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_InterestExpenseCarryforward" name="InterestExpenseCarryforward" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_CurrentAssetsMember" name="CurrentAssetsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NonCurrentLiabilitiesMember" name="NonCurrentLiabilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_CurrentLiabilitiesMember" name="CurrentLiabilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_WindcatWorkboatsLtdMember" name="WindcatWorkboatsLtdMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_InterestRateSwapAgreementThreePointThreeTwoPercentMember" name="InterestRateSwapAgreementThreePointThreeTwoPercentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_InterestRateSwapAgreementThreePointOneNineFivePercentMember" name="InterestRateSwapAgreementThreePointOneNineFivePercentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACOR88888Member" name="SEACOR88888Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DerivativesNotionalAmount" name="DerivativesNotionalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_StatementStatementNote9DerivativeInstrumentsAndHedgingStrategiesEffectOfDerivativeInstrumentsOnOtherComprehensiveIncomeLossDetails" name="StatementStatementNote9DerivativeInstrumentsAndHedgingStrategiesEffectOfDerivativeInstrumentsOnOtherComprehensiveIncomeLossDetails" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_JointVentureInterestRateSwapMember" name="JointVentureInterestRateSwapMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_StatementStatementNote9DerivativeInstrumentsAndHedgingStrategiesGainsLossesOnDerivativeInstrumentsDetails" name="StatementStatementNote9DerivativeInstrumentsAndHedgingStrategiesGainsLossesOnDerivativeInstrumentsDetails" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ConstructionReserveFundsFairValueDisclosure" name="ConstructionReserveFundsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_ClassOfWarrantOrRightExercisedDuringPeriod" name="ClassOfWarrantOrRightExercisedDuringPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_StockIssuedDuringPeriodSharesWarrantsExercisedSharesWithHeldAsPaymentOfExercise" name="StockIssuedDuringPeriodSharesWarrantsExercisedSharesWithHeldAsPaymentOfExercise" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_WarrantsIssuedInPrivatePlacementMember" name="WarrantsIssuedInPrivatePlacementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PIPEWarrantsMember" name="PIPEWarrantsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ExchangeWarrantsMember" name="ExchangeWarrantsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SeabulkOverseasMember" name="SeabulkOverseasMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MontcoOffshoreLLCMember" name="MontcoOffshoreLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_NumberOfLiftboatVesselsOperated" name="NumberOfLiftboatVesselsOperated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_AdjustmentToStockholdersEquityDueToUnamortizedDebtDiscount" name="AdjustmentToStockholdersEquityDueToUnamortizedDebtDiscount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_CommonStockHeldInTreasuryInExchangeForPaymentOfWarrantsConverted" name="CommonStockHeldInTreasuryInExchangeForPaymentOfWarrantsConverted" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_WindcatWorkboatsMember" name="WindcatWorkboatsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherNoncontrollingInterestsMember" name="OtherNoncontrollingInterestsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PensionAndOtherPostretirementBenefitsDisclosureLineItems" name="PensionAndOtherPostretirementBenefitsDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PensionAndOtherPostretirementBenefitsDisclosureTable" name="PensionAndOtherPostretirementBenefitsDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_UnitedKingdomMerchantNavyOfficersPensionFundMember" name="UnitedKingdomMerchantNavyOfficersPensionFundMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ForeignPensionPlanMember" name="ForeignPensionPlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_MerchantNavyRatingsPensionFundMember" name="MerchantNavyRatingsPensionFundMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherDefinedContributionPlanMember" name="OtherDefinedContributionPlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PensionAndOtherPostretirementBenefitInvoice" name="PensionAndOtherPostretirementBenefitInvoice" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_PensionAndOtherPostretirementBenefitPlansTotalFundingDeficit" name="PensionAndOtherPostretirementBenefitPlansTotalFundingDeficit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_PercentageOfNumberOfCommonStockSharesOutstanding" name="PercentageOfNumberOfCommonStockSharesOutstanding" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_EquityIncentivePlan2017Member" name="EquityIncentivePlan2017Member" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_RestrictedStockSpinoffMember" name="RestrictedStockSpinoffMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PaymentsForDistributionOfRestrictedStockSpinOff" name="PaymentsForDistributionOfRestrictedStockSpinOff" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DistributionOfRestrictedStockInConnectionWithSpinoff" name="DistributionOfRestrictedStockInConnectionWithSpinoff" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DirectorStockAwardsMember" name="DirectorStockAwardsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SEACORHoldingsMember" name="SEACORHoldingsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TransitionServicesAgreementMember" name="TransitionServicesAgreementMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SecondLienDebtMember" name="SecondLienDebtMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FabrikantMember" name="FabrikantMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_GellertMember" name="GellertMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LlorcaMember" name="LlorcaMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FabrikantAndGellertMember" name="FabrikantAndGellertMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LenderNonRecourseMember" name="LenderNonRecourseMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_JMGGSTLLCMember" name="JMGGSTLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PercentageOfReimbursementOfSeveranceAndRestructuringCost" name="PercentageOfReimbursementOfSeveranceAndRestructuringCost" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_HealthInsuranceMember" name="HealthInsuranceMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ManagementServicesMember" name="ManagementServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ProceedsFromIssuanceOfAdditionalRedeemablePreferredStock" name="ProceedsFromIssuanceOfAdditionalRedeemablePreferredStock" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_OwnershipPercentage" name="OwnershipPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="smhi_PercentageOfConvertibleNotesConvertedIntoCommonStock" name="PercentageOfConvertibleNotesConvertedIntoCommonStock" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_DebtIndebtedness" name="DebtIndebtedness" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_CommitmentsAndContingenciesLineItems" name="CommitmentsAndContingenciesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_CommitmentsAndContingenciesTable" name="CommitmentsAndContingenciesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DeficiencyNoticeMember" name="DeficiencyNoticeMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LitigationDeposit" name="LitigationDeposit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_CostAllocationPercentage" name="CostAllocationPercentage" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_SeacorMarineArabiaLLCMember" name="SeacorMarineArabiaLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_ZamilOffshoreMember" name="ZamilOffshoreMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TenLargestCustomersMember" name="TenLargestCustomersMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_SaudiAramcoMember" name="SaudiAramcoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_GeneralAndAdministrativeExpenseIncludingShortTermLeaseExpense" name="GeneralAndAdministrativeExpenseIncludingShortTermLeaseExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_AssetsExcludingCorporateAssets" name="AssetsExcludingCorporateAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_TimeCharterMember" name="TimeCharterMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_BareboatCharterMember" name="BareboatCharterMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherMarineServicesMember" name="OtherMarineServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_PersonnelMember" name="PersonnelMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_RepairsAndMaintenanceMember" name="RepairsAndMaintenanceMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DrydockingMember" name="DrydockingMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_InsuranceAndLossReservesMember" name="InsuranceAndLossReservesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_FuelLubesAndSuppliesMember" name="FuelLubesAndSuppliesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherDirectCostsAndExpensesMember" name="OtherDirectCostsAndExpensesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_LeasedInEquipmentMember" name="LeasedInEquipmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationIncomeLossBeforeEquityMethodInvestmentsAfterTax" name="DisposalGroupIncludingDiscontinuedOperationIncomeLossBeforeEquityMethodInvestmentsAfterTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationIncomeLossFromEquityMethodInvestments" name="DisposalGroupIncludingDiscontinuedOperationIncomeLossFromEquityMethodInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationIncomeLossBeforeIncomeTaxesAndIncomeLossFromEquityMethodInvestments" name="DisposalGroupIncludingDiscontinuedOperationIncomeLossBeforeIncomeTaxesAndIncomeLossFromEquityMethodInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationIncomeTaxExpenseBenefit" name="DisposalGroupIncludingDiscontinuedOperationIncomeTaxExpenseBenefit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationOtherNonoperatingIncomeExpense" name="DisposalGroupIncludingDiscontinuedOperationOtherNonoperatingIncomeExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_BostonPutfordOffshoreSafetyLimitedMember" name="BostonPutfordOffshoreSafetyLimitedMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_OtherRevenueMember" name="OtherRevenueMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationLeaseExpense" name="DisposalGroupIncludingDiscontinuedOperationLeaseExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationGainLossOnAssetsDispositionAndImpairmentsNet" name="DisposalGroupIncludingDiscontinuedOperationGainLossOnAssetsDispositionAndImpairmentsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="smhi_DisposalGroupDiscontinuedOperationOperatingRevenueAbstract" name="DisposalGroupDiscontinuedOperationOperatingRevenueAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DisposalGroupDiscontinuedOperationCostsAndExpensesAbstract" name="DisposalGroupDiscontinuedOperationCostsAndExpensesAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_DisposalGroupIncludingDiscontinuedOperationOtherNonoperatingIncomeExpenseAbstract" name="DisposalGroupIncludingDiscontinuedOperationOtherNonoperatingIncomeExpenseAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_AgreementExtensionTermPeriod" name="AgreementExtensionTermPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="smhi_OmnibusAmendmentMember" name="OmnibusAmendmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TermAndRevolvingLoanFacilityMember" name="TermAndRevolvingLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="smhi_TermLoanFacilityMember" name="TermLoanFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
</xsd:schema>
