contribution ntnu dr. lisnyk student competition
DESCRIPTION
Module handling vessel - new ship design conceptTRANSCRIPT
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DEPARTMENTOFMARINETECHNOLOGY,NTNU
ModuleHandlingVessel
Dr.JamesA.LisnykStudentShipDesignCompetiton20112012
TEAMNORTH,NTNU SNAMEnumber
AndreasKrossholm 20006955
YngvildSlettevold 20006953
KristinaKyllingstad 20006954
KristianOdland 20006952
EirikSimonsen 20006980
Adviser:ProfessorEmeritusStianErichsen
SNAMEnumber1371410
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
Preface
Thisreportisacontributiontothe20112012Dr.JamesA.LisnykStudentShipDesignCompetition
by the Society of Naval Architechts andMarine Engineers (SNAME) and the American Society of
NavalEngineers(ASNE).
AllgroupmembersareregisteredasstudentsattheNorwegianUniversityofScienceandTechnology
(NTNU),andarecurrentlyintheirthirdyear.
Participating in this contest has been very rewarding for all group members. Knowledge from
previous semesters have been refreshed, and at the same time each of us have extended our
knowledgewithinourareaofspecialization.Themainrestrictingelementhasbeenthetimescale.
Wewould like to thank our advisor Stian Erichsen, Professor Emeritius at NTNU, for all help and
support.Hehasalwaysbeenavailableforquestions,andhasalwayshadanswerstothem.Wefeel
verymuchindebted.
We have also benefited greatly from the Department of Marine Technology at NTNU; Professor
Harald Valland, Professor Anders Endal, Professor Dag Myrhaug, Professor Carl Martin Larsen,
ProfessorMauriceWhite,Professor JrgenAmdahlandAssistantProfessorBjrnSillerud.Forhelp
with the Twin Tail concept, we would especially like to thank Professor Sverre Steen. The
competitionswinners from2010havealsobeenveryhelpful,andthisappliesespecially toDaniel
NordsandMagnusLande,helpingwithsoftware,knowledgeandmotivation.
Toallthementionedabove,aswellasothershelpingusthroughoutthedesigningprocess,weare
verygrateful.
Trondheim,15.06.2012
AndreasK.Krossholm(teamleader)#ID20006955EirikSimonsen#ID2006980KristianOdland#ID20006952KristinaB.Kyllingstad#ID2006954YngvildSlettevold#ID20006953
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
TableofContents1 ExecutiveSummary.........................................................................................................................1
2 BackgroundInformation.................................................................................................................2
1.1 Introduction.............................................................................................................................2
1.2 MissionDescription.................................................................................................................2
1.3 AreaofOperation....................................................................................................................2
1.4 Duration...................................................................................................................................2
1.5 PortRestrictions......................................................................................................................3
2 SystemBasedShipDesign...............................................................................................................4
3 ConceptDevelopment.....................................................................................................................5
3.1 WantedQualities.....................................................................................................................5
3.2 Hullform..................................................................................................................................5
3.2.1 HullAlternatives..............................................................................................................5
3.2.2 EvaluationoftheAlternatives.........................................................................................5
3.3 SelectionofHullform...............................................................................................................6
3.4 ModuleHandling.....................................................................................................................6
3.4.1 WantedQualities.............................................................................................................6
3.4.2 DevelopmentoftheModuleHandlingSystem...............................................................6
4.4.1 Liftfromseabed..............................................................................................................7
4.4.2 Liftthroughopeninginstern...........................................................................................8
4.4.3 Developmentofdampingsystem...................................................................................8
4.4.4 Transportationofthemoduletodeck..........................................................................10
4.4.5 Conclusion.....................................................................................................................10
4 Missionequipment........................................................................................................................11
4.1 Aframe..................................................................................................................................11
4.2 Heavecompensatedwinches................................................................................................11
4.3 Shockabsorber......................................................................................................................11
4.4 Remotelyoperatedvehicles(ROV).......................................................................................12
4.5 Cleaningsystems...................................................................................................................12
4.6 Workmoonpool....................................................................................................................12
4.7 Cranes....................................................................................................................................12
5 TimeCalculation............................................................................................................................13
6 InitialDefinitionandSizing............................................................................................................15
6.1 EstablishingpreliminaryMainDimensions...........................................................................15
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
6.1.1 ShipBeam......................................................................................................................15
6.1.2 DeckArea.......................................................................................................................15
6.1.3 ShipLength....................................................................................................................16
6.1.4 Draught..........................................................................................................................16
6.1.5 Displacement.................................................................................................................16
6.1.6 LengthoftheTwinTail..................................................................................................16
6.1.7 Breadthofopeninginstern...........................................................................................16
7 Hulldesign.....................................................................................................................................17
7.1 Software................................................................................................................................17
7.2 DesignProcess.......................................................................................................................17
7.3 PrincipalCharacteristics........................................................................................................18
8 ManningEstimates........................................................................................................................19
9 FunctionAnalysis...........................................................................................................................20
9.1 Shipfunctions........................................................................................................................20
9.1.1 ConstructionOutfitting.................................................................................................20
9.1.2 ShipOutfitting...............................................................................................................21
9.1.3 CrewFacilities................................................................................................................22
9.1.4 ShipFacilities.................................................................................................................23
9.1.5 Machinery,speedandpower........................................................................................25
9.1.6 Tanksandvoidspaces...................................................................................................25
9.1.7 Volumesummary..........................................................................................................27
10 WeightCalculations...................................................................................................................28
10.1 SteelWeightEstimate...........................................................................................................28
10.1.1 SteelWeightbasedontheMidshipSection.................................................................28
10.1.2 SteelWeightbasedonSystemBasedShipDesign........................................................29
10.1.3 SteelWeightSummary..................................................................................................29
10.2 LightshipWeight....................................................................................................................30
10.2.1 Departurecondition......................................................................................................31
10.2.2 ModuleHandlingCondition..........................................................................................32
10.2.3 ArrivalConditionwithmodule......................................................................................33
10.3 CentreofGravity...................................................................................................................34
10.3.1 CenterofGravityoftheLightship.................................................................................34
10.3.2 CenterofGravityduringmodulehandling....................................................................35
10.3.3 CenterofGravityoftheArrivalCondition.....................................................................35
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
11 ShipDrawings............................................................................................................................36
11.1 LineDrawings........................................................................................................................36
11.2 CurvesofForm......................................................................................................................36
11.3 SAC.........................................................................................................................................37
11.4 GeneralArrangements..........................................................................................................38
12 TrimandStability.......................................................................................................................39
12.1 Software................................................................................................................................39
12.2 Specialconsiderationsregardingtheliftingoperation.........................................................39
12.2.1 Cranelift........................................................................................................................39
12.2.2 Dynamicstability...........................................................................................................40
12.2.3 Changeoftrimcausedbyliftingoperation...................................................................40
12.2.4 Openmoonpools..........................................................................................................40
12.3 Trimandloadfactor..............................................................................................................41
12.3.1 Installation.....................................................................................................................41
12.3.2 Recovering.....................................................................................................................41
12.3.3 Operatingconditionandlightshipcondition.................................................................42
12.4 Stability..................................................................................................................................42
12.4.1 Principle.........................................................................................................................42
12.4.2 Freesurfaceeffect.........................................................................................................42
12.5 Hydrostaticcalculations........................................................................................................42
12.5.1 Installation.....................................................................................................................42
12.5.2 Recovering.....................................................................................................................43
12.5.3 Modulehandlingconditionandlightshipcondition.....................................................43
12.6 IntactStability........................................................................................................................43
12.6.1 Installation.....................................................................................................................43
12.6.2 Recovering.....................................................................................................................44
12.6.3 CraneOperation............................................................................................................45
12.7 ConsiderationsregardingGMT..............................................................................................45
12.7.1 Passiveantirolltanks..................................................................................................45
12.8 Floodablelength....................................................................................................................47
12.9 Watertightintegrity...............................................................................................................48
12.10 Damagestability................................................................................................................48
12.10.1 Permeability..............................................................................................................48
12.11 Damagecases....................................................................................................................49
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
12.11.1 5damagecases.........................................................................................................49
12.11.2 Case1OffcenterfloodingofTwinTail..................................................................50
12.11.3 Case2Fire/Explosionintheengineroom/LNGroom............................................50
12.11.4 Case3Collisioninaft..............................................................................................51
12.11.5 Case4Frontcollision..............................................................................................51
12.11.6 Case5Collisionfromside.......................................................................................51
12.11.7 Approval....................................................................................................................51
13 PredictionofCalmWaterResistance........................................................................................52
13.1 General..................................................................................................................................52
13.2 EmpiricalMethods................................................................................................................52
13.3 Software................................................................................................................................52
13.4 GeneralAssumptions............................................................................................................52
13.5 Holtrop84.............................................................................................................................52
13.6 Hollenbach98.......................................................................................................................53
13.7 Results...................................................................................................................................54
14 PropulsorsandThrusters..........................................................................................................56
14.1 Thrustsystemtradeoff.........................................................................................................56
14.1.1 Azimuththruster...........................................................................................................56
14.1.2 Conventionalsternpropeller........................................................................................56
14.1.3 Electricdirectdrive........................................................................................................56
14.1.4 VoithSchneider.............................................................................................................56
14.1.5 Scores............................................................................................................................56
14.2 Thrustsystemselection.........................................................................................................57
14.3 Azimuththrusterselection....................................................................................................57
14.3.1 Pullingthrustermechanicaltransmission.....................................................................57
14.3.2 Pushingthrustermechanicaltransmission...................................................................58
14.3.3 Poddedthruster............................................................................................................58
14.3.4 Contrarotatingthruster................................................................................................58
14.3.5 Selection........................................................................................................................58
15 PowerFlow................................................................................................................................59
15.1 Alternatingcurrent................................................................................................................59
15.2 Directcurrent........................................................................................................................59
15.3 Selection................................................................................................................................60
16 PropulsionSystemEfficiency.....................................................................................................61
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
16.1 Propulsionefficiency.............................................................................................................61
16.1.1 Propellerefficiency,0..................................................................................................61
16.1.2 Relativerotationalefficiency,R...................................................................................61
16.1.3 Hullefficiency,H...........................................................................................................61
16.1.4 Propellerclearance........................................................................................................62
16.2 Electricalefficiency................................................................................................................64
16.3 Installedpropulsionpower....................................................................................................64
17 DynamicPositioning..................................................................................................................66
17.1 Software................................................................................................................................66
17.2 Calculationmethod...............................................................................................................66
17.3 RequiredCapabilities.............................................................................................................67
17.4 Forbiddenzones....................................................................................................................67
17.5 Requiredpower.....................................................................................................................68
17.6 Thrusterconfiguration..........................................................................................................70
17.7 SystemRedundancy..............................................................................................................70
17.8 ReferenceSystems................................................................................................................71
18 ElectricalDistribution................................................................................................................72
19 PowerRequirements.................................................................................................................73
19.1 Propulsion..............................................................................................................................73
19.2 Auxiliarysystems...................................................................................................................73
19.2.1 Pumppowerrequirement.............................................................................................73
19.2.2 Watercoolingsystem....................................................................................................73
19.2.3 Aircompression.............................................................................................................73
19.2.4 Engineroomventilation................................................................................................74
19.2.5 Lubricatingoilsystem....................................................................................................74
19.2.6 Fuelsystem....................................................................................................................74
19.3 Hullmachinery.......................................................................................................................74
19.3.1 Ballastsystem................................................................................................................74
19.3.2 Bilgesystem...................................................................................................................74
19.4 Deckmachinery.....................................................................................................................75
19.4.1 HeavecompensatedAframeandwinches...................................................................75
19.4.2 Cranesandmooringequipment....................................................................................75
19.4.3 LaunchandrecoverysystemforROV...........................................................................75
19.4.4 Navigationanddecklighting.........................................................................................75
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
19.5 Hotelfunction........................................................................................................................75
19.6 Emergencyload.....................................................................................................................76
19.7 Totalpowerdemands............................................................................................................77
19.8 Operatingprofile...................................................................................................................78
20 PowerPlant...............................................................................................................................79
20.1 Enginetypes..........................................................................................................................79
20.1.1 Dieselengines................................................................................................................79
20.1.2 Gasturbine....................................................................................................................79
20.1.3 Dualfuelengines...........................................................................................................80
20.1.4 Selection........................................................................................................................80
20.2 MachinerySelection..............................................................................................................81
20.2.1 Alternative1..................................................................................................................81
20.2.2 Alternative2..................................................................................................................82
20.3 Fuel........................................................................................................................................82
20.3.1 DieselOil........................................................................................................................82
20.3.2 NaturalGas....................................................................................................................83
21 MachineryArrangement...........................................................................................................84
21.1 Gensetdimensions................................................................................................................84
21.2 Manufacturerrecommendations..........................................................................................84
21.3 Engineroomlayout...............................................................................................................84
21.4 MachineryArrangementDrawing.........................................................................................84
22 Endurance..................................................................................................................................85
22.1 Fuel&LNGcalculations.........................................................................................................85
22.2 Lubricationoil........................................................................................................................86
22.3 Freshwater.............................................................................................................................86
7.4 Sewageholding.....................................................................................................................86
23 Summaryoftankvolumes.........................................................................................................87
23.1.1 Fuel................................................................................................................................87
23.1.2 PotableWater...............................................................................................................87
23.1.3 Sewageandlubricationoil............................................................................................87
23.1.4 Ballast............................................................................................................................88
24 Seakeeping................................................................................................................................89
24.1 Software................................................................................................................................89
24.2 Theory....................................................................................................................................89
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
24.3 Calculationparameters.........................................................................................................90
24.3.1 Vesselspeed..................................................................................................................90
24.3.2 Heading..........................................................................................................................90
24.3.3 Rolldamping..................................................................................................................90
24.3.4 Waveloads....................................................................................................................91
24.4 LimitingCriteria.....................................................................................................................91
24.4.1 Naturalperiods..............................................................................................................91
24.4.2 ModuleHandlingLimits.................................................................................................91
24.4.3 ShipSafety.....................................................................................................................92
24.4.4 CrewEffects...................................................................................................................92
24.5 Results...................................................................................................................................93
24.5.1 MaximumOperatingLimits...........................................................................................93
24.5.2 Availability.....................................................................................................................95
25 Maneuvering.............................................................................................................................98
26 StructuralAnalysis.....................................................................................................................99
26.1 Software................................................................................................................................99
26.2 MaterialSelection.................................................................................................................99
26.3 LongitudinalStrength............................................................................................................99
26.4 StillWaterBendingMomentandShearForces....................................................................99
26.4.1 DesignBendingMoment.............................................................................................100
26.4.2 WaveBendingMoment...............................................................................................101
26.4.3 MidShipSection..........................................................................................................102
26.4.4 Results.........................................................................................................................103
26.5 StrengthanalysisoftheTwinTail........................................................................................103
26.5.1 Establishingamodel....................................................................................................103
26.5.2 Estimationofmomentandrequiredsectionmodulus...............................................104
26.5.3 Comments...................................................................................................................104
27 CostAnalysis............................................................................................................................106
27.1 Buildingcost........................................................................................................................106
27.2 Operatingcosts....................................................................................................................109
27.2.1 Voyagecosts................................................................................................................109
27.2.2 Shoresideexpenses....................................................................................................111
27.2.3 Dailyrunningcost........................................................................................................112
27.3 Totalannualoperationalcost..............................................................................................113
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
27.4 Requireddailyrate..............................................................................................................113
28 RiskAssessment......................................................................................................................115
28.1 Concernsonmodulemovement.........................................................................................115
28.2 Developmentandintegrationofthesidedampingsystem................................................115
28.3 Developmentandintegrationofthetransportationsystem..............................................116
28.4 Inaccuratestationkeepinganalysis....................................................................................116
28.5 Problemsintegratingdirectcurrent....................................................................................116
28.6 Integrationofdualfuelsystem...........................................................................................116
28.7 Uncertaintiesregardingthestrengthanalysis....................................................................116
28.8 SpecialconcernsregardingTwinTailstrengthanalysis......................................................117
28.9 Maneuveringconcerns........................................................................................................117
28.10 Uncertaintyregardingresistanceprediction...................................................................117
28.11 Conclusiononriskassessment........................................................................................117
29 References...............................................................................................................................118
29.1 Books...................................................................................................................................118
29.2 Papers..................................................................................................................................118
29.3 Rulesandregulations..........................................................................................................119
29.4 Conversations/Correspondences........................................................................................119
29.5 Software..............................................................................................................................120
29.6 Webaddresses....................................................................................................................121
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
ListofTables
Table1:PrincipalCharacteristics............................................................................................................1
Table2:Choiceofhullform.....................................................................................................................6
Table3:ROVlaunchandrecoverysystem............................................................................................12
Table4:Timeschedulerecoveryandreinstallation.............................................................................13
Table5:Transitschedule.......................................................................................................................14
Table6:Operationschedule.................................................................................................................14
Table7:Comparisonships/67/.............................................................................................................15
Table8:PrincipalCharacteristics..........................................................................................................18
Table9:Manningestimate,marinepersonnel.....................................................................................19
Table10:Totalmanningestimate.........................................................................................................19
Table11:Constructionoutfitting..........................................................................................................21
Table12:Shipoutfitting........................................................................................................................22
Table13:Crewfacilities.........................................................................................................................23
Table14:Shipfacilities..........................................................................................................................24
Table15:Machinerycapacity................................................................................................................25
Table16:Machineryspaces..................................................................................................................25
Table17:Tanksandvoidspaces...........................................................................................................26
Table18:Volumesummary...................................................................................................................27
Table19:Steelweightestimatebasedonmidshipsection...................................................................29
Table20:SteelweightestimatebasedonSystemBasedShipDesign..................................................29
Table21:Steelweightcomparison........................................................................................................29
Table22:Lightshipweight.....................................................................................................................30
Table23:Departurecondition..............................................................................................................31
Table24:Modulehandlingcondition...................................................................................................32
Table25:Arrivalcondition....................................................................................................................33
Table26:Centerofgravity,lightship....................................................................................................34
Table27:Centerofgravity,modulehandling.......................................................................................35
Table28:Centerofgravity,arrival........................................................................................................35
Table29:Trimduringinstallation.........................................................................................................41
Table30:Trimduringrecovering..........................................................................................................41
Table31:Trimduringmodulehandlingandlightshipcondition..........................................................42
Table32:Hydrostaticdataduringinstallation......................................................................................42
Table33:Hydrostaticdataduringrecovering.......................................................................................43
Table34:Hydrostaticdataformodulehandlingandlightshipcondition.............................................43
Table35:Stabilitycheckforinstallation...............................................................................................44
Table36:Stabilitycheckforrecovering................................................................................................44
Table37:Stabilitycheckformodulehandling......................................................................................45
Table38:Permabilities..........................................................................................................................49
Table39:Damagecases........................................................................................................................50
Table40:Damagecaseresults..............................................................................................................51
Table41:ValidrangesofHoltrop'84....................................................................................................53
Table42:ParametersMVH...................................................................................................................53
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
Table43:ValidrangesofHollenbach98..............................................................................................53
Table44:Thrustsystemtradeoffmatrix..............................................................................................57
Table45:Propelleriteration.................................................................................................................63
Table46:Efficiencyelectricalcomponents...........................................................................................64
Table47:Resultingpowerforeachforcegenerator............................................................................69
Table48:Resultingpowerforeachforcegenerator,sternazimuthportsideidle..............................69
Table49:TotalrequiredpowerDP.......................................................................................................70
Table50:Maximumrequiredpowerforeachforcegenerator............................................................70
Table51:Thrusterconfiguration...........................................................................................................70
Table52:Emergencyload.....................................................................................................................76
Table53:Dieselengines........................................................................................................................79
Table54:Gasturbines...........................................................................................................................80
Table55:Relevantdualfuelengines.....................................................................................................81
Table56:Firstalternativeengineconfiguration...................................................................................81
Table57:Secondalternativeengineconfiguration..............................................................................82
Table58:Gensetdimensions................................................................................................................84
Table59:Specificconsumptionofengines...........................................................................................85
Table60:Fuelconsumptionintransit...................................................................................................85
Table61:Fuelconsumptioninotherconditions...................................................................................85
Table62:Totalconsumptionoffuelduringoneoperation..................................................................85
Table63:Consumables.........................................................................................................................86
Table64:Fuelcapacity..........................................................................................................................87
Table65:Potablewatercapacity..........................................................................................................87
Table66:Sewageandluboilcapacity...................................................................................................87
Table67:Ballastcapacity......................................................................................................................88
Table68:Eigenperiods..........................................................................................................................91
Table69:Limits,heavecompensatorandwinch..................................................................................91
Table70:Limits,shipsafety..................................................................................................................92
Table71:Limits,creweffects................................................................................................................93
Table72:Designstillwaterbendingmomentamidships...................................................................101
Table73:Wavebendingmomentsamidships....................................................................................102
Table74:SectionModulus..................................................................................................................103
Table75:Materialsandlaborcosts....................................................................................................108
Table76:Buildingprice.......................................................................................................................108
Table77:Bunkercosts........................................................................................................................110
Table78:Portcosts.............................................................................................................................111
Table79:Modulehandlingcosts........................................................................................................111
Table80:Shoresideexpenses............................................................................................................111
Table81:Shipexpenses......................................................................................................................112
Table82:Consumables.......................................................................................................................112
Table83:Manningcosts......................................................................................................................113
Table84:Totalannualoperationalcost..............................................................................................113
Table85:Requreddayrate.................................................................................................................114
Table86:Expectedresultperyear......................................................................................................114
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
ListofFiguresFigure1:Mapshowingtheprimaryandsecondaryoperatingfieldsforthevessel/75/.......................3
Figure2:ThedesignspiralofSystemBasedShipDesign/1/..................................................................4
Figure3:Sketchofthenewstern............................................................................................................7
Figure4:Simplifiedillustrationofguidewiresanddampingsystem.....................................................8
Figure5:Hydraulicdampingsystem.......................................................................................................9
Figure6:Dampingandsupportsystem..................................................................................................9
Figure7:Transportsystem....................................................................................................................10
Figure8:Wirearrangement..................................................................................................................11
Figure9:ROVlaunchandrecoverysystem...........................................................................................12
Figure10:Shipfunctions.......................................................................................................................20
Figure11:Approximatesteelweightdistribution................................................................................28
Figure12:Weightdistributionlightship................................................................................................30
Figure13:Weightdistributiondeparture.............................................................................................31
Figure14:Weightdistributionmodulehandling..................................................................................32
Figure15:Weightdistributionarrival...................................................................................................33
Figure16:Curvesofform......................................................................................................................36
Figure17:Curvesofform......................................................................................................................36
Figure18:Curvesofform......................................................................................................................37
Figure19:SectionalAreaCurve............................................................................................................37
Figure20:Increasedcenterofgravity...................................................................................................39
Figure21:GZcurveforinstallation.......................................................................................................43
Figure22:GZcurvesduringrecovering................................................................................................44
Figure23:GZcurveformodulehandling..............................................................................................45
Figure24:Sketchoffreesurfacetank...................................................................................................46
Figure25:Utank...................................................................................................................................47
Figure26:Floodablelengthcurve.........................................................................................................47
Figure27:Watertightdoorsintheengineroom..................................................................................48
Figure28:Damagecases.......................................................................................................................49
Figure29:Offcenterflooding...............................................................................................................50
Figure30:Fire,explosion......................................................................................................................51
Figure31:Collisioninaft.......................................................................................................................51
Figure32:Resultsofresistanceestimate..............................................................................................54
Figure33:Enginefueltestatvariablespeed/23/................................................................................60
Figure34Propellerclearance................................................................................................................62
Figure35:Propelleriteration................................................................................................................63
Figure36:Breakpower.........................................................................................................................65
Figure37:TheJONSWAPspectrumfor=17.......................................................................................66
Figure38:Twooftheforbiddenthrusterzones...................................................................................67
Figure39:Forcegeneratorresultingforceplot,environmentaleffect250degrees...........................68
Figure40:Mainswitchboard.................................................................................................................72
Figure41:OperatingprofilenormalDPload........................................................................................78
Figure42:OperatingprofilemaxDPload.............................................................................................78
Figure43:FuelsystemMDO.................................................................................................................82
Figure44:FuelsystemLNG...................................................................................................................83
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
Figure45:Userinteractioninseakeepinganalysis...............................................................................89
Figure46:Operatinglimits,heading0degrees....................................................................................94
Figure47:Operatinglimits,heading20degrees..................................................................................95
Figure48:3Dscatterdiagram,TheNorwegianSea..............................................................................96
Figure49:Probabilityversuswaveheight............................................................................................96
Figure50:LoaddistributionofthearrivalconditionfromHydromaxProanalysis............................100
Figure51:Calculatedbendingmomentanddesignbendingmoment...............................................101
Figure52:WavebendingmomentsamidshipsaccordingtoDNVRule..............................................102
Figure53:SimplifiedloaddistributionfortheTwinTail.....................................................................104
Figure54:Lifecyclecost......................................................................................................................106
Figure55:Buildingcost.......................................................................................................................106
Figure56:Buildingcost.......................................................................................................................108
Figure57:Operatingcost....................................................................................................................109
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
ListofFormulasFormula1:Increasedcenterofgravity.................................................................................................39
Formula2:Trimchanges.......................................................................................................................40
Formula3:GZvalue..............................................................................................................................42
Formula4:Naturalperiodofarolltank................................................................................................46
Formula5:ITTC57frictionalcoefficientlineforturbulentflow/7/....................................................54
Formula6:Reynold'snumber...............................................................................................................54
Formula7:Totalpropulsionefficiency..................................................................................................61
Formula8:Propulsionefficiency...........................................................................................................61
Formula9:Hullefficiency......................................................................................................................61
Formula10:Relationshipbetweenvesselspeedandwaterspeedintopropellerarea......................62
Formula11:Empiricalformulaforwakecoefficient/7/.......................................................................62
Formula12:Relationshipbetweenthrustreductionandwakecoefficient/17/.................................62
Formula13:Thrustreductioncoefficient/7/........................................................................................62
Formula14:Propellerclearance...........................................................................................................62
Formula15:BPvalue/7/.......................................................................................................................63
Formula16:Totalpropulsionefficiency................................................................................................64
Formula17:Electricaldistributionefficiency........................................................................................64
Formula18:Towingpower...................................................................................................................64
Formula19:Breakpower......................................................................................................................64
Formula20:SpectraldensityfunctionfortheJONSWAPspectrum/54/.............................................66
Formula21:Pumppower......................................................................................................................73
Formula22:Volumeflow,fuel..............................................................................................................74
Formula23:Diameterbilgepipes.........................................................................................................74
Formula24:Pumpcapacitybilgepump................................................................................................75
Formula25:Vessel'sresponcespectrum..............................................................................................89
Formula26:Massmomentofinertia....................................................................................................90
Formula27:Radiiofgyration................................................................................................................90
Formula28:Naturalperiods.................................................................................................................91
Formula29:Slammingcriteria..............................................................................................................92
Formula30:Shearandbendingmoment...........................................................................................100
Formula31:Thetrapezoidalrule........................................................................................................100
Formula32:Sectionmodulus..............................................................................................................104
Formula33:Realinterestrate.............................................................................................................113
Formula34:Lifecyclecosts.................................................................................................................113
Formula35:Neededyearlyincome....................................................................................................113
Formula36:Resultmargin..................................................................................................................114
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Dr.JamesA.LisnykStudentShipDesignCompetition20112012
Nomenclature
Ae Expandedbladearea
AWL Waterplanearea
AP Aftperpendicular
B Breadth
BM Buoyancytometacentre
CB Blockcoefficient
Cf Frictionalresistancecoefficient
CL CentreLine
Cm Midshipcoefficient
CO2 Carbondioxide
Cp Prismaticcoefficient
CT Totalresistancecoefficient
CWL Waterlinecoefficient
d Diameter
DNV DetNorskeVeritas
DWT Deadweighttonnage
EAR Expandedarearatio
f Frictioncoefficient
Fn FroudesnumberFLC Floodablelengthcurve
FP Foreperpendicular
g Gravity
GM Metacentreheight
GMT Transversemetacentreheight
GV Grossvolume
Hs Significantwaveheight
I Momentofinertia
IMO InternationalMaritimeOrganization
k Formfactor
KB,VCB Verticalcentreofbuoyancy
KG,VCG Verticalcentreofgravity
KM Transversemetacentricheight
LOA Lengthoverall
LPP Lengthbetweenperpendiculars
LWL Lengthinwaterline
LCB Longitudinalcentreofbuoyancy
LCC Lifecyclecost
LCF Longitudinalcentreoffloatation
LCG Longitudinalcentreofgravity
LNG Liquefiednaturalgas
M Moment
MCR Maximumcontinuousrating
MDO Marinedieseloil
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P(capital) Effect
Q Shearforce
r Radius
RAO Responseamplitudeoperators
ROV RemotelyOperatedVehicle
PRM Roundsperminute
RT Totalresistance
S Wettedsurface
SAC Sectionareacurve
SBSD Systembasedshipdesign
SOLAS InternationalconventionofSafetyoflifeatsea
t Thrustreduction/thickness
T Draught
v Velocity
w Wake
WAC Waterplaneareacurve
Wsteel Steelweight
1 Surge
3 Heave
5 Pitch
0 Openwaterefficiency
D Totalpropulsiveefficiency
H HullefficiencyR Relativerotativeefficiency Density
Displacement
Efficiency
Filmcoefficient
Frequency
Stress
Wavemotion
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1
1 ExecutiveSummaryTheOwners Requirements address a need for a vessel capable of executing lifting operations on subsea
moduleswithdimensionsof25meterslength,15metersbreadthand12metersheight.Approximatelythe
modulesweight500tons.
Themoduledimensionsaretoolargeforaconstructionvesselinservicetoday,andthedesignteamhadto
thinkofalternativemodulehandlingconceptstosolvethetask.
Thesolutionisamodulehandlingsystemthatcombinesadvantagesfromdifferentsolutionsexistingtoday.
The solution comprehends a ship hull splitting astern, converting the mono hull into a semicatamaran
named Twin Tail. The Twin Tail will be equippedwith amodule damping system in order to launch and
recoverthemoduleinasafemanner.AnAframecapableofliftingsuchmodulesisplacedondeckinfrontof
theTwinTail.
ThisreportstatesthattheTwinTailconcepthasthecapabilitytocomplywiththeOwnersRequirements.
Some issueshave tobe lookedclosely into in thenextdesign iteration.Ofmost importance themodules
abilitytocausedamagetovessel,equipmentorpersonnelduetouncontrolledmovementwhileexecutinga
lift.
SystemBasedShipdesignhasbeenusedtoestimatenecessaryareasandvolumes.Thegeometricdefinitions
ofthevesselaregiveninthetablebelow.
PrincipalCharacteristics
Lengthoverall,Loa 140 [m]Lengthbetweenperpendiculars 130 [m]Lengthonwaterline 133,9 [m]Breadth 30 [m}Draft 6,5 [m]Blockcoefficient 0,64 [] Weightdisplacement 16200 [tons]Volumedisplacement 15800 [m3]Payload(equipment) 1150 [tons]Berths 150 [persons] Machinery 6xDualFuelTotalinstalledpower 21612 [kW]Trialspeed 15 [knots]Servicespeed 12 [knots] Buildingcosts 190954106 [USD]Necessaryrateperday 152090 [USD]Table1:PrincipalCharacteristics
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2 BackgroundInformation
1.1 Introduction
Thesgardfield,discoveredin1982,ranksamongthe largestoilandgasdevelopmentsontheNorwegian
continentalshelf.Thefield,atapproximatelatitudeof65degreesandlongitudeof6degrees,isembracinga
total of 52 wells spread over an area of 20 by 60 kilometers. In order to retrieve more gas from the
reservoirs,theoperator,Statoil,nowaimstoinstallgascompressorsontheseabed.Thisistoberealizedin
2014,astheworldsfirstprojectofitskind,andisastepinthedevelopmentofcompletesubseafactoriesin
theNorthSea.SimilargascompressionprojectsareplannedfortheGullfaksandOrmenLangefield./73/
The gas compression system is installed on a large template at the seabed. The structure consists of
compressors, pumps, scrubbers and coolers that, put together as larger subsea modules, will require
installation,recoveryandmaintenanceoperations./40/.
Today, subsea modules are launched and recovered through moon pools with typical dimensions of
approximately7by7meters.Ifthemoonpoolofthevesselistoosmall,themodulemustbeliftedoverthe
vesselsshipsideorinsteadhandledbyaheavyliftvesselorcranevessel.Thehandlingoflargemodulesover
theshipsideisacriticalsituationwithregardtoboththecapsizingofthevesselandthehazardofdeckhands
beinghitbyhangingobjects.Furthermore,thehirerateofheavyliftvesselsishigh.Itisthuslikelythatthere
willbeaneedforvesselsthatcanhandlethenew,largemodulesbothforinstallationontheseabed,andfor
transportationtomaintenanceandrepairsites.
1.2 MissionDescription
Thevesselistoexecutetransportation,launchandrecoveryofsubseamodules,aswellasotherconstruction
and intervention related tasks. The operations are requiring a lifting capacity of 500 tons at sgard and
handlingofsubseamodulesofapproximately25meterslength,15meterswidthand12metersheight,tobe
adjustedtodevelopingdemand/39/.
1.3 AreaofOperation
Inadditiontooperationonthesgardfield,gascompressionsystemsattheGullfaksandOrmenLangefields
aretakenintoconsiderationassecondaryareasofoperation.
Theseadepthsatthesefieldsvarybetween130and1100meters.Atthesgardfield,theseadepthisfrom
240metersto310meters.
The surface temperature in the North and Norwegian Sea is typically 56 degrees in winter and 1215
degreesinsummer/74/.Thereisthusnoneedforicestrengthening.
ArelevantbaseforoffshoreoperationsisVestbasenearKristiansundatthewestcoastofNorway.Vestbase
holds a heavy lift crane as well as necessary equipment for maintenance of the modules. The distance
betweenVestbaseandthesgardfieldisapproximately150nauticalmiles.
1.4 Duration
A typical mission for the vessel will include mobilization, transit and recovery and reinstallation of two
respectivesubseamodules.Assuminganaveragespeedof12knots,thetotaldurationofsuchamissionwill
beminimum25daysdependingontheweather.
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1.5 PortRestrictions
ThedepthintheportofVestbaseis10meters,whichistheonlyportrestrictiontobeaccountedfor.
Figure1:Mapshowingtheprimaryandsecondaryoperatingfieldsforthevessel/75/.
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2 SystemBasedShipDesignThechosendesignmethodisSystemBasedShipDesign/1/.Byusingcoefficientsofcomparisonshipsand
factorssuchasthevesselsroute,restrictionsandrequiredcapacities,thenecessaryareasandvolumeson
boardthevesselareestimatedatanearlystageintheproject.
InSBSD,thedesignprocessisdividedintofivemainphases:Mission,Function,Form,Performance
andEconomics.Thedesignworkstartswithdefiningthemissionofthevessel,andbasedonthisafunction
descriptioncanbemade.Hereallthesystemsneededfortheshiptoperformitstasksarespecified,andare
used to estimate themain characteristics of the ship. Then Form, Performance and Economics are
adjustedtoeachotherasindicatedbythedesignspiral.
SBSDofferscoefficientvaluesfordifferenttypesofvessels,butifvaluesofthecoefficientscanbetakenfrom
a similar ship, this is an advantage. The chosen concept makes it a challenge to find correct values of
coefficients for SBSD, as no fully appropriate comparison ship is to be found. However, coefficients from
SBSD have been used initially. The results have been checked against offshore vessels performing similar
tasksas thevessel tobedesignedandprofessorsat theNorwegianUniversityofScienceandTechnology,
andhavebeenreevaluatedaccordingly.Othermethodshavealsobeenappliedwhennecessary.
Duetotheiterationprocess,somedetailsthroughoutthechaptersarebasedoncalculationsanddecisions
madelaterinthereport.
Figure2:ThedesignspiralofSystemBasedShipDesign/1/
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3 ConceptDevelopment
Differentconceptsforhullformandmodulehandlingwillbediscussedinthefollowingsection.
3.1 WantedQualities
Remark:TheinformationbelowisbasedonconversationsandmailcorrespondencewithemployeesinStatoil,
AkerSolutionsandSubsea7intheearlybeginningofthisproject.Thesecompaniesareallinvolvedintheoil
andgasindustryinNorway/38//39/.
Whendevelopingtheconceptformodulehandlingresearchwasdonebyinterviewingemployeesinoffshore
companiesanddiscussingthealternativeswithbothofficersanddeckhandsworkingonvesselsoffshore.The
statementsinthissectionarebasedontheirexperience./51/
Theownerstatestheneedforavesselwith500tonsliftingcapacityat310metersdeep.
Thedeckareamustbesufficientforstoringthesubseamodulesandauxiliaryequipmentduringtransit,as
wellasbeasafeworkingareaforthedeckhands.Alargeopendeckwillgivethevesselflexibilitytoperform
aspecterofworktasksoffshorewhichisemphasizedasanadvantage.
The vessels offshore operationwill be planned ahead of time, and a high transit speed is therefore not
requiredfromtheowner.
CapacitytoperformthedesignatedworkduringmostweatherconditionsintheNorwegianSeaisnecessary
to be a reliable instrument for the owner. Even though the operations will be planned ahead, a vessel
capable of working in a sea state of significant wave height up to 5 meter has been suggested as an
advantage. If this is achieved the vessel will have a higher availability than todays fleet of offshore
constructionvessels.
Minimalenvironmentalimpactandeconomicalaspectsarealsomatterstobeconsidered.
3.2 Hullform
3.2.1 HullAlternatives
Thefollowinghullalternativesareconsidered:
Barge
Semisubmersibleplatform(semisub)
SmallWaterplaneAreaTwinHull(SWATH)
Conventionalmonohull
3.2.2 EvaluationoftheAlternatives
Noneof thehull alternatives aboveare ruledoutby the required lifting capacityof500 tons, andall the
alternatives can easily have a large open deck. The desire for an environment friendly vessel does not
eliminate any of the alternatives since all vessels can be designed to leave a minimal environmental
footprint.Thissaid,conventionalhullsofferthemostenergyefficientwayoftransportingtoday.
Theavailabilityofthevesselisstrictlyconnectedtotheseakeepingcapacity.Theratiobetweendisplacement
and water plane area for the semisub and the SWATH cause small movements in almost all weather
conditions. The same ratio implies largemovements for the barge alternative. The conventional hull lies
somewhereinbetweenbutcanexperiencelargerollmovementswhenwavesishittingthevesselsideways.
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Capabilityofexecutingliftingoperationsinsignificantwaveheightupto5meterscanbeachallengeforthe
bargeandtheconventionalhull.
ThetransitspeedofthealternativesfavorstheSWATHandtheconventionalhull.Thebargeandsemisub
aredependentontugsduringtransitandhavemuchlowertransitspeed.
Thebuildingcostsarefavoringthebargewhichisanextremelycheaphullform.TheSWATHandthesemi
subarethemostexpensivealternativesduetotheircomplexstructures.
Duringtheoperation,theabilitytooperateindividuallyinfluencesthecostssignificantly.Theneedfortugs
formaneuveringandpropulsionisalargedisadvantagewithabarge.
3.3 SelectionofHullform
Inselectingtheoptimalhullformadecisionmatrixisused.Thesumofthescoresforonecriterionisone.The
differentscoresaremultipliedwiththeweightofeachcriterion.
Criteria Weight
(W)
Scores(S)
Barge Semisub SWATH Conventional
hull
Sum
Seakeeping 0,40 0,10 0,40 0,30 0,20 1Operationalcosts 0,30 0,10 0,20 0,30 0,40 1Buildingcosts 0,15 0,50 0,10 0,10 0,30 1Transitspeed 0,15 0,10 0,10 0,40 0,40 1
Sum(W*S) 0,16 0,25 0,285 0,305 1Table2:Choiceofhullform
Withabesttotalscoretheconventionalhull ischosen.Thenexttingtodetermine iswhatkindofmodule
handlingsystemwhichistobeused.
3.4 ModuleHandling
Inthischapter,methodformodulehandlingwillbedecided.
3.4.1 WantedQualities
Themodule handling system should not expose themodule, vessel or deckhands for any risk during the
liftingoperation.Itshouldbepossibletodimensioningthesystemsoitiscapableofhandlingmodulesduring
mostweather conditions in the area of operation.Themodules lengthmay be shorter, but thewidth is
fixed.
3.4.2 DevelopmentoftheModuleHandlingSystem
Duringthedevelopmentoftheconceptformodulehandling,thefollowingsystemswereevaluated:
Oversidewithaknuckleboomcrane OverthesternwithanAframecrane Throughmoonpoolbycraneorliftingtower
Liftingunitsovertheshipssidebyacraneisthemosttraditionalwayofperformingliftingoperations.This
methoddoesnotimmediatelysetasizelimitforthemodules,buttheweighthastobeconsideredcarefully
withregardtostabilityduringliftingoperation.
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Byliftingthemoduleoverthesternofthevessel,theliftingisdonethroughthecenterlineofthevesseland
doesnotexposethevessel foradirectmomentof tilt.The largermovementat thestern, leadstohigher
capacityrequirementsfortheheavecompensatorandwinchthanliftingnearthecenterofflotation.
Byliftingthemodulethroughamoonpoolplacedneartheshipsflotationcenter,themovementswherethe
lifting isdoneareminimized.Thepossibilityofwaveresonance in themoonpool,canalso limit thewave
periodsforwhichthevesselcanperformliftingoperations.
During evaluation of these alternatives, a new idea of module handling was suggested. By combining
advantagesandprinciplesfromalreadyexistingmethods,aconceptualsterndeveloped.
Splittingthestern,makinganopeningwideandlongenoughtoliftthemodulesthroughusinganAframe,
canbeawayofcombiningseveraladvantagesfromtheotheralternatives:
LiftingthemodulewillthenbedoneinthecenterlineoftheshipasforanAframeliftingoverthe
stern.
Movingtheliftingoperationsomedistancetowardstheflotationcenterreducesthemotionsinthe
positionofthelift.
Installing a support system inside the open stern to guide the module through the splash zone
increasesthemaximumwaveheightacceptableforoperation.
Theriskofwaveresonanceinsidetheliftingareawillbeeliminatedaswaveenergyisletoutofthe
opening.
Thisconcepthasanumerousofissuestobeconsideredbeforetheactualfeasibilitycanbedetermined.The
sternmustbetakenthroughadesignprocesstocalculatetheactualeffectandpossibleadvantages.Firstof
all,aconceptualmodulehandlingsystemmustbedeveloped.
Figure3:Sketchofthenewstern
Inorder todevelopa system formodulehandling, the stepsof theoperationmustbe furtherevaluated.
Threephasesaretobeconsidered;liftfromseabed,liftthroughopeninginsternandtransportationtodeck.
4.4.1 Liftfromseabed
Dueofthesizeofthemodule,currentandwavemotionwillhaveanimpactonthemodulesmovements.
Guide wires can thus be used tomake themodule follow a given path up to the vessel. The wires are
attachedtothemodulebyremotelyoperatedvehicles. Inorder toguideamoduleof500tons,theguide
wireswillhavetoyieldabout510tonstension/41/.
Toensureaconsistenthoistingspeedofthemoduleandavoidjerksinthewire,thesystemshouldbeheave
compensated.
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4.4.2 Liftthroughopeninginstern
Thewaveforce increasesexponentiallyasthemoduleelevatetowardsthesurface,andthemovementsof
themodulecanbecriticalinthesplashzoneofthesternopening.Toavoidcollisionsbetweenthemodule
andthehull,asystemforguidingthemodulesafelythroughthesternopeningisnecessary.
Inamoonpoolliftingofmodulesareoftendonebylockedcursorframes.AfterconsultingwithProfessorB.
Pettersen /37/,applyingsuchasolution in thesternwasconsidereddifficultduetothe largeweightand
dimensions of themodule. A gripping systemwith fenders lowered below the hullwas considered as an
alternative method, the advantage being the early guiding of the module. However, protrusions have
weaknessesregardingfoundationandthemethodwasthuseliminated.
A damping system starting at the base of the hull consisting of vertical rows of retractable wheels is
consideredpossible.Thewheelscanbemountedontheinsideofthesternopening,anddampthemodules
movements through the splash zone. Such a damping system is developed further.
Figure4:Simplifiedillustrationofguidewiresanddampingsystem.
4.4.3 Developmentofdampingsystem
Thewheelscanbeplacedonrodsconnectedtoshaftsgoingthroughacasinginawatertightbulkhead.Each
rodwillbeconnectedtoahydrauliccylinder,makingitpossibletoretractthewheelsduringtransit.Thisisin
ordertominimizetheeffectonresistanceaswellasreducingthewearofthewheels.This is illustrated in
Figure5.
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Figure5:Hydraulicdampingsystem
In order to exert a damping force on themodule, thewheelswill need support from pneumatic springs.
Thesereacttomovementsandchangeinload.
Asmorewheelsleadtoamorecomplexhydraulicsystem,thecostalsoincreaseswiththeamountofwheels.
Thusonewouldlikeaminimumnumberofwheels,whilstmaintainingsafesupport.Itisassumedthatitwill
besufficientwiththreeverticalrowsofwheelsoneachsideoftheinsideofthestern.Each,withwheelsof
diameter1.5metersandbreadthof0.8meters.The totalnumberofwheelswilldependon the finalhull
form.
Assumingoperationsinsignificantwaveheightsuptofivemeters,themoduleshouldbedampedfromabout
threemetersbeneaththewater line/44/,requiringahulldraftofat leastthreemetersatthefirststepof
support.
Asthedraftofthesternwillbereducedtowardstheaft(seechapter7,HullDesign),themodulewillfirstbe
dampedat twopoints, then,as itapproaches the surface, itwillbedampedby fourpointsand finallysix
pointsas itreachesthesplashzoneas illustratedinFigure6.Thedampingsystemisextendedfivemeters
overthemaindeckinordertopreventsidewaysmotionofthemodulewhenoutofwater.
Figure6:Dampingandsupportsystem
Inthefollowingitisassumedthatsuchasidedampingsystemisfeasible.
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4.4.4 Transportationofthemoduletodeck
Whenoutofwater, themodulemustbe transported safely todeck. Limiting the liftingoperation toonly
vertical movement is considered an advantage especially with regard to the safety of the manning and
stabilityoftheship.Liftingthemoduleinapendulummotionshouldthusbeavoided.Forthetransportation
ofthemodule,amovingAframewasconsidered.TheAframelegswouldthenbemountedonbracketsable
tomove in the longitudinal direction. However, feasibilitywas considered unsatisfactory due to concerns
regardingthelargeforcesoccurringatthefoundationoftheAframe.
Asolutionwithaplatformrunningonarailsystemwasthensuggested.Asthemoduleiselevated,theguide
wirescanbedismountedandtheplatformcanbemovedovertheopeninginthestern.Themodulecanthen
be loweredonto theplatformand transported to themaindeck.Due to thevertically extendeddamping
systemdescribed,theplatformmustpassthroughaninroadsystem.
Investigationsshowthata similar system isusedonheavyconstructionvesselFarSamson tomoveheavy
ploughs.Itisassumedthatthesystemisscalablefortheweightofthemodule.
Figure7:Transportsystem
4.4.5 Conclusion
Afterconsultingwith/28/,thesolutiondescribedabovewasconsideredfeasibleandwillbeusedfurtherin
thedesigning.Thesternandaccompanyingmodulehandlingsystemwillfromthispointonbereferredtoas
theTwinTail.
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4 Missionequipment
4.1 Aframe
TheAframemustbedimensionedforthesgardfield,withamaximumseadepthof310meters.The
weightofthewireisestimatedtobe100tons,assumingthethicknessofthewiretobe140[mm]/44/.
RequiredAframecapacityisthusminimum600tons.
Torestrictrotation,themoduleishingedinfourpointsintherespectivetopcornersofthemodule.Two
wiresareconnectedtotheAframebypulleys,leadingthewirealongthelegsoftheAframe,anddown
belowdeck.
Theworkingangleofthewiresshouldnotbelessthan30degreeswithrespecttostrain/10/.Theheightof
thefixingpointwillthusbesixmetersabovethemodule.Assumingonemeterofwirefromthefixingpoint
uptothepulleys,asevenmeterclearancebetweenthemoduleandpulleyisnecessary.
Itisassumedthatthemodulemustbeliftedonemeterabovemaindecklevelinordertobeplacedonthe
transportationplatform.Atthemidpointofthemodule,theverticaldistancebetweenthepulleysandthe
platformmustthusbe20meters.TheAframecanbeplaced2metersforwardoftheTwinTail.Duetothe
extendeddampingsystem,themaximumangleitcanheelis50degrees.TheheightoftheAframemust
thenbe26.2meters.
4.2 Heavecompensatedwinches
Tominimizethemodulesmovementsduetowaves,dynamicloadsandthevesselsmovements,eachwire
willbeconnectedtooneheavecompensatedsubsealiftingwinch.Heavecompensatedwinchescan
compensatevesselmovementupto+/threemetersfromstaticpositionwhen600tonsislifted/44/.
4.3 Shockabsorber
Heavecompensationdoesnotworkeffectivelyinthesplashzone/50/andtoavoidjerkonthewires,ashock
absorberistobeinstalledatthetipofthewire.Theshockabsorberconsistsofseveralaccumulatorsin
parallelfastenedtothewire.Ithasbeenusedwithweightsupto900tons/50/andmustbedesigned
speciallyaccordingtovesselandmodulemovementcharacteristics.
Figure8:Wirearrangement
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4.4 Remotelyoperatedvehicles(ROV)
Remotelyoperatedvehiclesareneededtodisconnect
subseamodulesfrompipingsystems,connectguide
wirestosubseamodulesandforvisualcontrolofthe
operation.Providedtimeforequipping,theROVscanbe
usedforalltypesofinterventiontasksandinspections.
TheworkROVQuantumandtheobservationROVSeaeye
TigerfromITech7werechosen.
Table3:ROVlaunchandrecoverysystem
TheROVswillbelaunchedthroughtwofivemeterbyfive
metermoonpools.AfterdiscussionswithaROVpilot
/49/,themoonpoolbasedsystemfromSeproTechnologywaschosen.Thisisanactiveheavecompensated
cursorbasedsystem,withthecursorframeasapassivedevicetocontrolthelatchbeamandrestrict
movementoftheROV.Atadepthabout30meterstheROVisunlockedfromthelatchbeam.Thetotal
launchingtimetoadepthof310metersisestimatedto30minutes/49/.
ThelaunchandrecoverysystemsfortheworkROVandobservationROVaresimilar.Eachsystemisdrivenby
ahydraulicpowerunitplacedbeneathdeck,andthesystemsareconnectedtoensureredundancy.
4.5 Cleaningsystems
Therecoveredsubseamodulemaycontainhydrocarbonresidues,whichneedtoberemovedsafely.The
removaldemandthreeunitsofspecialequipment;MEGfillinganddraination,hydrocarbonventilation
systemandnitrogensystemwithnecessaryhosesandpumps/38/.Thisisusuallyportableequipment,
mobilizedforthespecificoperation/42/.Theunitswillbeplacedondeckduringlargemoduleoperations.
Duringothertypesofoperations,thedeckspacewillbefreeforotherequipment.
4.6 Workmoonpool
Thevesselwillhaveamaineightmeterbyeightmetermoonpooldimensionedfornormalsizedsubsea
modules.
4.7 Cranes
Thevesselwillbeequippedwithoneoffshorecranewithcapacityof150tonsandoneshipboardcranewith
capacityfor5tons.Theoffshorecraneisintendedforconstructionrelatedtasksandlaunchingandrecovery
ofstandardmodulesthroughthemoonpool.Theshipboardcraneisintendedforcargohandlingonboard
andoutsidethevesselwhileinharbororinshelteredwaters,andonboardthevesselwhileatsea.
Type Quantum,workROV
Length[m] 3,58Breadth[m] 2Height[m] 2Weight[Te] 5,35Depth[m] 3000
Figure9:ROVlaunchandrecoverysystem
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5 TimeCalculationThevesselistobedesignedformoduleinstallation,recoveryandreinstallation.Atthesgardfieldtherewill
beaneedoftwotothreesuchrecoveryandreinstallationoperationsperyearasapartofamaintenance
program/39/,andareassumedtobeplannedaheadof time.Thesameneed isassumedfor the fieldsof
OrmenLangeandGullfaks.
Each operation starts withmobilization, wheremission specific equipment and resources will be loaded.
Majormissionsuchaslifingequipmentistobepermanentinstalledontheship,whereasotherequipment
andsupplieswillbeloadedforthespecificoperation.Thisistoensureflexibilityofthevesselandsufficient
deck space. As the complexity of the operation may require extra crew, this phase will also include
mobilizationofhumanresources.
Theshipisdimensionedforthesgardfield,whichis150nauticalmilesfromtheportVestbase.Thespeedis
assumedtobe12knotsbasedoncomparisonships,whichgives13hourspercrossing.
Therecoveryoperationatthesgardfieldwilllastapproximatelytendays/39/,andthefirststepwillbeto
disconnectthemodulefromthepipelinesystem.Afterwardsthemodulewillbeconnectedtoguidewires,
liftedonboard,andcleaningprocedureswillbedonetoensuresafe