5Current at-sea container transfer… Note: Size of the craneship Size of cranesSeastate (benign)
6(Open Ocean N Atlantic) Significant Wave Height SEA BASING CHALLENGESMATERIELAt-sea transfer of TEUs through seastate 4Quantities / rates / types / packaging / selectivityInterface with commercial / allied shippingWeight : ~15 tonsSize : 20’ x 8.5’ x 8’Seastate(Open Ocean N Atlantic)Significant Wave HeightSustained Wind SpeedModal Wave Period2mktssecs4mktssecscurrent limitgoalTEU : Twenty-foot Tonnage Equivalent Unit (i.e. Shipping Containers)
7(just for the shore based MEB) MARINE EXPEDITIONARY BRIGADE (MEB)- DAILY DEMANDSMEB ~13,000 troops6,800 troops ashore / 6,200 afloatMaterielST/dayWATER190CARGO FUEL225DRY STORES- Food15- Ammunition33- Other127Sub-total (liquids)415 ST/daySub-total (dry stores)75 ST/dayTOTAL490 ST/day1Materiel demandsfor troops ashore~ 30 to 70 TEU / day(just for the shore based MEB)1. May increase to 1,000 ST/day depending on OP-TEMPO
8Significant offshore use / experience Superior seakeeping SPAR TECHNOLOGYSignificant offshore use / experienceSuperior seakeepingLittle or no Military experienceLack of awareness / particularly performanceCan solve at-sea container transfer for militarySpeed x 3FLIPSHIP ‘flipping’
9Developed at NSWCCD / CISD Feb-May 2003 DWSC Concept OverviewSpar modeDeveloped at NSWCCD / CISD Feb-May 2003Container transfer capabilityDetachable spar to increase utility in littoralsPendulation minimized & low motions4 alternative seabasing uses(causeway, breakwater, DWSC, harbor craneship)Surface mode
12Powering - surfaced Speed ~20 knots 5,00010,00015,00020,00025,0001020304050Speed (knots)Effective Power (kW)Drag = frictional + residuary + correlation allowanceTrimaran Spar CraneshipLength (m)L/1/SH / DWSCModel test data for the High Speed Sealift Trimaran scaled to 2,200te1 kW = hp or 1 hp = kWL/1/3 : Slenderness RatioSpeed ~20 knotsSurface mode ie no crane usage, just hotel load (300kW)4MW installed powerMinus 0.3MW hotel loadEquals 3.7MW power available for propulsionAssumed PC of 0.6Then Effective Power = PC x Available Installed PowerPe = 0.6 x 3.7 = 2.22MWBut given uncertainty in PC, we have applied a band.DWSC Total Displacement ~2,200teCraneship = 650teSpar = 1,220teCasing = 100te (111m x 8.5m x 12mm x 7.85te/m3 = 89te rounded to 100te)Piping for ballast pumps = 50teMargin on weight = 80teFuel = 100te (typically would provide ~2,000nm range)TOTAL = 2,200te
13Powering - vertical DWSC Speed ~4 knots Effective Power (kW) 1,0002,0003,0004,000123456Speed (knots)Effective Power (kW)CD=0.417.4m105m2m6m8.5mDWSC1 hp = kWCD : Drag Co-efficientAssumed Propulsive Coefficient, PC = 0.5Speed ~4 knotsCRANE USE + HOTEL LOADHOTEL LOAD ONLYSpar mode, No crane usage, just hotel load (300kW)4MW installed powerMinus 0.3MW hotel loadEquals 3.7MW power available for propulsionAssumed PC of 0.5Then Effective Power = PC x Available Installed PowerPe = 0.5 x 3.7 = 1.85MW (NO CRANE USE)Spar mode, with crane usage (235kW) & hotel load (300kW)Minus 0.3MW hotel load, Minus 0.235MW crane useEquals 3.465MW power available for propulsionPe = 0.5 x = 1.73MW (INC CRANE USE)
14Catamaran Design Resistance & Powering predictions indicate 4MW of Installed Power would provide;~20kts hullborne~3kts sparborneRV Triton’s Integrated Propulsion Plant provides;4MW of installed powerPropulsion & electrical machinery weightsIntegrated Propulsion System (IPS)Prime movers drive generators that produce electricity for propulsion motors and ship services and combat systems.
15COTS Crane Hydralift Offshore Knuckle Boom Crane Weight (with pedestal) : 65.5 tonnesPower requirement : 235 kWFoldedExtended(max)30m (98ft)25m (82ft)DWSC sized for 15te 30m (98ft) & max heel +/-2.5 degreesThe crane requirements were;Max Reach of 30m (98.4ft)Lift 15te at max reachBe as light as possibleREACHA 30m reach allows for;half beam of catamaran (15.75m/2 = 7.875m)5m offset between catamaran and supply shipability to reach centreline of Panamax Containership at 32.3m (106ft)So,/2 = 29m (95.2ft)LOADThe 15te load was derived from 50% of the max load of a 20ft container.Since this figure was assumed, a load of 20te has been postulated. This is well within the capability of this crane.It is worth noting that the DWSC is scaleable.
16Methodology - used existing vessels to de-risk catamaran sizing MV DuplusUSNS HayesUSNS Hayes (T-AGOR16) - 3,600te Steel CatamaranOceanographic research / towed array ‘tug’Geometric scaling onlyRV Triton - 1,116te Steel TrimaranResearch vesselWeight scaling (SWBS groups 2-8)MV Duplus1 - 1,200te Steel SwathNorth Sea oil rig supply tender with central drilling rigVolumetric scaling for structural weight (SWBS group 1)MV/RV - Merchant Vessel / Research VesselSWBS - Ship Weight Breakdown StructureUSNS - United States Naval ShipSWATH - Small Waterplane Area Twin HullMWATH - Medium Waterplane Area Twin Hull1 MV Duplus later renamed MV Twindrill (modified to a MWATH : waterplane increased to improve stability during crane use)Methodology - used existing vessels to de-risk catamaran sizingRV TritonHAYES - used for geometric scaling only ie the overall size and dimensionsTRITON - used for weight scaling of SWBS groups 2-8DUPLUS - used for weight scaling of SWBS group 1 (structural weight)(speak to Dan about Rushcutter and exactly what he did here)
17Weight Summary 1 Group 1 Hull - Steel construction Units in metric tonnesSWBS - Ship Weight Breakdown Structure1 Group 1 Hull - Steel construction2 Group 6 Outfit & Furnishings - Crew (3 officers + 8 rates)3 Group 7 Armament - None fitted4 Group 9 Margins - Assumed prorated over Groups 1-8
18Crew Quarters Power Conversion Intake/Uptake Laundry Rec. Room Mess/GalleyAccess to DeckOfficers’ QuartersExercise AreaStoresGeneratorsMotorsGearsRec. SpaceGearboxRampDriving LaneCRANEpositioned amidships on CL to minimize trim/heelseat for spar provides ideal foundation for cranefull 360 operabilityUPPER DECK LAYOUTramp & driving lane for causeway operationsdeckhouse offset to facilitate ‘traffic’ laneINTERNAL ARRANGEMENTCrew - 3 officers in single berths + 8 rates in twin berthsMain propulsion machinery in sidehulls (centered about amidships)Power conversion in cross deckFUEL50te of fuelHULLSteel, cross deck aft braced rather than continuous deckANCHORINGAft (various positions - under cross deck, port quarter deck)
19Principal Characteristics Dimension(m)(ft)Length Overall (LOA)38.70127.0Beam (B)15.7571.7Draft (T)3.1310.3Side hull Beam (BSH)4.0013.1Side hull separation7.7525.4Wet Deck Clearance2.879.4Depth (D)9.6731.7GMt10.7035.1Air Draught (TAIR)14.8748.8Displacement650 teBEAMOverall beam of catamaran is driven by the diameter at the top of the spar. At 6m, it dictates the sidehull separation to be at least 7m.Stability, is another important consideration in terms of the beam of the ship, particularly stability during crane operations. The aim was to minimize the heel during a 15te lift at 30m to less than 2.5 degrees. This was achieved by providing adequate sidehull beam and sufficient sidehull separation. The resulting maximum beam was 15.75m with a 7.75m sidehull separation.WET DECK CLEARANCE (WDC)A US Swath TAGOS 19 is designed to operate at all headings while towing arrays at the top end of SS6 (H1/3 = 6m / 19.7ft) and has a wet deck clearances of 13ft bow, 9ft amidships and 11ft stern. (3.96/2.74/3.35m)The wet deck clearance for the craneship is much smaller (2.87m) given;Spar provides protection (when connected)No requirement to remain operational in higher seastatesA high WDC aggravates structural weight & total displacementA compromise was achieved between structural weight, slamming and the ability to physically fit the spar under the wet deck when in surface mode.
201 Heel angle during a 15te lift at 30m limited to +/-2.5 degrees SPAR - Primary Design Drivers;Top weight Catamaran weightCrane lift requirements heel angle1Length/Diameter (L/D) structural strengthPressure head structural weightOther considerations;Sidehull separationWet deck clearance / Draft of SPAR on surfaceLow waterplane area (for seakeeping)Resistance & poweringShape of bow / Upper surface (causeway)Integration of thrustersInterface with Catamaran (Hinge & Connectors)1 Heel angle during a 15te lift at 30m limited to +/-2.5 degreesTOP WEIGHTThe overall weight of the catamaran is significant not in terms of the ballasting/de-ballasting requirement (to lift it out of the water) but because it is top weight that has to be countered by a lot of seawater ballast which drives up the size of the spar.CRANE LIFT REQUIREMENTSThe lift and reach requirements for the crane will result in a certain angle of heel for a given GM. The heel angle can be minimized by providing adequate GM. GM is determined by the seawater ballast and the size and shape of the spar.L/DHigh L/D ratios result in large bending stresses in the keel and upper deck on slender structures in a seaway. Whipping is probably more significant and generally results in L/D ratios of 15 maximum. The US Navy have built and operated ships with higher L/D ratios.see colen for DDG51 FFG7It should be noted, the DWSC could accept a higher L/D than say a major surface combatant given that the DWSC does not have to maintain speed and /or heading in all sea-states and is not expected to withstand shock loadings. Its structural design is such that the pressure head is likely to call for heavy gauge steel plating. Structural weight does not need to be minimized on the SPAR since the center of gravity of the spar structure is below the CoG for the rest of the platform, it actually helps with stability and minimizes the amount of seawater ballast required and hence the size of the spar.PRESSURE HEADThe pressure head at the bottom of the spar is (118m draft);1.0252x1000 x 9.81 x = MN/m2 ~ 12bar1.0252x1000 x 9.81 x 59 = MN/m2 ~ 6barHence, the need to design submarine type structures in the areas where hard tank structure are required. The bottom 1/3 rd does not need to be ‘hard’ as the pressure differential will always be very low and so ship like structure is all that is required (as a result of pressure) at the bottom of the spar. A small hard tank may be provided at the bottom of the spar to assist with the transition to the surface. The middle 1/3rd will see high differential pressures and so overall collapse and interframe collapse are of concern – just as with submarines. The upper third is designed to provide hard tank structural requirements.
21Revised Baseline Baseline Dimension Revised 127.0 Length (m) 129.6 111.0Draft (m)118.011.9Lower diameter (m)8.56.9Upper diameter (m)6.016.0Freeboard1 (m)11.62,513Structural weight (te)1,2208,000Seawater ballast (te)4,74550.9KB (m)57.949.2KG (m)56.31.76GMT (m)1.57500Catamaran weight (te)65011,013Total Displacement (te)6,615RevisedBaselineSteps in developing the spar concept;Reduce clearance from 16m to 11.6m shorter sparMaintain original length reduce diameterRe-evaluated spar structural weight became lighterRefined estimate of Catamaran teThe combination of the lighter spar (3.) and the heavier catamaran (4.) resulted in a slight increase in overall length.Note 1 : both spars were designed to provide sufficient GM so that the maximum heel angle under a 15te lift at 30m would be <= 2.5degrees.The reduced freeboard, lighter spar structural weight and reduced ballast resulted in a 40% reduction in total displacement (11,013 to 6,615te).Note 2 : the 11.6m freeboard to the wet deck still allows for 5.6m from the water to the keels of the catamaran sidehulls (when sparborne). The significant waveheight in SS6 is 4-6m, so 5.6m is upper SS6. Even then it is the top of the wave where there is little energy. TAGOS 19 has maximum 3.96m wet deck clearance for continuous ops in SS6!Seawater BallastDraft (horizontal) = 2.4mwith 400te seawater ballast1 Freeboard here is the vertical distance from the waterline (in spar mode) to the wet deck of the catamaran.KB : Vertical center of Buoyancy, KG : Vertical center of GravityGMT is the Transverse Metacentric Height and is a measure of stability.Both Spars were designed for a maximum heel of 2.5 degrees under a 15te lift at 30m whilst spar-borne.
22DWSC Seakeeping (Seastate 4) Initial Spar (ROLL)Revised Spar (ROLL)SEASTATE 4Max heave amplitude ~ 0.11mMax roll/pitch angle +/- 0.80Max heel due to 15mt +/- 2.50Max roll angle of 0.8 degrees (DUE TO SEASTATE)Even allowing for heel of +/- 2.5 degrees (DUE TO STATIC HEEL DURING LIFT)Then;= ~3.3 degrees in SS4 !So well within the 5 degree limit of the crane in SS4 !Hence, MAX HEEL ~3.30 in SS4 with a 15mt
23SPAR Seakeeping (Seastate 6) Revised Spar (ROLL)SPAR Seakeeping (Seastate 6)SEASTATE 6Max heave amplitude ~ 0.90mMax roll/pitch angle +/- 2.90Max heel due to 15mt +/- 2.50Max roll angle of 2.9 degrees (DUE TO SEASTATE)Even allowing for heel of +/- 2.5 degrees (DUE TO STATIC HEEL DURING LIFT)Then;= ~5.4 degrees in SS6 !So ‘around’ the 5 degree limit of the crane in SS6 !RMS = sqrt.moSIGNIFICANT = 2xRMSMAXIMUM = 4.45xRMS (for N = 10,000 cycles)Hence, MAX HEEL ~5.40 in SS6 with a 15mt
24Comparison of Natural Periods Comparison of initial and revised spar;Smaller waterplane area of revised spar should have caused an increase in heave period, but the reduction in mass lowered the natural period.The increase in length of the revised spar increased the mass moments of inertia, increasing the natural roll and pitch periods.Displacement Summary (mt)LCU ,087LMSR 63,978DWSC (initial) 11,013DWSC (revised) 6,615
25Connector Design - Loadcases SPAR-BORNECatamaran athwartships bendingLTorsional loading due to craneList / heel angle loadingHMooring forcesHeave forcesLCG / TCG variation1Thruster torqueWind loadingRogue wave - stern slamRogue wave - immersionSURFACE-BORNEWet deck stern-slamHCatamaran side-slamQuartering sea loadsMRoll bendingCollision / groundingDeep ballast tensionLSpar side-slamWave-induced bendingPropeller / thruster torqueYawManeuveringL / M / H : Low / Medium / High1 LCG /TCG : Longitudinal and Transverse Centers of Gravity
26Connector Design - limiting loadcases MODELoadcaseForce (ton)Area req’d (ft2)SurfaceCollision (>10 sec)611 [-x]0.43Catamaran side-slam5,485 [+y]3.69Spar-borneRogue wave : stern-slam3,619 [+z]2.95Top-connectors(Surface mode)End-connectors(Spar-borne)Hinge/lugSpar-borneEnd-connectorsArea available 28m2Area required 12m2 (43%)Factor of Safety of 4Assumed 7Radius 0.73mSurface modeTop-connectorsArea available 45m2Area required 15m2 (33%)Factor of Safety of 4Assumed 12Radius 0.62mzxySpar Profile
27SPAR Operability : 200m depth contour Arabian SeaBangladesh~150nmIndiaIranIraqArabian SeaSaudiArabiaYemenEthiopiaOmanPakistanAfghanistanPersian GulfRed SeaBangladeshThailandBurmaShallow Water < 200mDeep Water >= 200mSource : National Imagery & Mapping Agency (NIMA) - World Vector Shoreline Plus (WVSPLUS®)
28Spar Craneship : Alternative Uses Harbor Craneship‘Shallower’ WaterBottom SittingOffload Facilityshown in transit(Seabase closer to shore)Spar-CausewayDeep WaterStable Craneship(Seabase offshore)Rapidly Deployable Breakwater
30Surface mode Spar mode Deep Water Stable Craneship Concept Spar and Catamaran craneship form trimaranSpar is detachable - providing useful craneshipSelf-propelled on surface & in spar mode~20kts surfaced, ~4kts in spar modeInspired by FLIPSHIPSurfacemodeSpar modeKey Design DriversConnectorsHingeSpeed on surface and in spar modeControl during ballastingStabilitySeakeepingDraft / depth of waterMilitary BenefitExtends crane transfer through SS5Pendulation minimized (>2minute roll period)Provides container transfer capabilityReduces fleet wide craneage requirementsIncreases interoperability with commercial ships
31Spar Technology has superior seakeeping De-risking to dateRevised/refined design of;SparCatamaran CraneshipSizing of hinge and connectorsShaping for powering and other usesVisit to FLIPSHIP to ‘FLIP’Worldwide OperabilityStability & SeakeepingStatusIdentified Design DriversQuantified performance in a credible seabased scenarioFurther WorkFAU Design, Build & Test 1:15 scale demonstratorDe-risk Key Design DriversDeliverables:We aim to demonstrate….Spar Technology hassuperior seakeepingAlternatives;Re-fuelling Lily-padSpecial Forces Operating BaseFLIP II (Craneship Critical Technology Demonstration)
32FAU Ocean Engineering Dept Design, Build & Test a 1:15 scale DemonstratorNo craneUnmanned (for safety)Self-deployingWorking ballast systemPartial funding from ONRProject Advice from CISDCritical Design Review : complete 01-Dec-04Construction started end JanuaryAt-sea testing mid-April 20054 Teams (Catamaran, Spar Structure, Ballast and Control Systems)