Making WavesNewsletter of Oceanic Consulting Corporation

Spring/Summer 2002

• IMD Offshore Engineering Basin • IMD 200 Meter Wave/Towing Tank

• OERC 58 Meter Wave/Towing Tank • IMD 90 Meter Ice/Towing Tank • IMD Cavitation Tunnel

• MI 22 Meter Flume Tank • MI Centre for Marine SimulationSpecification sheets can be obtained from the Oceanic website or by contacting one of our offices.

IMD Offshore Engineering Basin - Facility Specifications:

Specification Sheets are Available for all Major Facilities, Including:

In this issue...

Profiling Our Houston Office.

Meet us at:

St. John’s, NewfoundlandJune 19th - 20th

Booth 608oceanic@oceaniccorp.com www.oceaniccorp.com

95 Bonaventure Ave., Suite 401P.O. Box 28009, St. John’s, NewfoundlandA1B 4J8 CanadaTel: (709) 722-9060Fax: (709) 722-9064

In Canada:9801 Westheimer, Suite 302Houston, Texas77042 USATel: (713) 917-6805Fax: (713) 917-6806

In the United States:

Houston, TexasMay 6th - 9thBooth 2641

Length 75m

Width 32m

Max. Water Depth 3.2m

Wave Making System (power) 1800kW

Max. Wave Height (regular waves) 1m

Max Sig. Wave Height (irregular waves) 0.5m

Range of Wavelengths 0.5m to 20m

Articulation of Waves (modes) Flapper, Piston, Combination

Wave Spectra Regular, Irregular, Bi-modal,

Multi-directional

Current Speed Water-depth Dependent

(0.2m/sec at 2m depth)

Average Wind Velocity 11m/sec at 1m from Fan

5m/sec at 5m from Fan

Turbulent Wind Spectrum Mean Speed 12m/sec

Wind Spectra American Petroleum Institute

Standard, Norwegian Petroleum

Directorate Standard,

Other Industry Standards

Optical Tracking System Accuracy

Moored Models ±1mm

Free-running Models ±5mm

As announced in our last newsletter, Oceanic has opened abusiness development office in Houston, Texas, to establish apermanent presence in this major engineering/design center.

This is part of Oceanic’s strategic initiative to gain a preciseunderstanding of client needs and build strong

working relationships.

In the offshore industry, technology is continuously changingand manufacturers and designers strive to produce superiorsystems. Since Oceanic has conducted testing on a variety

of concepts for the marine and offshore industry, we canassist clients with specific design solutions and

determine the need for design fine-tuning.

Oceanic’s expert services are now more easilyavailable to clients in the United States. If

you contact our Houston office, we canvisit you and demonstrate how a test

program may help improve your design.The Houston office responds to questions

and provides clients with regular reports onproject progress. Oceanic also keeps abreastof new developments in the industry and will

inform clients directly of how model testing willallow them to use, or perfect the use, of new

technologies in their designs.

Oceanic provides quality answers to your questions.Our world-class facilities and expert technical and research

personnel can help you formulate a marine evaluationprogram for your specific requirements. Call Clint Gosse

at our Houston office, (713) 917-6805.

• Profiling Our Houston Office.• Charting the Course: Spring/Summer 2002.• DeepStar and Oceanic.• Testing FPSOs: A Core Business.

• Oceanic’s Deepwater Initiatives.• Profiling Project Manager: Bruce Paterson.• IMD Offshore Engineering Basin -

Facility Specifications.

• Decommissioning and Installation ofJacket Topsides.

• Evaluation of a Deepwater PipeLaying Vessel.

Oceanic Joins DeepStar.Oceanic is pleased to announce that it has signedup as a contributor to the next phase of theDeepStar project. DeepStar, an industry-sponsoredinitiative for the development of deepwatertechnology for the Gulf of Mexico, has thefollowing goals:

• to improve the profitability, execution,operability, flexibility and reliability of existingdeepwater production system technology

• to develop new technology which enablesproduction in currently technically unprovenareas, specifically economic production inwater depths up to 10,000 ft

• to ensure the acceptance of deepwatertechnology by facilitating the developmentof industry standards and practices, andby fostering communications withregulatory bodies

• to play a facilitator role by providing a forumand a process for discussion, guidance, andfeedback with contractors, vendors, operators,regulators, and academia regarding deepwaterproduction system technology capability gaps,and by promoting the standardization ofcomponent interfaces.

Oceanic’s Current ContributionOceanic has contributed to the present phase ofDeepStar by conducting high Reynolds Number risermodel tests to acquire high quality data for Vortex-Induced Vibration (VIV) analysis for the prediction ofriser response. Oceanic’s work has involved two-fold research into the Vortex-Induced Vibration (VIV)phenomena: an experimental program, andnumerical modeling using Computational FluidDynamics (CFD) tools. The overall objective of thisresearch is to provide a basic understanding of thecomplex interaction between the fluid and themoving structure or marine riser.

The experimental program is being conducted atReynolds Numbers in excess of 1x106 using a

specially fabricated test rig. The test equipmentweighs nearly 7 tonnes and is capable of over2 tonnes drag force and ±1.5 tonnes vertical force.The IMD 200 Meter Wave/Towing Tank waschosen for the tests as the tank’s width and depth,12 meters and 7 meters respectively, combined witha relatively powerful towing carriage, make it idealfor these experiments. Both free and forcedvibration experiments are among those planned.The test sample has a diameter of 0.32 meters anda length of 5.6 meters. Surface roughness can bevaried via jackets that slip over the pipe. Two jacketsare being tested in the current program: one with asmooth covering and one with a roughness with aheight of 0.3 percent of the pipe diameter. Theresults provide loading functions for finite elementmodels of slender risers in deep water.

The experimental program also examines the effectsof background fluid turbulence, multi-frequencyforced vibrations, and free vibration with twodegrees of freedom. A specially designed five-component force dynamometer measures thefluid loads acting on the cylinder surface. Forsome experiments, the turbulent wake behind thetest specimen is measured using Particle ImagingVelocitimetry (PIV). This will be particularly usefulin the correlation of the experimental results with

CFD modeling. Researchers at Memorial Universityof Newfoundland have modeled this problem usingthe commercial computer codes FLOW3D andFLUENT, and Oceanic has recently obtained CFX toadd to its arsenal of CFD modeling tools. CFX is aReynold’s Averaged Navier-Stokes (RANS) basedfinite volume code.

For more information in this area,contact Don Spencer.

Welcome to our annual OTC Newsletter. TheProvince of Newfoundland and Labrador hasa long history of offshore exploration.However, it didn’t start with the oil industry.For centuries, Newfoundland has been wellknown as a rich offshore fishing region. Withthe start of production of the Terra Nova FPSOwe are now becoming known as a richoffshore oil region. Like the growth of thefishery, the oil industry in this province isexploring further and deeper. With potentialdeepwater sites in the Flemish Pass, on theScotian Shelf and offshore Labrador, our long-term involvement in deepwater explorationand exploitation is inevitable.

That effort is evidenced in some of the workoutlined in this newsletter. Funded byDeepStar, Oceanic has been working on aproject to measure vortex-induced vibrationsusing both physical and numerical modelingtools. Backed by researchers at both theNational Research Council of Canada andMemorial University, Oceanic engineers anddesigners have developed a system that willbe able to measure both loads and motionsinduced on a segment of riser towedhorizontally in the IMD 200 MeterWave/Towing Tank. We are very proud of theproject for a number of reasons, not the leastof which is that the successful proposal wasthe first we had submitted to the consortium.

Speaking of firsts, we are pleased to have aproject with Global Maritime to evaluate anoffshore structure decommissioning system.Tests carried out in the IMD 200 MeterWave/Towing Tank and the IMD Offshore

Engineering Basin, aimed to establishrelative motions between two adjacentstructures during the topsides liftingprocess during decommissioning.

In keeping with the theme of exporting theknowledge gained on projects designed forthe harsh environment of Newfoundland toprojects around the world, another article inthis issue outlines our growing experience inthe evaluation of FPSOs. We have recentlycompleted projects for different geographicallocations around the world. From seakeepingto directional stability, we continue to build onthe experience gained on different FPSOs fromthe design evaluation stage to ongoinghydrodynamic support of projects in theproduction phase.

As this issue will come out just before OTC, Iwould like to extend a personal invitation toall our readers to visit us at the Newfoundlandand Labrador Pavilion. I look forward toseeing both new and old friends in Houstonagain this year.

For Oceanic Consulting Corporation,Best Regards,

Dan Walker, Ph.D., P.Eng.President

Charting the Course: Spring/Summer 2002. DeepStar and Oceanic.

Correction: In our last newsletter we incorrectly identified where the vessel "Cape May Light" was being built. The ship was built by Atlanta Marine in Jacksonville,Florida. Oceanic carried out a performance evaluation of different types of roll stabilization options for the “Cape May Light”.

Vortex-Induced Vibration Test Apparatusundergoing bench testing.

Riser section for Vortex-Induced Vibration tests.

Oceanic Joins DeepStar.Oceanic is pleased to announce that it has signedup as a contributor to the next phase of theDeepStar project. DeepStar, an industry-sponsoredinitiative for the development of deepwatertechnology for the Gulf of Mexico, has thefollowing goals:

• to improve the profitability, execution,operability, flexibility and reliability of existingdeepwater production system technology

• to develop new technology which enablesproduction in currently technically unprovenareas, specifically economic production inwater depths up to 10,000 ft

• to ensure the acceptance of deepwatertechnology by facilitating the developmentof industry standards and practices, andby fostering communications withregulatory bodies

• to play a facilitator role by providing a forumand a process for discussion, guidance, andfeedback with contractors, vendors, operators,regulators, and academia regarding deepwaterproduction system technology capability gaps,and by promoting the standardization ofcomponent interfaces.

Oceanic’s Current ContributionOceanic has contributed to the present phase ofDeepStar by conducting high Reynolds Number risermodel tests to acquire high quality data for Vortex-Induced Vibration (VIV) analysis for the prediction ofriser response. Oceanic’s work has involved two-fold research into the Vortex-Induced Vibration (VIV)phenomena: an experimental program, andnumerical modeling using Computational FluidDynamics (CFD) tools. The overall objective of thisresearch is to provide a basic understanding of thecomplex interaction between the fluid and themoving structure or marine riser.

The experimental program is being conducted atReynolds Numbers in excess of 1x106 using a

specially fabricated test rig. The test equipmentweighs nearly 7 tonnes and is capable of over2 tonnes drag force and ±1.5 tonnes vertical force.The IMD 200 Meter Wave/Towing Tank waschosen for the tests as the tank’s width and depth,12 meters and 7 meters respectively, combined witha relatively powerful towing carriage, make it idealfor these experiments. Both free and forcedvibration experiments are among those planned.The test sample has a diameter of 0.32 meters anda length of 5.6 meters. Surface roughness can bevaried via jackets that slip over the pipe. Two jacketsare being tested in the current program: one with asmooth covering and one with a roughness with aheight of 0.3 percent of the pipe diameter. Theresults provide loading functions for finite elementmodels of slender risers in deep water.

The experimental program also examines the effectsof background fluid turbulence, multi-frequencyforced vibrations, and free vibration with twodegrees of freedom. A specially designed five-component force dynamometer measures thefluid loads acting on the cylinder surface. Forsome experiments, the turbulent wake behind thetest specimen is measured using Particle ImagingVelocitimetry (PIV). This will be particularly usefulin the correlation of the experimental results with

CFD modeling. Researchers at Memorial Universityof Newfoundland have modeled this problem usingthe commercial computer codes FLOW3D andFLUENT, and Oceanic has recently obtained CFX toadd to its arsenal of CFD modeling tools. CFX is aReynold’s Averaged Navier-Stokes (RANS) basedfinite volume code.

For more information in this area,contact Don Spencer.

Welcome to our annual OTC Newsletter. TheProvince of Newfoundland and Labrador hasa long history of offshore exploration.However, it didn’t start with the oil industry.For centuries, Newfoundland has been wellknown as a rich offshore fishing region. Withthe start of production of the Terra Nova FPSOwe are now becoming known as a richoffshore oil region. Like the growth of thefishery, the oil industry in this province isexploring further and deeper. With potentialdeepwater sites in the Flemish Pass, on theScotian Shelf and offshore Labrador, our long-term involvement in deepwater explorationand exploitation is inevitable.

That effort is evidenced in some of the workoutlined in this newsletter. Funded byDeepStar, Oceanic has been working on aproject to measure vortex-induced vibrationsusing both physical and numerical modelingtools. Backed by researchers at both theNational Research Council of Canada andMemorial University, Oceanic engineers anddesigners have developed a system that willbe able to measure both loads and motionsinduced on a segment of riser towedhorizontally in the IMD 200 MeterWave/Towing Tank. We are very proud of theproject for a number of reasons, not the leastof which is that the successful proposal wasthe first we had submitted to the consortium.

Speaking of firsts, we are pleased to have aproject with Global Maritime to evaluate anoffshore structure decommissioning system.Tests carried out in the IMD 200 MeterWave/Towing Tank and the IMD Offshore

Engineering Basin, aimed to establishrelative motions between two adjacentstructures during the topsides liftingprocess during decommissioning.

In keeping with the theme of exporting theknowledge gained on projects designed forthe harsh environment of Newfoundland toprojects around the world, another article inthis issue outlines our growing experience inthe evaluation of FPSOs. We have recentlycompleted projects for different geographicallocations around the world. From seakeepingto directional stability, we continue to build onthe experience gained on different FPSOs fromthe design evaluation stage to ongoinghydrodynamic support of projects in theproduction phase.

As this issue will come out just before OTC, Iwould like to extend a personal invitation toall our readers to visit us at the Newfoundlandand Labrador Pavilion. I look forward toseeing both new and old friends in Houstonagain this year.

For Oceanic Consulting Corporation,Best Regards,

Dan Walker, Ph.D., P.Eng.President

Charting the Course: Spring/Summer 2002. DeepStar and Oceanic.

Correction: In our last newsletter we incorrectly identified where the vessel "Cape May Light" was being built. The ship was built by Atlanta Marine in Jacksonville,Florida. Oceanic carried out a performance evaluation of different types of roll stabilization options for the “Cape May Light”.

Vortex-Induced Vibration Test Apparatusundergoing bench testing.

Riser section for Vortex-Induced Vibration tests.

to the complete system must be developed usingthe available line length.

In addition to measuring the response of the intactsystem, it is generally required to investigate theloads that occur if a line is lost. Damage testsinvolve both steady state measurements, where datais collected over a full test with a line missing, andtransient tests, where the line is actively droppedusing a fuseable link. In the latter case, any suddenjump in loads or hull offset is recorded.

Greenwater and Seakeeping TestsGreenwater and seakeeping tests focus on the vesselresponse, in particular, the available freeboard andthe phasing of the response relative to the waveprofile. Greenwater is defined as a dense amount ofseawater coming on to the deck of a FPSO.Greenwater impact can cause substantialhydrodynamic loads as opposed to white water thatcontains large amounts of spray and therefore is lesscritical in terms of magnitude of loading.

Greenwater events are documented usingcomplementary instrumentation and videotapedrecords. Relative motion probes are capacitance-type instruments that measure wave elevation froma still waterline; they are placed along the sidesof the model at critical locations and provide aconstant measure of wave elevation during a test.The processed data generates a cumulativehistogram of wave elevation that can identify theprobability of exceeding a particular elevation,such as the main deck or production module levels.

A similar instrument can be mounted directly in thedeck to measure greenwater elevation at a specificlocation. These Greenwater probes can provide aprofile of greenwater over the deck as well as detailsof discrete events.

In addition to documenting greenwater elevation,most programs employ pressure panel devices tomeasure greenwater loads at specific locations suchas the waterbreaker. A pressure panel is comprisedof a contact plate of known area fitted to a load cell.

Current Drag TestsCurrent drag tests may be conducted in wind tunnelsat Reynolds scales. Oceanic, however, performsthese tests in one of the towing tanks using theability of the Planar Motion Mechanism (PMM) tomeasure drag force and moment over a full range ofheadings. It is believed that this type of testprovides a more accurate measure of current drag,particularly at low angles of attack.

Directional Stability TestsWhen mooring tests indicate a potential problem withthe yaw stability of a FPSO hull, it is possible toinvestigate the hull directional stability in the MI FlumeTank. A technique used to evaluate the directionalstability of barges has been adopted to evaluate theFPSO hull over a range of current conditions. Factorssuch as mooring compliance, turret position, and hullform can be investigated. In the absence of availablestandards for directional stability or weathervaningperformance of FPSO systems, data for a FPSO hullof known performance has been used to provide abaseline.

Ice Resistance TestsWhen conducting ice resistance tests, the FPSO hullis towed through a representative pack ice sheet atspeeds corresponding to design current speed. Theobjective of these tests is to identify the loads thatmight be exerted on the mooring under a heavyice incursion.

Riser TestsModeling of marine hoses and risers poses aparticular challenge due to the relatively low

bending stiffness required at model scale. By ajudicious choice of helical spring parameters, thebending stiffness and diameter of the hose can beprecisely matched. The weight of the hose in wateris then modeled by filling it with material of theappropriate density.

Turret Disconnect TestsOne of Oceanic’s unique specialties is evaluatingdisconnectable turret systems. Such systems, whichallows the FPSO to quickly disconnect from themooring system, usually involves a buoy whichfloats the chain table and is secured from the baseof the turret. When the FPSO is threatened byextreme conditions (e.g., typhoons or icebergincursions), the buoy is dropped and the vessel issailed out of danger. Turret disconnect testsestablish whether there is any interference betweenthe buoy and the hull during the dropping phaseand as the vessel moves off station.

In tune with industry interest in FPSO development,a significant portion of Oceanic's recent work hascentered on testing this type of platform. Much ofour past work was focussed on verification andimprovement in the design phase, but more recentcontracts have included analysis of hydrodynamicissues after FPSOs have progressed into theoperational phase. We are continually developingexpertise valuable to clients interested inperformance evaluation of FPSOs.

For more information in this area,contact Bruce Paterson or Shawn Searle.

Testing FPSOs: A Core Business.Floating Production Storage and Offloading Systems(FPSOs) seem to be one of the preferred options forthe future development of offshore oil fields andOceanic has built a significant FPSO referenceportfolio. The five latest FPSO assignmentsundertaken by Oceanic cover a variety of designconfigurations and geographical locations, rangingfrom the harsh Grand Banks environment offshoreNewfoundland to more benign waters in the FarEast, offshore Australia, and off the coast of WestAfrica. Although the designs and the environmentalconditions vary, the key parameters are basically thesame: motion characteristics, mooring systemcapabilities, the risk of encountering green seas ondeck, and possible operational limitations.

Why are these parameters important? Green season deck may result in equipment or structuraldamage. Operational limitations affect the regularityof production. As motion behavior affects thedesign and the performance of the process plant, theconcomitant selection and arrangement ofequipment is important. Design measures couldinclude level control and internal baffles in liquid-filled vessels. Pipe routing should account for staticheel and motion behavior. This is of specialrelevance for the flare system for safety reasons.Inclination and roll motion will also affect the designof drain systems and atmospheric tanks. Pipe stress

and fatigue exposure caused by hull beamdeflections, material handling, human comfort, aswell as the ability to operate the facilities are otherdesign factors to be considered.

The stationkeeping system of a FPSO must providerestoring capacity within acceptable excursion limits.Thrusters are frequently used for heading control ofFPSOs. They can also dampen second ordermotions and counteract static environmental forces.Where thrusters are integral parts of thestationkeeping system, the effect of theirmalfunction may be of interest. This could meanmodel testing as will transient motions and loadsresulting from mooring line failures. Possible riserinterference is also a potential design issue.

Model testing remains an important part of the FPSOdesign evaluation process because of the range andcomplexity of issues related to the hydrodynamicperformance of FPSO systems. The issues describedhere represent samples of the work recentlyundertaken at Oceanic.

Mooring TestsMooring tests generally verify a mooring systemdesign. There are many types of mooring systems.In extremely shallow water, a tower yoke systemmay be employed. Tower yoke systems are typicallyused in water depths that are too shallow forconventional mooring systems. As part of thesesystems a FPSO is moored directly to a fixed jacketby a soft yoke system. The turntable, containing theswivels, is attached to the jacket through a bearingsystem, which allows the vessel to weathervane.The yoke normally includes a large ballast tank,which can be customized to control the restoringforce thus controlling the vessel motions.Connecting the FPSO to the ballast tank of theyoke are normally two rigid arms with roll andpitch joints on either end allowing the vesselfreedom of motion.

During testing of such systems, we would measurethe roll and pitch motions at all the moving joints,the inline loads in the arms and the forces and

moments acting on the turntable. In addition, wecould examine the ballast tank to establish therequired mass to minimize the vessel surge motionsfor the design environments.

In deeper waters in benign environments, a spread-moored system, where the hull is directly anchoredto the seabed may be employed. The mooring linescan be taut, but are more often a catenary mooringwhere the line is lifted to create a restoring forcewhen the hull moves off station.

In terms of testing, this means that a range ofenvironments must be modeled to represent thedesign conditions for each orientation. In practicalterms, with a fixed current generating system, themodel and mooring must be rotated for eachcurrent direction. Loads in the mooring lines arerecorded via load cells at the hull/line interface,and the offset of the hull is tracked using anoptical infrared system.

In more severe environments, a typical mooringsystem involves a turret which allows the hull torotate or weathervane. The turret can be mountedon a frame structure forward of the vessel, orinternally through the hull. The system consists ofcatenary mooring lines. Turret systems are typicallytested in a range of collinear (wind/wave/currentaligned) and crossed conditions to determine theworst-case loading. Load cells in the mooring linesand dynamometers on the turret axis are used toestablish the loading in the lines and at the turret.The offset of the hull is measured using an opticaltracking system. With any system involving mooringlines, an extensive period of time is spent calibratingthe system. In this iterative process, the tensions inthe individual mooring lines are adjusted to matchthe desired stiffness characteristics, then the overallstiffness of the system is measured, and finallydecay tests are performed.

For mooring systems employed in deep water orinvolving a large horizontal radius, the moorings aretruncated to avoid testing at very small scales whereinstrument resolution and scale effects becomesignificant. When truncating a system, an analogue

Turret disconnect tests in the Offshore Engineering Basin.

FPSO in the Ice/Towing Tank.

FPSO in Flume Tank.

to the complete system must be developed usingthe available line length.

In addition to measuring the response of the intactsystem, it is generally required to investigate theloads that occur if a line is lost. Damage testsinvolve both steady state measurements, where datais collected over a full test with a line missing, andtransient tests, where the line is actively droppedusing a fuseable link. In the latter case, any suddenjump in loads or hull offset is recorded.

Greenwater and Seakeeping TestsGreenwater and seakeeping tests focus on the vesselresponse, in particular, the available freeboard andthe phasing of the response relative to the waveprofile. Greenwater is defined as a dense amount ofseawater coming on to the deck of a FPSO.Greenwater impact can cause substantialhydrodynamic loads as opposed to white water thatcontains large amounts of spray and therefore is lesscritical in terms of magnitude of loading.

Greenwater events are documented usingcomplementary instrumentation and videotapedrecords. Relative motion probes are capacitance-type instruments that measure wave elevation froma still waterline; they are placed along the sidesof the model at critical locations and provide aconstant measure of wave elevation during a test.The processed data generates a cumulativehistogram of wave elevation that can identify theprobability of exceeding a particular elevation,such as the main deck or production module levels.

A similar instrument can be mounted directly in thedeck to measure greenwater elevation at a specificlocation. These Greenwater probes can provide aprofile of greenwater over the deck as well as detailsof discrete events.

In addition to documenting greenwater elevation,most programs employ pressure panel devices tomeasure greenwater loads at specific locations suchas the waterbreaker. A pressure panel is comprisedof a contact plate of known area fitted to a load cell.

Current Drag TestsCurrent drag tests may be conducted in wind tunnelsat Reynolds scales. Oceanic, however, performsthese tests in one of the towing tanks using theability of the Planar Motion Mechanism (PMM) tomeasure drag force and moment over a full range ofheadings. It is believed that this type of testprovides a more accurate measure of current drag,particularly at low angles of attack.

Directional Stability TestsWhen mooring tests indicate a potential problem withthe yaw stability of a FPSO hull, it is possible toinvestigate the hull directional stability in the MI FlumeTank. A technique used to evaluate the directionalstability of barges has been adopted to evaluate theFPSO hull over a range of current conditions. Factorssuch as mooring compliance, turret position, and hullform can be investigated. In the absence of availablestandards for directional stability or weathervaningperformance of FPSO systems, data for a FPSO hullof known performance has been used to provide abaseline.

Ice Resistance TestsWhen conducting ice resistance tests, the FPSO hullis towed through a representative pack ice sheet atspeeds corresponding to design current speed. Theobjective of these tests is to identify the loads thatmight be exerted on the mooring under a heavyice incursion.

Riser TestsModeling of marine hoses and risers poses aparticular challenge due to the relatively low

bending stiffness required at model scale. By ajudicious choice of helical spring parameters, thebending stiffness and diameter of the hose can beprecisely matched. The weight of the hose in wateris then modeled by filling it with material of theappropriate density.

Turret Disconnect TestsOne of Oceanic’s unique specialties is evaluatingdisconnectable turret systems. Such systems, whichallows the FPSO to quickly disconnect from themooring system, usually involves a buoy whichfloats the chain table and is secured from the baseof the turret. When the FPSO is threatened byextreme conditions (e.g., typhoons or icebergincursions), the buoy is dropped and the vessel issailed out of danger. Turret disconnect testsestablish whether there is any interference betweenthe buoy and the hull during the dropping phaseand as the vessel moves off station.

In tune with industry interest in FPSO development,a significant portion of Oceanic's recent work hascentered on testing this type of platform. Much ofour past work was focussed on verification andimprovement in the design phase, but more recentcontracts have included analysis of hydrodynamicissues after FPSOs have progressed into theoperational phase. We are continually developingexpertise valuable to clients interested inperformance evaluation of FPSOs.

For more information in this area,contact Bruce Paterson or Shawn Searle.

Testing FPSOs: A Core Business.Floating Production Storage and Offloading Systems(FPSOs) seem to be one of the preferred options forthe future development of offshore oil fields andOceanic has built a significant FPSO referenceportfolio. The five latest FPSO assignmentsundertaken by Oceanic cover a variety of designconfigurations and geographical locations, rangingfrom the harsh Grand Banks environment offshoreNewfoundland to more benign waters in the FarEast, offshore Australia, and off the coast of WestAfrica. Although the designs and the environmentalconditions vary, the key parameters are basically thesame: motion characteristics, mooring systemcapabilities, the risk of encountering green seas ondeck, and possible operational limitations.

Why are these parameters important? Green season deck may result in equipment or structuraldamage. Operational limitations affect the regularityof production. As motion behavior affects thedesign and the performance of the process plant, theconcomitant selection and arrangement ofequipment is important. Design measures couldinclude level control and internal baffles in liquid-filled vessels. Pipe routing should account for staticheel and motion behavior. This is of specialrelevance for the flare system for safety reasons.Inclination and roll motion will also affect the designof drain systems and atmospheric tanks. Pipe stress

and fatigue exposure caused by hull beamdeflections, material handling, human comfort, aswell as the ability to operate the facilities are otherdesign factors to be considered.

The stationkeeping system of a FPSO must providerestoring capacity within acceptable excursion limits.Thrusters are frequently used for heading control ofFPSOs. They can also dampen second ordermotions and counteract static environmental forces.Where thrusters are integral parts of thestationkeeping system, the effect of theirmalfunction may be of interest. This could meanmodel testing as will transient motions and loadsresulting from mooring line failures. Possible riserinterference is also a potential design issue.

Model testing remains an important part of the FPSOdesign evaluation process because of the range andcomplexity of issues related to the hydrodynamicperformance of FPSO systems. The issues describedhere represent samples of the work recentlyundertaken at Oceanic.

Mooring TestsMooring tests generally verify a mooring systemdesign. There are many types of mooring systems.In extremely shallow water, a tower yoke systemmay be employed. Tower yoke systems are typicallyused in water depths that are too shallow forconventional mooring systems. As part of thesesystems a FPSO is moored directly to a fixed jacketby a soft yoke system. The turntable, containing theswivels, is attached to the jacket through a bearingsystem, which allows the vessel to weathervane.The yoke normally includes a large ballast tank,which can be customized to control the restoringforce thus controlling the vessel motions.Connecting the FPSO to the ballast tank of theyoke are normally two rigid arms with roll andpitch joints on either end allowing the vesselfreedom of motion.

During testing of such systems, we would measurethe roll and pitch motions at all the moving joints,the inline loads in the arms and the forces and

moments acting on the turntable. In addition, wecould examine the ballast tank to establish therequired mass to minimize the vessel surge motionsfor the design environments.

In deeper waters in benign environments, a spread-moored system, where the hull is directly anchoredto the seabed may be employed. The mooring linescan be taut, but are more often a catenary mooringwhere the line is lifted to create a restoring forcewhen the hull moves off station.

In terms of testing, this means that a range ofenvironments must be modeled to represent thedesign conditions for each orientation. In practicalterms, with a fixed current generating system, themodel and mooring must be rotated for eachcurrent direction. Loads in the mooring lines arerecorded via load cells at the hull/line interface,and the offset of the hull is tracked using anoptical infrared system.

In more severe environments, a typical mooringsystem involves a turret which allows the hull torotate or weathervane. The turret can be mountedon a frame structure forward of the vessel, orinternally through the hull. The system consists ofcatenary mooring lines. Turret systems are typicallytested in a range of collinear (wind/wave/currentaligned) and crossed conditions to determine theworst-case loading. Load cells in the mooring linesand dynamometers on the turret axis are used toestablish the loading in the lines and at the turret.The offset of the hull is measured using an opticaltracking system. With any system involving mooringlines, an extensive period of time is spent calibratingthe system. In this iterative process, the tensions inthe individual mooring lines are adjusted to matchthe desired stiffness characteristics, then the overallstiffness of the system is measured, and finallydecay tests are performed.

For mooring systems employed in deep water orinvolving a large horizontal radius, the moorings aretruncated to avoid testing at very small scales whereinstrument resolution and scale effects becomesignificant. When truncating a system, an analogue

Turret disconnect tests in the Offshore Engineering Basin.

FPSO in the Ice/Towing Tank.

FPSO in Flume Tank.

Oceanic’s Deepwater Initiatives.A safe and cost-effective method of decommissioningand installing jacket topsides has long been an objectivein the offshore industry and has recently becomea necessity. As the majority of installationsdecommissioned to date have been small structuresor installations, there has been little experience withthe decommissioning of large steel installations.Oceanic recently worked with Global Maritime in amodel test program that investigated a novel approachto this problem.

Global Maritime, in alliance with Prosafe ASA, hasdeveloped a single lift decommissioning and installationvessel with a lifting capacity of 22,000 tonnes, whichwould enable them to provide a service that is presentlyunavailable in the offshore industry. As part of its

development strategy, Global Maritime contractedOceanic to perform a series of model tests in theIMD Offshore Engineering Basin and 200 MeterWave/Towing Tank.

Oceanic conducted a detailed and highly complexmodel test program to investigate vessel motionresponse as well as lifting and stationkeepingsystems for a range of environmental conditions.This program included performing model testsduring various stages of the lifting process, rangingfrom initial contact with the topsides where dynamicloads are important, to the actual transport of thetopsides where vessel stability and motion responseare crucial. Global Maritime selected Oceanicbecause of its high level of service and ability to

undertake complex programs in helping clients achievetheir objectives.

For more information in this area,contact Shawn Searle.

Decommissioning and Installation of Jacket Topsides.

Evaluation of a Deepwater Pipe Laying Vessel.As technological advances allow additional deepwatersites to become viable for commercial production, ithas become necessary to develop oilfield servicevessels that are capable of operating in these oftenharsh environments. In developing a new breed ofdeepwater pipe laying vessel, Bender Shipbuildingand Repair Limited (Bender), in association with GuidoPerla and Associates Incorporated (GPAI), wanted toensure that their design would achieve the highstandards demanded by today’s oil industry.Consequently, Oceanic was contracted to evaluate thehydrodynamic performance of their 406-foot design.

The significant hull features of this design include abow bulb, two moonpools, two tunnel thrusters andthree z-drive units for the main propulsion. To assessthe vessel, Oceanic undertook a comprehensive testprogram of physical model experiments in conjunctionwith numerical modeling. The physical tests, completedwith a 1:17 scale model for various operationalconditions, included an assessment of bare hull andappended resistance in calm water as well as

self-propulsion tests. Flow visualization tests checkedfor possible flow problems in the vicinity of themoonpools and tunnel thrusters. Given the propulsionarrangement, a detailed wake survey assessed theflow into the propulsors. A milestone was achievedduring this project in that three model z-drive unitswere used for the self-propulsion tests. While theseinstrumented units were designed and fabricated

in-house specifically for this project, they allow Oceanicto further expand its overall testing capability.

Vessel seakeeping was examined numerically usingOceanic’s time domain seakeeping code MOTSIM.For zero and operational speeds, the code generatedResponse Amplitude Operators for various locationson the vessel. The possible inclusion of a roll tank onthe vessel was also assessed. Irregular spectrumsimulations were completed for specific sea conditions;the resultant motions and accelerations provided inputfor structural calculations.

Given the complexities of some of today’s new designs,quantitative assessment of hydrodynamic performanceat the design stage is imperative. With the resultsprovided by Oceanic’s team of engineers, Bender andGPAI have obtained advance knowledge of theexpected performance of their design.

For more information in this area,contact Michael Doucet.

The international petroleum industry is moving intodeeper water. This global trend poses new challenges,most importantly the development of a technologythat can predict the behaviour of the systems deployedto develop deepwater oil and gas fields. The targetsfor deepwater development are now approaching10,000 feet.

One of the most challenging technical tasks indeepwater development is the prediction of the globalresponse of a floating production system. Theuncertainties inherent in analytical approaches are

traditionally resolved by model testing which hasscaling law conflicts for various components and modelbasin depth limits. Scaling laws which would enablethe use of complete system model tests do not exist,and, for this reason, the industry tries variousapproaches to predicting the global response.

Oceanic is now part of the ongoing effort to resolvethese issues; participation in the DeepStar project(described on page 2) is one such initiative, and offeringa suite of complementary testing facilities for R&Dprojects is another. Oceanic offers the following

facilities for this type of work:• A 200 Meter Wave/Towing Tank, 7 meters deep• An Offshore Engineering Basin, 3.2 meters deep• A 90 Meter Ice/Towing Tank, 3 meters deep• A 22 Meter Flume Tank, 4 meters deep• A Wave Basin, 3 meters deep equipped with a 6 meter diameter and 15 meter deep pit at the center.

For more information in this area,contact Tor Naess.

Tests on the decommissioning and installation of Jacket Topside.

Model of Z-drive units - Deepwater Pipe Laying Vessel.

Profiling Project Manager: Bruce Paterson.As one of Oceanic’s senior project managers,Bruce Paterson offers consulting experience innumerical and physical model testing, field trials,software development, and concept design studies.In the role of project management, Bruce has beenlargely involved in FPSO test programs, particularlythe White Rose development project.

Prior to joining Oceanic, Bruce spent eleven years withBMT Fleet Technology Limited, ultimately as managerof the Marine and Offshore Group, where he handledprojects for government and commercial clients.Bruce’s experience includes the conceptual designand class approval of a semi-submersible transshipmentstation; technical support in the bidding stages for theshuttle tankers of the Hibernia project; engineeringsupport for the Canadian Coast Guard in the acquisitionof the icebreaker vessel Terry Fox; and concept studiesfor the Canadian Navy’s multi-role replenishmentsupport vessel and the United States Coast GuardGreat Lakes icebreaker replacement project. He hasconducted tests and trials aboard a range of vesselsfrom heavy icebreakers to coastal ferries; he has beeninvolved in seakeeping analyses and sales ofcommercial seakeeping software; and he has beenactive in marine safety work, specifically the stabilityand recovery of life rafts and the damage stability ofself-unloading bulk carriers.

Bruce has a Master of Ocean Engineering Degree fromMemorial University of Newfoundland, and is also agraduate of the University of British Columbia’sMechanical Engineering (Naval Architectureoption) program.

Bruce will represent Oceanic at the Offshore TechnologyConference in Houston, Texas, May 6th-9th, 2002.Past, present and potential clients with any questionspertaining to marine performance evaluation areinvited to visit him at Exhibit 2641.

Bruce Paterson, Senior Project Manager.

Oceanic’s Deepwater Initiatives.A safe and cost-effective method of decommissioningand installing jacket topsides has long been an objectivein the offshore industry and has recently becomea necessity. As the majority of installationsdecommissioned to date have been small structuresor installations, there has been little experience withthe decommissioning of large steel installations.Oceanic recently worked with Global Maritime in amodel test program that investigated a novel approachto this problem.

Global Maritime, in alliance with Prosafe ASA, hasdeveloped a single lift decommissioning and installationvessel with a lifting capacity of 22,000 tonnes, whichwould enable them to provide a service that is presentlyunavailable in the offshore industry. As part of its

development strategy, Global Maritime contractedOceanic to perform a series of model tests in theIMD Offshore Engineering Basin and 200 MeterWave/Towing Tank.

Oceanic conducted a detailed and highly complexmodel test program to investigate vessel motionresponse as well as lifting and stationkeepingsystems for a range of environmental conditions.This program included performing model testsduring various stages of the lifting process, rangingfrom initial contact with the topsides where dynamicloads are important, to the actual transport of thetopsides where vessel stability and motion responseare crucial. Global Maritime selected Oceanicbecause of its high level of service and ability to

undertake complex programs in helping clients achievetheir objectives.

For more information in this area,contact Shawn Searle.

Decommissioning and Installation of Jacket Topsides.

Evaluation of a Deepwater Pipe Laying Vessel.As technological advances allow additional deepwatersites to become viable for commercial production, ithas become necessary to develop oilfield servicevessels that are capable of operating in these oftenharsh environments. In developing a new breed ofdeepwater pipe laying vessel, Bender Shipbuildingand Repair Limited (Bender), in association with GuidoPerla and Associates Incorporated (GPAI), wanted toensure that their design would achieve the highstandards demanded by today’s oil industry.Consequently, Oceanic was contracted to evaluate thehydrodynamic performance of their 406-foot design.

The significant hull features of this design include abow bulb, two moonpools, two tunnel thrusters andthree z-drive units for the main propulsion. To assessthe vessel, Oceanic undertook a comprehensive testprogram of physical model experiments in conjunctionwith numerical modeling. The physical tests, completedwith a 1:17 scale model for various operationalconditions, included an assessment of bare hull andappended resistance in calm water as well as

self-propulsion tests. Flow visualization tests checkedfor possible flow problems in the vicinity of themoonpools and tunnel thrusters. Given the propulsionarrangement, a detailed wake survey assessed theflow into the propulsors. A milestone was achievedduring this project in that three model z-drive unitswere used for the self-propulsion tests. While theseinstrumented units were designed and fabricated

in-house specifically for this project, they allow Oceanicto further expand its overall testing capability.

Vessel seakeeping was examined numerically usingOceanic’s time domain seakeeping code MOTSIM.For zero and operational speeds, the code generatedResponse Amplitude Operators for various locationson the vessel. The possible inclusion of a roll tank onthe vessel was also assessed. Irregular spectrumsimulations were completed for specific sea conditions;the resultant motions and accelerations provided inputfor structural calculations.

Given the complexities of some of today’s new designs,quantitative assessment of hydrodynamic performanceat the design stage is imperative. With the resultsprovided by Oceanic’s team of engineers, Bender andGPAI have obtained advance knowledge of theexpected performance of their design.

For more information in this area,contact Michael Doucet.

The international petroleum industry is moving intodeeper water. This global trend poses new challenges,most importantly the development of a technologythat can predict the behaviour of the systems deployedto develop deepwater oil and gas fields. The targetsfor deepwater development are now approaching10,000 feet.

One of the most challenging technical tasks indeepwater development is the prediction of the globalresponse of a floating production system. Theuncertainties inherent in analytical approaches are

traditionally resolved by model testing which hasscaling law conflicts for various components and modelbasin depth limits. Scaling laws which would enablethe use of complete system model tests do not exist,and, for this reason, the industry tries variousapproaches to predicting the global response.

Oceanic is now part of the ongoing effort to resolvethese issues; participation in the DeepStar project(described on page 2) is one such initiative, and offeringa suite of complementary testing facilities for R&Dprojects is another. Oceanic offers the following

facilities for this type of work:• A 200 Meter Wave/Towing Tank, 7 meters deep• An Offshore Engineering Basin, 3.2 meters deep• A 90 Meter Ice/Towing Tank, 3 meters deep• A 22 Meter Flume Tank, 4 meters deep• A Wave Basin, 3 meters deep equipped with a 6 meter diameter and 15 meter deep pit at the center.

For more information in this area,contact Tor Naess.

Tests on the decommissioning and installation of Jacket Topside.

Model of Z-drive units - Deepwater Pipe Laying Vessel.

Profiling Project Manager: Bruce Paterson.As one of Oceanic’s senior project managers,Bruce Paterson offers consulting experience innumerical and physical model testing, field trials,software development, and concept design studies.In the role of project management, Bruce has beenlargely involved in FPSO test programs, particularlythe White Rose development project.

Prior to joining Oceanic, Bruce spent eleven years withBMT Fleet Technology Limited, ultimately as managerof the Marine and Offshore Group, where he handledprojects for government and commercial clients.Bruce’s experience includes the conceptual designand class approval of a semi-submersible transshipmentstation; technical support in the bidding stages for theshuttle tankers of the Hibernia project; engineeringsupport for the Canadian Coast Guard in the acquisitionof the icebreaker vessel Terry Fox; and concept studiesfor the Canadian Navy’s multi-role replenishmentsupport vessel and the United States Coast GuardGreat Lakes icebreaker replacement project. He hasconducted tests and trials aboard a range of vesselsfrom heavy icebreakers to coastal ferries; he has beeninvolved in seakeeping analyses and sales ofcommercial seakeeping software; and he has beenactive in marine safety work, specifically the stabilityand recovery of life rafts and the damage stability ofself-unloading bulk carriers.

Bruce has a Master of Ocean Engineering Degree fromMemorial University of Newfoundland, and is also agraduate of the University of British Columbia’sMechanical Engineering (Naval Architectureoption) program.

Bruce will represent Oceanic at the Offshore TechnologyConference in Houston, Texas, May 6th-9th, 2002.Past, present and potential clients with any questionspertaining to marine performance evaluation areinvited to visit him at Exhibit 2641.

Bruce Paterson, Senior Project Manager.

Making WavesNewsletter of Oceanic Consulting Corporation

Spring/Summer 2002

• IMD Offshore Engineering Basin • IMD 200 Meter Wave/Towing Tank

• OERC 58 Meter Wave/Towing Tank • IMD 90 Meter Ice/Towing Tank • IMD Cavitation Tunnel

• MI 22 Meter Flume Tank • MI Centre for Marine SimulationSpecification sheets can be obtained from the Oceanic website or by contacting one of our offices.

IMD Offshore Engineering Basin - Facility Specifications:

Specification Sheets are Available for all Major Facilities, Including:

In this issue...

Profiling Our Houston Office.

Meet us at:

St. John’s, NewfoundlandJune 19th - 20th

Booth 608oceanic@oceaniccorp.com www.oceaniccorp.com

95 Bonaventure Ave., Suite 401P.O. Box 28009, St. John’s, NewfoundlandA1B 4J8 CanadaTel: (709) 722-9060Fax: (709) 722-9064

In Canada:9801 Westheimer, Suite 302Houston, Texas77042 USATel: (713) 917-6805Fax: (713) 917-6806

In the United States:

Houston, TexasMay 6th - 9thBooth 2641

Length 75m

Width 32m

Max. Water Depth 3.2m

Wave Making System (power) 1800kW

Max. Wave Height (regular waves) 1m

Max Sig. Wave Height (irregular waves) 0.5m

Range of Wavelengths 0.5m to 20m

Articulation of Waves (modes) Flapper, Piston, Combination

Wave Spectra Regular, Irregular, Bi-modal,

Multi-directional

Current Speed Water-depth Dependent

(0.2m/sec at 2m depth)

Average Wind Velocity 11m/sec at 1m from Fan

5m/sec at 5m from Fan

Turbulent Wind Spectrum Mean Speed 12m/sec

Wind Spectra American Petroleum Institute

Standard, Norwegian Petroleum

Directorate Standard,

Other Industry Standards

Optical Tracking System Accuracy

Moored Models ±1mm

Free-running Models ±5mm

As announced in our last newsletter, Oceanic has opened abusiness development office in Houston, Texas, to establish apermanent presence in this major engineering/design center.

This is part of Oceanic’s strategic initiative to gain a preciseunderstanding of client needs and build strong

working relationships.

In the offshore industry, technology is continuously changingand manufacturers and designers strive to produce superiorsystems. Since Oceanic has conducted testing on a variety

of concepts for the marine and offshore industry, we canassist clients with specific design solutions and

determine the need for design fine-tuning.

Oceanic’s expert services are now more easilyavailable to clients in the United States. If

you contact our Houston office, we canvisit you and demonstrate how a test

program may help improve your design.The Houston office responds to questions

and provides clients with regular reports onproject progress. Oceanic also keeps abreastof new developments in the industry and will

inform clients directly of how model testing willallow them to use, or perfect the use, of new

technologies in their designs.

Oceanic provides quality answers to your questions.Our world-class facilities and expert technical and research

personnel can help you formulate a marine evaluationprogram for your specific requirements. Call Clint Gosse

at our Houston office, (713) 917-6805.

• Profiling Our Houston Office.• Charting the Course: Spring/Summer 2002.• DeepStar and Oceanic.• Testing FPSOs: A Core Business.

• Oceanic’s Deepwater Initiatives.• Profiling Project Manager: Bruce Paterson.• IMD Offshore Engineering Basin -

Facility Specifications.

• Decommissioning and Installation ofJacket Topsides.

• Evaluation of a Deepwater PipeLaying Vessel.