Evaluation of an Extendable Draft Platform....• Evaluation of an Extendable Draft Platform. •...

• Evaluation of an Extendable Draft Platform.

• Charting the Course: Spring/Summer 2004.

• Preparing Sakhalin II for Mating.• Flume Tank Aids Study of Vortex

Induced Motions.• Evaluation of a Mini Spar Concept.

• New Research in Escape, Evacuation and Rescue.

• Researcher Computes Ice Loads onOffshore Structures.

• Tandem Offloading Vessels and theProblem of Coordinated Control.

• Evaluation of Single Point Mooring Systems.

• Deepwater Moorings.• Researching Vortex Induced Vibration.• Journal Publications and

Conference Papers.• Personnel on National/

International Committees. • MI 22 Meter Flume Tank –

Facility Specifications.

In this issue...

The Extendable Draft Platform (EDP) is a unique concept developed by Technipthat offers the benefit of complete outfitting at dockside and minimal assistanceduring installation. Oceanic Consulting Corporation recently conducted an extensive model test program to evaluate the overall performance of the platform. Included in the program were tests to evaluate the stability andmotions of the EDP under tow during pre-service transportation, as well as experiments to investigate vessel response during the 100-year hurricane and 1-year winter storm conditions when installed on site.

In addition to a seakeeping evaluation, a structural load evaluation was conducted to investigate the forces and moments at the pontoon/column and deck/column interfaces.

Measurements included motions and accelerations on the EDP, forces andmoments at the column/deck and column/pontoon interfaces, as well as

mooring and riser tensions. Further seakeeping and structural evaluations of theconcept by Technip indicated a very good correlation with the model test results.

The full program was conducted in the IOT 200 Meter Towing Tank and the Offshore Engineering Basin (OEB). The testing program provided some interesting technical challenges. In particular, the requirement to accurately measure the forces and moments at the interfaces of the main components. This was overcome through the use of some novel dynamometry design.

Overall, the program was a success as Technip obtained valuble and reliable information that they can now use as they continue to enhance their concept and Oceanic increased its experience with novel deepwater platforms.

Shawn [email protected]

Evaluation of an Extendable Draft Platform.

Spring/Summer 2004

The Avalon Peninsula clings to the east coast of Newfoundland like a starfish holding a rock, with four legs stretched out into the Atlantic Ocean. The one connecting it to the rock calledNewfoundland is the Isthmus of Avalon, and fromthat thin strip of land one can literally watch theNewfoundland offshore oil industry grow.

On a clear day, you can see the first player in theindustry, the North Atlantic Refinery in the smalltown of Come by Chance. Just beyond is theWhiffen Head transshipment terminal in PlacentiaBay where crude oil is brought from the Hiberniaand Terra Nova oil fields some 225 nautical milesaway. As shuttle tankers travel up Placentia Bay,they pass the Cow Head Fabrication Site nearMarystown where the SeaRose FPSO is being outfitted for operations at the White Rose oil field.

Looking north, you can see Trinity Bay. TheHibernia gravity base structure was built at Bull Armin the bottom of the bay. A few years later TerraNova, Newfoundland’s first FPSO, was outfitted at the same site. Unlike Placentia Bay with its year-round ice free water, Trinity Bay is exposed

to the North Atlantic and for a good part of thespring is covered with pack ice and icebergs.

What you can’t see from the isthmus is whatmakes Trinity Bay most interesting. It is deep.

Trinity Bay is so deep, in fact, that it is really anunderwater canyon that leads out of the bay rightto the Orphan Basin, likely the site of some of the

most lucrative offshore oilfields in the western hemisphere. The Orphan Basin, with 2200 meters

of water, 20 meter wave heights, 150 knotwinds, multimillion tonne icebergs and substantial pack ice, is also likely to prove

to be the most technologically challengingoffshore site in the world.

This newsletter demonstrates how Oceanic and its partnerorganizations, the Institute forOcean Technology and Memorial

University, are up for the challenge.

On the cover you will read about our work for Technip Offshore in assessing its Extendable Draft Platform. On the facing page and in previousissues of Making Waves you will learn about flumetank evaluations of spars for the same company.Unique deepwater sites require unique solutions and Oceanic has been working with some of theworld’s leading experts in developing solutions for deepwater sites around the world. We are nowable to bring those lessons home to work on projectsoff our own coast.

While our deepwater projects off the coast of Africaand in the Gulf of Mexico may not have ice problems,the work we do for the east coast of Russia does.Testing has been carried out in the IOT 90 MeterIce/Towing Tank for a Single Buoy Moorings project off Sakhalin Island. Evaluating mooring loads in bothice and waves assists Oceanic in building a capabilitythat can be integrated with our deep water work as we help our own industry in the Orphan Basin. Our research efforts are also helping to broaden ourcapability to support the growth of our industry.Efforts are being undertaken at MUN and IOT inescape, evacuation and rescue. Work at IOT isexpanding our knowledge of ice loads on offshorestructures. Working with IOT and MUN personnel,Oceanic is continuing to build its capabilities in modeling deepwater moorings.

There is an expression in Newfoundland that says,“What goes around comes around”. It is usually usedin reference to revenge on practical jokers, but it isalso relevant here. Oceanic and its partners learned much about the offshore industry by working onHibernia and Terra Nova. We took that experienceand nurtured it on projects for Africa, the Gulf ofMexico, Sakhalin Island and Southeast Asia. Now we will need all those lessons for Newfoundland’sOrphan Basin, and beyond.

For Oceanic Consulting CorporationBest Regards,

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

Charting the Course: Spring/Summer 2004.

Preparing Sakhalin II for Mating.tested in open water, and then in place on the

GBS. Results of the tests were then usedto determine the correct force vector toapply to the model to simulate current

loading during the next phase of testing.

The final and most extensive testing phasewas conducted again in the OEB. The objective of Phase 4 was to determine the force interactions between the barge, topsides and GBS structures. The testing in this phase was broken into five stages.The first stage of these tests was designed

to determine fender loads at the mating pull-instage. To optimize the fender design, bargefenders were tested with three different spring rates. Starting at the pull-in stage,

with the topsides supported wholly by thetransportation barge and with clearancebetween the topsides and the GBS, the

barge was ballasted in stages until the topsides were fully supported on the GBS, with

clearance between the barge and topsides.

An extensive, four phase test program hasbeen completed for the transportationand float-over installation of atopsides unit for the Sakhalin II project.Phase 1 of the test program was conductedin the IOT 90 Meter Ice/Towing Tank todetermine drag forces on the transportationbarge. Using Oceanic’s Planar MotionMechanism (PMM), drag on the barge wastested in 15° increments for a full 180°.Phase 2 of testing was conducted in the IOT Offshore Engineering Basin (OEB), inwhich the seakeeping properties of the transportation barge with topsides was evaluated in regular and irregular waves.

After completion of the transportation tests, the next two phases of testing focused on the float-over and installation of the topsides.Phase 3 of testing was again conducted inthe IOT 90 Meter Ice/Towing Tank to identifythe effect of the GBS on the barge current drag loading. The drag of the transportation barge was

The second, third and forth stages of testing investigated the interactions of the three bodies at different stages (0%, 50% and 100%) of load transfer from the barge to the GBS. At the fifth and final stage of this phase of testing, the topsides were fully supported by the GBS and there was clearance between the barge and topsides. A further series of tests wereconducted on the same models in deeper water.The GBS structure was extended upwards and tests at two of the float-over conditions (pull-in and 100% load transfer) were repeated.

Specialized mechanical devices were necessary toreplicate the mechanical properties of the fendering,support and mating systems, and to accuratelyrecord force loading. In particular, to match the polymer materials of the leg mating system betweenthe topsides and GBS, a system was designed withthe specified non-linear spring properties.

Tim [email protected]

Testing of SPARs in the MI 22 Meter Flume Tankoffers several unique opportunities for the study of Vortex Induced Motions (VIM). As the Flume Tank allows tests to be conducted for a long duration, phenomenon such as beat envelops in the VIM can be observed. In addition, the underwater viewing gallery of the tank provides a unique opportunity for flow visualization.

Oceanic Consulting Corporation has recently completed a third set of SPAR VIM tests in the MI 22 Meter Flume Tank and the IOT 200 MeterTowing Tank. A control set of test runs was conducted in both tanks, the results of which indicated a good correlation between the tests conducted in the two facilities.

The Flume Tank also offers the possibility of creatingsheared flow profiles for testing deep draft vessels in wind generated currents. Phase 1 of the testing,involving the creation of sheared flow profiles, has shown promising results and Phase 2 of development is scheduled for March 2004. The primary focus will be to investigate simple methods of producing various shear flow profiles.Once completed, Phase 2 of the shear flow development should provide Oceanic with sufficient information to produce wind generated surface currents with relative ease.

A secondary focus for Phase 1 was placed onincreasing the efficiency of the uniform flume flow.Several minor inefficiencies were identified during

this phase of testing and improvements were implemented during the regularly scheduled annual maintenance.

John [email protected]

Tim [email protected]

Flume Tank Aids Study of Vortex Induced Motions.

interest are the basic motion characteristics and ability of the life-craft to execute maneuversrelated to rescue. The more recent experimentalwork, together with numerical modeling, will beincorporated in the Survival Craft Simulator beingdeveloped at the Centre for Marine Simulation.The project moved a step closer to the prototypestage when funding was received in January from NSERC under the i2i (idea-to-innovation) program.

Several months ago, the EER team conducted full-scale trials of lifeboat deployments at theOffshore Safety and Survival Centre in St. John’s.That data, along with data from previous physicalmodel experiments, was used to validate the 3-dimensional numerical model developed for the same systems. In January 2004 the EER teamboarded the drilling rig Galaxy II for time trials in the launch of the vessel’s lifeboats.

Over the last year the team conducted a comprehensive set of experiments on the

A multi-year, multi-partner collaboration on escape,evacuation and rescue (EER) is forging ahead withmodel test programs, numerical models and fieldtrials. The project is managed by NRC’s Institute for Ocean Technology and Memorial University’sEngineering Department, with stakeholders in industry, government, training centres and regulatory agencies.

The EER team is embarking on experimental testing related to life-craft survivability and rescuein different weather conditions. Of particular

New Research in Escape, Evacuation and Rescue.

Evaluation of a Mini Spar Concept.In a recent test program, Oceanic ConsultingCorporation evaluated a proposed Mini Spar forSparTEC Inc. The Mini Spar is a floating productionplatform designed to support a marginal, deepwaterfield development with topside payload in the range of 1000 – 3000 s. tons. The experiments were conducted with a spar model moored in the uprightposition while the model was subjected to simulatedenvironments for various headings. During testing, measurements included spar motions, deckaccelerations, air gap, green water occurrence, globalshear force at the structural interface between the topside and the mid-body and mooring line tensionsfor each of the environmental conditions investigated.

In addition to the in-place testing, a series of VortexInduced Motion tests (VIM) were performed in the

200 Meter Towing Tank. The environmental conditions included regular and irregular waves, current and wind. In total, four different stroke configurations were examinedfor intact and damaged moorings, as well as for intact and flooded hull compartments.

Vessel responses during the wave testing were proportional to the environment being tested. The hurricane environments were most severe with larger, more frequent motions experienced.The ten-year winter storm had some moderate vessel responses but the magnitudes were

significantly reduced, while the one-year storm produced little significant vessel motion.

John Monk

[email protected]

freefall lifeboat system in order to benchmark its performance in a range of weather conditions.EER personnel also examined lifeboats in ice-covered waters and waves in order to establish basic performance limits and the effects of additional power on the lifeboats’ operations.

All of this information is being added to the project’s database, which continues to be developed and upgraded by NRC’s CanadianInstitute for Scientific and Technical Information.The information gathered will be used to formulateguidelines for government and industry approval of safety equipment. The database is available at http://iot-ito.nrc-cnrc.gc.ca/eer/home_e.html.

Antonio Simoes Re

[email protected]

Brian Veitch

[email protected]

With increased oil and gas activity off the coast ofNewfoundland and Labrador, the risk for collisions of ships, offshore structures and marine installationswith ice is real. The probability for a severe accident(with significant environmental, human and capital liabilities) is increased by the fact that the environmentoff the Canadian East Coast is harsh and hazardous,with heavy sea states, wind and fog.

Designing offshore structures andships to withstand impact ice forcesis a major concern for structural engineers and naval architects

in the arctic and sub-arctic regions. In nature, there are various discrete ice masses, suchas bergy bits and growlers, and

there are various continuous ice features, such

as sea ice sheets, pack ice and ice ridges. At some point all of these interact and contact offshorestructures, marine installations and ships. The dynamicresponse of a structure to a collision with a discrete icemass is considerably different than its response when interacting with an ice sheet at low indentation speed.

Dr. Ahmed Derradji of the NRC’s Institute for OceanTechnology has developed what he calls “the universalfailure theory for ice.” The theory was developed afteranalyzing the results of over 500 tests on ice involvingsea ice, iceberg ice, fresh water ice and laboratorygrown ice. These test results were obtained from theopen literature and included the work of iceresearchers in various laboratories in North Americaand Europe over the last 30 to 35 years. In a way, Dr. Derradji’s theory is an extension of the traditionalfailure criteria developed for metals and geo-materials(rocks and soils) over the last 200 years.

Researcher Computes Ice Loads on Offshore Structures.

the two vessels. Also required is an improvedmethod of analyzing and validating the entirecontrol framework.

Millan has devised three approaches to the investigation, beginning with numerical analysis and thedevelopment of software tools.The second is scale-model testing to explore the efficacy of supervisory control systems versus independentcontrollers. The thirdapproach is full-scale trials,now under discussion withoffshore operators. Here, datawill be collected from ships operating in multi-vessel systems andthen compared with the model-scale results and numerically implemented systems.

“The research has potential benefits for a number of groups,”

Millan says. “They include controlequipment manufacturers, vessel

operators and regulatory agencies.”

Jim Millan

[email protected]

Researcher Jim Millan has been discussing withFPSO operators the problem of controlling tandemoffloading vessels. The difficulty lies with moored,dynamically positioned FPSOs offloading to similarly positioned shuttle tankers. The operationposes risks due to the close proximity of the twolarge vessels. Any number of factors can disrupt the offloading procedure, including excessivemotion of the shuttle tanker, dynamic positioningoperator error and abnormal interaction betweenthe positioning and power management systems, to name a few.

The NRC’s Institute for Ocean Technology researchersays the consequences of these problems can vary from excessive fuel consumption to incidentsthat could endanger life, the environment or thevessels. The solution, he believes, lies in increasedautomation through the use of a supervisory controller to coordinate the control systems on

Tandem Offloading Vessels and the Problem of Coordinated Control.

The universal theory has been implemented intoANSYS, a commercially available finite element analysis code. It has been validated against measurements of ice loads on the piers of theConfederation Bridge to PEI and on the Kemi-I lighthouse in the Gulf of Bothnia, between Finland and Sweden. In both cases, the capability of the universal model to predict actual ice loads was proven.

Dr. Derradji has also investigated ship-ice collisionforces and ice ridge impact forces on a cylindrical GBSdestined for the waters around Sakhalin, Russia. He is also involved in an effort to secure collaboration andfunding to study the effects of ice on a proposed fixedlink between Newfoundland and Labrador.

Ahmed Derradji

[email protected]

applied to the stern of the tanker to examine itseffects on tanker directional stability.

Phase 2, conducted in the IOT 90 MeterIce/Towing Tank, evaluated the performance of the TLU and tanker in ice conditions typical of the installation area. Ice floes ranging from 60 Meters - 7/10 coverage to 300 Meters - 9/10coverage and level ice were all examined for ballast and loaded tanker conditions.

Qualitative and quantitative evaluation of tankermotion, TLU ice loading, and interaction between

hawser and offloading hose was undertaken. Withthe TLU attached to the Planar Motion Mechanism(PMM) of the Ice Tank carriage, specific ice drift pat-terns were simulated. Modeling of straight-ahead,gradual (30°) and sudden (90°) ice drift shiftsallowed for force and motion analysis as well asidentification of specific operating issues.

The tests demonstrated that the proposed SPM system is capable of operating in the environmentalconditions identified for the installation location.

Paul [email protected]

Oceanic Consulting Corporation recently completed atest program to evaluate the proposed Single PointMooring (SPM) system for installation in Aniva Bay,Sakhalin Island, under the Sakhalin II Phase 2 Project.The SPM consisted of a Tanker Loading Unit (TLU) towhich a generic Suezmax Tanker was moored.

Phase 1 included the evaluation of the tankermotions and TLU response to open water environmental conditions. Current, wind and waves were simulated for a range of operatingenvironments, from normal operations to greater-than-maximum design conditions. Testing in the IOT Offshore Engineering Basin (OEB) allowed for wind and waves to be modeledat various directions relative to current.

During OEB testing, measurements includedmotions at the tanker CG, summer and winter oiloffloading manifolds, as well as yaw response ofthe rotating TLU head and mooring hawser loads.During one test, a simulated tug load was also

Physical modelling of floating structures moored in deepwater poses unique challenges in the representation of the mooring lines. Limitations of basin depths require that either the model scalemust be very small, or that a full depth modelmooring must be replaced with a mooring system offering an equivalent response butrequiring less basin depth. Ultra-small scalemodels (1:150 and less) are restrictive in thelevel of detail and instrumentation that can be used. Wave making at these scales is generally restricted to survival sea states, anddoes not allow fatigue testing. Larger modelscales (1:30 - 1:60) allow greater detail, range of instrumentation and sea states, but require an equivalent mooring system that will react

in the same manner as a full depth system.

As part of the DEEPSTAR (www.deepstar.org) research project, Oceanic has recently tested

an equivalent mooring system developed by Noble Denton Europe. Noble Denton used a numerical modelling program to develop mooring and Steel Catenary Riser systems in 2000ft and 3000ft depths that have an equivalent response to the design systems in 10,000ft. Oceanic built physical models of the 2000ft and 3000ft moorings and SCRs at two model scales. These lines were then tested with identical top connectionpoint motions and the response was compared.The tests verified that the systems in shallowerwater did produce equivalent force responses at the top connections, invariant of scale or depth. Some challenges still remain in understanding and matching the unique materialproperties of synthetic (polyester) mooring lines.

Don Spencer

[email protected]

Deepwater Moorings.

Evaluation of Single Point Mooring Systems.

Journal Publications and Conference Papers.Mukhtasor, Husain, T., Veitch, B., Bose, N. (2004).“An ecological risk assessment methodology forscreening discharge alternatives of producedwater.” Accepted for publication by J. Human and Ecological Risk Assessment.

Sadiq, R., Husain, T., Veitch, B. and Bose, N. (2004).“Evaluation of generic types of drilling fluids usinga risk-based analytical hierarchy process (AHP).”Environmental Management (In press).

Niu, H., Husain, T., Veitch, B., Bose, N. (2003).“Transport properties of offshore discharged syntheticbased drilling cuttings.” Oceans 2003, San Diego.

Sadiq, R., Husain, T., Veitch, B., Bose, N. (2003).“Distribution of arsenic and copper in sediment

pore water: an ecological risk assessment casestudy for offshore drilling waste discharges.” RiskAnalysis, Vol. 23, No. 6, 1309-1321.

Sarkar, S., Bose, N., Gosine, R., Walker, D., Sarkar, M. (2003). “Design and development of autonomous submersible dredger/miner.”International Conference on Coastal and OceanTechnology, National Institute of OceanTechnology, Chennai, India.

Thanyamanta, W., Hawboldt, K., Husain, T., Bose,N., Veitch, B. (2003). “Evaluation of offshore drilling cuttings management technologies usingmulti-criteria decision making.” EnvironmentalManagement (in press).

Oceanic Consulting Corporation has researched vortex induced vibration (VIV) of risers for the DEEPSTAR and VIVArray Joint Industry Projects (JIP).

A number of areas for improvement were identifiedafter initial testing and were addressed in Phase 2 to make a more versatile and reliable apparatus for general high Reynolds number VIV research. For instance, the stroke was increased to allow larger amplitude ratios, and forced VIV testing of a cylinder with amplitude ratios of 1.1 was recentlycompleted.

Significant improvements were also made in the freevibration setup including higher amplitudes, a bettertwo degree-of-freedom setup, and lower overall systemdamping. The towing linkages were redesigned to minimize cylinder rotation induced by the verticalmotion of the cylinder and tests confirmed the sameresponse for towing and pushing directions.

Improvements have been made to the control systemallowing better control of damping and smootherforced oscillations. As well, pre-assembly of majorsubsystems has streamlined installation, shorteningbasin time and reducing costs.

Commercial and fabricated strakes have been testedin free vibration mode, in forced mode, and in freevibration with inline as well as cross flow compliance(two degree-of-freedom). For free vibration testing,two turbulence grids are available giving approximately five and nine percent turbulence.

Some of the most interesting results have come from forced VIV tests with bare cylinders at differentroughness heights. The tests indicated that roughnesswas a very significant parameter in determining theresponse of a bare cylinder.

As part of the VIVArray JIP, the first forced tests with a straked cylinder have been completed mapping out areas of high damping at large amplitude ratios.Under the DEEPSTAR JIP the same strake was examined in free motion with two degree-of-freedomcompliance. Experiments with a rough cylinder with two degree-of-freedom compliance showed a significantly different response than those with the in-line motion constrained. The new extended datasets show good correlation with the previous DEEPSTAR Phase 1 results.

Don Spencer

[email protected]

Researching Vortex Induced Vibration. Personnel on National/InternationalCommittees.

Institute for Ocean TechnologyBruce Colbourne, Senior Research Officer

· Chair, Sea Operations Group, Canadian Standards Association

· Chair, ITTC Ocean Engineering Committee

· Groups SC7 and SC7/SC9 of the ISO (MarineOperations)

Ahmed Derradji, Research Officer

· Chair, ITTC Ice Committee

Pengfei Liu, Research Officer

· ITTC Azimuthing Podded Propulsion Committee

David Molyneux, Senior Research Officer

· Technical Committee/Canadian AdvisoryCommittee for ISO TC67/SC7

· Chair, Organizing Committee, 27th AmericanTowing Tank Conference

David Murdey, Director Facilities

· Chair, ITTC Advisory Committee

· Chair, 27th American Towing Tank Conference

· Chair, Host Committee, 25th Symposium on NavalHydrodynamics

Rob Pallard, Technical Officer

· International Technical Committee of the OffshoreRacing Council

Eric Thornhill, Research Officer

· Secretary of the Board, CFD Society of Canada

Mary Williams, Director General

· Chair, NSERC Faculty Awards Selection Committee

· Chair, Multidisciplinary Committee, CanadianFoundation for Innovation

Memorial UniversityNeil Bose, Canada Research Chair in Offshoreand Underwater Vehicles Design

· Chair, ITTC Specialist Committee on PoweringPerformance Prediction

· NSERC panel for evaluation of Strategic Projects

· Chair, Canadian Atlantic Branch of RINA

Brian Veitch, Associate Professor

· SNAME Education Committee

· ITTC Specialist Committee on the Assessment of Ocean Environmental Issues

Oceanic Consulting CorporationDan Walker, President

· Atlantic Innovation Fund

· Canada’s Shipbuilding and Industrial MarineAdvisory Committee

· SNAME Planning Committee

95 Bonaventure Ave., Suite 401St. John’s, NewfoundlandA1B 2X5, CanadaPhone: (709) 722-9060Fax: (709) 722-9064

[email protected] www.oceaniccorp.com

MI 22 Meter Flume Tank – Facility Specifications:

Specification Sheets are Available for all Major Facilities, Including:• IOT Offshore Engineering Basin • IOT 200 Meter Wave/Towing Tank

• OERC 58 Meter Wave/Towing Tank • IOT 90 Meter Ice/Towing Tank

• IOT Cavitation Tunnel • MI 22 Meter Flume Tank • MI Centre for Marine SimulationSpecification sheets can be obtained from the Oceanic website or by contacting our office.

Meet us at:

May 3-6, 2004Offshore Technology Conference (OTC)

Booth 1633

June 2-3, 2004Offshore Newfoundland Petroleum Show

Booth 613

Length 22m

Width 8m

Depth 4m

Max. Water Velocity 1m/secat Max. Water Depth

Max. Velocity of 1m/secMoving Ground Plane

Water Turning Vanes

20m x 3m Observation Window

Tank FiltrationSystem

Electric Drive MotorsImpellers and Diffusers

Moving Belt Ground Plane

Flow Straightening Devices

Flow Straightening ScreenWave Damper

Net Loft

4.7 Tonne Crane

Remotely Operated Towing Masts

Fishing Net Undergoing Testing

Underwater VideoSystemDebris Screen

Tests Performed:• Flow Visualization of Submerged Bodies

• Hydrodynamic Force Measurement

• Assessment of Fishing Gear Configuration

• Vortex Induced Motions

• Directional Stability

• Spar Motions

• Towed Vessels

Evaluation of an Extendable Draft Platform....• Evaluation of an Extendable Draft Platform. •...

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