Unlocking massive energy potential GustoMSC has designed the Tri-Floater,

a semi-submersible wind turbine support structure, for this purpose.

Proven semi-submersible technology developed for the off shore oil & gas

industry is applied to a completely new setting in a new industry. The Tri-Floater

con� rms some impressive claims.

THE PIONEERS OF OFFSHORE ENGINEERING

TRI-FLOATERFLOATING WIND TURBINE FOUNDATION

ROBUST AND COST-EFFECTIVE

NG-1800XSELF-PROPELLED JACK-UP SAFE & ECONOMIC

NG-14000XSELF-PROPELLEDINSTALLATION JACK-UP DEEPER WATERS& HIGH LOAD& HOISTING CAPACITIES

TRI-FLOATERFLOATING WINDTURBINE FOUNDATIONROBUST ANDCOST-EFFECTIVE

ENSISHEAVY LIFTCRANE VESSELHUGE TRANSPORT& LIFTING CAPACITY

The � at-plated design allows for an effi cient and highly automated fabrication process, which lowers the construction costs considerably and can be easily upscaled for commercial size � oating wind farms. The columns are not connected by bracings. The bene� t is that this solution avoids having any fatigue sensitive details located below the still water line, where access for inspection and maintenance would be expensive.

Deep water wind turbines will be key to unlocking the massive energy potential in global off shore deep water where winds blow hard and often, and bottom-founded structures are not economically feasible. Worldwide, various demonstrator projects with full-scale off shore � oating wind turbines are in operation or under development. Recently Japan, Norway, Scotland, France, Portugal and the US state of Maine are home to such facilities. It is an area in which GustoMSC designs will play a signi� cant role in the future.

Dynamic stabilityThe GustoMSC Tri-Floater is a three-column semi-submersible with an off shore wind turbine column at the center. “The semi-sub structure can be tailored to � t any desired turbine and optimized for local environmental conditions,” explains Fons Huij s, Technology Coordinator

TRI-FLOATER

FLOATING OFFSHORE WIND TURBINE FOUNDATIONFloating off shore wind turbines have a great potential to unlock deep water wind resources. The key requirements for the commercializing of � oating wind are lowering the costs and enabling the industrialization at large scale. The robust and cost-eff ective GustoMSC Tri-Floater satis� es these requirements.

Model testing in irregular waves and gusted wind

MAIN PARTICULARS FOR A 5 MW TURBINESurvival signi� cant wave height  9.4 mMax. operational sign. wave height 6.5 mWater depth 100 mWind turbine rated power 5 MWHub height above SWL 90 mLength overall 76 mBeam overall 87 mOperational draft 13.2 mTransit draft 7.5 mSteel structure 1,800 tOut� tting 150 tWind turbine 560 tWater ballast 970 tStatic mooring load 150 tTotal displacement 3,630 tExtreme static & dynamic roll/pitch < 10 degAccelerations nacelle (operational) < 3 m/s2

These particulars are for an example design case. The Tri-Floater can be tailored to � t any desired turbine and optimized for local environmental conditions.

This allows for a high level of automated welding, resulting in low construction costs. In addition, the fabrication process is very well suitable for industrialization and can easily be scaled up for commercial size � oating wind farms.

Validated by model testsModel tests con� rmed that the Tri-Floater design performs outstanding under the combined in� uence of wind and waves. For all tests, the � oater inclination, turbine accelerations, deck box air gap and mooring line tension were amply within the design limits.

Proven TechnologyThe Tri-Floater technology is based on GustoMSC’s long experience and track record in oil and gas semi-submersible design. In addition, several three-column semi-submersible � oating wind turbines have been installed off shore during recent years. The performance of these semi-submersibles matched the expectations based on model tests and coupled simulations. As the underwater shape is rather comparable with the Tri-Floater design, the same can be expected for the Tri-Floater. Thanks to the prototypes, three-column semi-submersible � oating wind turbines can nowadays be considered as proven technology.

GustoMSC has developed the Tri-Floater technology to such a level that it is ready for full scale off shore application, enabling the commercialization of � oating off shore wind energy.

Hydrodynamics at GustoMSC. “The design ensures the dynamic stability of the wind turbine. The semi-submersible hull design is such that the natural periods of motion are outside the range of the wave periods which means gentle motions and only mild accelerations.” The Tri-Floater can be moored using a catenary mooring system consisting of chain and drag anchors. The mooring system is connected to the Tri-Floater high up the columns to minimize the overturning moment induced by the wind load. It eff ectively reduces the mean inclination of the � oater due to wind. This allows for a relatively small � oater without an active ballast system for roll and pitch compensation. This reduces the number of active components and the related risk for failures.

Effi cient installationUnlike a tension leg platform (TLP), the semi-submersible does not rely solely on its mooring system for stability. The Tri-Floater equipped with the wind turbine is stable and can be towed to location on its own keel using tugs, where it is hooked up to a pre-laid mooring system. This installation procedure eliminates the need for expensive off shore crane vessels. The transit draft of the Tri-Floater is such that it can enter most ports or dry docks, allowing to install the wind turbine onto the � oater using an onshore crane, which is a major advantage compared to deep draft spar type of � oating wind turbines. At the wind farm site, passive sea water ballast is added to submerge the � oater to its operational draft. Although the unit will be designed for low maintenance, the unit can be towed to an inshore location for major maintenance or repair works.

Easy fabricationThe slender and robust structural design of the Tri-Floater is optimized for easy fabrication, based on stiff ened steel plating as commonly used for ships and conventional � oating off shore platforms.

GustoMSC is a reputable design & engineering company of mobile off shore units and equipment. In close cooperation with our clients, we translate experience, science and technical knowledge into realistic & innovative ideas. In this way, GustoMSC enables and supports safe and effi cient operations at sea, contributing to a sustainable future.

GustoMSC

Karel Doormanweg 35

3115 JD Schiedam

The Netherlands

T +31 (0)10 288 30 00

F +31 (0)10 288 30 01

GustoMSC USA

10353 Richmond Avenue

22nd   oor

Houston, Texas, 77042 USA

T +1 713 380 2600

www.gustomsc.com

info@gustomsc.com

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HIGH WAVES

EXCELLENT MOTION BEHAVIOUR

DEEP WATER

UNLOCKING NEW WIND RESOURCES

STRONG WINDS

HIGH TURBINE PERFORMANCE

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Annual average Bft.

FLOATING WIND

MAXIMIZING REVENUESMINIMIZING COSTS

GENTLE MOTIONSThe semi-submersible hull shape ensures that the natural periods of motion are outside the range of wave periods. This results in gentle motions and limited accelerations at the wind turbine nacelle.

INNOVATIVEMOORINGThe mooring lines are connected at a high level on the � oater, in order to minimize the wind over-turning moment. This allows for a smaller and more cost-eff ective � oater.

EFFICIENT MANUFACTURINGThe � at-plated structure enables effi cient manu-facturing, using a high level of automated welding. Standardized blocks can be manufactured at dedicated yards and assembled close to the wind farm.

SHALLOW DRAFTThe Tri-Floater is so stable that the wind turbine can be installed using an onshore crane, before towing the complete structure to site. The shallow draft allows to enter most ports.

NO BRACINGSThe slender and robust shipbuilding type structure is optimized for easy fabrication, without any bracings. All fatigue sensitive details are located above the still water line, easily accessible for inspection and maintenance.