GustoMSC has developed a new floating feeder solution, capable of loading wind turbine components in port and transporting them to turbine installation jack-ups at in-development offshore wind farm sites.
Monikered the Steady Top Feeder Vessel (STFV), the concept proposes a 120m x 32m ship with a BargeMaster BM-T1500G motion-compensated platform. When arriving at the wind farm, the STFV would switch to dynamic positioning (DP) mode, allowing the on-site installation jack-up to offload its haul of turbine components.
GustoMSC says: “Optimised main dimensions and hull design offer: a high transit speed; improved motion behaviour, for maximum workability; low air draught; a small beam, for increased port access; and a low depth, to allow for port loading using multi-wheelers.”
As well as being aimed at emerging offshore wind sites in Europe, Japan and Taiwan, the STFV is being mooted as a potential solution for US operations, where the Jones Act requires the use of US-flagged vessels for turbine component transportation, and where the number of ports capable of accommodating larger, self-transiting installation jack-ups is limited.
The BM-T1500G platform has been developed to measure vessel motions and actively compensate roll, pitch and heave motions using three hydraulic cylinders. GustoMSC adds: “Position-keeping in the lateral plane – surge, sway and yaw – is achieved by means of DP with the vessel’s thrusters. Additionally, the vessel is equipped with a flume type anti-roll system.”
The skidding system moves the turbine components from the storage area to the platform, for lift-off. It comprises fixed skid rails affixed to the skid deck, plus skid carts that support and propel the turbine components to the lift-off position. The turbine components are separated into five sections, positioned on five dedicated supports: three tower components; one nacelle and hub; and one blade rack, consisting of three blades.
“The skid carts are able to move in longitudinal and transverse direction while the vessel is afloat on DP,” GustoMSC adds.
The STFV’s deck measures 92m x 32m, spanning more than 3,000m2 of space, and is strengthened to 15tonnes per m2. The vessel will have a maximum lift-off capacity of 1,500tonnes and will be able to operate safely in wave heights of 1.5-2.5m.
The DP2 system will be supported by a pair of 3.5MW main propulsion thrusters, and the vessel will be fitted with twin 1.8MW tunnel thrusters and a 1.5MW retractable forward thruster. GustoMSC envisages a combined 16.2MW of diesel engine power for the STFV, backed by a 1,000kW emergency diesel generator.
In addition to carrying wind turbine components, the STFV has been designed to transport monopiles, transition pieces, jackets and topsides, a factor that could increase its scope for availability across the broader offshore sector. The customer also has the option for a gangway system and/or additional crew transfer facilities, plus the chance to incorporate LNG into the STFV's powertrain.