New windfarm vessel concept from Norway

By Peter Pospiech at October 24, 2013 07:30
Filed Under: Company News, drive systems, General, Shipyards, Workboats

This new design has been developed by the experienced Fjellstrand shipyard, Norway, which is noted for building advanced fast passenger ferry designs. These windfarm vessel designs were developed as the yard seeks to diversify into new markets and it received orders for six of the Windserver vessels from World Marine Offshore before the first vessel had been built. The hull design is a trimaran with the centre hull designed to operate as a SWASH (Small Waterline Area Single Hull) with the narrow side hulls providing stability The first two units of a revolutionary new type of windfarm vessel have been delivered by a Norwegian shipyard. The new design combines technology from SWATH and trimaran concepts with the addition of some fast ferry technology to create a vessel that is claimed to be both fast and seaworthy and to have good low speed stability. The Windserver design was one of the concepts that were shortlisted in a competition held by the Carbon Trust to find improved concepts to support and service windfarm installations. The Windserver designs come in two sizes, one of 25m in length and one of 30m, with the construction of both designs in aluminium. The 25m version is certified to carry 12 technicians whilst the larger version will be coded for 25 people. 

The hull design is a trimaran with the centre hull designed to operate as a SWASH (Small Waterline Area Single Hull) with the narrow side hulls providing stability. The lower bulbous section of the centre hull is supported by two slim vertical struts and the hull is fitted with a ballasting system that allows the vessel to operate at a lower resistance and a higher speed when de-ballasted. This allows a transit speed of 25 knots on the outward and return passages to a windfarm whilst the vessel is ballasted down to create a stable platform when performing transfers or when the speed reduces to 12.5 knots. The propulsion is provided by four diesel engines which are coupled in pairs to provide twin screw propulsion through Servogear CP propellers. This arrangement was selected to provide a flexible propulsion system with a high level of redundancy. Fjellstrand can also offer these designs with water jet propulsion as an alternative and features such as thrusters and dynamic positioning can also be added.

Fjellstrand has used their motion control experience to develop a passive system for these vessels that is based on two fins at the bow of the centre hull. These fins act as motion dampers in waves to provide a smoother ride for passengers. In developing these designs Fjellstrand has included the possibility for them to be used in alternative roles such as surveying, search and rescue, operating UAVs and for diving support so that the vessels can be used at windfarms as they industry moves from the construction phase to the maintenance phase. The larger sizes of wind farm service vessels, with their improved seakeeping, will find employment as the industry moves from the inshore development to locations farther offshore. It can be 100 miles or more from the shore in more exposed waters. The World Marine vessels will operate from Denmark in the Danish sector of the North Sea initially.


Image: courtesy of Fjellstrand

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