Case Studies > Design: Vessels

Windfarm Offshore Support Base Vessel

Houlder has developed a windfarm Offshore Support Base (OSB) vessel. The concept recreates the convenience of port facilities – but offshore.

Uniquely, Houlder has been able to turn to a highly stable proven hull design from its Oil & Gas heritage to deliver high crew comfort and excellent operability through stability.

The DSV (Dive Support Vessel) Orelia hull design has a long history of providing stable, safe and highly operable diving support. Its provides superior seakeeping to that of a standard monohull vessel. Motions are comparable to Semi-submersibles in North Sea conditions. Using a proven, highly stable design significantly improves comfort levels onboard for future windfarm maintenance crews. In typical North Sea crew transfer conditions, the Orelia hull design limits roll to +/- 1 degree.

A stable platform means a straight-forward walk to work personnel transfer system can provide direct turbine access. Expensive, complex motion compensating technology can be avoided. For further flexibility, Houlder’s design provides three docking stations for Crew Transfer Vessels. A helipad also maximises deployment and crew transfer options.

Taking Dogger Bank as an example, the vessel will stay in the windfarm continuously throughout the summer weather period. It will be re-supplied by standard supply boats. Crew and maintenance personnel can be changed out as required. During winter periods, when crew transfer becomes more challenging, returning the vessel to port on a 28 days’ cycle proves more cost effective.

Facilities are based on the latest offshore Oil & Gas standards including private cabins, wet rooms and project offices. Home comforts include cinemas, gyms and games rooms. The design leaves significant scope for additional client requirements.

Key particulars:
• LOA: 126m
• Breadth: 17.4m
• Moulded Depth: 11.25m
• Draft: 5m
• Speed: 10knts

• Windfarm Maintainers 80 (single cabin)
• Marine Crew: 27 (single cabin)