It isn’t only the design of the service operation vessel for the Hohe See and Albatros offshore windfarms that is innovative. The charter contract awarded to the company that owns it also broke new ground
More often than not, a service operation vessel (SOV) is chartered by the turbine supplier on an offshore windfarm, but Bibby WaveMaster Horizon is a bit different. It is set to start work shortly on two EnBW/Enbridge-owned windfarms – Hohe See and Albatros – providing a base at sea for windfarm technicians who will service turbines supplied by Siemens Gamesa Renewable Energy.
The 90-m vessel, based on Damen’s ASV 9020 design, combines walk-to-work capabilities with class 2 dynamic positioning. It has an innovative hullform that ensures excellent seakeeping and the ability to continue working in challenging environmental conditions.
Together, EnBW and Siemens Gamesa are to charter the SOV for 10 years. Siemens Gamesa will charter the vessel for the first five years of operation, and EnBW for the second five years. The reasons for doing so are partly operational and partly financial.
As EnBW head of renewable generation Ralf Neulinger explained at the time the deal was struck, the joint agreement will not only generate synergies in operations, but will also make it easier to secure an advantageous financing framework for the vessel. Put simply, a joint charter helped to reduce finance risk and reduce the cost of the deal. And for EnBW, the decision to participate in the charter for the ship was not a difficult one: it has plenty of experience of chartering vessels, having first done so back in 2010 when it chartered a vessel for the Baltic 1 offshore windfarm.
EnBW describes the new vessel as “part floating workshop, part warehouse, office and hotel.” It has accommodation for up to 60 people and will remain at sea for up to 30 days at a time, which will eliminate the need for time-consuming transits to and from Hohe See and Albatros by crew transfer vessels. This is important because Hohe See lies 95 km north of Borkum and 100 km northwest of Helgoland. Albatros is being built in the same area.
Bibby Wavemaster Horizon is similar to Bibby WaveMaster 1, but differs in a number of respects. It has a newly developed gangway from Dutch supplier SMST which, with a breadth of 1.20 m, is wider than on other SOVs, allowing it to be used to transfer material and tools on Euro pallets. The gangway will provide stepless access to turbines from the vessel and has a multi-stop elevator with access to the height-adjustable, motion-compensated gangway. Combined, the elevator and gangway will enable windfarm technicians to directly access the gangway from storage areas on the vessel and trolleys with tools and equipment can be manoeuvred from the warehouse space on the vessel on a lower deck directly to the transition piece of the wind turbine. It will be capable of transferring personnel with a significant wave height of up to 2.5 m.
Bibby Marine Services managing director Stephen Bolton says the gangway on the original vessel continues to perform well, but the technology has moved on. “This new integrated system does away with the need for an independent lift tower,” he explains. “Now, the gangway hangs off the tower and matches where the lift is. All in all, the small number of changes that we have made to this second vessel shows just how good the first one was.” Compared to shipowner’s first vessel, some changes have also been made to the warehousing at the charterer’s request, and the bridge has been reconfigured.