Østensjø Rederi has now received delivery of Edda Passat, the first of two purpose-built Service Operation Vessels (SOVs) that will carry out services in offshore wind farms. Its sister ship, Edda Mistral, is scheduled to be delivered in August. “The vessels will be under contract with Ørsted (formerly Dong Energy) for a period of five years. There is also an option to extend the contracts,” says Østensjø Rederi CFO Håvard Framnes. After Edda Passat’s delivery, the ship set sail for duty in the Race Bank offshore wind park, 27 kilometres off Norfolk, England, where it will assist in servicing the wind farm’s 91 turbines. Sister ship Edda Mistral will operate east of Race Bank, in Hornsea One, which will be the world’s largest offshore wind farm when completed in 2020. With its 174 turbines, the enormous wind farm will produce electricity equivalent to the annual consumption of 800,000 British households.

High standard

These thoroughly modern sister vessels will serve as mother ships for technicians working to maintain the turbines. The wind farms are situated well out at sea, so the crew must be able to remain aboard for long periods.

“The ships have all the facilities needed.” Håvard Framnes, Østensjø Rederi

“The ships have all the facilities needed to carry out their operations, and the standard is high throughout. They accommodate 60 people, including 40 technicians and a maritime crew of 20. There is a cabin for everyone on board, says Håvard Framnes. The two Østensjø vessels will act as floating bases in addition to carrying technicians and equipment to and from the wind turbines, so wind farm maintenance can be performed as needed. To ensure the safety of technicians as they board the turbines, the ships are equipped with a special heave-compensated gangway system. “The system compensates for the movements in the boat. The outermost part of the gangway, which is placed against the wind turbines, will remain completely still even in heavy seas,” Framnes explains, noting that the ships also have a heave-compensated crane for lifting equipment to and from the wind turbines.

Great potential

Østensjø Rederi, with 30 modern vessels in its fleet, has focused on tugs, offshore vessels and accommodation vessels. In recent years, the company has been eyeing opportunities in the ocean-based wind farms. “The offshore wind market is of great interest to us. There aren’t many purpose-built SOVs, and it is predicted that more will be needed. Major developments are being planned and some offshore wind farms are even being built without subsidies,” says Framnes, adding that Østensjø does not rule out constructing additional SOVs in future.

Easier to choose Norwegian

Export Credit Norway has contributed £25.8 million in financing for Norwegian equipment deliveries to the two service vessels. The loan has a 12-year term and is guaranteed by the Norwegian Export Credit Guarantee Agency (GIEK). “Export Credit Norway has made it easier for us to finance the project. Their financing also made it easier to choose Norwegian,” says Framnes, pointing out a great deal of equipment provided by Norwegian suppliers. Rolls-Royce provided the propulsion systems and design package. Numerous other small and large Norwegian suppliers participated as well, providing everything from Norwegian paint to the advanced gangway system. See video of Edda Mistral from Østensjø Rederi: