Ulstein Delivers for BS Offshore

The vessel is built to the ULSTEIN SX175 design, which according to Ulstein, emphasizes optimization of the vessel’s movements in order to ensure the safe transfer of technicians and equipment for the maintenance and servicing of wind turbines.

“We considered several yards worldwide, but Ulstein Verft was our final choice,” said Matthias Müller, Managing Director at Bernhard Schulte Offshore GmbH. “We saw the benefit of having the designer and the yard in one place. Ulstein has the same approach as us – always going the extra mile to delight the final customer.”

“Together, we have developed a flexible and effective ship solution for the offshore wind service market,” said Tore Ulstein, deputy CEO and Head of Market & Innovations in Ulstein Group. “The project process has been very smooth, and the combination of expertise in our companies has led to fruitful discussions. We are happy to deliver, on schedule, this state-of-the-art SOV vessel, and are certain that she will serve BS Offshore and Siemens in a most satisfactorily way.” 

During sea trial, the bridge crew noted the vessel’s smooth motions and the very low levels of noise and vibrations – important factors for a vessel that will transport service technicians to the Gemini Offshore Wind Park, 85 kilometers north of the Dutch province of Groningen and a five-hour trip from shore. 

Ulsteain said a major focus of the design is on the welfare of the technicians who will live on board. For example, the cabins and facilities are positioned where the vessel’s movements are lowest.

Furthermore, the vessel’s  X-STERN and the X-BOW hull design features increase the operability through positive effects on station keeping, wave response, comfort and safety, and with reduced power and fuel consumption while on DP. The new-developed X-STERN aft hull design has an importance when it comes to the flexibility of the vessel. At sea trial, she managed to keep up high speed forwards and also when backing, and she is easily maneuvered both ways.

The BLUEDRIVE PlusC electric propulsion system from Siemens lowers the operational costs by cutting the engine time at the rated speed and reducing the number of electrical components required. Emissions are reduced by optimizing combustion. The vessel has an integrated DC-based common main drive system, with variable rpm control of the diesel engines for power and propulsion system. In addition to the catalyst, these will fulfill IMO-Tier3 environmental requirements.

The vessel is equipped with two varieties of transferral to the wind turbines, an integrated Uptime heave-compensated gangway system and a daughter craft with a capacity of 10 people.

The load capacity is well exploited. Spare parts and equipment can be transported in containers, of which six can be placed on deck and six under deck. The vessel provides excellent workshop facilities. The SOV has accommodation for 60 in single cabins, of which 40 cabins are dedicated to the technicians. 

Vessel type: Service Operation Vessel (SOV) for offshore wind turbines

Design type: ULSTEIN SX175

Construction yard: Ulstein Verft AS

Design company: Ulstein Design & Solutions AS

Length: 88 m

Beam: 18 m

Deadweight: 3,150 t

Draught (max): 6.4 m

Speed: 13.9 knots (bow first), 12.1 knots (stern first)

Accommodation: 60 persons

Cargo deck area: 380 m2

Dynamic positioning: IMO Class II (DYNPOS AUTR)

Main propulsion system: Two azimuth thrusters, each driven by a frequency controlled variable speed electric motor. 

Additional thrusters: One retractable azimuth thruster, two side thrusters forward