Ulstein Lands First 'X-Stern' Order

An illustration of the ULSTEIN SX175 offshore wind service vessels for Windea. Illuatrations courtesy Ulstein

Norwegian shipbuilding group Ulstein says it has booked its first order for newbuilds featuring its ‘X-STERN’ technology, an obvious successor to the company’s proprietary X-BOW hull line.

The order came in the form of two offshore wind service operation vessels (SOVs) of the ULSTEIN SX175 design ordered by Germany-based Bernhard Schulte through its offshore wind affiliate WINDEA Offshore GmbH & Co. KG.

Ulstein says the order marks the first for vessels featuring the X-STERN hull line design, which was only recently unveiled in August 2014. The design of the vessels will of course the X-STERN with the unmistakeable and proven X-BOW.

“We have had a close and very good cooperation with the owner during the process and are very pleased that WINDEA chose this innovative solution, and that the first vessels with X-STERN will be built,” states Kolbjørn Moldskred, Sales Manager Offshore Wind at Ulstein Design & Solutions.

The vessels can accommodate 60 people in single cabins, of which 40 cabins are dedicated to technicians who service offshore wind turbines. The vessels will measure 88 meters long, have a beam of 18 meters, and will be operate at speeds up to 13.5 knots.

The main characteristic of the X-STERN is a sloping and higher stern, which allows for a sharp stern shape where the transom plate is replaced by a pointed aft. According to Ulstein, this results in increased station keeping, reduced wave response, improved crew safety and comfort, and reduced power consumption. Ulstein says that the design is particularly useful for vessels where the best possible motion characteristics are essential, as is the case for vessel’s servicing offshore wind farms. For station keeping, this means that a vessel featuring the X-Stern can be positioned with the stern faced towards the weather instead of the bow, leading to improved weathervaning, greater operability and reduced power and fuel consumption by as much as 25% while on DP, according to a statement from Ulstein announcing the X-STERN technology in August.

“Delivery schedule reliability was our number one priority when choosing the ship yard. We considered several yards worldwide, but Ulstein Verft was our final choice. They have a solid reputation, not only on keeping to delivery schedules, but also of delivering innovative vessels of high quality,” says Matthias Müller, Business Development Director at Bernhard Schulte.

“These are the first service operation vessels for the wind industry to be built at the yard and we look forward to delivering two state-of-the-art vessels in Q2 2016 and Q1 2017,” comments Kristian Sætre, Managing Director at Ulstein Verft.