New WTIV Design to Handle Next Generation Wind Turbines

SeaOwls and Ulstein have launched a new heavy lift jack-up vessel design – the SOUL, developed with the installation of next-generation offshore wind turbines (10-12MW) in mind. 

The SOUL’s cruciform structural lay-out makes it 10% lighter than conventional jack-up vessel designs, according to the two companies. “In combination with a high capacity crane, SOUL enables operators to take the next step in developing offshore wind farms,” the companies behind the new vessel design added.

The concept aims to install the 10-12MW wind turbines in the same time frame as currently used for installing 6-8MW units.

The SOUL series will come in various sizes, allowing the transport of up to 6 of the 10-12MW wind turbines, and all loading and installation operations can be performed without the need of ballast water.

Tore Ulstein, deputy CEO at Ulstein Group, said: “Combining the vast track record in heavy lift vessel designs from our Dutch Ulstein branch with SeaOwls’ experience in jack-up technology, resulted in an innovative jack-up vessel concept based on proven technologies.”

Scaling-up conventional heavy lift jack-up vessel designs proves challenging due to the disproportional weight increase compared to gain in Variable Deck Load (VDL).

“We noticed this created uncertainty with turbine manufacturers, wind farm operators and installation contractors on how to install the future generation wind turbines, as floating vessels are not a viable alternative”, said Erik Snijders, founder and managing director at SeaOwls. “So we went back to the optimal jack-up design, a square platform with the legs spaced out as much as possible. Rotating the platform by 45o provided a natural bow shape with two legs and the crane on vessel centre line.”

“This seemingly simple twist in the design allowed to make a huge improvement in operational aspects as well,” said Bram Lambregts, deputy managing director at Ulstein Design & Solutions BV. “With the main crane around the stern leg, optimal main deck reach and over-the-side lifting capabilities is created. And as the hull now houses much larger leg footings, bearing pressures on the seabed are reduced, while the wake of the spud cans does not interfere with the inflow to the propulsion thrusters.”