Offshore wind turbines are getting larger, with units under development with heights of more than 270 m and blades 120 m long. These increases in size and installation height create problems for currently available installation vessels.
In response, Belgium based Jan De Nul Group has ordered its third, and largest, offshore jack-up installation vessel, the Voltaire, at the COSCO Shipping Heavy Industry shipyard in China.
Key features include a main crane of over 3,000 tonnes, an operating depth of approximately 80 meters, a payload of about 14,000 tonnes and accommodations for 100 persons. The vessel has four legs to lift itself above the sea level for stable working conditions and is equipped with a DP2 system.
The vessel was designed by Jan De Nul while Danish based naval architectural firm Knud E. Hansen provided design review and contributed to the tender design package. Based on experience from designing the wind turbine installation vessels Pacific Orca and Pacific Osprey for Swire Blue Ocean, Knud E. Hansen provided the midship section and design of the three‐chorded truss work legs, the jacking frames, the leg wells and the main crane pedestal as well as global and local FEM strength calculations of the hull, the legs and the jacking frames.