At Arklow Bank offshore wind farm, located on a shallow water sandbank in the Irish Sea, we carried out maintenance that required the removal of wind turbine rotors and access to the hub. It was not possible to remove the blades individually so the entire rotors, each weighing 90 tonnes and with a diameter of 105 metres, had to be lifted.

We mobilised two jack-up barges - Excalibur and Deep Diver - for the complex lifting operations. Excalibur’s recently installed 300-tonne Huisman crane was the main crane whilst Deep Diver provided the ’tailing’ crane.

Extremely shallow water, strong currents and soft sediments all presented challenges to marine operations. Positioning and jacking-up required the professional approach that comes with 30 years’ experience of operating a fleet of jack-ups in difficult conditions.

Highly detailed lift planning was essential. We calculated the position, deck height and orientation of the jack-ups in order to avoid obstructions; to analyse the flight path of the rotor we used 3D modelling. With each lift, both cranes were used to place the rotors onto the deck of the jack-up platform with precision. The blades were then placed in a rack which was designed and built by our engineering department, along with other storage and sea fastening structures on the deck of Excalibur.

How we can help you

With 30 years’ experience, we deliver a range of services and innovative solutions from a fleet of jack-up platforms in worldwide locations – even in the most challenging conditions.