At Arklow Bank offshore wind farm, located on a shallow water sandbank in the Irish Sea, Fugro 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.
Fugro’s jack-up barges – Excalibur and Deep Diver – carried out 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 as well as strong currents and soft sediments presented their own 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.
As Matt Ford, Fugro Seacore Project Manager explains: “This project showcased Fugro’s ability to meet our client’s needs with precision. The execution of the works demonstrated not only the experience and skill of our personnel but also the ability to deliver a solution using vessels and equipment that are smaller than most clients would expect to see at an offshore wind farm.”
Highly detailed lift planning was essential. The position, deck height and orientation of the jack-ups were precisely calculated to avoid obstructions and 3D modelling was used to analyse the flight path of the rotor. Each lift used both cranes to place the rotors onto the deck of the jack-up platform with precision, after which the blades were placed in a rack. The storage and sea fastening structures to support the rotor hub and blades on the deck of Excalibur were designed and built by Fugro’s engineering department.
Chris Delahunt, GE Operational Site Lead at Arklow expressed: “Special thanks to Fugro for their flexibility, patience and expertise throughout the planning, design and operation phases of this project. Their professionalism was instrumental in the successful completion of this operation.”
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Press release, December 4, 2013; Image: Fugro