Huisman, the worldwide specialist in lifting, drilling and subsea solutions has developed an extremely lightweight type crane for the maintenance of offshore wind turbines: the ‘Foldable Offshore Crane’. This crane combines unparalleled lifting heights and more than sufficient lifting capacity with a foldable boom resulting in less required deck space and a low own weight of the crane. The selection of this crane for the maintenance of offshore wind turbines will therefore require a smaller, and thus more cost effective, jack-up vessel than currently required.
David Roodenburg, Director Strategy and Business Development said: “In addition to our innovative solutions for the installation of increasingly large wind turbines, we see many opportunities to improve efficiency, and thus lowering costs, for maintenance. With this new crane type we believe to have designed a cost-effective means to perform maintenance on existing and future wind turbines”.
The ideal maintenance jack-up has a small deck, is cost-effective and quick to mobilize, has a limited lifting capacity (up to 500-600mt) and a lifting height of over 160m. The Huisman ‘Foldable Offshore Crane’ is well suited for these types of jack-ups as it is capable of exchanging WTG components to around 160m above deck level from a small jack-up (JU vessel length of +/-70 m). The boom of the crane is foldable which results in a very small footprint when in storage position.
In addition, the folding mechanism leads to a much lighter crane compared to conventional cranes, which positively influences integration, and simplifies inspection and maintenance as the lifting hooks are safely stored inboard. By slightly tilting the knuckle, extra boom clearance is created. This simplifies lifting of large loads and reduces the required boom length to reach above the middle of a nacelle. Furthermore, the crane can be retrofitted on existing jack-ups which is especially useful for operators in need of more hook height in answer to the growing demands of the offshore wind industry.