A mobile off shore unit primarily intended for the installation, maintenance and repair of wind turbines in off shore and coastal waters, including pile driving, tower installation, and nacelle and blade installation.
Usually a self-elevating unit with movable legs capable of raising its hull above the surface of the sea. Once on location, the hull is raised to a predetermined elevation above the surface on its legs, which are supported by the sea bed. The legs may be designed to penetrate the sea bed, may be fi tted with enlarged sections or footings, or may be attached to a bottom mat.
Jacking systems are used to elevate and lover the hull and to raise and lower the legs in the afloat condition. The hull of the unit is maintained stationary in the elevated condition by means of a holding mechanism. The same mechanism is used to maintain the legs stationary in the afloat condition.
Deck cargo includes wind turbine nacelles, towers, blades and any other items which are installed in association with a wind power generation structure. It also includes any temporary structures such as racks, stands, or cradles which are not permanently attached to the unit.
See also Wind Turbine Installation Vessel INNOVATION.
Further reading: ABS “Guide for Building and Classing Mobile Offshore Units”