Wind-farm Installation Vessel (WIV)

A wind-farm installation vessel (WIV) erects offshore wind turbines and their foundations, almost always a self-elevating jack-up that lowers legs to the seabed and lifts its hull clear of the waves to form a stable platform for the main crane. Jacking up removes wave motion, so a large crane, often 1,200 to 3,000 tonnes, can lift towers, nacelles, and blades to hub heights now exceeding 150 meters. Deck space and crane height set the turbine count per trip, and newer designs target 15-megawatt-plus machines in deeper water. Foundation work uses the same jack-up to drive or drill monopiles. A floating heavy-lift crane vessel is the alternative where water is too deep to jack up.