Patent ID: 8230802

Claim:
A method for installing or replacing a unit on a tower of an offshore wind turbine comprising: pre-assembling a unit ashore or on a platform such that the unit includes a rotor consisting of a hub and one or two rotor blades, and a nacelle receiving a gearbox and a generator; testing the unit either ashore or on the platform to verify the unit constitutes a fully functional unit; placing the functional unit on a watercraft in such a manner that a center of gravitation of the functional unit lies in a region of a longitudinal axis of the watercraft and each of the one or two rotor blades extends in a longitudinal direction of the watercraft; transporting the functional unit to a site of the offshore wind turbine; lifting the functional unit from the watercraft using a crane aboard the watercraft; placing the functional unit on the tower of the offshore wind turbine; and fastening the functional unit on the tower of the offshore wind turbine.