Patent ID: 8820254

Claim:
A catamaran boat suitable for use in assembling off-shore wind turbines, in transporting them, and in placing them on the sea bottom, the wind turbine comprising at least: a base for resting on or being anchored to the sea bottom; a pylon suitable for being supported by said base; and a wind engine suitable for being fitted to the top of said pylon; said boat comprising two side floats having longitudinal axes arranged in parallel in the longitudinal direction XX′, said side floats being connected together by a transverse connection structure, and a front transverse float extending in a direction YY′ perpendicular to said longitudinal direction XX′, and connecting together said front transverse float being connected to the two side floats at one of the ends of the two side floats so as to constitute a U-shaped floating structure; and the open space between the two branches of the U-shape constituted by the two side floats being suitable for receiving said base, said floats being fitted with gripper means suitable for gripping said base between said two side floats, said side floats including watertight compartments suitable for being ballasted and de-ballasted; wherein said gripper means are suitable for gripping said base at, at least the following two different grip levels: an upper grip level in which it is possible to grip said base when the bottom of said base is above the bottoms of said side floats and when said two side floats are at least partially de-ballasted; and a lower grip and lock level in which the bottom of the base is situated below the bottoms of said side floats, said gripper means of the base for said lower level including locking means for locking the base and suitable to provide a rigid connection between said side floats and said base, said gripper means and said locking means being secured to the side floats and to the base once the base is locked with the locking means at the lower grip level so that the base can be lowered merely by ballasting the side floats without movement of the base relative to the side floats.