Device and a ship for maintaining an offshore wind turbine

A maintenance device for maintaining an offshore wind turbine, the device being suitable for pressing against and traveling along a pylon of the wind turbine, and comprising:

• a maintenance platform including a notch defining two branches suitable for placing on either side of the pylon of the wind turbine so that the pylon of the wind turbine can penetrate into said notch with the vertical longitudinal axis XX′ of the pylon of the wind turbine being perpendicular to a work plane of a top surface of said maintenance platform;
• and
• travel means for causing said maintenance platform to travel along the pylon of the wind turbine in the vertical longitudinal axial direction XX′ of the pylon of the wind turbine, the travel means comprising a plurality of motor-driven crawlers arranged under said maintenance platform so that when the pylon of the wind turbine is placed in said notch with the vertical longitudinal axis of the pylon of the wind turbine perpendicular to the work plane of said maintenance platform, said crawlers having tracks are suitable for pressing against said pylon of the wind turbine and traveling along the pylon of the wind turbine.