Design.

The floater can be entered via an air tight lock as inside the climate is controlled. The floater is kept under a constant over pressure of ca. 0,1 bar to prevent salt water or vapours to enter. This way the hydraulic and electric systems are protected and can be maintained in a controlled environment. If any leak might occur, it'll be instantly noticed by a pressure drop but water still can't enter due to the over pressure. The leaking air will be supplanted by a compressor until repairs are ffinished. 

The prototype is 20m long, 8m deep and has a 2,5 m diameter floater. The 70 t/MW machine is optimised for North Sea conditions with resonance blades that reach till about 3m under the surface to capture the lion share of the North Sea wave energy.