Abstract: In a stationary wave-motion-driven power generator station, a rotatable cylindrical steel structural body is mounted, with its axis substantially horizontal. The ends of the axle of the body are located in bearings which can move up and down to immerse the lower portion of the body in the sea. Vanes are provided on the body to cause the latter to be rotated by wave motion and are in the form of annular prominences around the body having outwardly-decreasing approximately triangular cross-sections.