Abstract: A fixed structure encloses a vertically spaced plurality of superimposed channels that are open at one end of the sea to receive deep sea waves approaching a shoreline. Each of the channels has an entrance ramp that slopes upwardly shorewardly to induce breaking of a wave at and over an apex of trailer service ramp that merges into a shorewardly downwardly sloping convergent conduit having fluid communication with a pressure chamber of the structure through a one-way valve controlled aperture at which the wave energy is concentrated. A portion of each ramp is overlain by a roof which may comprise the underside of a superimposed ramp of another channel. Each of the ramps is of upwardly convex configuration, transversely to the wave direction, and at opposite sides is provided with re-entrant scuppers for draining backwash from a receding wave.