Abstract: A buoy type wave energy extraction construction in which the natural frequency of vertical oscillation of the buoy is mechanically altered to at least partially conform to the wave frequency occurring during a period of operation, whereby the maximum amount of energy available from each successive wave front is extracted. The device includes a buoy, a vertically oscillating shaft supporting said buoy, a horizontally oriented motion output means driven by said vertical shaft, a braking means for arresting movement of the buoy at its uppermost limit of travel during any given oscillation, said braking means holding the buoy until the buoy may be dropped under gravity into a following wave trough.