NOVELTY - The device has a buoyant structure, tethered to the bed of a body of water in freely rotational manner, including a water holding chamber (11) attached with an inner reservoir (12). Both reservoir and chamber are shaped to facilitate overtopping and retention of water from the chamber into the reservoir due to oscillations of enclosed water in the chamber at a frequency equal to that of the waves of largest energy on the water surface. The differential head of water between the reservoir and chamber is released to drive a low head turbine (13) in the reservoir.    USE - Device for converting wave energy, such as from sea water waves, into electricity.    ADVANTAGE - The device is partly or totally submerged, providing the device with protection from effect of severe seas and corresponding wave forces. Securing the buoyant structure to the sea bed provides a fixed frame of reference against which it can operate while allowing it to move with the waves, reducing excessive wave forces. Use of careful choice of design parameters to achieve resonance ensures optimal energy transfer from the waves to the sides of the structure and to the enclosed water, yet allows for size reduction of the structure. The capability of the device to absorb energy through horizontal motion in direction of incident waves provides a potential for absorbing more energy than that energy absorbed through vertical motion. The device may be axisymmetric in construction so as to operate equally regardless of direction of incident waves. The device utilizes a well-established power take-off technology to realize a robust structure with small number of moving mechanical parts.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method of converting wave energy into electricity.    DESCRIPTION OF DRAWING(S) - The drawing shows the cut-away sectional view of a device for converting wave technology into electricity.    Chamber (11)    Inner reservoir (12)    Turbine (13)    Internal curved surface (14)    Air space (15)