The 'Waveglider' [1] by Liquid Robotics employs a variation of this. Tethered to a buoy on the surface, the main underwater vehicle is propelled forward by the

The 'Waveglider' [1] by Liquid Robotics employs a variation of this. Tethered to a buoy on the surface, the main underwater vehicle is propelled forward by the wave's upward force acting on spring loaded foils. [1] http://liquidr.com/technology/waveglider/how-it-works.html http://liquidr.com/technology/waveglider/how-it-works.html