Patent ID: 7682126

Claim:
An entirely submerged power generating device comprising: two counter-rotating, water current driven turbine propellers; a plurality of frame connected chambers supporting the turbine propellers, and housing the ballast, switchgear, generating, and power transmission equipment; said device being tethered underwater; means for setting a predetermined maximum water velocity and a predetermined minimum water velocity; means for sensing water velocity of the water channel in which said device is submerged, and; means operative in response to said means for sensing water velocity of the water channel in which said device is submerged, and; selectively invoking a protocol for adding or removing ballast to force the device to ascend or descend to seek the predetermined optimal velocity as follows: a. when water velocity is below nominal, the device will expel water ballast, climbing to a higher elevation in search of optimal water velocity, or; b. when water velocity exceeds nominal conditions, the device will take on water ballast, sinking to a lower elevation in search of optimal water velocity.