Patent ID: 7878873

Claim:
An apparatus for providing thrust adjustment on an underwater vehicle having an annular water passageway formed by the vehicle body and a propeller shroud, whereby the vehicle propulsion system is operable within the water passageway, comprising: a circumferential portion of the vehicle body forming a compliant surface forward of the propulsion system with respect to a relative flow of water, said compliant surface following contours of said circumferential portion of the vehicle body in a neutral position, whereby in the neutral position thrust adjustment is entirely dependent upon the propulsion system; and means, within the vehicle body, for applying an expansion force to said compliant surface in the neutral position in response to a request for decreased thrust wherein said compliant surface expands to choke the relative flow of water through the water passageway and for applying a contraction force to said expanded compliant surface to increase the relative flow of water through the water passageway.