Patent ID: 9701378
Date: 2017-07-11
CPC Classifications: B63G

Claim:
1. A combination comprising an autonomous underwater vehicle with an exterior surface and a displaced volume, and an external expendable ballast tank releasably deployable from the autonomous underwater vehicle; the external expendable ballast tank is releasably connected to the exterior surface of the autonomous underwater vehicle by a releasable mechanism; the external expendable ballast tank includes a hull having a first section and a hollow section; a plurality of openings formed in the hull that place the hollow section in fluid communication with an exterior of the hull; the first section includes at least one battery that provides power to the external expendable ballast tank and control electronics that control operation of the external expendable ballast tank; the hollow section includes an air outlet through which air from the hollow section can flow and a first valve controlling the flow of air through the air outlet; and the external expendable ballast tank includes a tank containing a supply of high pressure gas, a high pressure gas outlet fluidly connected to the tank and discharging into the hollow section, and a second valve controlling the flow of high pressure gas from the tank into the hollow section through the high pressure gas outlet.