Patent ID: 8092265

Claim:
A jet propulsion device for operating in an ambient liquid, comprising: a housing having a nose having a tip; a tail; a longitudinal axis; and an outer surface; at least one liquid inlet for allowing the ambient liquid to enter the device positioned a distance substantially R from the inlet to the longitudinal axis of the housing, and a distance substantially l from the tip of the nose along the longitudinal axis; the distance R is greater than the radius of the outer surface of the housing at the distance substantially l; where R and l are non-zero; at least one exhaust opening; a reaction chamber; the reaction chamber is connected to the at least one liquid inlet by a liquid conduit; the reaction chamber is connected to the at least one exhaust opening; the reaction chamber is configured to vaporize at least a portion of the ambient liquid entering the reaction chamber from the liquid conduit to produce vapor, and to pass at least a portion of the vapor through the at least one exhaust opening.