Abstract: The present invention relates to an underwater weapon having a barrel with n opening through which a projectile is discharged. The weapon further has an apparatus for pressurizing the interior of the barrel to a pressure greater than the ambient pressure to keep water from entering the gun barrel at any point around the circumference of the muzzle opening. The pressurizing apparatus includes a source of gas, a pressure regulator for adjusting the flow of the gas and the pressure within the barrel, and a distribution network for distributing the gas near the muzzle opening and at an end of the barrel remote from the muzzle opening.

Abstract: An induced flow underwater vehicle motor cooling jacket adaptable to an urwater vehicle motor is provided. The cooling jacket has a self-priming inlet incorporated into the afterbody motor shell section which ingests seawater during either vehicle movement through the water or operation of the vehicle motor. The motor cooling jacket has a coiled tubing assembly, forming a heat exchanger with a variable tube cross-section, wrapped tightly around the motor. One end of the tubing is attached to the self-priming inlet and the coolant discharge nozzle at the opposite end of the tubing exhausts to the region immediately ahead of the vehicle propeller. Solder is applied between each coil to maintain strength and the tightly wrapped configuration of the cooling jacket.