Abstract: A hydraulic cylinder assembly for use in a variable external pressure envnment is provided. A hydraulic cylinder exposed to the variable external pressure environment has two chambers separated from one another by a piston. Hydraulic fluid fills each of the two chambers. In an "at rest" mode, the hydraulic fluid in the two chambers is pressurized to the variable external pressure. In an "at work" mode, pressure of the hydraulic fluid is selectively varied from the variable external pressure in one of the two chambers such that the piston moves. The entire assembly can be installed between the pressure and outer hulls of a submarine and utilize seawater to equalize the pressure in a balanced power stroke circuit.

Abstract: A firing assembly for a stored energy projectile launcher of the type hav an energy storage device that is pressurized by a fluid. The projectile is mechanically latched in its launch tube and the aft end of the projectile cooperates with the breach end of the launch tube to define a breach chamber that communicates with and is pressurized with the bladder. A valve in a line from the breach chamber is electrically controlled to move a piston and release the mechanical latch when fluid pressure is provided to the piston chamber. The pressure used to overcome the force needed to raise the piston is taken from the energy storage device. No addition of energy to the system is required, with the exception of a short electrical impulse signal, to open a full port valve acting instantaneously on the rear face of the projectile.