Abstract: An ejection pump apparatus of a torpedo launching system is provided with improved water piston which is more stable during use and which enables the intake end of the water cylinder and the sea valve to have a smaller diameter than that of the piston. In order to assemble the piston through the smaller diameter opening, the piston is segmented into four pie-shaped segments which are assembled together in adjacent relation with bolt fasteners that extend through the sidewalls of the segments. The outer wall of the piston includes a circumferential slot which divides the outer wall into two spaced bearing lands which provide the piston with more stability. The circumferential slot also enable water to flow through the sidewall of the piston into the piston and outwardly through an open top thereof.

Abstract: The invention is low-noise, low-pressure torpedo launching system having cially designed ports connecting a water cylinder to an impulse tank and to a method for designing such ports. The invention uses specially designed C-shaped water cylinder discharge ports to provide a continuous and minimized pressure gradient as the ports are closed by the water piston. The resulting controlled deceleration of the water piston reduces operational noise, reduces mechanical stresses and eliminates the need for auxiliary dashpot components.