check 

 valve 



Figure 2. Saf e-and-arm device. 



breaks a 400-psi (2,800 kPa) shear 

 disk and drives the firing pin down- 

 ward with an energy in excess of 500 

 inch-ounces (3.5J).* A safety lock- 

 out plunger prevents firing pin motion 

 unless the plunger is moved in line by 

 a preselected level of hydrostatic 

 pressure. Normally, a separate elec- 

 trical line is extended to the sea 

 surface to provide actuation, although 

 an on-vehicle battery pack coupled to 

 a touchdown or acoustic trigger could 

 be employed. 



The propellant cartridge consists 

 of a cartridge base, capable of con- 

 taining the gun barrel pressure, a 

 plastic tube and foam plastic plug to 

 contain the charge, and a standard 

 M-58 primer. Firing occurs when the 

 firing pin in the S/A device strikes 

 the percussion cap at the rear (top) 

 of the primer. A peak force of about 

 2.8 million pounds (12 MN) is generated 

 during firing to act downward on the 

 projectile assembly and simultaneously 

 upward on the launch vehicle. 



Projectile Assembly 



The projectile assembly (Figure 3) 

 includes the piston, shown separately 

 in Figure 4 and the anchor projectile, 

 or ''fluke.'' The dimensions of the 

 flukes are given below: 



* M-58 primer detonation requires 

 between 60 and 160 inch-ounces 

 (0.4 to 1.1J). 



