page 104 



DOWN BUT NOT OUT. A diver from the "Wid- 

 geon" goes down to adjust cable attachments on 

 the submarine "Apogon." In the external control 

 method of submerging a submarine, heavy weights 

 are attached to it at bow and stern by cables of 

 carefully chosen length. The weights overcome the 

 sub's positive buoyancy and draw her down to the 

 desired depth. To surface the sub, air is pumped 

 into the ballast tanks. Submergence and surfacing 

 were controlled from a salvage ship. 



