At each end of the float there is a water ballast tank 

 that is separate from the gasoline tank system. The ballast 

 tanks provide a negative buoyancy for the craft when they 

 are flooded at the time of diving. The forward ballast tank 

 is internally reinforced to withstand the stresses of towing. 

 In addition, these end tanks serve as "bumper" protection 

 for the gasoline tanks; the rupture of one of them through 

 accident would not cause loss of the craft or of any of its 

 gasoline. 



The nine main gasoline tanks in the float are fitted 

 with a compensating system so that it is possible to pres- 

 sure-equalize the entire tank system by means of a single 

 valve located in the center tank. Also located inside the 

 center tank is a tenth tank called the maneuvering tank, 

 that serves three vital purposes: (1) it is an independent 

 reservoir for some 12 00 gallons of gasoline that may be 

 slowly released by the pilot to control buoyancy; (2) with 

 a wall thickness of 0. 33 inch it is a strength member, and 

 provides at its bottom the mounting pad for the cabin of 

 the craft; and (3) it supports, at its top, the lifting pad to 

 which the crane hook is attached for raising TRIESTE out 

 of the water. Since this tank is disconnected from the rest 

 of the gasoline system, inadvertent release of the gasoline 

 from this tank by the pilot or failure of its release valve 

 would cause the loss of only 12 00 gallons of gasoline and 

 not of the entire contents of the float. 



At the bottom of the float are located two recesses, 

 one forward of the sphere and one aft of the sphere, for 

 the shot ballast tubs. In addition, the float provides a 

 generous area for the attachment of instrumentation and 

 various other fixed and temporary devices. 



A free-flooding superstructure on top provides ade- 

 quate working room for the handling crew and also pro- 

 vides protection for equipment located beneath. 



THE SPHERE 



The sphere functions as the cabin of the craft. It con- 

 tains all the controls and instrumentation readouts nec- 

 essary for operation of the craft and for performance of 

 its scientific mission. The two-man crew of the craft 

 maintain their diving station inside the sphere. When all 

 the operating controls, instrumentation, and power sup- 

 plies are installed, a little over 17 cubic feet of working 

 space remains for the crew. 



12 



