78 



DESIGN, CONSTRUCTION, AND OUTFITTING 



SEALAB n CHARACTERISTICS 



Hull Exterior 



Sealab II is essentially a nonpropelled submarine built to withstand an internal working 

 pressure of 125psi (Fig. 45). It is a cylinder of one inch thick mild steel, 12 ft in diameter and 

 57-1/2 ft long. The cylinder is surmounted by a conning tower 8 ft in diameter and 7-1/2 ft 

 high. The conning tower provides dry access when surfaced as well as reserve buoyancy dur- 

 ing the pressurizing operation, but is designed to withstand aAp of only 15 psi. 



B TOWING 

 - CHOCK 



ESCAPE HATCH 



Fig. 45. Sealab II exterior 



The cylinder is set in a cradle-like structure with trays underneath for permanent lead 

 ballast stowage. A walking flat is provided around the conning tower and extending fore and 

 aft. Variable lead ballast is stowed under this flat for ready access to adjust final trim if 

 necessary. 



Access while on the bottom is through a 48-in. diameter hatch aft. Entry is from the sea, 

 into a protective anti-shark cage, up a sloping ladder, though the water-atmosphere interface 

 in an 8-ft-square access trunk, and into the main cylinder. The water level in the access 

 trunk is maintained by regulating the internal Sealab pressure. The trunk is designed to allow 

 sufficient volume to accommodate the severest expected tidal change. 



