98 



HANDLING CHARACTERISTICS 



Preparations for submergence included a complete systems checkout (see Sealab n Lower- 

 ing Plan, this chapter), the final loading of supplies and equipment for the aquanauts, and the 

 flooding of ballast tanks 1 and 3. When tanks 1 and 3 were flooded, the waterline was on the 

 conning tower at a point which indicated that, when the conning tower was flooded, Sealab would 

 be approximately 10,000 pounds negatively buoyant. 



The Sealab was then placed in a four-point moor between the Gear and the stern of the sur- 

 face support craft (Fig. 50). Prior to this, the Gear was placed in a three-point moor parallel 

 to the stern of the surface support craft about 100 yd away, so it could assist in the lowering of 

 Sealab. 



NYLON 



Fig. 50. Sealab attitude from surface to 30 feet depth (also 



see Fig. 66) 



The actual lowering was done from a boom that extended only ten feet from the surface - 

 support craft. Thus, the Sealab habitat had to remain about 30 ft clear until it was well 

 submerged. 



The lowering wire was 1-1/8-in. nonrotating and was connected to a winch. To absorb the 

 dynamic loads of Sealab due to wave and swell action of four to six feet, the lowering wire had 

 a counterweight of 13,000-lb, which was controlled by the second winch on the surface craft. 



When all was ready, the flooding of the conning tower was started, and a mixture of helium 

 and oxygen gas was maintained at 30 to 40 lb over ambient water pressure inside the Sealab. 

 When Sealab became slightly negative, it submerged gently and rotated down to a depth of about 



