84 DESIGN, CONSTRUCTION, AND OUTFITTING 



addition a TV receiver for entertainment as well as closed circuit monitoring is provided in 

 Sealab. A two-way intercom system is available in the laboratory to the staging vessel. There 

 it may be patched into the helium unscrambler. Another two-way intercom channel is alloted 

 but this passes through Sealab for further transmission to shore. An FM entertainment re- 

 ceiver, a wedge spirometer output (measuring subject respiration remotely), and O2 partial 

 pressure sensing comprise the remainder of the channels in the communications link in the 

 Umbilical. 



Communications Via the Benthic Laboratory — Scrlpps Institute has developed an underwater 

 multichannel data transmission station, called the "benthic laboratory" which is situated on the 

 bottom close to Sealab IT, A trunk is provided in Sealab aft on the portside of the laboratory 

 which can be opened and through which cables can be passed. These cables then can run to and 

 from benthic to provide the link with a shore based benthic control station. The link is audio, 

 visual (TV), and digital and analog data transmission. 



Buoyancy and Stability 



The following tables should illustrate the various conditions of buoyancy and displacement. 

 Refer to Fig. 43. 



Structure weight (less ballast, including outfit) 



Fixed Concrete Ballast 



Fixed Lead Ballast 



Variable 



Surface Displacement = Total Weight 



Submerged Displacement (defined as volume 

 of conning tower, main cylinder, 

 entrance skirt, and appendages): 



Ballast Tank 1 



Ballast Tank 2 



Ballast Tank 3 



Conning Tower 



Total Water Ballast 



Entrance Skirt 



Condition I Surface displacement 



1' 8" freeboard 

 Flood tanks 1 and 3 



Condition n Sealab n floating at 



mid-height of conning 

 tower 



