Chapter 5 

 THE SEALAB II SURFACE-SUBSURFACE COMPLEX 



INTRODUCTION 



While most of the machinery and equipment used in Sealab II were off-the-shelf items, 

 there were four major pieces of equipage which were unique to the project and were not di- 

 rectly associated with the programs of the preceding section. These four were: 



1. Sealab n habitat 



2. Personnel Transfer Capsule (PTC) 



3. Deck Decompression Chamber (DDC) 



4. Surface support vessel 



These four, with their installed machinery as discussed below, comprised the Sealab n 

 complex. 



SEALAB II HABITAT 



The Sealab II habitat (Chapters 8, 11, and 12) is a nonpropelled, seagoing craft which can 

 be lowered into the ocean and emplaced on the ocean floor. It served as an underwater habitat 

 wherein ten aquanauts lived for periods of 15 to 30 days in an artificial atmosphere. 



When on the ocean bottom, Sealab II's living compartment was at a pressure equal to am- 

 bient pressure. In effect, the aquanauts lived in an "air" bubble contained beneath a dome. 

 The boundaries of the compartment were subjected only to the differential pressure between 

 the "air" and the water outside. Therefore, although the habitat was designed as a pressure 

 vessel so that it could be pressurized on the surface, the living compartment was not subjected 

 to total bottom pressure when it was emplaced. 



The living compartment is a cylinder 12 ft in diameter and 57 ft long, designed for an in- 

 ternal working pressure of 125 psi, in accordance with the ASME Unfired Pressure Vessel 

 Code. When the habitat was submerged, access was gained through an antishark cage suspended 

 below a four-foot-diameter hatch in the bottom of the hull. 



The living compartment was divided into four areas, the aftermost of which was the entry 

 way, into which the access hatch opened. This entry way contained showers and stowage space 

 for diving gear. 



Just forward of and separated from the entry way by a waterproof dutch door was the labo- 

 ratory area. The laboratory area contained a built-in sink and cabinets, a 50-gallon water 

 heater, a 150-gallon emergency fresh-water tank, the breathing-gas control panel (Fig. 20), 

 and the communication station with its associated equipment. 



Forward of the laboratory area was the galley area, which contained a built-in sink and 

 cabinets, electric cook top, chill box, freezer, electrical power transformers, and the major 

 components of the habitat air-conditioning system (Fig. 21). 



The forwardmost space was the berthing area. It contained bunks for the ten aquanauts, 

 storage lockers, a large drop-leaf table, and at the forward end, a 30-in. emergency escape 

 hatch. A total of eleven 24-in. viewing ports were provided throughout the four spaces. 



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