The pressure vessel weighs less than 10,000 pounds including internal 

 equipment and supports, and displaces about 27,000 pounds. Internal volume 

 of the pressure vessel is 425 cubic feet and the internal volume of the ambient 

 pressure wet room is approximately 400 cubic feet. 



There are four 8-inch diameter view ports equally spaced around the cylinder. 

 A false deck is installed at a level which provides seven feet of head room. 

 A 36-inch transfer lock is provided in the bottom of the pressure vessel 

 between the false deck and the dished head. 



Seals, gaskets, and lubricants were selected on the basis of oxygen compat- 

 ibility, corrosion cracking, galvanic corrosion, etc. While the minitat is 

 not a certified system according to DOD standards, every effort was made, 

 within the time and appropriation available, to conform to such standards. 



The pressure vessel mates with and seals to the wet room which is an inte- 

 gral part of the catamaran deck (see figure 1) . The wet room is 9 x 9 feet 

 with a maximum head room at the edges of 7 feet. Only 5 feet of the wet 

 room appears above deck level. The wet room is used as a work room, storage 

 area, and diving station. It is not designed, however, to withstand any 

 appreciable pressure differential. After the habitat is on the bottom the 

 wet room is blown dry and activated. The wet room contains a 42 inch hatch- 

 way in the steel deck for ingress/egress, a pneumatic collar for sealing to 

 the habitat, four vent valves attached to the top-exterior to allow gas to 

 escape during flooding, and a wet room skirt. An entry trunk is located on 

 the wet room deck to permit entry of umbilical and other lines. Twenty four 

 inch diameter plexiglass ports are installed in each side of the wet room 

 and one wall has a water-tight door that swings inward for ease of access 

 while on the surface. 



The habitat is attached to the pontoon catamaran via four upright steel 

 I-beams which bolt to an I-beam ring welded around the pressure vessel and 

 to transverse I-beams connecting the pontoons. Four additional steel I-beams 

 are bolted to the upright beams and angled down to bolting pads on transverse 

 beams. The bolted steel support beams are sized to allow proper mating 

 between the pressure vessel and the wet room sealing flange. 



The pontoon catamaran consists of two steel pontoons; 35 feet in length, 

 5 feet in diameter, and 1/4 inch wall thickness with ellipsoidal caps welded 

 on the ends. The pontoons have a spread of 20 feet center to center and are 

 bolted together with 6 transverse I-beams. Each pontoon is compartmentized 

 with welded transverse steel bulkheads at a point 9 feet from each cap. This 

 results in three separate compartments in each pontoon, two about 8 feet in 

 length and the center compartment approximately 17 feet long. 



Each of the six compartments can be flooded with sea water and emptied with 

 compressed air in a controlled manner to aid in raising and lowering the 

 minitat. Each compartment is equipped with a water valve for flooding and 

 a vent tube leading to the control console shown in figure 3. At the control 

 console air can be vented from the compartments to allow them to flood in 

 diving the minitat. Compressed air can be admitted from on-board storage 

 bottles or from the support ship via the umbilical for emptying the pontoons 

 to raise the minitat. Sufficient compressed air storage capacity is provided 

 imder the deck to very nearly blow dry all six compartments at a depth of 



III-3 



