Decompression is accomplished by swimming to the surface and immediately entering a deck recompression chamber. HYDRO-LAB (Figure 14-4), although not the smallest facility, is of a simple design and inexpensive to operate, using a self-contained unattended surface life-support buoy. The main structure is an 8-foot by 16-foot cylinder supported on four short legs 3 feet above a concrete base. The habitat is submerged by venting ballast tanks in the concrete base and saddle buoyancy tanks located along the habitat cylinder. Pipe fittings which project from the base permit the ballast tanks to be filled with air when the habitat is to be raised. Entry into the habitat is through a well at one end which also functions as a lock when the chamber pressure is less than ambient. Personnel can dry transfer from a lockout submersible to the habitat through a tunnel fitted with a mating pedestal. The single room is furnished with two bunks, two folding chairs, a collapsible table, a dehumidifier and air conditioner. A 23-foot long life-support barge floats at the surface above the habitat. Umbilicals carry electrical power (7.5 kw, 110 vac, 60 Hz) and high and low pressure air to HYDRO-LAB from a diesel-powered generator and compressor. A 250-gallon water storage tank gravity feeds fresh water at ambient temperature to a hand-held shower nozzle next to the entry trunk. Decompression is conducted in the habitat. EDALHAB (Figure 14-5) was designed and built as an engineering project by students from the University of New Hampshire. The habitat was constructed mainly of salvaged and donated materials. The living quarters are enclosed in an 8-foot by 12-foot cylinder with a small viewing port at each end. The interior is insulated using 12-inch thick unicellular foam. Entry is made through a hatch centrally located in the floor. The interior has two permanent bunks (which fold to form a large seat), and a collapsible canvas cot. The habitat rests on an I-beam frame which, in turn, is supported 8 feet off the bottom by four adjustable cylindrical legs. Large (4.600 lb.) weights suspended from either end of the frame are raised and lowered by diver-operated hand winches. Four large emergency buoyancy tanks are located along the of the cylinder and can be filled |