Link demonstrated a similar rubber-walled habitat, Sea Igloo, in 

 1964. The rubber habitat supported a man for 24 hours in 33 feet of water 

 (Link, 1964). 



An underwater diver rest station, named Sublimnos, has been used at 

 30-foot water depths in the Great Lakes (Somers, 1970). The 8-foot-diameter 

 by 8-foot-long vertical cylinder is ballasted for negative buoyancy. The foun- 

 dation consists of four pads, each about 2 feet square. This structure has been 

 successfully located on cohesive soils. 



Other Planned Habitats. Atlantis was a joint planned program 

 between the University of Miami and Chrysler Corporation (University of 

 Miami, 1968; Chrysler Corporation, 1968; Breckenridge, 1969). The two 

 organizations intended to emplace a 1 -atmosphere manned laboratory on the 

 continental shelf (to 1 ,000-foot water depths). The tentative habitat consisted 

 of a horizontal cylinder, 12 feet in diameter by 80 feet long, applying a nega- 

 tive buoyancy of 64,000 pounds to the seafloor through two 17-foot by 33-foot 

 spread footings (Figure 31). Static bearing pressures would equal 57 psf. The 

 overall design was based on the following criteria: 



1. maximum bottom currents of 5 knots 



2. soil bearing capacity of 72 psf 



3. a maximum slope of 5 degrees 



Each spread footing is connected to the superstructure by a hydraulic leveling 

 system. 



Preliminary designs for a similar manned underwater station (MUS) 

 were developed by NCEL and several contractors (General Dynamics, 1968). 

 The selected concept consisted of two vertical cylinders; one containing a 

 nuclear power generator and the other housing six men. The habitat would 

 be capable of 30-day missions in water depths to 6,000 feet (Figures 32 and 

 33). The structure was designed to be slightly buoyant until the addition of 

 a 1 2,000-pound anchor clump. This clump would be placed on the seafloor 

 and the station winched down to it. Upon approaching the seafloor, four 

 boom-mounted footing pads would swing out and stabilize the station in a 

 vertical position on slopes as steep as 1 5 degrees and in currents as large as 

 1 knot. The design was such that negligible loads would be applied to the 

 seafloor soil by the 12-foot-diameter bearing pads. Design criteria assumed 

 a soil bearing capacity of 144 psf. In the most critical situation, a current- 

 induced overturning moment would be resisted by a single boom-mounted 

 footing pad. In this situation, a vertical force of 12,000 pounds (108 psf) 

 and a horizontal force of 1 2,600 pounds would be transmitted by the pad 

 to the seafloor. The circular pads were to be made of a permeable screen to 



53 



