2 days, undermining of the concrete slab along a major portion of one side 

 and a corner was obvious (Hallanger, 1970). The resulting pit was estimated 

 to be 3 feet deep and to extend 3 to 5 feet under the foundation slab. Only a 

 small portion of this pit extended beyond the slab. Bottom currents estimated 

 at 3/4 knot were prevalent during the 2-day project. This strong bottom cur- 

 rent obviously contributed to the undermining. Marine animals inhabiting 

 the area may also have contributed to the pit's existence and extent. An 

 additional external effect may have resulted when a support ship was moored 

 to one corner of the slab. Dynamic action of the mooring line might have 

 caused an up— down movement of the habitat, resulting in a pumping action 

 in the sediment. However, this movement was not noted by inhabitants. A 

 slight increase in the inclination of the Hydrolab was observed by at least one 

 of the aquanauts during the habitation. The inclination apparently had no 

 adverse effect on the overall experiment. 



Makai Habitat II (Aegir). Aegir is a submersible habitat designed to 

 support six men on missions for 1 4 days in water depths to 580 feet (Fahlman, 

 1968). The 400,000-pound, three-section habitat is made up of two 9-1/2- 

 foot-diameter by 1 7-foot-long cylinders which connect axial ly to a central 

 10-foot -diameter sphere. This structure is mounted athwart two large flood- 

 able pontoons. The pontoons are 9 feet in diameter by 70 feet in length and 

 rest directly on the seaf loor during use. 



The structure is designed to be towed on the surface to the site, where 

 ballast tanks are flooded. Two anchored lines are used as lowering guides. A 

 third and fourth anchor block are suspended beneath the habitat complex and 

 supply the additional weight required to make the complex negatively buoyant. 

 Once these blocks are on the bottom, the complex becomes positively buoyant 

 and must be winched down to the bottom. Additional ballast tanks, which are 

 flooded after the complex is on the bottom, give a total negative buoyancy of 

 80,000 pounds. The system was designed to include four hydraulically oper- 

 ated legs for leveling on slopes up to 10 degrees. 



Aegir underwent its first sea trial during November of 1969 when five 

 men spent 2 days on the seaf loor in 200 feet of water (Ocean Industry, Feb. 

 1970). Since no large difficulties were encountered during the overall test, it 

 is assumed that the foundation performed adequately. 



Tektite I Program. The Tektite I habitat was placed on the ocean 

 floor at Lameshur Bay, St. Johns, Virgin Islands, as a joint effort involving 

 the Navy, Department of Interior, NASA (National Aeronautics and Space 

 Administration), and General Electric Company (Pauli, 1969; General Elec- 

 tric, 1969; Stevenson, 1969; and Pauli and Cole, 1970). A four-man crew 

 occupied the habitat for 60 days beginning in February of 1969. 



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