struction of large hyperbaric chamber facilities for research, development 

 and training, and use by Government, university and industry. The suc- 

 cessful French series of Conshelf experiments has placed aquanauts at a 

 depth of 330 feet for 21 days; these experiments are continuing and a mobile 

 habitat is under construction. 



The Soviet manned-diver habitat program began in 1965; to date some 

 seven structures have been placed in shallow water. The German Govern- 

 ment experimented with a new bottom habitat to conduct biological 

 studies last summer off the island of Heligoland in the North Sea. The British 

 and Germans are constructing shallow water habitats; the Canadians have 

 begun tests in a habitat at 50 feet in Lake Erie, and the Czechs, Bulgarians, 

 Poles, East Germans and Cubans have all experimented with modest habitats 

 in shallow water. 



Developing Advanced Diving Techniques 



Advances in diving techniques over the past two decades have freed divers 

 from the restrictions of tethers and have increased working depths. This is 

 largely the result of the self-contained underwater breathing apparatus 

 (scuba) and the use of helium and oxygen breathing atmospheres. Advances 

 in saturation diving and employment of habitats provide a pressurized at- 

 mosphere at working depths. And, hatch access to and from the habitat 

 permits divers to live and work in comparative comfort and safety without 

 the need for repeated decompressions. 



One of these techniques is the development of submersibles with lockout 

 capabilities which permit delivery of a diver to a site of interest where 

 he can sortie into the ocean environment when and if desired. At present 

 three commercial submersibles possess lockout capability — the Deep Diver, 

 the Roughneck, and the Shelf Diver. The submersible Ben Franklin, which 

 this year completed a 1,500-mile Gulf Stream drift, described in chapter IX, 

 will receive lockout modifications. 



Another technique being used to provide extended work time at depth 

 involves the use of saturated diving techniques, but without the support- 

 ing facility of an underwater habitat. In this operation, divers remain pres- 

 surized to their working depths for long periods and decompress only after 

 completing multiple-dive objectives. They are raised and lowered from the 

 surface in a pressurized personnel transfer capsule, and while on the surface 

 are housed in a compression chamber at working depth pressure. Com- 

 mercial systems exist, for example, such as that used by industry for suc- 

 cessful oil rig salvage in the Gulf of Mexico. By 1972, the Navy will have 

 three systems in use. 



The advanced diving techniques were envisaged by the Navy in 1957, 

 and incorporated in a formal program under the title "Man in the Sea" 

 in 1961. The program has included two Sealab experiments which placed 

 two habitats at 200 feet, with aquanauts living for about 2 weeks at am- 

 bient pressure. Presently, Sealab III is designed to extend the capability 

 to 850 feet. Structured in four phases, the program will use a habitat in 

 one phase to continue development of deep submergence capabilities to 

 meet defense needs. 



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