12. Can a "hard hat" diver go deeper than a skin diver? 



Going to great depths presents many problems to a hard hat diver. 

 First of all, he is tied to the surface by breathing tubes. Also, the high 

 air pressure causes some of the nitrogen in the diver's air supply to dis- 

 solve in his blood (air is composed of about 80% nitrogen, 20% oxygen). 

 The emergency limit for Navy divers is about 500 feet, although divers 

 have gone much deeper. 



The main advantages of the hard hat gear are that the diver has pro- 

 tective clothing and telephone connections to the surface. A helmet 

 diver could spend perhaps 3 or 4 hours working at 200 feet, but he 

 would then have to make a very slow return to the surface. 



Scuba divers have more mobility, but in practice they are limited to 

 less than 200 feet, unless they have a special diving apparatus and gas 

 mixtures. A "closed circuit scuba," which has been tested at depths of 

 600 feet by Westinghouse Underseas Division, is expected to provide 

 safe breathing mixtures at depths exceeding 1,000 feet. This would pro- 

 vide the capability of working at great depths for extended periods. 



The underwater structures, tested by Cousteau and Link, from which 

 scuba divers emerge to work, make it possible for divers to live and work 

 under water for weeks at a time. 



Gaskell, T. F. 



World Beneath the Oceans, American Museum of Natural History, 



1964. 

 Pell, Claiborne (Senator) 



Challenge of the Seven Seas, William Morrow and Company, 1966. 

 Rebikoff, Dimitri 



Free Diving, E. P. Dutton and Company, 1956. 



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