75. How deep can submarines operate safely? 



The maximum operating depth of submarines is a military secret; 

 however, the engineering facts that determine safe operating depths are 

 well known. 



The bathyscaph TRIESTE, which reached the deepest depth of the 

 oceans, is no more like a true submarine than a stratosphere balloon is 

 like an airplane. A true submersible should be positively buoyant and 

 carry a considerable payload. A submarine built by today's methods to 

 withstand a depth of 4,000 feet would not have sufficient buoyancy to 

 carry a useful payload. 



Submersibles (not military submarines) have dived and operated under 

 power at depths greater than 6,000 feet; 4 Z. VIN and ALUMINAUT are 

 two of these. ALUMINAUT has a depth capability of 15,000 feet. 



Newer construction materials, such as filament-wound, glass-rein- 

 forced plastic, produce high hull strength in respect to weight and may 

 be used in the future for submersibles designed for deeper depths. 



According to Geo-Marine Technology magazine (March 1967), 

 World War I submarines had a capability of 100-200 feet; World War II 

 submarines, 200—400 feet; and present day submarines, 750—1,500 

 feet. By 1970 the depth is expected to reach 4,000 feet; small, high- 

 speed interceptor submarines may be capable of diving to 6,000 feet or 

 more. 



Hull, Seabrook 



The Bountiful Sea, Prentice-Hall, 1964. 

 Soule, Gardner 



The Ocean Adventure, Appleton-Century, 1966. 



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