OCEAN SCIENCES AND NATIONAL SECURITY 35 



(d) Reciprocal case of shallow receivers and source at various great depths. 



(e) Investigation of ambient noise types, levels, vertical, and geographical dis- 



tribution. 



Is operation at greater depths possi])le? 



For vertical mobility, a submarine is designed so that its buoyancy 

 produced by displacement of sea water is just about equal to its weight ; 

 moreover, the weight includes the items of hull structure, of mechani- 

 cal plant and of payload in terms of weapons, or scientific equipment, 

 etc. At the same time, the hull structure must be sufficiently strong 

 to resist the crushing effects of water pressure, which itself increases 

 linearly with depth : about 1 pound per square inch of pressure is added 

 for each 2, '4 feet of depth below the surface. Thus, any requbement for 

 increased operating depth involves the use of stronger and, ordinarily, 

 heavier hulls. The requisite balance between buoyancy and weight can 

 thus be met when the hull is heavier only if other components are made 

 relatively lighter. This may imply smaller power with diminished 

 speed, or less payload. One performance characteristic must be traded 

 for another, and in the past, insofar as submarine designers were 

 concerned, depth was not a primary choice because it was believed to 

 entail unacceptable penalties in weight. 



Structural designers of submarines were thus faced with the same 

 dilemma that confronted designers of aircraft which have similar 

 weight-penalty problems. Solutions were thus sought from research 

 on materials and engineering technology for either other substances 

 out of which the hull coidd be built or other geometric forms that dis- 

 played an increased ratio of strength to weight. By such means, in- 

 creased depth could be achieved in a submarine without undue for- 

 feiture of other performance characteristics. The vital necessity of 

 pursuing a deep-diving adversary or taking advantage of depth for 

 enhanced listening range is now considered by some naval experts to 

 force an eventual increase in depth capabilities, even at the sacrifice 

 of certain other capabilities. 



Prompted by studies of the Committee on Undersea Warfare, 

 National Academy of Sciences — ^National Research Council, the 

 U.S. Navy, through the Office of Naval Research and the David 

 Taylor Model Basin, began a program of research on the strength of 

 hulls for deep diving submarines about 2 years ago. 



B. THE EMERGING OCEAN TECHNOLOGIES 



The barrier which has historically restrained man from submarine 

 operations at all depths in the ocean now shows promise of being 

 dissolved by technological advancement. High-strength steels, high- 

 strength aluminum alloys, fiberglas reinforced plastic, titanium, and 

 beryllium as engineering materials show the promise of producing 

 structures wliose strength-to-weight characteristics will permit their 

 use in submarine hulls for operation 10 to 20 times deeper than the 

 depth cited for the Nautilus. Exactly what will be the scientific as 

 well as practical benefits are unpredictable, but recent experience has 

 dramatically sho^vn the advantage of priorit}' in scientific achievement. 

 Vehicles in increased number, either self-buoyant as are submarines 

 or bottom crawlers, and even fixed underwater stations in which men 

 ma.v live and work safely, constitute some of the emerging realities 

 that now make possible an attack on the entire ocean. 



