OCEAN SCIENCES AND NATIONAL SECURITY 31 



water operations, and for extended endurance. It was the develop- 

 ment of nuclear propulsion that released the submarine from its 

 dependence on a periodic replenishment of air for diesel recharging of 

 batteries. Nuclear power thus gave the U.S.S. Nautilus unprece- 

 dented performance in sustained, high-speed operation while fully sub- 

 merged. Other exploits followed of the U.S.S. Nautilus, Skate and 

 Sargo in traversing the North Pole under the ice cap and, more re- 

 cently, of the Triton in chcling the Earth, a sea route of 36,000 miles, 

 without completely surfacing. The technological capability of ex- 

 ploring and even operating in shallow water is well proved. Recently', 

 too, Piccard and Walsh proved in the submersible vehicle Trieste that 

 man can descend to the very deepest regions of the ocean, some 35,800 

 feet near Guam. But the Trieste is a "bottom dunking" device with 

 limited capabilities other than for depth seeking. It is not a sub- 

 marine. What then is the potential for more ambitious undertakings 

 in deep water? 



True submarines consist of thin, cigar -shaped shells that, like sur- 

 face ships, develop their buoyancy from displacement of sea water. 

 Through the use of ballast, usuall}^ sea water, their weights can be 

 delicately adjusted so as to be heavy enough to sink when submerged 

 performance is desired, or to operate near or at the surface. 



In general, these operations have not been very deep. Jane's 

 "Fighting Ships of the World" for 1957-58 notes that the U.S.S. 

 Nautilus, which at that time was dramatizing the spectacular achieve- 

 ment and merit of nuclear power, is able to operate only at depths of 

 700 feet. The working depth for combat submarines has always been 

 regarded by the U.S. Navy as classified so that this figure may repre- 

 sent only an order of magnitude. 



The significance of this limitation is evident from data regarding 

 the depths of the ocean set forth in Table 1. There, the oceans are 

 expressed in percent of their total area versus depth. From this in- 

 formation, it is clear that the Nautilus could operate to the bottom in 

 less than 5 percent of the ocean. To operate deeper would require a 

 stronger and essentially, a heavier hull, so that increased depth would 

 have been achieved at the penalty of some other performance char- 

 acteristic. As far as the Nautilus was concerned, its capabilities of sus- 

 tained high speed when submerged even when operating within that 

 depth were considered by naval designers as satisfactory. 



The point, however, is that depth is essentially an unexplored di- 

 mension of the sea. It is just being realized that it may be as signifi- 

 cant as the more familiar wavy surface or shoreline. In these depths, 

 in fact all the way to bottom, there is evidence of marine life; perhaps 

 not so prolific as in the regions nearer the surface where photosynthetie 

 processes maintain a rich supply of organic food. There are certainly 

 minerals in the sea water at depth, on and in the bottom. The water 

 at these depths is just as much in circulation as are the surface cur- 

 rents, and it is the vertical "upwelling" that resupplies mineral con- 

 tent to support life at the surface. At depths on the order of several 

 thousand feet, a "deep sound channel" develops that, by processes of 

 reflection between water layers of different density and the bottom, 

 serves as a duct for long-distance sound transmission. By way of 

 example, a small explosive charge detonated in the Indian Ocean was 

 heard with underwater hydrophones 9,000 miles away in New York. 



