GENERAL CONSIDERATIONS 



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Before and during World War II submarines had been developed 

 that could cruise on the surface at high speeds and had long ranges of 

 operation under diesel power. They could dive when the occasion arose 

 to attack ships and/or avoid detection, but they had to operate at greatly 

 reduced speeds and for short periods of time on battery power while 

 submerged until the need for air and battery-power replenishment re- 

 quired them to surface. Thus they and the post-World War II submarines 

 shown in Figures 1 and 2 could be termed surface ships which were capa- 

 ble of submerging. The long and narrow hull configuration shown, per- 

 mitted high surface speeds but offered only marginal underwater perform- 

 ance. Improvements in radar and sonar detection techniques almost 

 immediately dictated that the underwater ships of the future be capable of 

 prolonged submergence at greater depths and higher underwater speeds. 



Therefore, in 1946 the Navy started a serious effort to develop a 

 nuclear power plant for marine use; this effort culminated in the 



NAUTILUS (SSN-571) (shown in Figures 1 and 3) which made it 



possible for man to cruise beneath the surface of the sea for extended 

 periods of time. At the same time, a systematic study of the hydro- 

 dynamic characteristics of different hull shapes (similar to that conducted 

 by the then NACA on airfoil sections) undertaken at the Model Basin led to 

 the whale-like hull shape incorporated in the experimental submarine 

 ALBACORE (AGSS-569) (shown in Figures 1 and 4), designed to give high 

 underwater speeds. 



