OVERVIEW: The PORPOISE is a diesel-powered patrol submarine (SSK).

DETAILS:  The PORPOISE class were exceptionally quiet underwater, in part due to careful attention to detail in the mounting of  
machinery, and advances made in propeller design to prevent cavitation. Their quietness, combined with a very effective long-range sonar suite, made them a very capable in their role patrolling chokepoints to detect transiting Soviet submarines.
 

Specifications:
 
	Displacement: 2,030 (surfaced);  2,410 tons submerged.
	Speed: 12 knts (surfaced) 17 knts  (submerged)
       	Engineering: 2 diesel engines; 2 -3-bladed propeller
	Diving Depth: 800-900 feet	
	Range: 9,000 nm (surfaced)	
      	Complement: 71       
     	Hulls built: 8 
	Period of Service: 1956-88  

NOTES: Units in class: PORPOISE (S 01); RORQUAL (S 02); NARWHAL (S 03); GRAMPUS (S 04); FINWHALE (S 05); CACHALOT (S 06); SEALION (S  
07); WALRUS (S 08).  

SOURCES:  Moore, John Evelyn. Jane's Fighting Ships 1987-88.  London: Jane's Pub, 1987, pg. 659 ; British Porpoise-class submarine -  
Wikipedia, the free encyclopedia. (n.d.). Retrieved May 4, 2015, from http://en.wikipedia.org/wiki/British_Porpoise-class_submarine ; Overview | Porpoise Class | Collections | Research | National Cold War Exhibition. (n.d.). Retrieved from http://www.nationalcoldwarexhibition.org/research/collections/porpoise-class/ ; http://arl.g3w1.com/Subs/index.htm
