United States Porpoise-class submarine

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USS Porpoise
USS Porpoise on 20 July 1944
Class overview
Name: Porpoise class
Builders: Electric Boat Company, Portsmouth Naval Shipyard, Mare Island Naval Shipyard[1]
Operators:  United States Navy
Preceded by: Cachalot class[1]
Succeeded by: Salmon class[1]
Built: 1933–1937[2]
In commission: 1935–1945[2]
Completed: 10[1]
Lost: 4[1]
Retired: 6[1]
General characteristics P-1 Type
Type: Diesel-electric submarine
Displacement: 1,316 tons surfaced[3] 1,934 tons submerged[3]
  • 289 ft (88 m) (waterline)
  • 301 ft (92 m) (overall)[4]
Beam: 24 ft 11 in (7.59 m) [3]
Draft: 14 ft 1 in (4.29 m) maximum[3]
  • 18 knots (33 km/h) surfaced[3]
  • 8 knots (15 km/h) submerged[3]
  • SS-172-175: 6,000 nautical miles (11,000 km) surfaced at 10 knots (19 km/h)[6]
  • SS-176-181: 11,000 nautical miles (20,000 km) surfaced at 10 knots (19 km/h)[3]
Test depth: 250 ft (80 m)[3]
Complement: 54 [3] -55[5]

The Porpoise class were submarines built for the United States Navy in the late 1930s, and incorporated a number of modern features that would make them the basis for subsequent Salmon, Sargo, Tambor, Gato, Balao, and Tench classes. Based on the Cachalots, enlarged to incorporate additional main diesels and generators,[7] the Portsmouth boats were all riveted while the other boats were welded.[8] In some references, the Porpoises are called the "P" class.[9]


In general, they were around 300 feet (91 m) long and diesel-electric powered. Displacement was 1,934 tons submerged for the first four boats, 1,998 tons for the later ones.

The goal of a 21-knot fleet submarine that could keep up with the standard-type battleships was still elusive. The relatively high surfaced speed of 18 knots (33 km/h) was primarily to improve reliability at lower cruising speeds.[10] A major improvement essential in a Pacific war was an increase in range from Perch onwards, nearly doubling from 6,000 nautical miles (11,000 km) to 11,000 nautical miles (20,000 km) at 10 knots (19 km/h). This allowed extended patrols in Japanese home waters, and would remain standard through the Tench class of 1944.[6]

Although it proved successful with improved equipment beginning with the Tambor class of 1940, the diesel-electric drive was troublesome at first. In this arrangement, the boat's four main diesel engines drove only electric generators, which supplied power to high-speed electric motors geared to the propeller shafts. The engines themselves were not connected to the propeller shafts. For submerged propulsion, massive storage batteries supplied electricity to the motors. Problems arose with flashover and arcing in the main electric motors. There was also a loss of 360 hp (270 kW) in transmission through the electrical system.[11] The Winton Model 16-201A 16-cylinder diesels also proved problematic, and were eventually replaced with 12-278As.[12]

Five of the class received an additional pair of external bow torpedo tubes, probably early in World War II: Porpoise, Pike, Tarpon, Pickerel, and Permit.[13][14] The original Mark 21 3 inch (76 mm)/50 caliber deck gun proved to be too light in service. It lacked sufficient punch to finish off crippled or small targets quickly enough to suit the crews. It was replaced by the Mark 9 4 inch (102 mm)/50 caliber gun in 1943-44, in most cases removed from an S-boat being transferred to training duty.[15]

Ships in class[edit]

The Porpoise class consisted of the following three subclasses:

P-1 Type

Name Hull no. Builder Laid down Launched Commissioned Decommissioned Fate
Porpoise SS-172 Portsmouth Naval Shipyard 27 October 1933 20 June 1935 15 August 1935 15 November 1945 Reserve training ship; scrapped 1957
Pike SS-173 Portsmouth Naval Shipyard 20 December 1933 12 September 1935 2 December 1935 15 November 1945 Reserve training ship; scrapped 1957

P-3 Type

Name Hull no. Builder Laid down Launched Commissioned Decommissioned Fate
Shark SS-174 Electric Boat 24 October 1933 21 May 1935 25 January 1936 11 February 1942 Lost 11 February 1942, probably to gunfire from destroyer Yamakaze
Tarpon SS-175 Electric Boat 22 December 1933 4 September 1935 12 March 1936 15 November 1945 Reserve training ship; expended as target 1957

P-5 Type

Name Hull no. Builder Laid down Launched Commissioned Decommissioned Fate
Perch SS-176 Electric Boat 25 February 1935 9 May 1936 19 November 1936 3 March 1942 Lost 3 March 1942
Pickerel SS-177 Electric Boat 25 March 1935 7 July 1936 26 January 1937 April 1943 Lost to enemy action April 1943
Permit SS-178 Electric Boat 6 June 1935 5 October 1936 17 March 1937 15 November 1945 Scrapped 1958
Plunger SS-179 Portsmouth Navy Yard 17 July 1935 8 July 1936 19 November 1936 15 November 1945 Reserve training ship; scrapped 1957
Pollack SS-180 Portsmouth Navy Yard 1 October 1935 15 September 1936 15 January 1937 21 September 1945 Scrapped 1947
Pompano SS-181 Mare Island Navy Yard 14 January 1936 11 March 1937 12 June 1937 August or September 1943 Lost August or September 1943, possibly to enemy action on 17 September 1943


Following participation in exercises from 1937, all but three of the ten Porpoise class were forward deployed to the Philippines in late 1939. In October 1941 most of the front-line submarine force, including all sixteen Salmon and Sargo class boats, joined them. The Japanese occupation of southern Indo-China and the August 1941 American-British-Dutch retaliatory oil embargo had raised international tensions, and an increased military presence in the Philippines was felt necessary.[16] Fortunately, the Japanese did not bomb the Philippines until 10 December 1941, so almost all of the submarines were able to get underway prior to an attack. Two of the class were lost in Southeast Asian waters in early 1942, and another two were lost near Japan in 1943. By early 1945, all six surviving boats had been transferred to New London, Connecticut for training duties. Of these, four were used postwar as decommissioned reserve training submarines until they were scrapped in 1957.

See also[edit]


  1. ^ a b c d e f Bauer, K. Jack; Roberts, Stephen S. (1991). Register of Ships of the U.S. Navy, 1775–1990: Major Combatants. Westport, Connecticut: Greenwood Press. p. 269. ISBN 0-313-26202-0. 
  2. ^ a b Friedman, Norman (1995). U.S. Submarines Through 1945: An Illustrated Design History. Annapolis, Maryland: Naval Institute Press. pp. 285–304. ISBN 1-55750-263-3. 
  3. ^ a b c d e f g h i j k l m n Miller, David (2001). The Illustrated Directory of Submarines of the World. London: Greenwich Editions. ISBN 0-86288-613-9. 
  4. ^ Lenton, H. T. American Submarines (New York: Doubleday, 1973), p.39.
  5. ^ a b Lenton, p.39.
  6. ^ a b c Friedman, p. 310
  7. ^ Alden, John D., Commander, USN (retired). The Fleet Submarine in the U.S. Navy (Annapolis, MD: Naval Institute Press, 1979), p.210.
  8. ^ Alden, p.210.
  9. ^ Silverstone, pp. 189-190
  10. ^ Friedman, pp. 198-200
  11. ^ Alden, pp.58 and 65.
  12. ^ Alden, p.58.
  13. ^ Silverstone, p. 190
  14. ^ Gardiner and Chesneau, p. 143
  15. ^ Alden, p.93.
  16. ^ Submarine Force locations on 7 December 1941


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