Any of several small gregarious toothed whales (genus Phocaena)
(SS–172: dp. 1,310 (surf.), 1,934 (subm.); l. 301’; b. 24’11”; dr. 13’1”; s. 19 k. (surf.), 8 k. (subm.); cpl. 50; a. 6 21” tt., 1 3”, 2 .50 mg; cl. Porpoise).
The fifth Porpoise (SS–172) was laid down by the U.S. Navy Yard, Portsmouth, N.H. 27 October 1933; launched 20 June 1935; sponsored by Miss Eva Croft; and commissioned 15 August 1935, Lt. Comdr. S. S. Murray in command.
After shakedown, Porpoise transited the Panama Canal and joined the Pacific Fleet at San Diego 1 September 1936. After gunnery and torpedo practice off the West Coast, Porpoise participated in Fleet Problem No. 18 in the Hawaiian area, April–May 1937, and toward the end of the year underwent extensive overhaul at Mare Island Navy Yard. In January 1938 she returned to Pearl Harbor for fleet exercises, and on 19 November 1939 got underway for Manila to join the Asiatic Fleet. From December 1939 to December 1941, she was engaged in various exercises with Submarines, Asiatic Fleet.
At the outbreak of the war with Japan, 8 December 1941, Porpoise was at Olongapo, P.I., undergoing a refit. With all four main engines being overhauled and her entire after battery out, the required work was accomplished in record time. The sub moved to Manila 20 December, and two days later was enroute, on her first war patrol (22 December31 January 1942) in Lingayen Gulf and the South China Seaoff French Indo-China. Retiring by way of Balikpapan, where the Dutch were blasting their oil wells, Porpoise attacked two ships without result before ending her patrol at Surabaya, Java.
Conducting her 2nd war patrol in the Netherlands East Indies (9 February–30 March), she scored on a cargo ship before anchoring at Fremantle, Australia. Then, with the ultimate destination of Pearl Harbor, she returned to the East Indies for her 3rd war patrol (26 April–17 June). She made one unsuccessful attack on a cargo ship and rescued five airmen off the enemy held island of Ju before heading out across the Pacific.
After major overhaul at Mare Island, Porpoise departed Pearl Harbor for her 4th war patrol (30 November–15 January 1943) off the coast of Honshu. On 1 January 1943 she sank 4,999-ton cargo ship Renzan Maru, then set course for Midway where she completed the patrol. Her 5th war patrol (6 February–15 April), off Jaluit Atoll, was highlighted by the sinking of 2,024-ton cargo ship Koa Maru 4 April 1943.
After refit at Pearl Harbor, Porpoise sailed on her sixth war patrol (20 June–28 July), performing reconnaissance of Taroa Island and in the Marshalls. Scoring hits on two cargo ships early in her patrol, she then sank 2,718-ton passengercargo ship Mikage Maru No. 20 on 19 July before returning to Pearl Harbor.
Due to leaky fuel oil tanks Porpoise departed Pearl Harbor for New London, Conn., where she was to be used as a training sub. The submarine arrived at New London in September 1943, and, interrupted only for overhaul, at Philadelphia, May–June 1944, she served on this duty until inactivated. She decommissioned 15 November 1945 at Boston, Mass., and remained out of commission in reserve until 8 May 1947, when she was placed in service and assigned to the 8th Naval District. For the next 9 years she trained Naval Reservists in the Houston, Tex., area. Struck from the Navy List 13 August 1956, she was sold for scrap to Southern Scrap Material Co., Ltd., New Orleans, La. 14 May 1957.
Porpoise earned 5 battle stars for World War II service.