|Ship Class||Balao-class Submarine|
|Builder||Mare Island Navy Yard|
|Laid Down||25 Jun 1943|
|Launched||23 Mar 1944|
|Commissioned||22 May 1944|
|Decommissioned||27 Jun 1946|
|Sunk||16 Sep 1969|
|Displacement||1550 tons standard; 2463 tons submerged|
|Machinery||Four Fairbanks-Morse Model 38D8-? 10-cyl diesel engines rated at 5,400hp total, two 126-cell Sargo batteries, four General Electric motors rated at 2,740hp total, two shafts|
|Range||11,000nm at 10 knots|
|Armament||6x533mm forward torpedo tubes, 6x533mm aft torpedo tubes, 24 torpedoes, 1x127mm deck gun, 1x40mm Bofors gun, 1x20mm Oerlikon cannon|
|Submerged Speed||8.75 knots|
|Submerged Endurance||48 hours at 2 knots|
Contributor: C. Peter Chen
ww2dbaseWhen USS Trepang was launched on 23 Mar 1944, she was sponsored by Mrs. Davenport, the wife of the man who was to take command of the ship when she was to be commissioned in two months, Commander Roy Milton Davenport. She held her shakedown cruise off San Diego, California, United States before departing to Hawaii, United States for training.
ww2dbaseOn 13 Sep 1944, Trepang departed Pearl Harbor, Hawaii for her first war patrol south of Honshu, Japan. At about 0400 hours on 1 Oct, she spotted a Japanese convoy departing from Tokyo Bay; the convoy was consisted of two tankers, one freighter, and one escort vessel. One of the six torpedoes she fired struck and sank the freighter Takunan Maru. On 11 Oct, she came across another convoy that was consisted of two tankers and one escort vessel; she claimed to have sunk a tanker, but post-war analysis removed her credit for the sinking. On 12 Oct, she came across Japanese warships and identified them as two battleships and two destroyers. She fired six bow and four stern torpedoes, and Commander Davenport claimed to have scored two hits with the bow torpedoes, damaging a battleship and sinking a destroyer. This action earned him his fourth Navy Cross award, but Japanese records studied after the war could not confirm the success of this attack. She reached Majuro, Marshall Islands on 23 Oct for repairs (by submarine tender USS Bushnell) and training, ending her first war patrol.
ww2dbaseTrepang departed for her second war patrol in the Philippine Islands area on 16 Nov 1944, together with sister ships Segundo and Razorback. Off Luzon, Philippine Islands on 6 Dec at about 2100 hours, she detected seven large freighters escorted by three vessels coming from the north. She radioed her findings to the other two submarines and then proceeded to dive for an attack, sinking Banshu Maru Number 31, Jinyo Maru, and Fukuyo Maru; Segundo and Razorback arrived shortly after and sank two additional ships. She arrived at Pearl Harbor in late Dec 1944 to end her second war patrol. Davenport was reassigned as an instructor at the United States Naval Academy in Maryland, United States, and Commander Allen R. Faust took command of the submarine.
ww2dbaseIn Jan 1945, Trepang joined four other submarines during her third war patrol to form an anti-picket boat sweep in the Nanpo Islands south of Tokyo, Japan as indirect support for the preparation for the invasion of Iwo Jima; she encountered no targets during this action. On 24 Feb 1945, she sank the 875-ton Japanese freighter Usuki Maru and blew the bow off of another small coastal vessel; she was unable to finish off the damaged ship as anti-submarine vessels arrived and subjected her to a seven-hour depth charge barrage. On her fourth war patrol which began in early Apr 1945, she sailed into the Yellow Sea. On 28 Apr, she sank Japanese Transport Number 146, followed by the sinking of Miho Maru at 0600 hours on 30 Apr. On 2 May, she surfaced to shell a sampan with her deck gun, but after realizing that the boat was of little value, Trepang's crew gave the lone Korean crewman some food and sent him off along with his cargo of lumber. On 4 May, she hit Minesweeper Number 20, which sank after a very large explosion as its magazine was detonated; the explosion was so large that Faust thought his submarine had sunk a destroyer escort. She served in lifeguard duties briefly off Shanghai, China and south of Japan before heading for Guam, Mariana Islands to end her fourth war patrol.
ww2dbaseIn Jun 1945, Trepang departed for her fifth war patrol. She began this patrol on lifeguard duties southeast of Tokyo Bay, rescuing P-51 Mustang fighter pilots Second Lieutenant Lamar Christian and First Lieutenant Frank Ayres from the water on the first day of the patrol. Three days later, she rescued 7 of 8 survivors from a downed B-29 Superfortress bomber while USS Springer picked up the 8th. During the offensive portion of her fifth war patrol, she sank a freighter at 0600 hours on 30 Jun; about 12 survivors refused to be rescued, thus Trepang left them to die. In the afternoon of 7 Jul, she spotted a convoy of three ships and proceeded to attack, sinking the leading ship Koun Maru Number Two, but in turn also attracted the attention of a Japanese aircraft which attacked them with depth charges, though the attack caused no damage. Before she ended her fifth war patrol, she was put on lifeguard duty once again, rescuing Lieutenant (junior grade) Bill Kingston on 14 Jul.
ww2dbaseTrepang returned to Pearl Harbor for a refit upon the completion of her fifth war patrol, and the war ended while she was out of commission. She was decommissioned from service in mid-1946 and placed in reserve at the Mare Island Navy Yard in California. On 11 Jun 1963, she was reclassified an auxiliary submarine with the hull number of AGSS-412. She was sunk as a target ship off southern California in Sep 1969.
Last Major Revision: Sep 2010
Submarine USS Trepang (SS-412) Interactive Map
USS Trepang Operational Timeline
|24 Sep 1942||The planned submarine Senorita was renamed Trepang.|
|25 Jun 1943||The keel for the future submarine Trepang was laid down at the Mare Island Naval Shipyard in California, United States.|
|23 Mar 1944||Submarine Trepang was launched at the Mare Island Naval Shipyard in California, United States.|
|22 May 1944||USS Trepang was commissioned into service.|
|15 Aug 1944||USS Trepang departed for Pearl Harbor, US Territory of Hawaii.|
|13 Sep 1944||USS Trepang departed Pearl Harbor, US Territory of Hawaii for her first war patrol.|
|1 Oct 1944||USS Trepang attacked a Japanese convoy, sinking freighter Takunan Maru.|
|11 Oct 1944||USS Trepang attacked a Japanese convoy, claiming the sinking of landing ship No. 105.|
|12 Oct 1944||USS Trepang claimed damaging a Japanese battleship and sinking one destroyer during an attack conducted at 2100 hours, earning Commander Roy Davenport a Navy Cross. Post-war studies could not confirm this success, however.|
|23 Oct 1944||USS Trepang arrived at Majuro, Marshall Islands, ending her first war patrol.|
|16 Nov 1944||USS Trepang departed for her second war patrol.|
|6 Dec 1944||USS Trepang reached the Philippine Islands area off Luzon; in the evening, she attacked a Japanese convoy and sank three freighters.|
|24 Feb 1945||USS Trepang sank freighter Usuki Maru and damaged another ship, and then survived a seven-hour depth charge barrage by multiple Japanese anti-submarine vessels.|
|28 Apr 1945||USS Trepang sank landing ship No. 146 in the East China Sea about 20 miles southwest of Goto Islands, Nagasaki Prefecture, Japan, hitting her with 1 of 8 torpedoes fired.|
|30 Apr 1945||USS Trepang sank Miho Maru in the Yellow Sea.|
|2 May 1945||USS Trepang surfaced to shell a sampan, but later called off the attack and allowed the boat to leave.|
|4 May 1945||USS Trepang sank Japanese Minesweeper Number 20 in the Yellow Sea.|
|30 Jun 1945||USS Trepang sank a Japanese freighter at 0600 hours; the Japanese survivors refused to be picked up, thus were left to die.|
|7 Jul 1945||USS Trepang sank Japanese freighter Koun Maru Number Two; the subsequent attack by depth charges from an aircraft resulted in no damage to the submarine.|
|14 Jul 1945||USS Trepang rescued down US Navy airman Lieutenant (junior grade) Bill Kingston from the water.|
|3 Sep 1945||USS Trepang arrived at San Diego, California, United States.|
|27 Jun 1946||USS Trepang was decommissioned from service and entered the reserves at the Mare Island Navy Yard, California, United States.|
|11 Jun 1963||USS Trepang was reclassified an auxiliary submarine with the hull number of AGSS-412.|
|30 Jun 1967||USS Trepang was struck from the Naval Vessel Register.|
|22 Dec 1967||USS Trepang was authorized by the US Navy for disposal as a target ship.|
|16 Sep 1969||USS Trepang was sunk as a target during the exercise Strike Ex 4-69 by destroyers USS Henderson and USS Fechtler.|
Did you enjoy this article? Please consider supporting us on Patreon. Even $1 per month will go a long way! Thank you.
Visitor Submitted Comments
All visitor submitted comments are opinions of those making the submissions and do not reflect views of WW2DB.
» Trepang Submarine Operations Research Group Attack Data
- » 1,049 biographies
- » 330 events
- » 36,190 timeline entries
- » 729 ships
- » 331 aircraft models
- » 185 vehicle models
- » 342 weapon models
- » 104 historical documents
- » 181 facilities
- » 458 book reviews
- » 25,310 photos
- » 290 maps
James Forrestal, Secretary of the Navy, 23 Feb 1945