(SS-412: dp. 1,662 (surf.), 2,424 (subm.), 1. 311'10" b. 27'4"; dr. 16'2", s. 20.26 k. (surf.), 8.76 k.(subm.); cpl. 66; a. 10 21" tt., 1 6", 1 40mm., 1 20mm., 2 .60-car. mg.; cl. Balao)
SS-412 was originally projected as Senorita but was renamed Trepang on 24 September 1942. The submarine was laid down on 26 June 1943 at Vallejo, Calif., by the Mare Island Navy Yard, launched on 23 March 1944 sponsored by Mrs. R. M. Davenport, the wife of the submarine's prospective commanding officer, and commissioned on 22 May 1944, Comdr. Roy Milton Davenport-already a three-time Navy Cross winner-in command.
Following shakedown out of San Diego Trepang departed the west coast on 16 August 1941 and proceeded to Hawaii where her crew trained and prepared the ship for combat. Setting out from Pearl Harbor on 13 September for her first war patrol, the submarine prowled the waters south of Honshu, the largest and most important of Japan's home islands. She remained below during daylight hours and came up after dark to get a better view as she recharged her batteries and filled up with fresh air. On the night of 30 September Trepang spotted a fast convoy departing Tokyo Bay. The submarine gave chase and closed in on a group of ships which included two large tankers, a small freighter, and an escort. The submarine fired an overlapping spread of torpedoes which struck the freighter 760-ton Takunan Maru, and sent her to the bottom
On 10 October, Trepang attacked her second convoy which consisted of a pair of tankers and a single escort. Although the submarine claimed a "kill," a postwar assessment of the action did not credit her with a sinking. The following day, the error was reversed. The submarine fired four torpedoes at another Japanese ship, and her commanding officer recorded that all of the "fish" had missed. This time, however, postwar accounting credited Trepang with the destruction of the 1,000-ton Transport No. 105.
On 12 October, the submarine cruised some 12 miles southwest of the entrance to Tokyo Bay. Soon after she came to the surface, and her radar swept the surrounding seas. Four pips showed themselves on the phosphorescent screen-two large and two small-which were identified as two battleships and two destroyers.
Despite the fact that the phosphorescent waters would make his submarine stand out starkly in the night, Davenport closed at flank speed and fired a full spread of six torpedoes. The "fish" sped through the water toward their targets. He claimed success when explosions rumbled across the water, and flames lit up the night. Davenport turned the submarine to precept her stern tubes to the enemy and lossed four more torpedoes. These all missed.
Davenport's gallant and skillfully pressed attacks won him his fourth Navy Cross. He felt that he had damaged a Yamashiro-class battleship and had sunk a destroyer; but, unfortunately, a study of Japanese records after the war did not verify either claim.
Her supply of torpedoes exhausted, Trepang cleared the area and headed for the Marshalls. She reached Majuro on 23 October for voyage repairs alongside Bashnell (AS-15) and brief training which lasted until 16 November. On that day, Trepang got underway for the Philippines leading a wolfpack which also included Segundo (SS-398) and Razorhack (SS-394).
The weather was dark, windy, and rough on 6 December, as Trepang's conning tower broke the surface after a day's submerged inshore patrol off Luzon. While shifting course toward deeper water, she detected a group of ships approaching from the northward. Upon closing to investigate, Trepang counted seven large ships and three escorts in the convoy which slowly approached the Philippines.
Trepang radioed news of her "find" to her packmaster and then submerged. The submarine shot straight and true-sending freighter Banshu Maru No. 81 and Jinyo Maru to the bottom in quick succession and damaging a third vessel-Fukuyo Maru. However, as Trepang came about to administer the coup de grace to Fukugo Maru the third cargo ship "obligingly blew up and sank.' Meanwhile, as Segundo and Razorback arrived on the scene, Trepang fired all of her remaining torpedoes at a fourth ship which, she reported, blew up and sank soon thereafter. However, this fourth sinking was not confirmed by Japanese records. In the meantime, the other two American submarines were trying to finish off the fleeing remnants of the shattered convoy and managed to sink two ships-one with the aid of American naval aircraft. Trepang, now out of torpedoes, sped back to Pearl Harbor, arriving before Christmas.
Following this war patrol, Davenport, one of the most highly decorated submariners of the war, left Trepang for shore duty as an instructor at the Naval Academy.
Again sailing for Honshu, Trepang-now under Comdr. Allen Russell Faust-teamed up with Piper (SS-409), Pomiret (SS-391), Bowfin (SS-287), and Sterlet (SS-392) on an anti-picket boat sweep past Nanpo Shoto, the eastern island chain south of Tokyo, to clear the sea lanes for the carriers of Task Force 6g which in turn was about to strike the Japanese home islands to neutralize them during the assault on the strategic island of Iwo Jima. Trepang encountered no worthwhile targets during the patrol and had to settle for performing lifeguard duty for carrier assaults on Tokyo. On 24 February 1945, the submarine sank the 875-ton freighter Usuki Maru and blew the bow off another small coastal vessel. While maneuvering to finish off the crippled ship, several antisubmarine vessels appeared on the scene from behind a nearby headland and converged on the fleet boat. Trepang dove deep as the Japanese subjected her to a seven-hour depth charge barrage.
Following her return to Guam in March, Trepang headed for the Yellow Sea a "hazardous duty" area due to its vast stretches of shallow water. Despite the danger, the submarine performed well, bagging the 1,000-ton landing craft, Transport No. 146, on 28 April, the 4,667-ton, heavily laden freighter, Miho Maru, two days later, and Minesweeper No. 20 which blew sky-high with a hit on her magazine on 4 May. In addition the submarine surfaced to shell a junk with a load of lumber. The sole member of this victim's crew, a Korean understood little sign language, and looked to be of little value for intelligence purposes, so he was put back on board his barely seaworthy craft, with tools and food, and sent on his way. Leaving the Yellow Sea, Trepang did a short tour of lifeguarding for B-25 strikes on Shanghai, China, and for the continuing series of B-29 raids on Tokyo, before she returned to Guam.
Trepang's fifth war patrol was divided into two parts —the first saw the ship operating in a lifeguard capacity while the second gave her a more offensive role off northeastern Honshu and eastern Hokkaido. In the former role, she arrived on station to the southeast of Tokyo Bay. Having experienced two previous tours of lifeguarding, Trepang's men expected a series of long dull days, spent moving in circles, squares, or triangles to break the monotony.
However, shortly before noon on her first day, lookouts spotted a blossoming parachute overhead and soon saw the splash of a crashed P-51 Mustang fighter damaged while escorting B-29's to Tokyo. Trepang bent on full power and soon picked up the downed aviator 2d Lt. Lamar Christian, USAAF, safe and sound. During the maneuver, another Mustang, piloted by 1st Lt. Frank Ayres, USAAF, radioed that it, too, was in trouble; and the pilot requested permission to bail out. Trepang replied telling Ayres to "be patient" until the first rescue was complete. Ayres circled the submarine until Christian was safely on board the submarine. Ayres then executed a perfect jump and landed some 400 yards away from Trepang and was soon hauled on board.
Three days after rescuing the two airmen, Trepang turned them over to Tigrone (SS-419) which was on her way home with 30 other aviators already on board. In the middle of the transfer, the submarines picked up a radio message from a "Boxkite" (rescue search plane) that a B-29 Superfortress crew, downed the previous day, was floating a mere seven miles from the Japanese seaport of Nagoya. Accompanied by Springer (SS-414) which had also been discharging passengers to Tigrone Trepang surged ahead.
The two submarines raced to save the Superfortress's crew. Trepang put on full speed and arrived on the scene first. She found eight survivors in four groups of rafts, spread over about four miles of ocean. By the time Springer arrived on the scene, Trepang had picked up seven of the fliers. Springer picked up the last man.
En route to a rendezvous with Devilfish (SS-292)Trepang sighted a small, troop laden freighter and sank the ship with her deck guns. A dozen or so Japanese soldiers from the flaming vessel refused to be picked up and taken prisoner and so were left to drown.
Subsequently patrolling off the eastern coast of Honshu, Trepang went scoreless until July, when she spotted a coastal convoy of three ships. She torpedoed and sank the lead ship-Koun Maru No. 2—but the other vessels conducted evasive action and sped away from the scene at full speed.
Satisfied that she had done her best, Trepang, heading to seaward, suddenly shuddered under the impact of two depth bomb explosions. A solitary Japanese plane had spotted Trepang's shadow in the shallow waters and had attacked with depth bombs. Fortunately, all missed their mark.
Given another lifeguarding assignment, Trepang stood on the alert to pick up possible downed airmen from British and American carrier strikes on the Japanese home islands. During this tour in July 1945, she rescued one pilot Lt. (jg.) Bill Kingston, USNR. In addition, on 14 July, she witnessed a shore bombardment conducted by three battleships and a heavy cruiser against Kamaishi.
By now, the war was moving fast, and Trepang returned to Pearl Harbor for a refit. There, she watched the tumbling succession of staggering headlines-first the atomic bombs on Hiroshima and Nagasaki, the Russian entry into the Far Eastern War, Japan's tentative acceptance of surrender terms, and finally-on 15 August-peace at last.
After completion of her refit, Trepang departed Pearl Harbor and arrived at San Diego on 3 September 1945. Decommissioned on 27 June 1946 and placed in reserve at Vallejo, Calif., at the Mare Island Navy Yard, Trepang remained in reserve into the 1960's. She was redesignated as an auxiliary submarine and classified AGSS-412 on 11 June 1962. Struck from the Navy list on 30 June 1967, the submarine was authorized for disposal on 22 December 1967. She was subsequently sunk as a target during Exercise "Strike Ex 4-69" on 16 September 1969 by the combined gunfire of Henderson (DD-785) and Feakteler (DD-870).
Trepang received five battle starts for World War II service and a Navy Unit Commendation.