View source for USS Trigger (SS-237)

{{short description|United States Navy submarine}}
{{other ships|USS Trigger}}
{{Use American English|date=November 2024}}
{{Use dmy dates|date=November 2024}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=USS Trigger;0823701.jpg
|Ship caption=USS ''Trigger'' (SS-237) underway off Mare Island Navy Yard, 6 April 1942
}}
{{Infobox ship career
|Hide header=
|Ship country=United States
|Ship flag={{USN flag|1945}}
|Ship name=''Trigger''
|Ship ordered=
|Ship builder=[[Mare Island Naval Shipyard]]<ref name="FriedmanSubs1-dates">{{cite book
  | last = Friedman
  | first = Norman
  | title = U.S. Submarines Through 1945: An Illustrated Design History
  | publisher = [[United States Naval Institute]]
  | year = 1995
  | location = [[Annapolis, Maryland]]
  | pages = 285–304
  | isbn = 1-55750-263-3 }}</ref>
|Ship laid down=1 February 1941<ref name="FriedmanSubs1-dates"/>
|Ship launched=22 October 1941<ref name="FriedmanSubs1-dates"/>
|Ship sponsor=Mrs. Walter N. Vernou
|Ship acquired=
|Ship commissioned=31 January 1942<ref name="FriedmanSubs1-dates"/>
|Ship decommissioned=
|Ship in service=
|Ship out of service=
|Ship reinstated=
|Ship fate=Sunk 28 March 1945<ref name="Register">{{cite book
  | last = Bauer
  | first = K. Jack
  |author2=Roberts, Stephen S.
   | title = Register of Ships of the U.S. Navy, 1775-1990: Major Combatants
  | publisher = Greenwood Press
  | year = 1991
  | location = [[Westport, Connecticut]]
  | pages = 271–273
  | isbn = 0-313-26202-0 }}</ref>
}}
{{Infobox ship career
|Hide header=yes
|Ship struck=11 July 1945
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship class={{sclass|Gato|submarine|0}} [[diesel-electric]] [[submarine]]<ref name="Register"/>
|Ship displacement=*{{convert|1525|LT|t|0|abbr=on}} surfaced<ref name="Register"/>
*{{convert|2424|LT|t|0|abbr=on}} submerged<ref name="Register"/>
|Ship length={{convert|311|ft|9|in|abbr=on}}<ref name="Register"/>
|Ship beam={{convert|27|ft|3|in|abbr=on}}<ref name="Register"/>
|Ship draft={{convert|17|ft|abbr=on}} maximum<ref name="Register"/>
|Ship propulsion={{Fleet-boat-propulsion-early-FM-4-GE}}
|Ship speed=*{{convert|21|kn|abbr=on|lk=in}} surfaced<ref name="FriedmanSubs1-specs">''U.S. Submarines Through 1945'' pp. 305-311</ref>
*{{convert|9|kn|abbr=on}} submerged<ref name="FriedmanSubs1-specs"/>
|Ship range={{convert|11000|nmi|km|abbr=on}} surfaced at {{convert|10|kn|km/h|0|abbr=on}}<ref name="FriedmanSubs1-specs"/>
|Ship endurance=*48 hours at {{convert|2|kn|km/h|0|abbr=on}}  submerged<ref name="FriedmanSubs1-specs"/>
*75 days on patrol
|Ship test depth={{convert|300|ft|m|-1|abbr=on}}<ref name="FriedmanSubs1-specs"/>
|Ship complement=6 officers, 54 enlisted<ref name="FriedmanSubs1-specs"/>
|Ship sensors=
|Ship EW=
|Ship armament={{Fleet-boat-armament-3-inch}}
}}
|}

'''USS ''Trigger'' (SS-237)''' was a {{sclass|Gato|submarine|0}} [[submarine]], the first ship of the [[United States Navy]] to be named for the [[triggerfish]].

==Construction==
''Trigger''{{'}}s keel was laid down on 1 February 1941 at [[Mare Island]], California, by the [[Mare Island Navy Yard]]. She was [[Ship naming and launching#United States|launched]] on 22 October 1941, sponsored by Mrs. Walter N. Vernou, and [[Ship commissioning#United States Navy|commissioned]] on 30 January 1942.

==Battle of Midway==
The submarine sailed for [[Hawaii]] on 22 May and reached [[Pearl Harbor]] the following week. She sortied for [[Midway Island]] with Task Group 7.2 (TG&nbsp;7.2) on 29 May in anticipation of a Japanese attack on that island. Her station during the ensuing [[Battle of Midway]] was northeast of Midway, but her usefulness was curtailed when she ran aground.  She freed from her grounding and returned to Pearl Harbor on 9 June.

== First patrol: June–August&nbsp;1942 ==
On 26 June, ''Trigger'' got underway for the [[Aleutian Islands]] to patrol an area west of [[Cape Wrangell]], [[Attu Island]]. She encountered six destroyers, three freighters and a patrol boat, attacking none, before calling at [[Dutch Harbor]] on 8 August ''en route'' back to [[Hawaii]].

== Second patrol: September–November&nbsp;1942 ==
[[Roy S. Benson]] assumed command before ''Trigger'' began her second war patrol, conducted from 23 September to 8 November in "Empire Waters" (the seas immediately surrounding Japan). In the early morning hours of 5 October, the submarine sighted smoke on the horizon and headed for it. A vessel soon appeared, coming toward the submarine. As the target approached, the submarine identified it as a small ship. ''Trigger'' then surfaced and manned her machine guns. As the target neared, however, the submarine learned that the Japanese ship was larger than initially thought. Enemy shells soon began exploding close to ''Trigger'', and the 4,000&nbsp;ton ship turned and accelerated in an attempt to ram the submarine. ''Trigger'' barely avoided a collision as she submerged for an attack; she launched two torpedoes and heard one hit. She then surfaced and gave chase, only to have the target again open fire. The submarine missed with three more torpedoes and then discontinued the pursuit.

Before dawn on the morning of 17 October, ''Trigger'' made a surface attack on a [[cargo ship|freighter]] off the [[Bungo Suido]]. She fired two spreads of torpedoes which sank ''Holland Maru'' with her guns still firing. That night, a [[destroyer]] came out of Bungo Suido and dropped a string of [[depth charge]]s near the submarine. ''Trigger'' launched three torpedoes "down the throat" at the onrushing destroyer and, one minute later, observed an explosion so powerful it threw enough flame and water into the air to obscure the target. When the air cleared, the enemy ship was still intact, suggesting ''Trigger'''s first torpedo may have exploded prematurely, detonating the next two by its turbulence. The submarine fired one more torpedo as the enemy disappeared, but failed to score a hit.

Near midnight of 20 October, ''Trigger'' fired a spread of four torpedoes from very close range, {{convert|900|yd}}, in a surface attack on a 10,000-ton [[Tanker (ship)|tanker]]. Two torpedoes hit the enemy ship as it turned in an attempt to ram. The submarine went to {{convert|100|ft}} to evade a counterattack, and heard a heavy explosion as either gasoline, magazines, or boilers blew up. ''Trigger'' then came up to periscope level but found nothing in sight. (This sinking was not confirmed by [[JANAC]] postwar.) Four days later, ''Trigger'' attacked a large enemy tanker in ballast. A spread of three torpedoes produced three observed hits, one near the target's stern. The screws of the enemy ship stopped, and she began emitting heavy white smoke aft, but she soon got underway again. ''Trigger'' fired her last torpedo at the ship as it was moving off and missed. That night, she surfaced and began her homeward voyage.

== Third patrol: December&nbsp;1942–January&nbsp;1943 ==
[[File:IJN Okikaze sinking by USS Trigger.jpg|thumb|Periscope camera shot from USS Trigger, of the sinking of Imperial Japanese Navy destroyer Okikaze.]]
From 3 December 1942 to 22 January 1943, the submarine conducted a combined minelaying and offensive patrol, again in waters surrounding the Japanese home islands. On 20 December, she began planting a minefield off [[Inubo Saki]], [[Honshū]]. ''Trigger'' planted the northern half of the field and was working on the southern part when a [[cargo ship]] passed her, heading into the newly-laid mines. Five minutes later, a violent explosion rocked the freighter which sank while an escort circled her. The submarine later heard another explosion from the direction of the minefield and, when she surfaced the next day, found the field was covered by smoke.

On 22 December, ''Trigger'' sighted a ship approaching from [[Uraga, Kanagawa|Uraga]] and made a surface attack. A spread of three torpedoes produced one hit forward of the bridge, and the target started to settle by the bow. The submarine fired one more torpedo into the ship and, when last seen, ''Teifuku Maru'' was awash forward with her screws nearly out of the water. On 31 December 1942, she attacked a cargo ship loaded with planes. ''Trigger'' fired three torpedoes from extremely close range {{convert|700|yd}}, and watched two hit. The target began to list to starboard and was down by the bow. Sound reported a heavy secondary explosion. The submarine came up to periscope level and saw the freighter with her stern high out of the water and a destroyer approaching. ''Trigger'' went deep and when she next came up for a look, there was nothing to be seen. (The sinking was not confirmed by JANAC postwar.)

On 10 January 1943, a Japanese destroyer approached ''Trigger'', and the submarine fired three torpedoes from {{convert|1600|yd}}. One hit under the well deck and folded the destroyer's [[forecastle]] up at a 45° angle, and another hit the target's stern. Soon, the {{sclass|Minekaze|destroyer|0}} destroyer {{ship|Japanese destroyer|Okikaze||2}} sank on an even keel.

== Fourth patrol: February–April&nbsp;1943 ==
''Trigger'' stood out of Midway on 13 February to patrol off the [[Palau Islands]]. Two weeks later, she launched four torpedoes at a freighter, but the target managed to steer between them. Heavy air cover prevented a second attack. On 4 March, the submarine attacked a freighter in a rain squall, but all three of her torpedoes missed. On 15 March, ''Trigger'' sighted a convoy steaming in two columns. There were two freighters in the right hand column and three in the left, with an escort on the outboard bow of each column. ''Trigger'' worked her way between the two columns and launched three torpedoes at each of the leading ships. She hit the lead freighter in the left hand column twice but missed her target on the right because it unexpectedly changed course. ''Trigger'' then fired three more torpedoes at the right lead ship at just {{convert|700|yd}} and observed two hits before the escorts forced her to go deep. When she surfaced again, there was nothing to be seen. ''Trigger'' was later officially credited with having sunk ''Momoha Maru'', a 3,103-ton cargo ship.

That night, the submarine fired six torpedoes at a ship that was being towed by a smaller freighter. Five of the torpedoes missed, and the sixth made a circular run and passed over the submarine's engine room. A shaken crew broke off the attack.

On 20 March, the submarine launched three torpedoes at the lead ship in a convoy of four cargo ships. One hit caused the target to list 10° to port and stop, but it soon got underway and rejoined the convoy. ''Trigger'' terminated the patrol at the Submarine Base, Pearl Harbor, on 6 April.

== Fifth patrol: April–June&nbsp;1943 ==
Between 30 April and 22 June, the submarine made a patrol which returned her to Empire waters. Directed by an [[Ultra (cryptography)|Ultra]] from Pearl Harbor, ''Trigger'' lay athwart the projected track of [[Mineichi Koga|Admiral Koga]]'s [[task force]] returning from [[Chuuk Lagoon|Truk]]. Koga's force came in sight the morning of 22 May, but zigged away, out of range, "a bitter disappointment".<ref>Blair, ''Silent Victory'', p.428</ref> On 28 May, ''Trigger'' contacted two freighters off [[Iro Saki]] and fired three torpedoes at the larger. One hit aft. When last seen, the ship was down by the stern. The next day, the submarine fired a spread of three torpedoes at a small cargo ship. Two missed and the third exploded prematurely. She then fired a fourth torpedo, which apparently hit but failed to explode.

On 1 June, the submarine was searching for Japanese shipping off [[Sagami Nada]] when she sighted two columns of smoke. She closed the range toward a firing position, made out two cargo ships, and fired a spread of three torpedoes at each target. Hit in her stern, the lead ship, ''Noborikawa Maru'', sank immediately. The second ship saw the torpedo wakes, turned and passed between them. ''Trigger'' then fired a torpedo at the oncoming ship; if the torpedo reached the target, it failed to explode.

Again alerted by Ultra, on 10 June (her last day on station), ''Trigger'' sighted an [[aircraft carrier]] protected by two [[destroyer]]s. She closed and fired six torpedoes from only {{convert|1200|yd}}.<!--is it clear this is, again, Koga's force?--> Although as she went deep the submarine heard four explosions, postwar accounting showed two of the torpedoes missed ahead and one failed to explode. The escorts kept ''Trigger'' down for several hours.<ref>Blair, ''Silent Victory'', p.430</ref> The damaged {{ship|Japanese aircraft carrier|Hiyō||2}} limped into [[Tokyo Bay]] and was out of action for almost a year. [[Admiral]] [[Charles A. Lockwood|Lockwood]] (<small>[[COMSUBPAC]]</small>), who knew ''Hiyō''{{'}}s fate, was furious. Had the torpedoes functioned correctly, Benson would have sunk her. The next day, ''Trigger'' began her return voyage to [[Pearl Harbor]]; just after her triumphant return, the [[Mark 14 torpedo]]'s defective [[Mark 6 exploder]] was ordered deactivated.

== Sixth patrol: September&nbsp;1943 ==
On 1 September, after a yard overhaul, ''Trigger'' (now in the charge of [[Commander (United States)|Commander]] [[Robert Edson Dornin|Robert "Dusty" Dornin]]) was ready to begin her sixth war patrol. The patrol took her into the [[East China Sea]], off the [[China]] coast, north of [[Taiwan|Formosa]]. On 17 September, she made two hits on a Japanese freighter, one aft and one on the bow, but both torpedoes proved to be duds. The next day, she again contacted the same ship and launched four torpedoes at her. One struck ''Yowa Maru'', and the 6,435-ton cargo ship slid beneath the waves.

21 September was ''Trigger''{{'}}s best day. She was patrolling some {{convert|30|mi|km}} north of the [[Hoka Sho]] light when she sighted a convoy of three tankers and three freighters protected by Japanese planes. The submarine attacked the tankers first, firing three torpedoes at the leader and three at the second. One hit aft was seen on the lead tanker, and flames shot over {{convert|500|ft}} into the air. The target's crew, dressed in whites, could be seen running forward to escape the fire. One torpedo hit the second tanker amidships, and it broke in half beneath the stack and sank immediately. ''Trigger'' turned and fired three stern tubes at the third tanker. This target swung toward the submarine, and all three torpedoes missed. ''Trigger'' then fired another torpedo which hit that ship's starboard side. When the submarine went deep, Dornin slipped and fell into the periscope well as the quartermaster was lowering it. He supported himself on his elbows, and the quartermaster heard his shouts in time to prevent a serious accident. Sonar reported two more explosions before the submarine came back up to [[periscope depth]] to resume the attack. ''Trigger'' fired two bow torpedoes at the third freighter in the column and scored two hits on the target which went down by the bow. The submarine then made two more attacks on the freighter, but all of her torpedoes either missed or were duds. During the three and one-half hours of action, ''Trigger'' sank two tankers, ''Shiriya'' and ''Shoyo Maru'', and a freighter, ''Argun Maru'', for a total of 20,660&nbsp;tons of enemy shipping. The submarine returned to Midway on 30 September to be refitted and rearmed.

== Seventh patrol: October–December&nbsp;1943 ==
The [[East China Sea]] and [[Yellow Sea]] were ''Trigger''{{'}}s objective for her seventh patrol. She stood out of Midway on 22 October and proceeded to her patrol area. At 22:00 on 1 November, she sighted a convoy that was steaming in two columns. When a ship in the nearer column overlapped one in the more distant group, ''Trigger'' fired a spread of three torpedoes at them. One torpedo struck the nearer freighter in the bow and one hit the farther ship amidships. The submarine saw the nearer ship go down by the bow, before she herself was forced to go deep where she was severely depth-charged by two escorts.

Early the next morning (2 November), ''Trigger'' launched three torpedoes at a freighter and scored one hit. At 00:50, she attacked the ship again with another three-torpedo spread. Two of them hit forward, and ''Yawata Maru'' went down, bow first, in a vertical plunge. Two hours and 25&nbsp;minutes later, ''Trigger'' launched three torpedoes at a 7,148-ton transport. All hit, and ''Delagoa Maru'' disintegrated. On 5 November, the submarine attacked a convoy of three cargo ships protected by one destroyer and two planes. ''Trigger'' fired three bow tubes at the second ship in the convoy and one bow tube at the third before going deep to avoid the escort which dropped 20 [[depth charge]]s. Thinking she was clear, the submarine came to periscope depth and was greeted by five near bomb misses.

On 13 November, ''Trigger'' made a submerged approach on a convoy of nine merchantmen and four escorts. After the Japanese ships zigged, the submarine found herself between two columns of ships, but ''Trigger'' had no torpedoes remaining in her bow tubes. She emptied her stern tubes at the last and biggest ship, believed to be a transport, from a [[pointblank]] range, {{convert|800|yd}}. The target, which carried a large deck cargo, took one hit aft and one under her stack. The submarine went deep, received a short [[depth charge]] attack, and came up to periscope depth to learn that her target had gone down. On 21 November, ''Trigger'' sighted a cargo ship and closed to {{convert|2000|yd}} before firing four torpedoes. Two hits started the victim down by the bow as the submarine's crew took turns at the periscope to watch ''Eizan Maru'' sink. More than a fortnight later, the submarine arrived at Pearl Harbor on 8 December 1943.

== Eighth patrol: January–February&nbsp;1944 ==
''Trigger'' stood out to sea on [[New Year's Day]] 1944 to begin her eighth war patrol, this time in the [[Chuuk Lagoon|Truk]]-[[Guam]] shipping lanes. On 27 January, she sighted the conning tower of an {{sclass|Ro|submarine|0}} submarine dead ahead. ''Trigger'' set up to fire a bow shot from {{convert|800|yd}}. She came to periscope depth and saw the Japanese submarine, then less than {{convert|100|yd}} away, was preparing to attack. ''Trigger'' submerged to {{convert|150|ft|-1}}, expecting a torpedo at any minute, but sound heard no torpedo screws. She came up to periscope depth and saw the Japanese periscope so she decided to make an end around. When ''Trigger'' returned to periscope depth, the enemy had disappeared.

Four days later, she contacted a convoy of three ships accompanied by two {{sclass|Fubuki|destroyer|0}} destroyers. The submarine scored two hits on the coastal [[minelayer]] ''Nasami'', which disappeared in a cloud of smoke and debris. The nearer destroyer began closing the range, and ''Trigger'' missed it with four aft tubes. She caught up with the convoy again and fired five torpedoes at the last ship. Two hits produced flames that reached [[mast (sailing)|mast]] height and several secondary explosions that marked the end of the 11,933-ton converted [[submarine tender]] {{ship||Yasukuni Maru|1930|2}}. Over three weeks later, the submarine terminated the patrol when she arrived at Pearl Harbor on 23 February.

==Ninth patrol: March–May 1944==
On 23 March, ''Trigger'' (now in the able hands of Commander [[Frederick J. Harlfinger II|Frederick J. "Fritz" Harlfinger II]], and still with [[Edward L. Beach Jr.|"Ned" Beach]] as [[executive officer]]) headed for the [[Palau Islands]] on her ninth war patrol. In the early morning of 8 April, she contacted a convoy of approximately 20 large ships with an estimated 25 escorts, and closed to attack. When she raised her periscope, she saw a destroyer {{convert|150|ft}} away firing at the scope and attempting to ram. The submarine loosed four torpedoes at the convoy and went deep as several more escorts joined the attack. On her way down, she heard four explosions. ''Trigger'' ran at {{convert|300|ft}} or more for 17 hours as six escorts dogged her trail and rained down numerous depth charges. Six exploded extremely close. When the submarine surfaced, her forward torpedo room was flooded to her deck plates, and the hull air induction and most compartments were in about the same condition. The bow planes, trim pump, sound gear, and both radars were all dead. Her radio antenna was grounded, and the submarine could not transmit. The crew spent the next four days making repairs "by use of spares, baling wire, and considerable ingenuity."{{Citation needed|date=February 2007}}

''Trigger'' met submarine {{USS|Tang|SS-306|6}} on 14 April and exchanged information by line gun. The next day, ''Trigger''{{'}}s executive officer went on board ''Tang'' by a rubber boat, to borrow an air compressor part and to make plans for a coordinated search and attack. On 18 April, ''Tang''{{'}}s executive officer delivered spare parts for the air compressor to ''Trigger'', and she continued on patrol.

Shortly before midnight on 26 April, ''Trigger'' contacted a convoy of six ships off the eastern Palaus. She fired six torpedoes, from {{convert|2400|yd}}, at four ships that were closely bunched and overlapping. Four hits were seen and heard, with a big explosion on each ship. Suddenly, a terrific explosion blew up one of the closer ships. One of the more distant ships stood straight up on her bow and sank immediately. At six minutes after midnight, ''Trigger'' launched three torpedoes at another group of ships and heard one timed explosion. At 01:57, she launched four torpedoes at a damaged cargo ship and two at an escort. The cargo ship received two more hits. Five minutes later, the submarine fired three stern tubes at a group of three escorts, and the middle one disappeared in a cloud of smoke. During the attack, ''Trigger'' sank the 11,739-ton passenger/cargo ship ''Miike Maru'' and heavily damaged the destroyer escort ''Kasado'', the 9,467-ton cargo ship {{ship||Hawaii Maru}}, and the 8,811&nbsp;ton cargo ship ''Asosan Maru''. ''Trigger'' returned to Pearl Harbor on 20 May and four days later, headed for the [[United States]] for a major overhaul. She arrived at [[San Francisco, California]], on 31 May and, after overhaul, returned to Hawaii on 11 September.

== Tenth patrol: September–November&nbsp;1944 ==
On 24 September, ''Trigger'' got underway to take station off the east coast of [[Taiwan|Formosa]] and perform life guard patrol for bomber strikes due on 12 October. The morning of the strikes, she rescued a pilot from [[aircraft carrier]] {{USS|Bunker Hill|CV-17|6}} whose burning plane had crash-landed nearby. On 19 October, as the invasion of the [[Philippines]] was about to begin, ''Trigger'' contacted a convoy of two {{sclass|Takao|cruiser|0}} [[heavy cruiser]]s, one {{sclass|Nagara|cruiser|0}} [[cruiser]], two other light cruisers, and several destroyers with air cover. ''Trigger'' had no chance to fire but reported the contact. On 30 October, she launched four torpedoes at a tanker but missed. She then fired another four from her stern tubes and heard one hit the target before running up the periscope to watch the other three blow off part of the stern, but the ship did not sink. ''Trigger'' went deep as 78 depth charges were rained down on her within the next hour, but caused no damage. The damaged 10,021-ton tanker ''Takane Maru'' was later sunk by submarines {{USS|Salmon|SS-182|6}} and {{USS|Sterlet|SS-392|6}}. The next morning, ''Trigger'' received word from ''Salmon'' that she had been heavily damaged by depth charges and was unable to submerge. ''Trigger'' rendezvoused with ''Salmon'' that night and was joined by {{USS|Silversides|SS-236|6}} and ''Sterlet'' to escort the damaged submarine to [[Saipan]]. They were provided with air cover from the [[Mariana Islands]] and arrived at [[Tanapag Harbor]] on 3 November. A week later, ''Trigger'' departed with six other submarines but was ordered to discontinue her patrol on 17 November and returned to [[Guam]].

== Eleventh patrol: December&nbsp;1944–February&nbsp;1945 ==
On 28 December 1944, ''Trigger'' headed for the Bungo Suido-[[Kii Suido]] area to begin her 11th war patrol. At 21:05 on 3 January 1945, she sighted a light, and radar made a doubtful contact. Thirty minutes later, a torpedo passed by her starboard side. ''Trigger'' reversed course and cleared the area but returned two days later. That day, she sighted a periscope at {{convert|2000|yd}}, and—realizing that instead of hunting, she was being hunted—she slipped away.

On 29 January, the submarine made radar contact from {{convert|23000|yd}} on a large convoy with six escorts and well covered by aircraft. As she closed, the moon came out bright and clear. An enemy bomber turned and started in as radar picked up another plane coming in astern at {{convert|5000|yd}}. The submarine went deep, and the convoy slowly pulled away. The next day, the ship was ordered to terminate her patrol, and she returned to [[Guam]] on 3 February.

== Twelfth patrol: March&nbsp;1945 ==
[[File:ISS near Olympia and Becuna 3.JPG|thumb|right|"USS Trigger Still on Patrol" plaque at the [[Independence Seaport Museum]]]]
''Trigger'' (with new skipper Commander [[David R. Connole]]) stood out to sea on 11 March to begin her 12th war patrol and headed for the [[Nansei Shoto]] area. On 18 March, she attacked a convoy west of the islands, sinking the cargo ship ''Tsukushi Maru No.3'' and damaging another. She reported the attack on 20 March, and the submarine was subsequently ordered to radio as many movements of the convoy as possible to help find a safe passage through a known mined area of the [[East China Sea]]. On 24 March, ''Trigger'' was ordered to begin patrolling west of the islands the next day, outside the {{convert|100|fathom|adj=on|lk=in}} curve, and to steer clear of restricted areas. On 26 March, she was ordered to join a [[wolf pack (submarines)|wolf pack]] called "Earl's Eliminators" and to acknowledge receipt of the message. A weather report came from the submarine that day but no confirmation of her having received the message. The weather report was ''Trigger''{{'}}s last transmission. On 4 April, she was ordered to proceed to Midway, but she had not arrived by 1 May and was reported as presumed lost.

Postwar records indicate she torpedoed and sank the [[repair ship]] {{ship|Japanese repair ship|Odate||2}} on 27 March. The next day, Japanese planes and ships joined in a two-hour attack on a submarine heard by ''Silversides'', {{USS|Sea Dog|SS-401|2}}, {{USS|Hackleback|SS-295|2}}, and {{USS|Threadfin|SS-410|2}} in adjacent areas. ''Threadfin'' was the only one of these submarines attacked that day, and she reported hearing many [[depth charge]]s and several heavy explosions east of her after the attack on her ceased. Postwar Japanese records showed a Japanese aircraft detected and bombed a submarine on 28 March 1945. ''[[Kaibokan]]'' ''[[Japanese escort ship Mikura|Mikura]]'', ''CD-33'', and ''CD-59'' were then guided to the spot and delivered an intensive depth charging. After two hours, a large oil slick appeared.

''Trigger'' was stricken from the [[Naval Vessel Register]] on 11 July 1945.

''Trigger'' was immortalized and eulogized in Beach's 1952 book ''Submarine!''.

Destroyer escort {{USS|Connole|FF-1056|6}} (DE-1056, later FF-1056) was named in honor of Commander David R. Connole.

== Awards ==
''Trigger'' received 11 [[battle star]]s for [[World War II]] service and the [[Presidential Unit Citation (United States)|Presidential Unit Citation]] for her fifth, sixth, and seventh war patrols. She is credited with sinking 18 ships (tied with {{USS|Seawolf|SS-197|2}} and {{USS|Rasher|SS-269|2}} for seventh on the list of confirmed sinkings by number of ships), totaling 86,552&nbsp;tons (seventh on the list of confirmed sinkings by tonnage), according to the official [[Joint Army-Navy Assessment Committee|JANAC]] accounting postwar.<ref>Blair, pp.989-990.</ref>
<!-- [http://www.rddesigns.com/ww2/listt.html]
Or "... a total of 27 ships sunk, for 180,600&nbsp;tons, and 13 ships damaged, for 102,900&nbsp;tons, during the ship’s entire career."[http://www.csp.navy.mil/ww2boats/trigger.htm] That's based on an inaccurate wartime credit. JANAC doesn't even credit Harlfinger or Connole with 5 ships each, so Blair doesn't mention them, & between them Dornin & Benson got 19 by JANAC.-->

===Presidential Unit Citation===
[[File:United States Navy Presidential Unit Citation ribbon.svg|left|50px]]
;Citation: ''For outstanding performance in combat during her Fifth, Sixth, and Seventh War Patrols against the enemy. Employing highly daring and hazardous tactics, the USS TRIGGER struck at the enemy with consistent aggressiveness, seeking out and pursuing her targets with dogged determination regardless of unfavorable attack conditions. Her exceptionally notable record of severe damage inflicted on hostile shipping and the gallant fighting spirit of her officers and men reflect great credit upon the United States Naval Service.''<ref>([http://www.applmath.com/csds50/pdfs/RADMRoyStanleyBenson.pdf PDF] {{Webarchive|url=https://web.archive.org/web/20070928234629/http://www.applmath.com/csds50/pdfs/RADMRoyStanleyBenson.pdf |date=2007-09-28 }}) – Text of Citation from biography former Commanding Officer Rear Admiral Roy Stanley Benson</ref>

==See also==
* [[List of most successful American submarines in World War II]]

== References ==
{{reflist}}
* {{DANFS|http://www.history.navy.mil/research/histories/ship-histories/danfs/t/trigger-i.html}}
* [[Clay Blair|Blair, Clay, Jr.]] ''Silent Victory''. Philadelphia: J. B. Lippincott, 1975.
* [[Edward L. Beach, Jr.|Beach, Edward L., Jr.]] ''Submarine!''  Annapolis: United States Naval Institute Press, 2003 (reprints 1952 edition)

== External links ==
*[http://www.history.navy.mil/research/histories/ship-histories/danfs/t/trigger-i.html history.navy.mil: USS ''Trigger'']
*[http://www.navsource.org/archives/08/08237.htm navsource.org: USS ''Trigger'']
*[http://hazegray.org/danfs/submar/ss237.txt hazegray.org: USS ''Trigger'']
*[http://www.oneternalpatrol.com/uss-trigger-237.htm On Eternal Patrol: USS ''Trigger'']
*[http://www.atule.com/USS_Trigger_SS_237.htm www.atule.com: USS ''Trigger'']

{{Gato class submarine}}
{{March 1945 shipwrecks}}

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{{DEFAULTSORT:Trigger (Ss-237)}}
[[Category:Gato-class submarines]]
[[Category:World War II submarines of the United States]]
[[Category:Lost submarines of the United States]]
[[Category:World War II shipwrecks in the Philippine Sea]]
[[Category:Ships built in Vallejo, California]]
[[Category:1941 ships]]
[[Category:Maritime incidents in March 1945]]
[[Category:Warships lost in combat with all hands]]
[[Category:Submarines sunk by Japanese warships]]