Seahorse

Contributor: C. Peter Chen

ww2dbaseUSS Seahorse was commissioned into service in Mar 1943. After shakedown and training cruises, she departed the west coast of the United States for Pearl Harbor, US Territory of Hawaii, from where she would embark on her first war patrol in Aug 1943. She would make a total of eight war patrols, most of which saw her sinking Japanese vessels ranking from small sail boats to large cargo ships; on 20 Apr 1944, she encountered a warship, Japanese submarine RO-45, and promptly destroyed her as well. She ended the war while on lifeguard station 40 miles southeast of Hachijo Jima of Izu Islands south of Japan, about 250 kilometers south of Tokyo, Japan. She was decommissioned from service at Mare Island Naval Shipyard at Vallejo, California, United States in Mar 1946 and was placed in reserve until she was removed from the US Navy Register in Mar 1967. She was sold for scrap in the following year.

ww2dbaseSource: Wikipedia

Last Major Revision: Apr 2013

Submarine Seahorse (SS-304) Interactive Map

Seahorse Operational Timeline

1 Jul 1942 The keel of submarine Seahorse was laid down at Mare Island Naval Shipyard, Vallejo, California, United States.

9 Jan 1943 Submarine Seahorse was launched at Mare Island Naval Shipyard, Vallejo, California, United States, sponsored by the wife of Chester C. Smith.

31 Mar 1943 USS Seahorse was commissioned into service with Commander Donald McGregor in command.

3 Aug 1943 USS Seahorse departed Pearl Harbor, US Territory of Hawaii for her first war patrol.

29 Aug 1943 USS Seahorse attempted to attack a Japanese convoy in the Pacific Ocean, but was counterattacked prior to the launching of torpedoes. She suffered minor damage from depth charges.

6 Sep 1943 USS Seahorse sank a Japanese transport in the Palau Islands, hitting her with three of four torpedoes fired. The subsequent depth charge counterattack caused severe leaks.

14 Sep 1943 USS Seahorse attacked a Japanese tanker in the Palau Islands; all eight torpedoes missed.

27 Sep 1943 USS Seahorse arrived at Midway Atoll, ending her first war patrol.

20 Oct 1943 USS Seahorse departed Midway Atoll for her second war patrol.

29 Oct 1943 USS Seahorse sank a small Japanese vessel with her deck gun south of Japan.

30 Oct 1943 USS Seahorse sank a small Japanese vessel with her deck gun south of Japan.

31 Oct 1943 USS Seahorse sank a small Japanese vessel with her deck gun south of Japan.

2 Nov 1943 USS Seahorse sank Japanese cargo ships Chihaya Maru and Ume Maru south of Japan; nine torpedoes were expended during this attack, seven of which hit.

22 Nov 1943 USS Seahorse sank Japanese cargo ship Daishu Maru south of Japan, hitting her with two of four torpedoes fired.

26 Nov 1943 USS Seahorse sank Japanese tanker San Ramon Maru south of Japan, hitting her with two of three torpedoes fired.

1 Dec 1943 USS Seahorse damaged a Japanese transport south of Japan, hitting her with two of four torpedoes fired. She ran out of torpedoes and set sail for Hawaii Islands.

12 Dec 1943 USS Seahorse arrived at Pearl Harbor, US Territory of Hawaii, ending her second war patrol.

6 Jan 1944 USS Seahorse departed Pearl Harbor, US Territory of Hawaii for her third war patrol.

16 Jan 1944 USS Seahorse sank Japanese cargo ship Nikko Maru off the Mariana Islands, hitting her with three of four torpedoes fired.

21 Jan 1944 USS Seahorse sank Japanese cargo ship Yasukuni Maru and passenger-cargo ship Ikoma Maru in the Pacific Ocean, expending nine torpedoes, five of which scored hits.

28 Jan 1944 USS Seahorse began an 80-hour chase of a Japanese convoy off the Palau Islands.

30 Jan 1944 USS Seahorse sank Japanese cargo ship Toko Maru south of Japan, which she had been chasing for many hours, hitting her with all three of three torpedoes fired.

31 Jan 1944 USS Seahorse sank Japanese cargo ship Toei Maru south of Japan, which she had been chasing for many hours, hitting her with two of eight torpedoes fired.

16 Feb 1944 USS Seahorse arrived at Pearl Harbor, US Territory of Hawaii, ending her third war patrol.

16 Mar 1944 USS Seahorse departed Pearl Harbor, US Territory of Hawaii for her fourth war patrol.

8 Apr 1944 USS Seahorse detected a Japanese convoy off the Mariana Islands. After dark, attacked the convoy and sank cargo ship Kizugawa Maru, hitting her with four of eight torpedoes fired. After evading depth charges, she attacked again, sinking cargo ship Bisaku Maru, hitting her with two of six torpedoes fired.

12 Apr 1944 USS Seahorse assumed lifeguard station duty for US aircraft attacking Saipan, Mariana Islands.

20 Apr 1944 USS Seahorse sank Japanese submarine RO-45 west of Saipan, Mariana Islands, hitting her with three of four torpedoes fired.

27 Apr 1944 USS Seahorse sank Japanese cargo ship Akigawa Maru west of Saipan, Mariana Islands.

3 May 1944 USS Seahorse was relieved from lifeguard station duty in the Mariana Islands and set sail for Milne Bay, Australian Papua.

11 May 1944 USS Seahorse arrived at Brisbane, Australia, ending her fourth war patrol.

11 Jun 1944 USS Seahorse departed Brisbane, Australia for her fifth war patrol.

27 Jun 1944 USS Seahorse sank Japanese tanker Medan Maru and damage two other ships off Taiwan, hitting them with five of six torpedoes fired.

3 Jul 1944 USS Seahorse sank Japanese cargo ship Nitta Maru and passenger-cargo ship Gyoyu Maru off Taiwan, hitting her with four of five torpedoes fired.

4 Jul 1944 USS Seahorse sank Japanese cargo ship Kyodo Maru No. 28 off Taiwan, hitting her with five of her last six torpedoes.

19 Jul 1944 USS Seahorse sank arrived at Pearl Harbor, US Territory of Hawaii, ending her fifth war patrol.

6 Oct 1944 USS Seahorse claimed the sinking of a Japanese destroyer off Taiwan with one torpedo hit of six torpedoes fired.

18 Oct 1944 USS Seahorse arrived at Midway Atoll, ending her sixth war patrol.

9 Mar 1945 USS Seahorse departed for her seventh war patrol.

8 Apr 1945 USS Seahorse sank a small Japanese vessel with gunfire off Japan.

18 Apr 1945 USS Seahorse was damaged by two Japanese patrol vessels off Japan; she fired one torpedo in return, but it missed. She set sail for Guam, Mariana Islands for repairs.

12 Jul 1945 USS Seahorse departed Pearl Harbor, US Territory of Hawaii for her eighth war patrol.

2 Mar 1946 USS Seahorse was decommissioned from service at Mare Island Naval Shipyard at Vallejo, California, United States.

6 Nov 1962 USS Seahorse was reclassified an auxiliary submarine and was given the new hull number AGSS-304.

1 Mar 1967 Submarine Seahorse was struck from the US Naval Register.