USS Seahorse (SS-304)
History of the USS Seahorse Submarine
The USS Seahorse (SS-304) was ordered for the U.S. Navy during World War II. Her keel was laid down at Mare Island Naval Shipyard in California on July 1, 1942. She was launched on January 9, 1943 and commissioned on March 31, 1943 under the command of Commander Donald McGregor.
The USS Seahorse departed Pearl Harbor for her first war patrol off the Palau Islands on August 3, 1943. While attacking on Japanese convoy on September 6, she was damaged by enemy depth charges by able to remain on patrol. Her patrol ended on September 27 at Midway.
After refitting, the USS Seahorse sailed for her second war patrol on October 20 off Honshu. On November 2, she sank the Japanese troop transport Chihaya Maru and the transports Yawata Maru and Ume Maru. Her torpedoes sank the transport Daishu Maru on November 22 and the tanker San Ramon Maru five days later. She returned to Pearl Harbor on December 12.
On January 6, 1944, the USS Seahorse got underway for her third war patrol off the Palaus. Ten days later, she sank the Japanese merchant ship Nikko Maru. Her torpedoes sank the troop transport Ikoma Maru and the transport Yasukuni Maru on January 21. The submarine then moved on to sink the transport Toko Maru nine days later and the troop transport Toei Maru two days after that. This patrol ended on February 16 at Pearl Harbor.
The USS Seahorse headed out for her fourth war patrol on March 16 in the Mariana Islands. On April 8, she damaged the Japanese ammunition ship Aratama Maru and the water carrier Kizugawa Maru with her torpedoes. The explosion from the Aratama Maru damaged the destroyer Asakaze; the ammunition ship herself exploded and sank the next day. On April 9, the submarine sank the troop transport Misaku Maru. Eleven days later, she claimed to sink the Japanese sub RO-45, but there is evidence that the enemy vessel was active after this date. Her torpedoes sank the troop transport Akikawa Maru on April 27 before she put in at Brisbane on May 11.
Exactly one month later, the USS Seahorse set sail for her fifth war patrol between Formosa and Luzon. On June 27, she sank the Japanese tanker Medan Maru. Her torpedoes sank the Japanese merchant ships Gyoyu Maru, Niito Maru, and Kyodo Maru No. 28 on the night of July 3-4. This patrol ended at Pearl Harbor on July 19.
When the USS Seahorse set out for her sixth war patrol, she helped support the capture of the Palau Islands before moving on to patrol Luzon Strait. On October 6, she sank the Japanese corvette Kaibokan No. 21. The submarine then performed lifeguard services before putting in at Midway on October 18.
From Midway, the USS Seahorse was ordered to Mare Island Navy Yard for overhaul. Once her yard work was complete, she commenced her seventh war patrol of the Tsushima Strait on March 9, 1945. One month later, she sank a small junk with her gunfire. On April 18, she was damaged by enemy depth charges and forced to end her patrol early at Guam.
The USS Seahorse sailed for Pearl Harbor for permanent repairs and overhaul before she began her eighth and final war patrol on July 12 in the Japanese home waters. After World War II ended, she returned to Midway before being sent on to Mare Island in California.
The USS Seahorse was decommissioned on March 2, 1946. She was reclassified as an auxiliary submarine, AGSS-304, on November 6, 1962. The submarine was struck from the Naval Vessel Register on March 1, 1967 and sold for scrap on December 14, 1968. She earned nine battle stars for her service in World War II.
The use of asbestos was common in shipbuilding components for much of the 20th Century because of its resistance to heat, fire, water and corrosion. Because of their asbestos exposure onboard ship and in the shipyards, seaman, shipyard workers and longshoreman are at risk for developing asbestos-related diseases like mesothelioma.
Sources include:
Asbestos and Ship-Building: Fatal Consequences, by John Hedley-Whyte and Debra R Milamed
