USS Seahorse (SS-304), a Balao-class

Balao class submarine

The Balao class was a successful design of United States Navy submarine used during World War II, and with 122 units built, the largest class of submarines in the United States Navy. An improvement on the earlier Gato class, the boats had slight internal differences...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

, was the first submarine and second ship of the United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 to be named for the seahorse

Seahorse

Seahorses compose the fish genus Hippocampus within the family Syngnathidae, in order Syngnathiformes. Syngnathidae also includes the pipefishes. "Hippocampus" comes from the Ancient Greek hippos meaning "horse" and kampos meaning “sea monster”.There are nearly 50 species of seahorse...

, a small fish whose head and the fore part of its body suggest the head and neck of a horse.

The first submarine Seahorse (SS-304) was laid down on 1 August 1942 by the Mare Island Navy Yard, Vallejo, Calif.

Vallejo, California

Vallejo is the largest city in Solano County, California, United States. The population was 115,942 at the 2010 census. It is located in the San Francisco Bay Area on the northeastern shore of San Pablo Bay...

; launched on 9 January 1943; sponsored by Mrs. Chester C. Smith; and commissioned on 31 March 1943, Comdr. Donald McGregor in command.

First war patrol, August – September 1943

Following shakedown along the California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 coast, Seahorse sailed to Pearl Harbor

Pearl Harbor

Pearl Harbor, known to Hawaiians as Puuloa, is a lagoon harbor on the island of Oahu, Hawaii, west of Honolulu. Much of the harbor and surrounding lands is a United States Navy deep-water naval base. It is also the headquarters of the U.S. Pacific Fleet...

 and, on 3 August 1943, got underway for her maiden war patrol, conducted off the Palau Islands. On the morning of 29 August, while the submarine was gaining attack position on a Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese convoy

Convoy

A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support, though it may also be used in a non-military sense, for example when driving through remote areas.-Age of Sail:Naval...

, she was detected by escorting destroyer

Destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s and suffered minor damage from a depth charge

Depth charge

A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...

 attack.

Seahorse scored three torpedo hits on a transport on 6 September, and then went deep to evade a depth charge attack that caused severe leaks and put her number four torpedo tube out of commission. A week later, she expended eight torpedoes in an unsuccessful attempt to sink a large tanker

Tanker (ship)

A tanker is a ship designed to transport liquids in bulk. Major types of tankship include the oil tanker, the chemical tanker, and the liquefied natural gas carrier.-Background:...

. The submarine terminated her first patrol at Midway

Midway Atoll

Midway Atoll is a atoll in the North Pacific Ocean, near the northwestern end of the Hawaiian archipelago, about one-third of the way between Honolulu, Hawaii, and Tokyo, Japan. Unique among the Hawaiian islands, Midway observes UTC-11 , eleven hours behind Coordinated Universal Time and one hour...

 on 27 September.

During this patrol, Seahorses commanding officer ignored several potential targets, rather than face sonar-equipped escorts, which unrealistic prewar training indicated was virtual suicide.

Second war patrol, October – December 1943

Following refit, Seahorse sailed on 20 October for her second war patrol. Between 29 October and 31 October, the submarine sank three enemy trawlers

Naval trawler

A naval trawler is a vessel built along the lines of a fishing trawler but fitted out for naval purposes. Naval trawlers were widely used during the First and Second world wars. Fishing trawlers were particularly suited for many naval requirements because they were robust boats designed to work...

 in surface actions and then commenced a two-day attack on a 17-ship convoy. Early on the morning of 2 November, following an attack on the convoy by another United States submarine, Seahorse evaded three escort ships and launched three torpedoes into two freighters. Four hours later, she again attacked, sending three torpedoes toward a tanker and another spread at a third freighter. Flames burst from each target as two Japanese destroyers turned toward Seahorse but too late to catch the rapidly departing submarine. Sunk in this action were the 7,089-ton cargo ship Chihaya Maru, and the 5,859-ton cargo ship, Ume Maru. Seahorse later closed again on the convoy but was driven down by depth charges and departed the vicinity.

On 22 November, Seahorse skillfully maneuvered past three enemy escorts, launched four torpedoes from periscope

Periscope

A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle....

 depth, and sank the cargo ship, Daishu Maru. On 26 November, the submarine contacted another enemy convoy and began to close the range. Determined to mount an attack before the targets entered the mined Tsushima Strait

Tsushima Strait

is the eastern channel of the Korea Strait, which lies between Korea and Japan, connecting the Sea of Japan and the East China Sea.The Tsushima Strait is the broader eastern channel to the east and southeast of Tsushima Island, with the Japanese islands of Honshū to the east and northeast, and...

, the submarine launched four torpedoes at long range quickly sinking a cargo ship; and then, dodging enemy escorts, let go four stern shots at a second target. The results seemed disappointing—until a sudden blast sent flames and debris mushrooming high into the air, completely destroying the 7,309-ton tanker, San Ramon Maru.

Seahorse expended the last of her torpedoes on the night of 30 November and 1 December. After maneuvering for several hours, the submarine was finally able to fire her stern tubes at an enemy convoy. However, one torpedo exploded just after it left the tube, and the entire convoy opened fire on the vicinity of the submarine. With so many explosions around her, it was impossible for Seahorse to determine whether any torpedoes had hit. Low on fuel and out of torpedoes, the submarine returned to Pearl Harbor on 12 December from a successful second patrol, with five ships and three trawlers sunk.

Third war patrol, January – February 1944

Seahorse departed Pearl Harbor on 6 January 1944 for her third war patrol. On 16 January, while en route to the Palaus, she evaded four escorts and destroyed the 784-ton cargo ship, Nikkō Maru, with three torpedo hits. She spent 21 January tracking two enemy cargo ships in company with three escorts. In the late evening, she pressed home four consecutive attacks to sink the 3,025-ton cargo ship, Yasukuni Maru, and the 3,156-ton passenger-cargo ship, Ikoma Maru.

On the evening of 28 January, Seahorse began an 80-hour chase of an enemy convoy off the Palaus. After being continually harassed by escorts and aircraft throughout the next day, Seahorse launched three torpedoes at the cargo ship, Toko Maru. After the sinking, the submarine lost contact with the convoy for several hours, but again had it in sight at dawn on 31 January.

Early on the morning of 1 February, Seahorse launched four torpedoes for no hits followed by two more, again without result. With the crew exhausted from the extended chase, the submarine fired her final two torpedoes and headed for deeper water. After evading the escorts, she surfaced in time to see the results of her latest attack as the cargo ship, Toei Maru, slipped beneath the waves. Seahorse terminated her third patrol at Pearl Harbor on 16 February.

Fourth war patrol, March – May 1944

Seahorses fourth war patrol was conducted in the Marianas

Mariana Islands

The Mariana Islands are an arc-shaped archipelago made up by the summits of 15 volcanic mountains in the north-western Pacific Ocean between the 12th and 21st parallels north and along the 145th meridian east...

. She departed Pearl Harbor on 16 March and intercepted a large enemy convoy on 8 April. After nightfall, the submarine launched four torpedoes at overlapping targets, sinking the converted seaplane tender, Aratama Maru. Shortly thereafter, her second spread of torpedoes sank the cargo ship, Kizugawa Maru. Although a counterattack by escorting destroyers drove the submarine from the vicinity, she quickly regained contact and continued the chase into the following day, sinking the cargo ship, Bisaku Maru.

Seahorse took up lifeguard station for the carrier

Aircraft carrier

An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

 airstrikes on Saipan

Saipan

Saipan is the largest island of the United States Commonwealth of the Northern Mariana Islands , a chain of 15 tropical islands belonging to the Marianas archipelago in the western Pacific Ocean with a total area of . The 2000 census population was 62,392...

 that commenced on 12 April and, while west of Saipan on 20 April, sighted and sank the Japanese submarine, RO-45

Japanese submarine RO-45

Ro-45 was an Ro-35-class submarine of the Japanese Navy during World War II. It was completed and commissioned at Mitsubishi Shipbuilding on January 11, 1944. It was based in the Maizuru Naval District under the command of Commander Hamazumi Yoshihisa. It was later reassigned to the Sixth Fleet...

. In the same vicinity a week later, Seahorse sank the 5,244-ton cargo ship, Akigawa Maru. The submarine departed her lifeguard station on 3 May to refuel at Milne Bay

Milne Bay

Milne Bay is a large bay in Milne Bay Province, southeastern Papua New Guinea. The bay is named after Sir Alexander Milne.The area was a site of the Battle of Milne Bay in 1942....

, New Guinea

New Guinea

New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...

, and arrived at Brisbane

Brisbane

Brisbane is the capital and most populous city in the Australian state of Queensland and the third most populous city in Australia. Brisbane's metropolitan area has a population of over 2 million, and the South East Queensland urban conurbation, centred around Brisbane, encompasses a population of...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, on 11 May.

Fifth and sixth war patrols, June – October 1944

Seahorse put to sea for her fifth war patrol on 11 June 1944, patrolling between Formosa

Taiwan

Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

 and Luzon

Luzon

Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...

. On the morning of 27 June, she sank the tanker, Medan Maru, and damaged two other enemy vessels; and, on 3 July, sank the cargo ship, Nitta Maru

Nitta Maru

The was a Japanese ocean liner owned by Nippon Yusen Kaisha. The ship was built in 1938-1940 by Mitsubishi Shipbuilding & Engineering Co. at Nagasaki, Japan...

, and the passenger-cargo ship, Gyoyu Maru. The following day, the submarine expended the last of her torpedoes sinking the cargo ship, Kyodo Maru No. 28, and returned to Pearl Harbor on 19 July.

Seahorse spent the first part of her sixth war patrol supporting the capture of the Palaus and then headed for the Luzon Strait

Luzon Strait

The Luzon Strait is the strait between the island country of Taiwan and Luzon island of the Philippines. The strait thereby connects the Philippine Sea to the South China Sea in the western Pacific Ocean....

. Despite intensive efforts, the submarine could locate only one worthwhile target, Coast Defense Vessel No. 21, a frigate

Frigate

A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...

 of 800 tons, which she sank. Five days later, Seahorse took up lifeguard station for the carrier airstrike on northern Luzon and then returned to Midway on 18 October.

Seventh and eighth war patrols, March – August 1945

Upon completion of an overhaul at Mare Island Navy Yard, Seahorse put to sea on 9 March 1945 for her seventh war patrol. Following patrol in the Tsushima Strait

Tsushima Strait

is the eastern channel of the Korea Strait, which lies between Korea and Japan, connecting the Sea of Japan and the East China Sea.The Tsushima Strait is the broader eastern channel to the east and southeast of Tsushima Island, with the Japanese islands of Honshū to the east and northeast, and...

, she sank a small junk with gunfire on 8 April. On 18 April, an attack by two patrol boats left the submarine's interior a shambles of broken glass, smashed instruments, and spilled hydraulic oil. Seahorse made hasty repairs and headed for Apra Harbor

Apra Harbor

Apra Harbor is a deep-water port on the western side of Guam in the Mariana Islands. The harbor is formed by Orote Peninsula in the south and Cabras Island in the north. To the south, the harbor narrows and then widens again to form an inner harbor. The southern end of the harbor is the location...

, Guam

Guam

Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...

, and then to Pearl Harbor for overhaul.

Seahorse put to sea for her eighth and final war patrol on 12 July. When hostilities ceased on 15 August, the submarine was on station 40 miles (64.4 km) southeast of Hachijo Shima.

Following her return to Midway, Seahorse sailed for Mare Island where she was decommissioned on 2 March 1946. She was assigned to the Pacific Reserve Fleet and remained inactive for the remainder of her career. She was reclassified an auxiliary submarine, AGSS-304, on 6 November 1962, struck from the Navy list

Naval Vessel Register

The Naval Vessel Register is the official inventory of ships and service craft in custody of or titled by the United States Navy. It contains information on ships and service craft that make up the official inventory of the Navy from the time a vessel is authorized through its life cycle and...

 on 1 March 1967, and sold on 14 December 1968 to Zidell Explorations Inc., Portland, Oregon, for scrapping.

Seahorse (SS-304) received nine battle stars for World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 service.

External links

• www.ussseahorse.org/ website for (SS-304) and (SSN-669)
  USS Seahorse (SSN-669)
  USS Seahorse , a Sturgeon-class attack submarine, was the second submarine and third ship of the United States Navy to be named for the seahorse, a small fish whose head and upper body suggest the head and neck of a horse....