First war patrol, July – September 1944 Following shakedown training along the coast of California,
Spadefish departed San Francisco on 14 June and arrived at
Pearl Harbor on 22 June. On 23 July, she got underway from Pearl Harbor for her maiden war patrol, as a member of a
coordinated attack group with and . On 19 August, while patrolling in
Philippine waters off the northwest coast of
Luzon,
Spadefish torpedoed and sank her first enemy target the 9,589-ton, passenger-cargo ship
Tamatsu Maru. Three days later, she trailed three large
tankers through
Babuyan Channel along the northern Luzon coast; closed range; and fired two spreads of torpedoes, sinking the 10,023-ton tanker
Hakko Maru No. 2, and damaging a second tanker that, protected by a
destroyer, limped back to a shallow cove off Luzon. For several hours into the next day,
Spadefish attempted to get around the escort to attack the damaged ship anchored in the cove. The submarine finally let go with four stern torpedoes at the destroyer, but the enemy zigged clear and proceeded to
depth charge the entire area. Having only three torpedoes remaining,
Spadefish set course for
Tanapag Harbor, Saipan, to replenish her supply. On 8 September,
Spadefish was patrolling in waters of
Nansei Shoto when she contacted a
convoy of eight cargo ships. During a daring night surface attack, she fired a total of 20 torpedoes, sinking cargo ships
Nichiman Maru,
Nichian Maru,
Shinten Maru, and
Shokei Maru and damaging another. The following morning, she fired her final four torpedoes at an escort guarding the stricken ship; but they ran under the target. The submarine's only reward on this occasion was a rain of depth charges. Although she was out of torpedoes,
Spadefish continued to trail the remaining ships of the convoy that first took refuge in the harbor of
Ishigaki; and then, in company with five escorts, continued their voyage.
Spadefish terminated her first war patrol at Pearl Harbor on 24 September, having sunk six enemy ships for a total of over 31,500 tons. With the additional 33,000 tons sunk by her sister submarines, the coordinated attack group accounted for a total of 13 ships and over 64,000 tons of enemy shipping.
Second war patrol, October – December 1944 in November 1944
Spadefish sank the 1902 cargo ship
Daiboshi Maru No. 6. This photo shows her as the British ship
Gracchus, which was her name until Japanese owners bought her in 1923. On 23 October, she got underway from Pearl Harbor for her second war patrol, in a coordinated attack group with and . While patrolling in the
Yellow Sea on 14 November, she torpedoed and sank the Japanese cargo ship . Three days later, she contacted an enemy convoy headed directly at her. After letting the convoy pass overhead, she surfaced after darkness had set in and commenced an "end around". She first fired six torpedoes at the prime target, the 21,000-ton
escort aircraft carrier ; and then turned rapidly to port and fired four stern torpedoes at a tanker. The unarmored fuel tanks of the escort carrier
Shinyo exploded and started a huge fire that destroyed the ship and killed most of her crew. Only 70 men from her crew of 1,200 officers and men survived. Damage to the tanker could not be confirmed. Later that same night,
Spadefish drove in for another attack, firing four stern torpedoes at
Submarine Chaser No. 156. As the enemy disappeared in the resulting explosion, the submarine quickly evaded other escorts and left the vicinity.
Spadefish sank the fourth ship of her second patrol on 29 November by torpedoing the 3,760-ton cargo ship
Daiboshi Maru No. 6; and then concluded her patrol at
Majuro Atoll in the
Marshall Islands on 12 December.
Third war patrol, January – February 1945 After spending the holidays at Majuro,
Spadefish departed on 6 January 1945 for her third war patrol, conducted with , , and in the
Yellow Sea. On the day of her departure, two
United States Marine Corps SBD Dauntless dive bombers of
Marine Scouting Squadron 245 (VMSB-245) mistook her for a Japanese submarine and dropped two
depth charges on her after she submerged off Majuro. She suffered only superficial damage and no casualties, She sustained no damage or casualties, but her crew found bomb fragments on her deck after she surfaced.{{cite web |url= http://www.kscnet.ru/ivs/bibl/paperno/for_65_engl.htm |last=Paperno |first=Alla
Spadefish was preparing for another war patrol when
hostilities with Japan ended on 15 August 1945 (14 August across the
International Date Line in Hawaii.
Post-World War II Spadefish remained at Pearl Harbor until 2 September 1945 and then set course for
Mare Island Naval Shipyard where she was decommissioned on 3 May 1946 and placed in
reserve. She was reclassified an
auxiliary submarine,
AGSS-411, on 6 November 1962, struck from the
Navy List on 1 April 1967, towed to New London, CT Submarine Base full of spare parts and later sold for scrap in 1969. ==Honors and awards==