USS Swordfish began her first war patrol from Manila the day after the attack on Pearl Harbor. On December 9 Swordfish’s crew attacked their first enemy merchant ship. Having heard an explosion, they believed they had sunk it. This was the first attack of the war by a U.S. submarine on an enemy merchant ship.
Swordfish’s first confirmed sinking came on December 16th. Her crew spotted a merchant convoy and they fired three torpedoes at the lead merchant ship, sinking the Atsutasan Maru.
Swordfish’s first war patrol, resulting in four freighters sunk and a fifth damaged, was a tremendous success, particularly in light of the then-unknown Mk14 torpedo problems, the general climate of risk aversion among submarine skippers, and submarine tactics untested in combat.
During her 12th war patrol, Swordfish was lining up for an attack on a guarded convoy. A destroyer became aware of the submarine’s presence and rapidly zig-zagged in Swordfish’s direction. At a distance of only 1,200 yards, Swordfish fired four Mk18 torpedoes at the destroyer and went deep. Two torpedoes struck the destroyer Matsukaze, sinking it.
Swordfish went missing during her 13th war patrol. The boat received three Navy unit commendations and eight battle stars.
According to JANAC, Swordfish sunk 11 non-combatant vessels, one of which was a converted gunboat, and one combatant vessel, the destroyer Matsukaze, for a total of 47,928 tons. Another source claims that Swordfish sunk 18 non-combatants and the Matsukaze and damaged 10 others for a total, sunk or damaged, of 130,362 tons.
The image above, taken in 1944, was painted on the side of the boat’s conning tower. The flag shows that Swordfish had sunk 20 merchant vessels and two combatant vessels.