USS Threadfin (SS-410) - First War Patrol

First War Patrol

Threadfin stood out of Pearl Harbor on 25 December. Early in January 1945, she reached her assigned patrol area in the waters just south of Kyūshū. There, she spent 30 of her 54 days at sea. She encountered numerous enemy aircraft, patrol craft, and fishing vessels, but only six targets worthy of a torpedo.

On 30 January, Threadfin sighted a large enemy patrol craft, but prudently allowed her to pass unmolested in the hope of drawing a bead on any merchant vessels for which she might be running interference. Presently, a 2000-ton coastal freighter escorted by two patrol vessels and a plane crossed her path. Threadfin fired a spread of six torpedoes from a range of about 2,900 yards (2,700 m). At least one of them struck home, obscuring the target in smoke and steam. The cargoman probably sank; but Threadfin could not verify that result visually because the escorts drove her deep with a persistent, though ineffective, depth charge attack.

Two days later, the submarine encountered a Japanese Ro-60-class submarine. However, the enemy's course changes kept Threadfin from gaining an advantageous attack setup, and the Japanese "pig-boat" disappeared in the distance. Threadfin next happened upon two freighters escorted by three patrol craft. This time, the small convoy's position close inshore defied the American submarine's efforts to attack.

The following day, she mistook another patrol vessel for a cargo ship and discovered her mistake in just enough time to make a deep dive to safety. That escapade also robbed her of a chance at a small convoy consisting of two small cargomen and two escorts. She sighted the convoy later when she returned to periscope depth; but, by then the ships had passed out of range. A week later, she launched six torpedoes at a minesweeper 2,500 yards (2,300 m) distant. In spite of an excellent fire-control solution, all six missed. They apparently ran too deeply. Three days later, she concluded a somewhat discouraging, but still successful, first war patrol at Midway Island.