USS Thresher (SS-200) - Seventh Patrol

Seventh Patrol

After arriving back in Fremantle on 10 January 1943, the boat got underway 15 days later for her seventh war patrol, with four torpedoes short of a normal load. At 11:00 on 14 February, Thresher made contact with a Japanese I-boat east of Thwartway Island. She launched two torpedoes; one was a dud, and the other exploded on the ocean bottom. Turning north and firing deck guns, Thresher's adversary soon disappeared over the horizon.

Proceeding to the Flores Sea, Thresher intercepted a three-ship convoy escorted by two anti-submarine vessels on 21 February. One of the sub's two torpedoes hit the stern of a transport. Thresher then evaded 13 depth charges before returning to periscope depth a little more than an hour later. She observed her target lying dead in the water while barges lightered troops to an undamaged mate. As escorts searched the waters nearby, Thresher closed and torpedoed the second transport, which had stopped to transfer survivors. Two loud explosions reverberated in the background as the boat dived to avoid possible countermeasures.

The following day, Thresher returned to celebrate Washington's Birthday by finishing off the first transport which jack-knifed into a "V" shape and sank within three minutes.

Thresher prowled for more game and came upon a tanker and a freighter on 2 March. A single torpedo hit on the 5,232-ton tanker and it sank. The freighter, sighting torpedo wakes, took evasive action to avoid being hit. Then, a nearby escort arrived on the scene and kept Thresher at bay while the target escaped. The boat subsequently concluded this patrol arriving at Fremantle on 10 March.

On her return to base, her skipper roundly criticized the torpedoes, especially the failure to sink the I-boat. Admiral Ralph W. Christie denied it and relieved him.