USS Thresher (SS-200) - Fifth and Sixth Patrols

Fifth and Sixth Patrols

After refit, Thresher loaded mines and departed Fremantle on 15 September 1942, bound for the Gulf of Siam. She fired torpedoes at two freighters north of Lombok Strait on 19 September but was unable to determine the results of her attacks. On the night of 25 September, luck again failed to smile on her as a single torpedo streaked beneath a large, high-speed target in the Sulu Sea.

Thresher later surfaced at 23:00 and proceeded on a course which took her north to Pearl Bank. There, in the northernmost reaches of the Gulf of Siam, she made one of the first mine plants by a submarine in the Pacific War. These strategic mine fields laid by Thresher and her sisters in subsequent patrols, covered Japanese shipping lanes in areas of the Southwest Pacific Command previously unpatrolled by submarines. Later, these minefields filled the gap between patrol zones along the coastal waters of Malaya, Siam, and Indochina, when many boats were diverted to participate in the Solomon Islands campaign.

While reconnoitering off Balikpapan, Borneo, and the Celebes coast, Thresher sighted a tanker aground on a reef off Kapoposang Island in the Java Sea. She soon surfaced for a deck gun attack and left the enemy ship with decks awash. The boat then returned to Fremantle on 12 November for refit.

Underway from Fremantle on 16 December 1942, she arrived off Soerabaya, Java, on 25 December. She intercepted a convoy of freighters, escorted by two destroyers, several subchasers, and two aircraft. Slipping past the escorts, Thresher sent five torpedoes towards the leading three ships. Two successive explosions followed. Rising to periscope depth, the boat observed the second ship in the column down by the bow, with her stern up in the air and her screws, still revolving, out of the water. A second ship lay dead in the water, enveloped in smoke. Escaping unscathed from this tangle with a coastal convoy, Thresher sighted an enemy aircraft carrier the next night, but was picked up by escorts and held at bay for more than an hour while the tempting target faded into the night.

On the night of 29 December 1942, Thresher (now in the hands of William J. "Moke" Millican, Class of 1928) made contact with a 3,000-ton freighter. Just before midnight, she fired a spread of torpedoes at the cargoman; but all missed or ran too deep. Undaunted, she waited for the moonrise and then surfaced to use her deck gun. Outmaneuvering the enemy, who tried to ram her, Thresher scored eight hits in succession with her 5 inches (130 mm) main gun, where he probably sank in the shallow water, one of the few sunk entirely by deck guns.