then began an "end around," a long circling maneuver designed to bring her in front of the remaining four tankers, and late that afternoon she was again ready to attack. Two torpedoes sank two more of the frantically zigzagging ships, and Jack moved in on the trailing tanker. Her first spread of torpedoes missed and the tanker replied with a salvo from guns, but Jack returned three hours later to sink her with four torpedoes. In this remarkable series of attacks, the submarine sank four tankers (earning the nickname "Jack the Pack", after the convoy commander radioed that he was under attack from a "wolfpack"), all over 5,000 tons: Kokuie Maru, Nanei Maru, Nichirin Maru, and Ichiyo Maru. After several more attacks Jack set course for Fremantle, Australia, her new base, where she arrived 13 March 1944. Fourth and fifth war patrols, April – July 1944 Departing Australia 6 April 1944, Jack returned to the South China Sea for her fourth war patrol. She chased the Take Ichi convoy through the afternoon of 25 April, and shortly after midnight next day attacked, sinking and damaging two others. Jack also used her deck gun to sink a radio-equipped trawler, Daisun, 27 April before returning to Fremantle 10 May 1944. Jack left Fremantle for her fifth war patrol 4 June 1944, again returning to Japan's important lifelines in the South China Sea. Early 24 June she made an approach on a large convoy and fired three torpedoes, sinking a large tanker, San Pedro Maru, before escorting aircraft forced her to retire. Five days later the submarine came upon another large convoy, and by early 30 June was in position. Three successive attacks sent cargo ships Matsukawa Maru and Tsukushima Maru to the bottom. Jack returned to Fremantle 14 July 1944. For her highly successful and aggressive first, third, and fifth war patrols, the submarine was awarded the coveted Presidential Unit Citation. Sixth and seventh war patrols, August – December 1944 The submarine sailed from Fremantle 6 August 1944 to the Celebes Sea for her sixth war patrol. Attacking a convoy 29 August, she sank a small minesweeper (Minesweeper No 28) and started in pursuit of a cargo ship. After her torpedo missed and she was raked with gunfire by her adversary, Jack deftly evaded the attacker and returned later to sink Mexico Maru. Jack arrived at Fremantle following this patrol 24 September