second war patrol. The three submarines were assigned to relieve the submarines , , and on a submarine picket line in Hawaiian waters. At dawn on 28 January 1942 she was in Alenuihaha Channel off Maui's Hana Coast north of ʻUpolu Point, the northernmost point on the island of Hawaii, when she attacked a three-ship convoy on a voyage from Kahului, Maui, to Hilo, Hawaii, consisting of the 622-ton United States Army Transport , the small cargo ship Kalae with a barge in tow, and their escort, the destroyer minesweeper . I-71 fired two torpedoes at General Royal T. Frank which missed, then fired a third torpedo that struck the transport, which exploded and sank in less than 30 seconds. Of the 60 people aboard — including 26 U.S. Army recruits — Kalae rescued 36. I-71 returned to Kwajalein on 16 February 1942. February–May 1942 On 18 February 1942, I-71 departed Kwajalein to patrol in defense of Rabaul, which the U.S. Navy's Task Force 11 was approaching with an intention to launch air raids against Japanese forces and bases there. After Task Force 11 lost the element of surprise, however, it withdrew, and I-71 was diverted to a patrol area east of Wake Island. After uneventful operations, she proceeded to Japan, where she arrived on 6 March 1942 at Kure. During her stay at Kure, Submarine Division 20 was disbanded, and she was reassigned to Submarine Division 12. I-71 got underway from Kure on 15 April 1942 to begin her third war patrol, operating as part of a submarine patrol line with I-72. This patrol also was uneventful, and she concluded it with her arrival at Kwajalein on 10 May 1942. During her stay at Kwajalein, she was renumbered I-171 on 20 May 1942. Midway operation On 24 May 1942, I-171 departed Kwajalein to participate in Operation MI, the planned Japanese invasion of Midway Atoll. Her first task was to support a preliminary phase of the Midway operation, Operation K-2, which called for the submarines and to refuel two Kawanishi H8K (Allied reporting name "Emily") flying boats at the French Frigate Shoals in the Northwest Hawaiian Islands so that the two aircraft could make a reconnaissance flight over Pearl Harbor, while the submarine patrolled south of Pearl Harbor to rescue the crews of the aircraft if they were shot down and I-171 operated east of the French Frigate Shoals to