some smaller ships in the harbor. The floatplane made another flight on 1 March 1943 to investigate the Chesterfield Reefs, and was damaged during its recovery after it returned to I-11. I-11 concluded her patrol with her return to Truk on 10 March 1943. Fourth war patrol I-11 got underway from Truk with Rear Admiral Komazaki and his staff aboard on 10 April 1943 to conduct her fourth war patrol. I-11 and the submarines , , and , which also departed that day, all were tasked with attacking Allied shipping off Australia. I-11 was assigned a patrol area in the Tasman Sea off the east coast of Australia. While north of Gabo Island on 27 April 1943 she made an unsuccessful attack on Convoy OC-90 during its voyage from Melbourne, Victoria, to Newcastle, New South Wales. On 29 May 1943, she fired two torpedoes at the American Liberty ship northeast of Sydney, Australia, but both missed. She returned to Truk on 10 June 1943. Fifth war patrol I-11 departed Truk with a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane embarked to commence her fifth war patrol on 1 July 1943. Her patrol area was in the New Caledonia area. At sunset on 20 July 1943 she was off San Cristóbal when she sighted the mixed Royal Australian Navy–U.S. Navy Task Force 74. She fired two Type 95 torpedoes at the heavy cruiser . They passed astern of Australia, but at 18:45 one of them struck the Australian light cruiser on her port quarter at , breaking her keel, blowing off two propellers, unseating "Y" turret, knocking out all power and steering control, and killing 13 crewmen and badly injuring seven others. Hobart took on a port list, but made port at Espiritu Santo. Repairs kept her out of the war for 17 months. After sunset on 25 July 1943, I-11′s floatplane made a reconnaissance flight over the Nouméa area, its crew reporting cruisers and smaller ships in the harbor there. She was off Nouméa on 11 August 1943 when she hit the American 7,176-ton Liberty ship with one torpedo at . The torpedo opened a long hole in Matthew Lyon′s No. 3 hold and injured one sailor, but the ship managed to reach Espiritu Santo under her own power. I-11 returned to Truk on 13 September 1943. September–December 1943 While I-11 was at Truk, Submarine Squadron 3 was abolished on