15 September 1943, and I-11 became flagship of Submarine Squadron 1. She departed Truk on 18 September 1943 bound for Kure, which she reached on 26 September. After undergoing repairs, she departed Kure on 4 December 1943 and headed back to Truk, where she arrived in mid-December 1943. Sixth war patrol On 21 December 1943, I-11 departed Truk with a Yokosuka E14Y1 (Allied reporting name "Glen") floatplane aboard for her sixth war patrol, bound for a patrol area in the vicinity of the Ellice Islands, Samoan Islands, Fiji Islands, and Tonga Islands. On 31 December 1943, she conducted a submerged reconnaissance of Funafuti in the Ellice Islands, reporting that she observed two battleships, two other large warships resembling battleships, and two cruisers there. On 11 January 1944,she transmitted a report from the Funafuti area and received orders to attack Allied ships in the vicinity of the Ellice Islands and Samoan Islands, as well as to reconnoiter Funafuti again in early February 1944. The Japanese never heard from her again. Loss I-11′s fate remains a mystery. One source claims the U.S. Navy destroyer sank her on 17 February 1944 but that assertion appears to confuse I-11 with the submarine , sunk off Wotje Atoll in the Marshall Islands on 4 February 1944. Post-World War II Japanese research has suggested that a mine laid by the U.S. Navy minelayer sank I-11. On 20 March 1944, the Japanese declared I-11 to be presumed lost south of Funafuti. She was stricken from the navy list on 30 April 1944. Notes References Type A1 submarines 1941 ships World War II submarines of Japan Japanese submarines lost during World War II Maritime incidents in January 1944 World War II shipwrecks in the Pacific Ocean Ships built by Kawasaki Heavy Industries Ships lost with all hands Missing submarines of World War II