to Hikari, which she reached on 1 April 1945. After disembarking her kaitens there, she proceeded to Kure for repairs. Arriving there on 2 April, she was drydocked until 15 April 1945. Fourth kaiten mission With her repairs complete, I-47 departed Kure on 17 April 1945 bound for Hikari. There on 20 April 1945 she and I-36 formed the Tenmu ("Heavenly Warriors") Kaiten Group, each carrying six kaitens, with orders to attack Allied sea lines of communication between Okinawa, Ulithi Atoll, and the Mariana Islands. Bound for the waters east of Okinawa, I-47 got underway from Hirao on 22 April 1945. During her voyage, she was on the surface recharging her batteries on 23 April 1945 when her radar detector picked up a radar signal and she submerged. She avoided attack, but when she surfaced she sighted a sonobuoy apparently dropped by an American patrol plane that had been searching for her. I-47 arrived in her patrol area southeast of Okinawa on 26 April 1945. Her starboard diesel engine immediately broke down, and her crew began repairs. She received a message from I-36 on 27 April 1945 in which I-36 reported a successful kaiten attack on an Allied convoy. I-47′s crew completed repairs to her engine on 28 April 1945. On 1 May 1945, I-47 was south-southwest of Okidaitōjima when she detected an Allied convoy on radar at a range of . She closed the range and launched three kaitens at a range of , subsequently hearing large explosions. On 2 May, she was south-southwest of Okidaitōjima when she sighted a 10,000-ton tanker heading northwest at escorted by two destroyers. She launched a kaiten five minutes later, and subsequently heard two heavy explosions. Her sound operator then heard the propeller noises of two destroyers, and at 11:20 I-47 launched another kaiten. I-47 temporarily lost sound contact with the kaiten, but then heard high-speed propellers, followed by a heavy explosion. I-47 then departed the area at flank speed, heading southeast. On 7 May 1945, I-47 detected what she identified as a British Leander-class light cruiser south-southwest of Okidaitōjima on radar. She launched a kaiten and reported a hit on the cruiser. She could not launch her two remaining kaitens because of malfunctioning torpedoes, and the 6th Fleet ordered her to return to Hikari, which she reached on 12 May 1945. After disembarking her two kaitens and their pilots, she got back