I-33 and by raising her bow. This so badly compromised the partially flooded I-33′s buoyancy that the hawsers securing her stern to the wharf broke, her forward torpedo hatch flooded, and she sank in two minutes with the loss of 33 members of her crew. A rescue operation began immediately. A diver found I-33 on the bottom in of water and reported that some crewmen were still alive aboard the submarine. Lacking the equipment necessary to try to save the crew, the 6th Fleet abandoned rescue attempts on 27 September 1942, and an investigation of the sinking began that day. Salvage and repair On 30 September 1942, the Ministry of the Navy ordered the salvage of I-33, and, without proper equipment available at Truk, the Combined Fleet passed this order to the 4th Fleet on 2 October 1942. Eventually, a salvage attempt began and on 19 December 1942 I-33′s hull was pressurized and her bow came to the surface, but three minutes later the pressure blew a hatch open and she sank again. The submarine rescue ship Mie Maru and tanker Nippo Maru began another salvage attempt on 25 December 1942 and this time succeeded, refloating I-33 on 29 December 1942. Nippo Maru departed Truk with I-33 under tow on 2 March 1943 bound for Japan. During the voyage, the auxiliary gunboats and joined them, and on 9 March 1943 the destroyer also joined the convoy. On 17 March 1943, the ships reached Saeki, Japan, and I-33 arrived at Kure on 18 March 1943 to undergo repairs at the Kure Naval Arsenal. On 1 April 1944, I-33 was assigned to the Kure Guard Unit. Work on her — including the installation of radar and a radar detector — continued until early May 1944. I-33′s repairs were declared officially complete on 1 June 1944, and she was assigned to Submarine Squadron 11 in the 6th Fleet that day for work-ups. Loss I-33 got underway from Kure at 07:00 on 13 June 1944 to complete her acceptance trials by making a series of dives in the Iyo-nada in the Seto Inland Sea. When she conducted her second crash-dive of the morning at 08:40, her starboard main induction valve did not close, and all compartments aft of her control room flooded. Her crew managed to blow her main ballast tanks partially, and 10 minutes after submerging her bow broke the surface. Flooding continued,