Japanese submarine I-42

I-42 was an Imperial Japanese Navy Type B2 submarine. Completed and commissioned in 1943, she served in World War II and was sunk during her first war patrol in March 1944.

Construction and commissioning
I-42 was laid down on 18 March 1942 at the Kure Navy Yard at Kure, Japan, with the name Submarine No. 372. Renamed I-42 on 20 August 1942 and provisionally attached to the Yokosuka Naval District that day, she was launched on 10 November 1942. She was completed and commissioned on 3 November 1943.

Service history
Upon commissioning, I-42 was attached formally to the Yokosuka Naval District. In late November 1943 she took part with the submarines JAPANESE SUBMARINE I-43, JAPANESE SUBMARINE I-184, JAPANESE SUBMARINE Ro-40, and JAPANESE SUBMARINE Ro-113 and the submarine tender JAPANESE SUBMARINE TENDER Chōgei in antisubmarine warfare exercises in the Iyo-nada in the Seto Inland Sea. By 1 January 1944, she was part of Submarine Division 11 in Submarine Squadron 7 along with I-43, I-184, Ro-40, Ro-113, and the submarines JAPANESE SUBMARINE I-52, JAPANESE SUBMARINE I-183, JAPANESE SUBMARINE Ro-41, JAPANESE SUBMARINE Ro-43, JAPANESE SUBMARINE Ro-114, and JAPANESE SUBMARINE Ro-115. On 31 January 1944, she was reassigned to Submarine Division 15 in the 6th Fleet.

On 12 February 1944, I-42 departed Yokosuka on her first war patrol, assigned a patrol area northeast of Truk. She reached her patrol area on 20 February 1944. She called at Saipan in the Mariana Islands from 3 to 4 March 1944, then proceeded to Truk, where she arrived on 7 March 1944. She got back underway on 15 March 1944 to make a supply run to Palau, which she reached on 19 March 1944. After embarking cargo and passengers, she departed Palau on 23 March 1944 on a supply run to Rabaul on New Britain, with an estimated date of arrival of 30 March 1944.

I-42 was zigzagging on the surface at 18 kn on the first evening of her voyage when the United States Navy submarine USS Tunny (SS-282), which had been alerted to I-42′s schedule by Ultra intelligence information, detected I-42 on radar at a range of 13,000 yd at 21:19 on 23 March 1944. Also on the surface, Tunny closed to within visual range and identified I-42 as a Japanese I-boat. I-42 also sighted Tunny, and for almost 90 minutes each submarine maneuvered on the surface to obtain a firing position against the other while trying to deny one to her opponent. Finally, at 23:24, when the two submarines were 6 nmi southwest of Angaur, Tunny fired four torpedoes at I-42 at a range of 1,900 yd, then immediately turned hard to starboard to avoid a collision and crash-dived to prevent I-42 from making a torpedo attack of her own. Just before Tunny′s hatch closed, her crew saw a bright flash and felt and heard two explosions. Diving to 150 ft, Tunny circled the area, and her sound operator heard I-42′s propeller noises stop. Tunny′s crew heard the noises of I-42 breaking up for the next hour. I-42 sank with the loss of all 102 men aboard at 6.66667°N, 134.05°W.

On 27 April 1944, the Imperial Japanese Navy declared I-42 to be presumed lost with all hands north of the Admiralty Islands. She was stricken from the Navy list on 30 April 1944.