was the fifth Type C cruiser submarines built for the Imperial Japanese Navy. During World War II, she operated as the mother ship for a midget submarine during the attack on Pearl Harbor and the attack on Sydney Harbour, supported Japanese forces during the Battle of the Coral Sea and the Battle of the Santa Cruz Islands, and served in the Guadalcanal campaign, New Guinea campaign, and Aleutian Islands campaign. She was sunk in June 1943.
Design and description The Type C submarines were derived from the earlier Kaidai-type VI with a heavier torpedo armament for long-range attacks. They displaced surfaced and submerged. The submarines were long, had a beam of and a draft of . They had a diving depth of .Bagnasco, p. 192
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater.Chesneau, p. 201 On the surface, the C1s had a range of at ; submerged, they had a range of at .
The boats were armed with eight internal bow torpedo tubes and carried a total of 20 torpedoes. They were also armed with a single /40 deck gun and two single or twin mounts for Type 96 anti-aircraft guns. They were equipped to carry one Type A midget submarine aft of the conning tower.Carpenter & Dorr, p. 104
Construction and commissioning
Ordered under the 3rd Naval Armaments Supplement Programme and built by the Sasebo Naval Arsenal at Sasebo, Japan, I-24 was laid down on 5 December 1938 with the name Submarine No. 48. While she was on the building ways, she was renamed I-24 on 30 September 1939, the second submarine of that number, the first I-24 having been renumbered on 1 June 1938 to make the number I-24 available for her. She was launched on 12 November 1939 and was completed and commissioned on 31 October 1941.
Service history Pre-World War II Upon commissioning, I-24 was attached to the Yokosuka Naval District. She soon underwent conversion into a mother ship for a Type A midget submarine; the conversion work was completed on 10 November 1941. The submarines , , , and also underwent the conversion. By 15 November 1941, I-24 was a part of Submarine Division 3 in Submarine Squadron 1 in the 6th Fleet.
At the Kure Navy Club in Kure, Japan, on 17 November 1941, the commander of Submarine Division 3 briefed the commanding officers of the five converted submarines on the upcoming attack on Pearl Harbor and on the role of their submarines in it. He had been designated the commander of the Special Attack Unit, made up of all five submarines, each of which was to launch a Type A midget submarine off Pearl Harbor so that the midget submarines could participate in the attack. I-22 was to serve as flagship of the Special Attack unit.
On 18 November 1941, the five submarines moved from Kure to the Kamegakubi Naval Proving Ground (34.1115° N, 132.5886° E), where each embarked a Type A midget submarine. At 02:15 on 19 November 1941, the five submarines got underway from Kamegakubi bound for the Hawaiian Islands, taking a direct route that took them south of Midway Atoll. While at sea, they received the message "Climb Mount Niitaka 1208" () from the Combined Fleet on 2 December 1941, indicating that war with the Allies would commence on 8 December 1941 Japan time, which was on 7 December 1941 on the other side of the International Date Line in Hawaii.
World War II Pearl Harbor At 03:33 on 7 December 1941, I-24 launched her midget submarine, No. 19, west-southwest of the entrance to Pearl Harbor. No. 19 began to broach after I-24 launched her, but her two-man crew got her back under control.
No. 19 reached the entrance of the harbor at 07:00, but was unable to enter before the air strike began. No. 19 surfaced at around 08:00 and ran aground on a reef, where the United States Navy destroyer sighted her. Helm opened fire, her shells missing but blowing No. 19 free of the reef. The concussion disabled No. 19′s torpedo firing mechanism and knocked her commander, Ensign Kazuo Sakamaki, unconscious. After Sakamaki regained consciousness, No. 19 again ran aground. Her two-man crew shifted her ballast and refloated her, but after that No. 19 would not answer the helm. While drifting, No 19 survived several depth charge attacks. Her crew tried to beach her, but she ran aground again on a reef. Sakamaki lit the fuses of No. 19′s self-destruct charges, which did not explode, and both men abandoned ship. Knocked unconscious in the surf, Sakamaki washed ashore at Waimanalo Beach on the east coast of Oahu on 8 December 1941 and was captured, becoming the first Japanese prisoner-of-war of World War II. His crewman drowned, but No. 19 was captured and in 1991 went on display in the United States at the National Museum of the Pacific War in Fredericksburg, Texas.
I-24 and the other four "mother" submarines proceeded to the planned recovery area for their midget submarines west of Lanai, where they spent the night of 7–8 December 1941. None of the midget submarines returned. Early on 9 December 1941, I-18, I-20, and I-24 received orders to leave the recovery area. The remainder of I-24′s patrol was uneventful, and she concluded it with her arrival at Kwajalein.
First war patrol
On 4 January 1942, I-18, I-22, and I-24 departed Kwajalein to begin their first war patrols, assigned patrol areas off the Hawaiian Islands. On 18 January 1942, they departed their patrol areas, and I-18 and I-24 received orders to bombard Midway Atoll in the Northwestern Hawaiian Islands. On 25 January 1942, the two submarines surfaced in darkness off Midway and I-24 opened fire with her deck gun. United States Marine Corps coastal artillery promptly returned fire, forcing I-24 to submerge after firing only six rounds. I-18 also submerged without ever having opened fire on the atoll.
After the bombardment attempt, I-24 as well as I-18 and I-22 set course for Japan. Unknown to them, the U.S. submarine had received Ultra intelligence information alerting her to their activities and routes. She did not sight any of them, but while searching for them she encountered and sank the submarine , which was following the same route, west of Midway on 27 January 1942. I-24 arrived at Yokosuka along with I-18, I-22, and the submarines , , , and on 2 February 1942.
February–April 1942 While I-24 was in Japan, she and the other 10 submarines of Submarine Squadron 8 conducted extensive exercises in the Seto Inland Sea, which they completed on 11 April 1942. By that date, I-24 was assigned to Submarine Division 3 with and I-22, which together with Submarine Division 14 — consisting of , , and — made up the Eastern Advanced Detachment, which was under the overall command of Submarine Division 3's commander.
On 15 April 1942, I-24 got underway from Kure bound for Truk along with the other submarines of the detachment. During their voyage, 16 United States Army Air Forces B-25 Mitchell bombers launched by the aircraft carrier struck targets on Honshu in the Doolittle Raid on 18 April 1942. The detachment received orders that day to divert from its voyage and head east-northeast at flank speed to intercept the U.S. Navy task force that had launched the strike, but the orders were canceled on 19 April and the submarines resumed their voyage to Truk, which they reached on 24 April 1942.
Second war patrol
On 30 April 1942, I-22, I-24, I-28, and I-29 got underway from Truk to form a patrol line southwest of Guadalcanal in support of Operation MO, a planned Japanese invasion of Tulagi in the Solomon Islands and Port Moresby on New Guinea. While they were en route, aircraft from the aircraft carrier — both SBD Dauntless dive bombers of Scouting Squadron 5 (VS-5) and TBD Devastator torpedo bombers of Torpedo Squadron 5 (VT-5) — attacked I-24 on 2 May 1942, but she avoided damage.
The Battle of the Coral Sea began on 4 May 1942 as Allied forces moved to block the Japanese offensive. As the battle continued, the four Japanese submarines arrived in their assigned areas and formed their patrol line on 5 May 1942. While the Japanese seized Tulagi and were turned back from Port Moresby, I-24′s patrol passed quietly. The four submarines received orders on 11 May 1942 to return to Truk. While they were en route, the submarine sighted two Japanese submarines — probably I-22 and I-24 — proceeding separately on the surface and unsuccessfully attacked one of them early on the morning of 17 May 1942, but a few hours later sank I-28, which was trailing I-22 and I-24 on the same course. I-24 arrived safely at Truk later that day.
Attack on Sydney Harbour and third war patrol
On the day she arrived at Truk, I-24 embarked a Type A midget submarine delivered by the seaplane tender . Assigned to a Special Attack Unit along with her fellow midget-submarine mother ships I-22 and I-27 and the seaplane-carrying submarines I-21 and I-29 — each of them with an embarked Yokosuka E14Y1 (Allied reporting name "Glen") floatplane — she got underway in company with I-24 and I-27 on 18 May 1942 bound for Sydney, Australia, to launch a midget submarine attack against ships in Sydney Harbour. On 19 May 1942, when she surfaced to charge her batteries and conduct maintenance work on her midget submarine, the midget's two-man crew smelled a strong scent of chlorine when they entered their craft, and when its enlisted crewman turned on a light, a large explosion occurred which blew him overboard and severely burned the midget's commander. The enlisted man's body was never found despite an extensive search. I-24 returned to Truk on 20 May 1942, unloaded the damaged midget submarine and its injured commander, and embarked another midget submarine — M17 — and crew originally intended for the sunken I-28. She quickly got back underway for Truk.
During the voyage to Sydney, I-22, I-24, and I-27 received reconnaissance reports from I-29, which launched her floatplane to reconnoiter Sydney Harbour on 23 May 1942, and I-21, whose floatplane conducted a reconnaissance flight early on the morning of 29 May 1942 and sighted the heavy cruiser at Sydney, mistakenly reporting her as a battleship. That day, the commander of the Eastern Advanced Detachment ordered the three submarines to launch the midget submarine attack.
On 30 May 1942, I-22, I-24, and I-27 arrived off Sydney. Late on the afternoon of 31 May, they launched their midget submarines to begin what became known as the attack on Sydney Harbour; I-24 launched M17 off Sydney at 17:40. At 22:07 on 31 May, all ships in the harbor were alerted to the presence of Japanese submarines, and Chicago opened fire on M17 with her antiaircraft guns. At 00:29 on 1 June 1942, M17 fired a torpedo at Chicago which missed her but exploded against a breakwater. The explosion sank , an old ferry in use as a Royal Australian Navy barracks ship, killing 21 sailors sleeping on board, and damaged the Royal Netherlands Navy submarine HNLMS K IX. Her second and last torpedo went aground on Garden Island. M17 subsequently disappeared, and her crew later was listed as missing in action.