Pacific Wrecks
Pacific Wrecks    
  Missing In Action (MIA) Prisoners Of War (POW) Unexploded Ordnance (UXO)  
Chronology Locations Aircraft Ships Submit Info How You Can Help Donate
  I-24 Japanese Submarine
Type C1 submarine

1 x 140mm deck gun

Sub History
Built at the Sasebo Navy Yard. Commissioned in the Imperial Japanese Navy (IJN) into the Yokosuka Naval District.

Wartime History
On November 10, 1941 converted into a midget submarine carrier. On November 17, 1941 officers of the Special Attack Unit are briefed on the Hawaii Operation. The I-24 is assigned to Captain Sasaki Hankyu's Special Attack Unit with the I-16, I-18, I-20 and the flagship, the I-22.

Pearl Harbor Attack
On December 7, 1941 at 3:33am the submarine was in position 10.5 miles WSW off the entrance to Pearl Harbor on Oahu and launched HA-19 Type A Midget Submarine (Midget C).


On May 20, 1942 arrives at Truk and the damaged midget submarine is removed and exchanged for HA-24 Type A Midget Submarine (M24) plus her crew: captain Lt(jg) Katsuhisa Ban and crew PO1c Mamoru Ashibe and departs the same day proceeding southward to Sydney as the flagship of the mission to reconnoiter and launch her midget submarine to attack Allied warships in Sydney Harbor.

Sydney Harbor Attack
On May 29, 1942 I-21 launches a E14Y Glen to reconnoiter Sydney. At 4:20am, it circles over Sydney Harbor twice citing the heavy cruiser USS Chicago (CA-29) anchored off Garden Island. First thought to be an American plane, RAAF fighters are sent to intercept, but are unsuccessful. The Glen returns and reports sighting a battleship. Captain Sasaki orders an attack with midget submarines and the next day arrives off Sydney.

On May 31, 1942 at 5:40pm roughly 7.5 miles east of Sydney I-24 launches HA-24 Type A Midget Submarine (M24). At 2207, all vessels in the harbor are alerted of the presence of an enemy submarine. At 10:50pm USS Chicago spots the HA-17 midget submarine (M24) and fires on it with her AA guns at the same time HA-21 midget submarine (M22) enters Sydney Harbor.

On June 1, 1942 at 0029, HA-17 fires one torpedo at USS Chicago (CA-29) but it misses and explodes under HMAS Kuttabul killing 21 sailors and damaging the moored Dutch submarine K-IX. Another torpedo runs aground on the east side of Garden Island. The midget sub fails to return from the mission.

On June 3, 1943 I-24 takes up position roughly 35 miles southeast of Norah Head to recover her midget submarine, but it fails to return and is presumed lost. While recharging her batteries on the surface, spots Australian coastal steamer Age and fires a torpedo that misses and fires four rounds from her 140mm deck gun that also miss. I-24 sees the vessel disappear and claims it as sunk but in fact it was undamaged. Ninety minutes later roughly 27 miles off Sydney I-24 fires two torpedoes at Australian merchant Iron Chieftain en route from Newcastle to Whyalla with a cargo of coke and shipyard materials. One torpedo hits her port side amidships. Her heavy load drags her to the bottom in about five minutes.

On June 5, 1942 roughly 17 miles off Wollongong, I-24 chases Echunga enroute from Whyalla to Port Kembla but fails to damage to her.

On June 8, 1942 after midnight after crossing Stockton Bight, I-24 surfaces four miles off Sydney and during four mines fires her 140mm deck gun ten times at 30 second intervals aimed at Sydney Harbor Bridge. None hit the bridge. Only one shells explodes and demolishes part of a house in the eastern suburbs. The others are duds and cause only minor damage. Ashore, searchlights are illuminated but the submarine crash dives before any shore batteries can return fire. Although the shelling causes no casualties, but some of Sydney's residents panic and flee the city in fear of a Japanese invasion. P-400 Airacobra pilot Cantello takes off at night to intercept the submarine, but crashes shortly after takeoff.

On June 9, 1942 southeast of Jervis Bay before dawn, I-24 sights the 7,748-ton British merchant ORESTES. Cdr Hanabusa attacks her twice with torpedoes, but they explode prematurely. The I-24 surfaces and shells the merchant with her 140mm deck gun. She scores a single hit, but does not sink ORESTES. Since no fire is visible, Cdr Hanabusa decides to abandon the attack.


On May 30, 1943 departs Paramushir bound for Attu to rescue any survivors of the Japanese garrison. In early June 1943 off Chichagof Bay, the submarine makes three unsuccessful attempts to contact any survivors. On June 5, 1943 departs Attu bound for Kiska. On June 7, 1943 I-24 sends her last message, reporting many U.S. ships in the area.

Sinking History
On June 10, 1943 departs Kiska westward bound for Paramushir. In heavy fog, USS PC-487 spots on sonar then at 8:09am makes visual contact observing both of the submarine's periscopes raised roughly 40 miles north-northeast of Shemya. Immediately, PC-487 made a depth charge attack forcing I-24 to the surface, then attempts to ram the submarine but passes above the hull, then rams the conning tower. Damaged, I-124 rolls over and sinks at roughly Lat t 53-16N, Long 174-24E. Lost with all 104 crew. On August 1, 1943 officially removed from the Navy list.

Japanese sources indicate the ramming and sinking as June 11, 1943, the date of the loss across the International Dateline in Japan.
NARA USS PC-487 War Diary pages 2-8 (June 10, 1943), 12-13 (Antisubmarine action by surface ship, June 10, 1943)
Combined Fleet - HIJMS Submarine I-24: Tabular Record of Movement

Contribute Information
Are you a relative or associated with any person mentioned?
Do you have photos or additional information to add?

Last Updated
June 10, 2022


  Discussion Forum Daily Updates Reviews Museums Interviews & Oral Histories  
Pacific Wrecks Inc. All rights reserved.
Donate Now Facebook Twitter YouTube Instagram