31 May 1942
On the night of 31 May 1942, 3 Japanese submarines – I-27, I-22 and I-24 – dispersed in an arc formation outside the entrance to Sydney Harbour. Each of them released a 2-man midget submarine to launch an audacious, clandestine attack on the harbour.
The first of the midget submarines, M-27, entered Sydney Harbour at approximately 8pm. It had not gone far, however, when the vessel’s propellers became entangled in anti-submarine nets close to the western boom gate. Two patrol boats were dispatched to investigate. The submarine’s crew, realising that they could not free the midget’s propellers, set demolition charges and destroyed their craft at 10:37pm. The explosion raised a general alarm in the harbour.
The second midget submarine, M-24, successfully entered the harbour at 9:48pm. Some time later, USS Chicago, lying at the Man-of-War anchorage, near the Harbour Bridge, sighted the midget’s periscope. It quickly lit searchlights and fired shots in the general direction of M-24. Half an hour later, M-24 fired 2 torpedoes at Chicago, both of which missed the intended target. One ran ashore at Garden Island and failed to explode, while the second passed under the Dutch submarine K9, striking the sea wall at Garden Island. It exploded on impact beneath the RAN depot ship HMAS Kuttabul. Kuttabul sank immediately, and 21 Allied naval ratings – 19 Australian and 2 British – were killed.
Later, in the early hours of 1 June, the third midget submarine, M-22, entered the harbour. It was later detected in Taylors Bay, where it was attacked repeatedly with depth charges by the patrol boats.
- HMAS Sea Mist
- HMAS Steady Hour
- HMAS Yarroma.
The following day, RAN divers were sent to investigate the crippled vessel. They found its engines still running and its contra-rotating propellers slowly turning. It was subsequently raised, and its 2-man crew found dead inside from self-inflicted gunshot wounds.
M-24, meanwhile, evaded further detection and subsequently disappeared without trace. Its wreck was discovered by recreational divers off Sydney’s northern beaches in 2006. It had apparently made good its escape from the harbour, but subsequently failed to rendezvous with its ‘mother’ submarine.
On 1 January 1943, the naval depot at Garden Island was commissioned as HMAS Kuttabul to honour the memory of the 21 Allied sailors killed during the attack.