Japanese midget submarines raid Sydney Harbour


Sydney, NSW 1942-06-10. Japanese midget submarine No. 21, which took part in the raid being raised from the harbour bow first. (AWM 305046)

A surprise attack on Sydney Harbour by the Japanese 75 years ago on 31 May 1942, was a wake-up call which resulted in fear and panic in the nation’s largest and oldest city.

As a prelude to the attack on Sydney Harbour, the Japanese Navy had used five Ko-hyoteki-class midget submarines at Pearl Harbour, in an unsuccessful operation against US battleships. It was hoped that upgraded submarines, improved crew training and the selection of a less well defended target, would lead to better results and an increased chance of the crews of the midgets returning alive from their mission.

In the late afternoon of 31 May 1942, three Japanese submarines, sitting approximately 13 kilometres out to sea from Sydney Harbour, each launched a Type A midget submarine for an attack on shipping in Sydney Harbour. The previous evening, one of these submarines had launched a small floatplane that flew over the harbour, spotting the American heavy cruiser the USS Chicago.  This was the main Japanese target – they hoped to sink the war ship but also believed there may be others in the harbour.

After launching the three two-man midget submarines, which slowly and silently made their way to the harbour, the three mother submarines moved to a position off Port Hacking to await the return of the submariners. They were still waiting three days later on 3 June.

The three midget submarines had reached the harbour and were mistaken for ferries or some other craft and were initially dismissed by the Australian Maritime Service Board. It was later that evening that a watchman identified an object caught in an anti-torpedo net and naval patrol boats were dispatched to investigate. The crew of the midget submarine, Lieutenant Kenshi Chuma and Petty Officer Takeshi Ohmori, realising they were trapped, blew up their craft and themselves.

The second midget submarine was spotted from the deck of USS Chicago by sailors and by gunners on the corvette HMAS Geelong and, while both opened fire, the submarine escaped unharmed. In an attempt to fire on the USS Chicago, a torpedo from the midget submarine missed its target and struck the HMAS Kuttabul, a converted harbour ferry serving as a naval depot ship.  19 Australian and two British sailors on the Kuttabul were killed. A second torpedo fired by the same submarine ran aground on rock on the eastern side of Garden Island and failed to explode. The submarine made for the harbour entrance and mysteriously disappeared, not to be seen again until 2006 when recreational divers discovered the wreck off Sydney’s northern beaches.

The third of the midget submarines was spotted in Taylors Bay, adjacent to Taronga Zoo, by HMAS Yandra before it reached the harbour. Naval harbour patrol vessels attacked the submarine with depth charges and in the ensuing battle, Lieutenant Keiu Matsuo and Petty Officer Masao Tsuzuki committed suicide.

When it became obvious that the midget submarines were not returning, the mother submarines departed the area.

The raid was over by 5.00am on 3 June 1942. The two wrecked midget submarines were recovered from the harbour later that day, along with the bodies of the four crewmen. In a decision which drew strong criticism from many Australians, the crewmen were cremated at Sydney’s Eastern Suburbs Crematorium with full naval honours. In defence of his very unpopular decision to accord the enemy a military funeral, Rear Admiral Muirhead-Gould, in charge of Sydney Harbour defences, said he hoped that showing respect for the dead men might help to improve conditions for the many Australians in Japanese prisoner of war camps.

The attack on Sydney Harbour was viewed as a failure on both sides and exposed flaws in both the Allied defences and the Japanese tactics. The Japanese lost all three midget submarines in exchange for the sinking of a single barracks ship. The impact of the midget submarine attack on the civilian population was mainly psychological. Sydneysiders had believed they were immune to Japanese attack but the tragic loss of the Kuttabul sailors had highlighted Australia’s close proximity to the Pacific War. The realisation that Sydney was within reach of the Japanese navy caused many to move away from the coast for fear of an impending Japanese invasion and the Australian military was forced to upgrade defences, including the commencement of convoy operations to protect merchant shipping.