The attack on Sydney Harbour

On the evening of Sunday 31 May 1942 three Japanese Ko-hyoteki class midget submarines slipped into Port Jackson, the harbour on whose shores Sydney stands. They were to torpedo the Allied warships lying in Australia’s largest port, foremost among them the American heavy cruiser USS Chicago. None of them returned. One became entangled in the anti-submarine net and was blown up by its own crew, the second was destroyed by depth charges, and the third fired two torpedoes which missed Chicago, but one of them sank the old ferry Kuttabul, which served the navy as a floating barracks. Twenty-one sailors were killed. Militarily the attack was a failure for the Japanese, but it shook the Australians, who for the first time saw the war reach their largest city.

A plan for a diversion

The Japanese navy had already used midget submarines in the attack on Pearl Harbor, to no effect at all. It did not, however, give up the weapon. The two-man craft, less than 24 metres long and carrying two torpedoes, were transported on the decks of large submarines and released close to the target. In the spring of 1942 Captain Hankyu Sasaki’s 8th Submarine Flotilla was given the task of carrying out two simultaneous attacks on Allied ports: in the Indian Ocean and in the South Pacific. They were to divert the enemy’s attention from the main blow that Admiral Isoroku Yamamoto was preparing against Midway atoll; the preparations for that battle were just entering their decisive phase.

The western group chose Diego Suarez in Madagascar, a port recently captured by the British in the course of the landing on Madagascar. On the evening of 30 May its midget submarines torpedoed and damaged the battleship HMS Ramillies there and sank the tanker British Loyalty. The eastern group considered Nouméa, Suva, Auckland and Sydney. The submarines I-22, I-24 and I-27 took on their midget craft at Truk atoll; a fourth carrier, I-28, was sunk on the way on 17 May by the American submarine USS Tautog.

There was no lack of warnings. On 16 May the submarine I-29 attacked the Soviet steamer Uelen off Newcastle, but the commander of the Sydney naval area, Rear Admiral Gerard Muirhead-Gould of the Royal Navy, concluded that the attacker had been operating alone and had moved on. On 23 May a Yokosuka E14Y seaplane from I-29 flew over Sydney; radar detected it, but the report was put down to a fault in the equipment. The Japanese airmen spotted several large warships in the harbour, and this decided the choice of target. Australian monitoring partly intercepted their report, and the New Zealanders took bearings on radio exchanges between submarines approaching Sydney, but all the anti-submarine vessels happened to be escorting a convoy. Before dawn on 29 May a seaplane from I-21 flew over the harbour; observers took it for an American aircraft, and the fighters sent up after the alarm was raised found nothing. That day five Japanese submarines gathered some 35 nautical miles north-east of the harbour entrance.

Night in the harbour

In the harbour lay the heavy cruisers Chicago and HMAS Canberra, the light cruiser Adelaide, corvettes, armed merchant cruisers, the Dutch submarine K IX and, alongside the wharf of the Garden Island base, Kuttabul. The entrance was protected by underwater indicator loops that detected passing vessels, some of which were not working or gave false signals, and by an unfinished boom net with wide gaps at either end. The ferries were running as usual, and the dockyard at Garden Island was working through the night under floodlights.

The first to enter the harbour was the craft known in the literature as M-14 (from I-27), with Lieutenant Kenshi Chuman and Petty Officer Takeshi Omori. At about 8.15 p.m. a harbour watchman spotted it: the submarine struck a pile, backed off and stuck fast by the stern in the net. The report reached headquarters only shortly before 10 p.m., and as patrol boats were preparing to attack, at 10.35 p.m. the crew detonated the scuttling charge and died with their craft. Muirhead-Gould raised the alarm but did not stop the ferry traffic, reckoning that movement in the harbour would force the enemy to stay submerged.

The second, M-24 (from I-24), with Sub-Lieutenant Katsuhisa Ban and Petty Officer Mamoru Ashibe, slipped through a gap in the net in the wake of a ferry bound for Manly. At about 10.50 p.m. it was picked up by Chicago’s searchlight. The cruiser opened fire, but her guns could not be depressed far enough; the shells ricocheted off the water, and fragments fell on the harbourside suburbs. The cruiser’s captain, Howard Bode, who had spent the evening at dinner with Muirhead-Gould and, like him, did not believe the reports, cancelled preparations to put to sea when he returned on board. The admiral went in person to the patrol boats and is said to have mocked their crews for chasing imaginary submarines around the harbour. The third craft, M-21 (from I-22), with Lieutenant Keiu Matsuo and Petty Officer Masao Tsuzuku, entered the harbour at roughly the time Chicago was firing at M-24; attacked with depth charges, it most probably waited it out on the bottom.

At about 12.30 a.m. on 1 June, a few minutes after the floodlights on Garden Island were switched off, M-24 fired two torpedoes towards Chicago. Both missed. One ran ashore on Garden Island and failed to explode; the other passed under the Dutch submarine and Kuttabul and exploded beneath the wharf at which she was moored. The old wooden ferry broke in two and sank. Nineteen Australian and two British sailors were killed, and ten were wounded. M-24 escaped from the harbour; its fate remained a mystery until November 2006, when amateur divers found the wreck a few kilometres off the beaches north of Sydney.

Only now was the alarm taken seriously, and ships began to put to sea. Before dawn M-21 returned to the harbour. In the morning patrol boats spotted it in Taylors Bay and pounded it with depth charges for several hours. The submarine was unable to fire its damaged torpedoes, and its crew committed suicide. The Japanese mother submarines waited off the coast south of Sydney for two nights for the midget craft to return; on 3 June Sasaki gave them up for lost.

Victims and echoes

The authorities at first announced that three submarines had been destroyed in the harbour and that losses were limited to “one small harbour vessel of no military value”. The morning papers of 1 June were in any case full of reports of the British thousand-bomber raid on Cologne. The truth came out gradually, in spite of the censorship. No official inquiry was held; John Curtin’s government, still mindful of the political consequences of the inquiry after the raid on Darwin, feared spreading defeatism. The conduct of Muirhead-Gould and Bode is still criticised by historians.

The bodies of the four Japanese sailors from M-14 and M-21 were recovered and cremated in Sydney with full military honours, their coffins draped with the Japanese flag. Muirhead-Gould, criticised for this gesture, defended it as a mark of respect for the enemy’s courage; Australian politicians also hoped that Tokyo would respond by treating Australian prisoners better. That did not happen. In the second half of 1942 the ashes were taken back to Japan, as part of an exchange of diplomats, by Ambassador Tatsuo Kawai, and Japanese propaganda made use of their return. From the two recovered wrecks a single submarine was assembled and taken on tour around Australia to raise money for naval relief funds; today it stands in the Australian War Memorial in Canberra.

Significance

The attack ended in failure for both sides. The Japanese lost three midget submarines and six men, and instead of a capital ship they sank a defenceless hulk; both main targets survived, although Canberra was sunk as early as August in the Battle of Savo Island, and Chicago in January 1943 off Rennell Island. The harbour defences, however, had acted sluggishly and chaotically, and Chicago owed her survival largely to chance. Nor did the diversion deceive the Americans, who, having broken the Japanese code, knew Yamamoto’s objective; a few days later they fought the Battle of Midway.

After the night of 31 May Sasaki’s large submarines attacked shipping off Australia’s east coast, sinking three ships in June. On the night of 7/8 June I-24 shelled Sydney’s eastern suburbs, and I-21 shelled Newcastle with its BHP steelworks; most of the shells failed to explode, and no one was killed. The authorities introduced a convoy system in coastal waters and strengthened the defences of the ports.

The most important effects were psychological. After the raids on Darwin and Broome, the destruction of the cruiser Sydney by Kormoran and the arrival of MacArthur, the war had reached the very heart of the country. In Sydney rumours of imminent invasion multiplied, some of the better-off residents moved inland, and house prices in the eastern suburbs fell. These fears were understandable but unfounded: as early as February and March 1942 the Japanese army had rejected ideas for an invasion of Australia put forward by part of the naval staff, judging that it would require at least ten divisions and shipping that Japan did not have. Instead Tokyo wanted to cut Australia off from the United States by seizing Port Moresby, New Caledonia, Fiji and Samoa. This plan foundered first in the Coral Sea, and finally at Midway and on Guadalcanal.