Western Australian emergency of March 1944

Western Australian emergency of March 1944
Part of the Pacific War
One of the anti-aircraft guns assigned to the defence of Fremantle during a training exercise in November 1943 One of the anti-aircraft guns assigned to the defence of Fremantle during a training exercise in November 1943
Objective	Reinforcement of Western Australia in response to a feared Japanese attack
Date	6–20 March 1944
Outcome	No attack eventuated, all units involved returned to their normal dispositions

In early to mid-March 1944 the Allies rapidly reinforced the military forces located in the state of Western Australia to defend against the possibility that a force of Japanese warships would attempt to attack the cities of Fremantle and Perth. This redeployment began on 8 March after concerns were raised about the purpose of Japanese warship movements near the Netherlands East Indies, and concluded on the 20th of the month when it was concluded that no attack was likely to occur.

Background

In February 1944, the Japanese Combined Fleet, the Imperial Japanese Navy's main striking force, withdrew from its base at Truk in the Central Pacific to Palau and Singapore. The appearance of a powerful naval force at Singapore concerned the Allies, as it was feared that these ships could potentially conduct raids in the Indian Ocean and against Western Australia. In response, the Allies strengthened their naval forces in the central Indian Ocean by transferring two British light cruisers from the Atlantic and Mediterranean as well as several US Navy warships from the Pacific to the British Eastern Fleet. The number of air units in Ceylon and the Bay of Bengal region was also increased.

General Douglas MacArthur's General Headquarters assessed in February that the Combined Fleet could potentially attack the Western Australian port of Fremantle. It was thought that the purpose of any such raid would be to divert Allied forces away from the offensives they were preparing to launch in the Pacific. While MacArthur did not move any additional forces to Western Australia at this time, he developed plans to reinforce the area if necessary. It was believed that land-based aircraft would be sufficient to counter any attacks on Fremantle, and on 28 February General Headquarters directed General George Kenney, the commander of the Allied Air Forces, to prepare to:

#Concentrate a striking force of sixty heavy bombers in Western Australia on twenty-four hours' notice.

1. Reinforce this heavy bomber striking force with medium bombers when directed by this headquarters.
   
2. Provide three fighter squadrons for the defence of Perth.
   
3. Operate heavy and medium bombers from Darwin, Corunna Downs, Geraldton and Carnarvon.
   
4. Supply the air forces operating in Western Australia by air in an emergency.

On 4 March Australian Prime Minister John Curtin sent a cable to British Prime Minister Winston Churchill seeking the British Government's assessment of the likelihood of Japanese raids into the Indian Ocean, and the capacity of the Allied forces in the region to defeat any such attacks. Curtin's cable crossed a message Churchill had sent the previous day, in which he stated while Japanese forces could conduct raids against Allied shipping in the Indian Ocean "it is not thought that serious danger, either to India or to Western Australia, is likely to develop". Churchill's cable also noted that the Japanese would likely seek to preserve their remaining major warships for use in the later stages of the war.

While the Australian Government was reassured by Britain's assessment of the situation, the Allied military units stationed in Western Australia made preparations to resist a possible Japanese attack. The Royal Australian Air Force's (RAAF's) Western Area Command improved the readiness of its forces stationed near Perth and Exmouth Gulf in the north-west of the state. It also stockpiled bombs at Cunderdin to the north-east of Perth for use by any heavy bombers sent as reinforcements. The readiness of the Army garrison units in the Fremantle-Perth area were also increased. The Fremantle Fortress command, which was responsible for the defence of the port against naval bombardment or air attack, was placed on alert and ordered to station additional heavy anti-aircraft guns near the city's docks. On 4 March the local Volunteer Defence Corps personnel were also ordered to be able to man their assigned anti-aircraft and coast defence positions within six hours, rather than the normal warning time of 24 hours.

The emergency

Japanese movements

Despite the Allied concerns, the Japanese did not intend to send the main body of the Combined Fleet into the Indian Ocean. The ships had been withdrawn west from the Central Pacific to avoid a major United States offensive which was expected to be launched against the area. Singapore had been selected as the Fleet's new base as it was close to sources of fuel and had suitable facilities to enable the ships to undertake a period of training and maintenance before counter-attacking the Allies in the Pacific. However, it was decided to send a small force of warships into the Indian Ocean to conduct the first raid by Japanese surface ships on the area since early 1942.

In late February 1944, Vice-Admiral Shiro Takasu—the Commander in Chief, of Japan's Southwest Area Fleet—ordered the heavy cruisers Aoba, Chikuma, and Tone to raid Allied shipping on the main route between Aden and Fremantle. The three ships departed the Combined Fleet's anchorage in the Lingga Islands on 27 February. The light cruisers Kinu and Ōi and three destroyers (which were designated a "Security and Supply Formation") escorted the raiding force through the Sunda Strait on 1 March. These five ships were to remain at sea for the duration of the raid, and then escort the heavy cruisers back through the Sunda Strait. The Allies were not aware of the raiding force, or its departure. However, Allied code breakers subsequently detected the sailing from Singapore on 4 March of a force comprising two battleships, an aircraft carrier and multiple destroyers, and determined that the ships were headed east towards Surabaya. Rear-Admiral Ralph W. Christie, the commander of the Allied submarines based at Fremantle, was concerned that this force could attack the Fremantle-Perth area. In response, he ordered the US Navy submarine USS Haddo under the command of Lieutenant Commander Chester Nimitz Jr. to patrol the Lombok Strait and report the movement of any Japanese ships into the Indian Ocean.

On 6 March Haddo briefly made radar contact with, but did not sight, what Nimitz believed may have been at least two large Japanese warships near the Lombok Strait. Nimitz was unsure whether to report this inconclusive contact, but decided to do so to prevent Fremantle from being the target of a surprise attack; he later wrote that "'Remember Pearl Harbor' was the message that kept sticking in my mind". The Japanese ships detected by Haddo were Kinu and Ōi heading towards the Sunda Strait.

Nimitz's report caused significant concerns. On 8 March the Australian Chiefs of Staff Committee advised the Australian Government that there was a possibility that the Japanese task force had entered the Indian Ocean with the goal of attacking the Fremantle-Perth area during the full moon period around 9 March. Accordingly, actions were initiated to improve the area's defences. Also on 8 March, the commander of the Eastern Fleet Admiral James Somerville directed all Allied ships travelling in the Indian Ocean between 80 and 100° east to divert to the south or west.

Based on the radar contact on 6 March, moon conditions and assumptions of the Japanese force's speed and likely flying off positions if it included any aircraft carriers, the Allied militaries judged that any attack on the Fremantle-Perth area was most likely to occur during the early hours of 11 March. However, it was possible that such an attack could be conducted any time between the night of 9/10 March and the morning of 14 March.

Allied reinforcements

Allied actions to improve the Fremantle-Perth area's defences began on 8 March. All of the region's defences were manned and air patrols off the coast of Western Australia were increased and the five seaworthy submarines at the Fremantle submarine base were ordered put to sea and patrol along the expected route of the Japanese force. The port of Fremantle was closed to shipping, and the merchant ships there at the time were dispersed to the nearby Gage Roads and Cockburn Sound. In addition, the two US Navy submarine tenders based at Fremantle were sailed to Albany on the south coast of Western Australia. Several US Navy submarines conducting patrols in the Indian Ocean and Netherlands East Indies were also directed to take up stations where they could potentially intercept Japanese ships bound for Fremantle, or attack such a force while it was returning to base.

At a conference held at the Allied Air Headquarters in Brisbane on 8 March, Kenney ordered Air Vice-Marshal William Bostock to take command of the air defence of Western Australia and dispatch several Royal Australian Air Force (RAAF) squadrons there. Kenney also directed the heavy bomber-equipped United States Army Air Forces' 380th Bombardment Group to return from New Guinea to Fenton Airfield near Darwin, and be ready to move to Cunderdin or Geraldton if a threat to the Fremantle area developed.

The official history of the RAAF in World War II states that on 8 March, Bostock ordered the following redeployments of RAAF units:

No. 43 Squadron to move to Darwin
Nos. 452 and 457 Squadrons to Perth as fighter defence squadrons
No. 18 Squadron to Potshot (Exmouth Gulf)
No. 31 Squadron to Potshot (Exmouth Gulf)
No. 84 Squadron from Horn Island to Strauss to take the place of the Spitfires in the defence of North-Western Area
No. 120 Squadron to Potshot from Canberra

A large number of USAAF transport aircraft were assigned to help transport the squadrons' personnel and equipment, and additional fuel supplies and bombs were also shipped to Western Australia. The movement of each squadron took place in two parts: their aircraft and crews travelled together as the first echelon, and maintenance personnel with 14 days supplies formed the second echelon.

Air Commodore Raymond Brownell, the head of the Western Area Command, disagreed with Bostock's decision to station three squadrons at Exmouth Gulf. Brownell believed that Exmouth Gulf was unlikely to be attacked, and units stationed there would be too far from Perth to be able to come to the assistance of that region it was the target of a Japanese raid. However, Bostock was concerned that the Japanese force might attack the Darwin area, and wanted to retain air units at Exmouth Gulf where they could rapidly redeploy to Darwin if necessary.

The RAAF squadrons received orders to redeploy on 8 March, and after hasty preparations began to depart their home bases the next day. The two Spitfire squadrons from No. 1 Wing endured difficult weather conditions during their long trip along the west coast from Darwin to Perth. Inadequate servicing equipment and support personnel at the airfields which they used to refuel also resulted in delays. One of the Spitfires crashed at Carnarvon, and another made a forced landing at Gingin near Perth. The two squadrons eventually arrived at Guildford outside of Perth on 12 March, two days later than originally planned. The squadrons' replacement at Darwin, No. 84 Squadron, also experienced difficultly moving there from Horn Island. The initial attempt by this unit's 24 P-40 Kittyhawk fighters to fly from Horn Island had to be abandoned when they struck bad weather, with one of the Kittyhawks crashing with the loss of its pilot. No. 120 (Netherlands East Indies) Squadron's long light from Canberra to Exmouth Gulf was less eventful, though operations by the squadrons stationed there were greatly disrupted when a severe cyclone struck the area on 10 March and flooded the airfield.

Fremantle-Perth defences

The Allied air units in Western and Northern Australia conducted patrols into the Indian Ocean in search of the feared Japanese force. These operations included patrols by PBY Catalinas from the US Navy's Patrol Wing 10, which was stationed in Perth, as well as RAAF Bristol Beauforts based in Western Australia. In addition, No. 43 Squadron RAAF's Catalinas flew night patrols out of Darwin. These aircraft did not sight any Japanese vessels. The cyclone off the coast of Western Australia greatly hampered the flights, and the resultant loss of warning caused concerns.

The air defences of the Fremantle-Perth area were improved in response to the threat of attack, and as reinforcements flowed into the region. The CAC Boomerang-equipped No. 85 Squadron was initially the only fighter squadron available for the air defence of the region, but the two Spitfire squadrons also assumed responsibility for this task within hours of their arrival on 12 March. No. 25 Squadron was also stationed near Perth before the crisis, and was assigned to attack any Japanese warships with its Vultee Vengeance dive bombers. In addition to these air units, the warships HMAS Adelaide and HMS Sussex were anchored near the merchant ships in Gage Roads on 10 March to provide anti-aircraft defence to them in the event of an attack.

All units in the main Australian Army command in the state, III Corps, were placed on six hours notice to respond to attacks from 8 March, with training exercises being cancelled so its personnel and formations could be concentrated near the threatened region. Personnel drawn from the 104th Tank Attack Regiment were used to man anti-aircraft machine guns near the flying boat station in the Perth suburb of Crawley. The coastal defences on Rottnest Island were also fully manned, and the 10th Garrison Battalion took up defensive positions on the island. The build-up of the region's defences was noticed by civilians, leading to rumours that a raid or invasion was imminent. However, the reason for the reinforcements was kept secret and not reported until August 1945.

On the afternoon of 10 March the radar station at Geraldton repeatedly detected what its crew believed was an unidentified aircraft. Acting upon advice from Brownell, the commanding officer of III Corps Lieutenant General Gordon Bennett ordered an air raid warning for Fremantle and Perth. This led to No. 85 Squadron being readied, air raid sirens being sounded, air raid wardens taking their posts and the evacuation of hospitals. However, no raid eventuated and the "all clear" siren was soon sounded. The military authorities and government did not give any reason for the air raid alert until the next day when the Minister for Civil Defence released a brief statement noting that the alarms had been sounded on legitimate grounds and that it had not been a hoax.

Further military activities took place on 11 March. That morning one of the Allied submarines patrolling off Western Australia reported detecting radar signals from a Japanese warship, but this also proved to be a false alarm. Also that day, HMAS Adelaide escorted eight merchant ships to sea and then proceeded to Albany to protect the submarine tenders. In addition, the 10th Light Horse Regiment established coast watching positions, and an exercise practising the full activation of Volunteer Defence Force-manned coastal and anti-aircraft defences on the night of 11/12 March was successful.

Concerns over the prospect of an attack soon dissipated. Air patrols conducted in improving weather conditions on 11 March did not locate any Japanese warships, and most units other than Fremantle Fortress' anti-aircraft and coast defence positions were stood down on 12 March. The units normally stationed in Western Australia returned to their usual locations and activities on 13 March, and the submarine tenders were escorted back to Fremantle by Adelaide. On 20 March Kenney advised Bostock that the threat of attack had passed, and ordered that all of the additional RAAF units sent to Western Australia be returned to their bases.

Aftermath

The Japanese raiding force encountered only a single Allied ship during its operation. On the morning of 9 March Tone shelled and sank the British steamer Behar in the central Indian Ocean. This ship was bound from Fremantle to Colombo, as part of a voyage to the United Kingdom. Behar's crew broadcast a distress signal after being attacked to warn other Allied ships, causing the commander of the raiding force to abandon the operation. The heavy cruisers were escorted through the Sunda Strait by Kinu, Ōi and five destroyers, and arrived back at the Netherlands East Indies on 16 March. Shortly afterwards, 89 of the 104 Behar survivors who had been rescued by Tone's crew were murdered on board the cruiser. The commanders of the raiding force and Tone were convicted of this crime after the war and imprisoned. The Allies were unaware of the attack on Behar until a ship which had picked up the steamer's distress signal arrived in Fremantle on 17 March. The orders diverting Allied shipping from the central Indian Ocean were cancelled on 18 March.

Allied concerns over the Combined Fleet's presence at Singapore eased considerably during March when it was learned that the ships there were being put through a maintenance program and the Japanese did not intend to undertake major operations in the Indian Ocean area. Allied military commanders believed that the March 1944 emergency had some beneficial effects. Rear-Admiral Christie judged that military personnel and civilians in Western Australia had become complacent before the emergency, and the mobilisation had gone some way to addressing this. The RAAF and USAAF also regarded the transfer of forces to Western Australia as having provided useful experience in rapidly redeploying combat units. An editorial published in the newspaper The West Australian on 13 March also judged that the air raid alert on 10 March had given Perth's population a reminder of the potential threat posed by "hit and run" raids, but was highly critical of the lack of information which had been released on the cause of the alert, especially in light of the rumours which were sweeping the city.