By Dr Alan Stephens
This week marks the 74th anniversary of the Battle of the Bismarck Sea, arguably the most significant action fought by Australians during World War II.
Between December 1941 and April 1942, Imperial Japanese forces shocked Australians with their victories over the United States at Pearl Harbor and in the Philippines; and over the British Commonwealth in Malaya, Singapore, the Dutch East Indies and Rabaul. When enemy forces occupied northern New Guinea, an invasion of Australia, with its unthinkable consequences, seemed possible. However, supported by their American and British allies, Australia’s servicemen and women regrouped and fought back.
From mid-1942 onwards, Australian victories with American support at Milne Bay and Kokoda, and the triumph of American naval air power at Coral Sea and Midway weakened Japan’s hold on New Guinea. Further Allied successes on New Guinea’s northeast coast at Buna, Gona and Sanananda between November 1942 and January 1943 left the Japanese position substantially weakened.
Then, intercepted radio messages revealed that an enemy convoy would sail from Rabaul with reinforcements for the vital Japanese garrison at Lae on the northeast coast of New Guinea in late-February. This was likely to be Japan’s last throw of the dice in New Guinea. If the convoy were stopped, then so too would be the likelihood of an invasion of Australia
Allied Air Forces under the command of the American General George Kenney immediately began preparing for an all-out assault against the convoy. A critical factor was the brilliant plan largely conceived by the Royal Australian Air Force’s (RAAF) Group Captain William “Bull” Garing. Garing had already fought in Europe for two years with the RAAF’s No. 10 Squadron, and his experience of maritime warfare was to prove decisive.
It was Garing who convinced General Kenney of the need for a massive, coordinated attack. Garing envisaged large numbers of aircraft striking the convoy from different directions and altitudes, with precise timing.
Initially, the allies would rely on reconnaissance aircraft to detect the convoy, which would then be attacked by long-range United States Army Air Force (USAAF) bombers. Once the convoy was within range of the allies’ potent anti-shipping aircraft – RAAF Beaufighters, Bostons and Beauforts, and American Mitchells and Bostons – a coordinated attack would be mounted from medium, low, and very low altitudes.
During the waiting period, crews practised their navigation and honed their formation flying, bombing, and gunnery skills.
Six thousand four hundred Japanese troops embarked at Rabaul between 23 and 27 February 1943, and the convoy of eight merchant ships and eight destroyers sailed just before midnight on the 28th, planning to arrive at Lae on 3 March. Air cover was provided by about 100 fighters flying out of bases in New Ireland, New Britain and New Guinea.
The enemy convoy initially was favoured by poor weather, which hampered Allied reconnaissance. It was not until mid-morning on 2 March that USAAF B-24 Liberators sighted the ships. General Kenney immediately launched eight B-17 Flying Fortress heavy bombers, followed shortly afterwards by another 20. The B-17s attacked from an altitude of 2000 metres with 450-kilogram demolition bombs. Later in the day, another strike was made by 11 B-17s whose crews reported that vessels were ‘burning and exploding […] smoking and burning amidships’ and ‘left sinking’.
By nightfall, the enemy was only hours from Lae, which meant that in the morning it would be within range of the entire allied strike force. If the coordinated attack were to succeed, the precise location of the convoy had to be known at daybreak; consequently, throughout the night, it was tracked by an RAAF Catalina from No. 11 Squadron, which occasionally dropped bombs and flares to keep the Japanese soldiers in a state of anxiety. Also during the night, eight RAAF Beaufort torpedo bombers from No. 100 Squadron took-off from Milne Bay to try to use the darkness to their advantage. The heavy frontal weather made navigation hazardous, and only two aircraft found the convoy. Neither scored a hit.
The moment the Allied Air Forces had been waiting for came on the morning of 3 March 1943, when the Japanese convoy rounded the Huon Peninsula. For much of the time the adverse weather had helped the enemy avoid detection, but now clear conditions favoured the allies. Over 90 aircraft took-off from Port Moresby and set heading for their rendezvous point. While the strike force was en route, RAAF Bostons from No. 22 Squadron bombed the enemy airfield at Lae.
By 9:30 a.m. the AAF formations had assembled, and by 10:00 a.m. the Battle of the Bismarck Sea had begun.
The allies attacked in three waves and from three levels, only seconds apart. First, 13 USAAF B-17s bombed from medium altitude. In addition to the obvious objective of sinking ships, those attacks were intended to disperse the convoy by forcing vessels to break station to avoid being hit.
Second, 13 RAAF Beaufighters from No. 30 Squadron hit the enemy from very low level, lining up on their targets as the bombs from the B-17s were exploding. With four cannons in its nose and six machine guns in its wings, the Beaufighter was the most heavily armed fighter in the world. The Australians’ job was twofold: to suppress anti-aircraft fire, and to kill ships’ captains and officers on their bridges.
The Beaufighters initially approached at 150 metres above the sea in line astern formation. The pilots then descended even lower, to mast-level height, set full power on their engines, changed into line abreast formation, and approached their targets at 420 kilometres an hour.
It seems that some of the Japanese captains thought the Beaufighters were going to make a torpedo attack because they altered course to meet the Australians head-on, to present a smaller profile. Instead, they made themselves better targets for strafing. With a slight alteration of heading the Beaufighters were now in an ideal position to rake the ships from bow to stern, which they did, subjecting the enemy to a withering storm of cannon and machine gun fire.
According to the official RAAF release:
[e]nemy crews were slain beside their guns, deck cargo burst into flame, superstructures toppled and burned.
With the convoy now dispersed and in disarray, the third wave of attackers was able to concentrate on sinking ships. Thirteen American B-25 Mitchells made a medium level bombing strike while, simultaneously, a mast-level attack was made by 12 specially modified Mitchells, known as ‘commerce destroyers’ because of their heavy armament. The commerce destroyers were devastating, claiming seventeen direct hits. Close behind the Mitchells, USAAF Bostons added more firepower.
Following the coordinated onslaught, Beaufighters, Mitchells and Bostons intermingled as they swept back and forth over the convoy, strafing and bombing. Within minutes of the opening shots, the battle had turned into a rout. At the end of the action:
[s]hips were listing and sinking, their superstructure smashed and blazing, and great clouds of dense black smoke [rose] into a sky where aircraft circled and dived over the confusion they had wrought among what, less than an hour earlier, had been an impressively orderly convoy.
Overhead the surface battle, 28 USAAF P-38 Lightning fighters provided air defence for the strike force. In their combat with the Zeros which were attempting to protect the convoy, three of the Lightnings were shot down, but in turn, the American pilots claimed 20 kills. Apart from those three P-38s, the only other allied aircraft lost was a single B-17, shot down by a Zero.
With their armament expended the allied aircraft returned to Port Moresby. However, there was to be no respite for the enemy. Throughout the afternoon the attacks continued. Again, B-17s struck from medium level, this time in cooperation with Mitchells and RAAF Bostons flying at very low level. (Incidentally, the Bostons were led by Squadron Leader Charles Learmonth, after whom the RAAF’s present-day base in north-west Australia is named.) At least 20 direct hits were claimed against the by-now devastated convoy.
That was the last of the coordinated attacks. The victory had been won. For the loss of a handful of aircraft, the Allied Air Forces had sunk twelve ships – all eight of the troop transports and four of the eight destroyers – and had killed more than 3,000 enemy soldiers.
The brilliantly conceived and executed operation had smashed Japanese hopes of regaining the initiative in New Guinea and had eliminated any possibility that Australia might be invaded. In the words of the supreme command of the Southwest Pacific Area, General Douglas MacArthur, the Battle of the Bismarck Sea was ‘the decisive aerial engagement’ of the war in the Southwest Pacific.
However, there was still a terrible yet essential finale to come. For several days after the battle, Allied aircrews patrolled the Huon Gulf, searching for and strafing barges and rafts crowded with survivors. It was grim and bloody work, but as one RAAF Beaufighter pilot said, every enemy soldier they prevented from getting ashore was one less for their Army colleagues to face. Moreover, after fifteen months of Japanese brutality, the great immorality, it seemed to them, would have been to have ignored the rights of their soldiers.
Japanese media never mentioned the battle, but in a macabre footnote, two weeks later, Tokyo announced that in future all Japanese soldiers were to be taught to swim.
The Battle of the Bismarck Sea was a master-class in air power. The RAAF and the USAAF had smashed Japanese hopes of regaining the initiative in New Guinea; they had forced the enemy into a defensive posture from which ultimate victory was unlikely, and they had eliminated any possibility that Australia might be invaded.
This was arguably Australia’s most important victory in World War II.
This post first appeared at The Central Blue, the blog of the Sir Richard Williams Foundation.
Dr Alan Stephens is a Fellow of the Sir Richard Williams Foundation. He has been a senior lecturer at UNSW Canberra; a visiting fellow at ANU; a visiting fellow at UNSW Canberra; the RAAF historian; an advisor in federal parliament on foreign affairs and defence; and a pilot in the RAAF, where his experience included the command of an operational squadron and a tour in Vietnam. He has lectured internationally, and his publications have been translated into some twenty languages. He is a graduate of the University of New South Wales, the Australian National University, and the University of New England. Dr Stephens was awarded an OAM in 2008 for his contribution to Australian military history.
Header Image: During the Battle of the Bismarck Sea in which the Japanese suffered heavy losses while attempting to reinforce their garrison at Lae, a RAAF Beaufighter attacks a camouflaged Japanese transport. A burst is poured into the burning vessel. (Source: Australian War Memorial)