Battle of the Bismarck Sea

By Ms Rosalind Turner
History and Heritage – Air Force (HH–AF)
February 2023

‘Please extend to all ranks my gratitude and securing Port Moresby, the capital of Papua.
felicitations on the magnificent victory which Intelligence reports were filtering into the
has been achieved. It cannot fail to go down Allies from a number of sources that included
in history as one of the most complete and Australian Coastwatchers who had oversight
annihilating combats of all time. My pride and of all shipping that left Rabaul harbour, the
satisfaction in you all is boundless.’ monitoring of Japanese communications, air
reconnaissance and the use of
General Douglas MacArthur, Supreme radar surveillance.
Commander of Allied Forces in the South-West
Pacific, 4 March 1943 On 1 March 1943, a patrolling US Liberator
aircraft sighted an enemy convoy outward-
bound from Rabaul. The convoy consisted of
The Battle of the Bismarck Sea, which took eight troop transports escorted by eight
place on Australia’s doorsteps from 2 to 4 destroyers with air cover being provided by
March 1943, has a special place in Australia’s Zero aircraft operating out of both Rabaul and
military history. It was a defining battle that Lae. This was a much bigger convoy than the
thwarted Japan’s attempt to secure a one that landed Japanese troops at Lae on
permanent foothold in Australia’s nearest 7 January. At first, bad weather hid this
neighbour, which was then the Australian second fleet from Allied reconnaissance
territory of Papua and territory protectorate aircraft, and the convoy was not sighted again
of New Guinea. While action in the battle until the following day.
occurred at sea, it was Allied air power that
was the deciding factor. The success of air In a seemingly unconnected operation, on
power was only made possible through a 2 March, six Boston aircraft from the RAAF’s
series of carefully planned and orchestrated No 22 Squadron made a dawn raid on Lae
operations, which today would be collectively airfield. While easily seen as just another raid,
termed a joint operation. the attack was in fact mounted to prevent
Japanese aircraft intended as the fighter
Japan was providing vital logistics support escort for the convoy from operating from the
from Rabaul to their New Guinea base in Lae. airstrips, thereby ceding air control over the
The Allies missed an opportunity to intercept convoy to the Allies.
a Japanese convoy in January 1943 but they
knew well that further convoys were needed Searching United States Army Air Force
to support the Japanese advance over the (USAAF) Liberator aircraft relocated the
Owen Stanley Range to their final prize of convoy mid-morning. Eight Flying Fortresses
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were launched, followed shortly afterwards to suppress anti-aircraft fire, and to target the
by 20 more. The Flying Fortresses attacked ships’ executives located on the bridge of the
the convoy from 6500 feet using 100 lb ships. The Beaufighters initially approached at
demolition bombs, and one transport was 150 m (around 400 feett) in line-astern
sunk. Later in the day, a further attack was formation. The pilots then dived to mast-level
conducted by 11 Flying Fortresses, but this height, set full power on their engines,
attack yielded no results. After dusk, RAAF changed into the abreast formation, and
Catalinas from No 11 Squadron shadowed the approached their targets at 420 km/h (around
convoy throughout the night, with the 225 knots).
purpose of providing detailed information on
the movements of the convoy to the various It seems that some of the Japanese captains
Allied headquarters located throughout the thought the Beaufighters were going to make
South West Pacific. Throughout the night, the a torpedo attack because they altered course
extremely poor weather conditions favoured to meet the Australians head-on, to present a
the Japanese convoy. A lone Beaufort from smaller profile. Instead, this exposed the
No 100 Squadron made an unsuccessful bridge of the vessels and made them better
torpedo attack while the Japanese transited targets for strafing as the Beaufighters altered
Vitiaz Strait. their heading in response and raked the ships
from bow to stern, subjecting the enemy to a
On the morning of 3 March, eight Beauforts storm of cannon and machine gun fire.
from No 100 Squadron made an unsuccessful
dawn torpedo attack. This was a precursor to
a more coordinated attack to be made later,
which involved RAAF Bostons, Beauforts and
Beaufighters working in unison with USAAF
Flying Fortress, Mitchell and Boston aircraft.
By 0930 hrs, more than 90 Allied aircraft
rallied at the rendezvous point over Cape
Ward Hunt to synchronise their strike on the
convoy. Their attacks were made in three
waves and from different levels with split- Japanese vessel under attack. Credit: Department of Defence
second timing.
With the convoy now dispersed and in
Firstly, 13 USAAF Flying Fortresses bombed disarray, the third wave of attackers was able
from medium altitude. In addition to the to concentrate on sinking ships. Thirteen
obvious objective of sinking ships, these USAAF Mitchells made a medium-level
attacks were intended to disperse the convoy bombing strike and made low-level ‘skip
by forcing vessels to break their tight convoy bombing’ attacks while, simultaneously, a
grouping to avoid being hit. mast-level attack was made by 12 other
specially modified USAAF Mitchells,
Secondly, 13 RAAF Beaufighters from No 30 commonly referred to as ‘commerce
Squadron hit the enemy from very low destroyers’ because of their heavy armament.
altitude, lining up on their targets as the The commerce destroyers were devastating,
bombs from the Flying Fortresses were claiming 17 direct hits. Close behind the
exploding. The Australians’ job was twofold:

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Mitchells, USAAF Bostons added destroying barges and rafts crowded with
more firepower. Japanese survivors.
The Battle of the Bismarck Sea provides a
Following the coordinated onslaught, classic example of the effective integration of
Beaufighters, Mitchells and Bostons a wide range of air power roles. For the loss of
intermingled as they swept back and forth a handful of aircraft, the Allied air forces had
over the convoy, strafing and bombing sunk 12 ships – all eight of the troop
selected targets at will. The Japanese ships transports and four of the eight destroyers –
were now listing and sinking, their and killed nearly 3000 enemy soldiers. The
superstructures smashed and blazing, brilliantly conceived and executed operation
producing great clouds of smoke. Above the had smashed Japanese hopes of regaining the
surface battle, 28 USAAF Lightning fighters initiative in their New Guinea campaign and
provided air defence for the strike force. In eliminated any possibility that Australia might
their combat with the Zeros, which were be invaded. It also allowed the Australian
attempting to protect the convoy, three of the Army to prepare for the Salamaua and Lae
Lightnings were shot down, but in turn the campaigns later in 1943.
American pilots claimed 20 kills. The only
other USAAF aircraft lost was a single Flying General MacArthur described the battle as
Fortress, shot down by a Zero. ‘the decisive aerial engagement’ of the war in
the South-West Pacific Area.
By midday on 3 March, the Allied aircraft then
returned to Port Moresby for refuelling Key Points
and rearming.
 Allied Air Forces involved in the Battle
The attacks on the convoy continued of the Bismarck Sea included
throughout the afternoon. Again, USAAF elements of the United States Army
Flying Fortresses struck from medium level, Air Force, the Royal Australian Air
this time in cooperation with USAAF Force, the Royal Air Force, the Royal
Mitchells and five RAAF Bostons from No 22 New Zealand Air Force and the
Squadron, flying at very low level. At least 20 Netherlands East Indies Air Force.
direct hits were claimed against the by-now  The Japanese convoy was decimated
devastated convoy. by a three-wave attack made over
three levels, with the majority of ships
On 4 March, Allied aircraft attacked Malahang lost at the expense of only a few
airfield near Lae and destroyed many enemy Allied aircraft.
aircraft and ground installations. This was the
 The success gained in the Battle of the
last to be seen of the invading Japanese
Bismarck Sea paved the way ahead
convoy. In the days following the attacks,
for other Australian and Allied
RAAF and USAAF aircraft patrolled the Huon
operations in New Guinea.
Gulf area between Lae and Rabaul in what
was described by official historian Douglas This article was originally published in Pathfinder #256,
Gillison as ‘the terrible yet essential finale’, November 2015

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