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Pacific Historian
The Battle of the Bismarck Sea was a battle in the South West Pacific Area (SWPA) during World War II, in which planes of the United States Fifth Air Force and the Royal Australian Air Force (RAAF), attacked a Japanese convoy carrying troops to Lae, New Guinea (now Papua New Guinea). Most of the task force was destroyed, and Japanese troop losses were extremely high.
Background
On December 23, 1942, the Japanese high command decided to transfer about 105,000 troops from China and Japan to Lae in New Guinea to reinforce their forces there. This would allow the Japanese to fall back from their defeat at the Battle of Guadalcanal, which they ordered evacuated the following week. The troops were needed near Lae, where an Allied offensive was expected.
Relocating such a large force was a great burden on Japanese shipping capability, but the high command considered it a military necessity. By late February 1943, the 20th and 41st divisions had been safely transported to [[Wewak], also in New Guinea]. Next, the 51st Division was to be transported from the major Japanese base at Rabaul to Lae, a perilous maneuver because Allied air power in the area was very strong, especially in the Vitiaz Strait through which the ships would have to pass.
On February 28 the convoy assembled for the task, comprising eight destroyers and eight troop transports with an escort of approximately 100 fighter aircraft departed from Simpson Harbour in Rabaul. The commanding officer of the 51st Division, Lieutenant-General Hidemitsu Nakano, was aboard the destroyer Yukikaze, while Rear Admiral Masatomi Kimura, commanding Destroyer Squadron 3, was aboard the destroyer Shirayuki.
Allied air forces, under the air commander SWPA, Major-General George Kenney, and based in Allied territory on New Guinea, had been preparing for such an eventuality. In particular, the crews of specially modified USAAF B-25 Mitchells and RAAF Bristol Beaufighters had been practicing attacks on shipping. The Mitchell crews were developing a new technique called "skip bombing": after flying only a few dozen feet above the sea towards their targets, they would release their bombs, which would then skip across the surface.
Battle
The convoy, moving at a top speed of seven knots, was not detected for several days because of two tropical storms which struck the Solomon and Bismarck Seas between February 27 and March 1. However, at about 15:00 on March 1 the crew of a patrolling B-24 Liberator bomber spotted the convoy north of Cape Hollman. U.S. heavy bombers were sent to the location but failed to locate the convoy.
At about 10:00 on March 2, another Liberator found the convoy, and clear skies allowed several flights of U.S. B-17 Flying Fortress bombers to attack and sink up to three merchant ships, including the Kyokusei Maru. A B-17 was seriously damaged by a New Britain-based Mitsubishi Zero fighter, and the crew was forced to take to their parachutes. The Japanese pilot machine-gunned some of the B-17 crew members as they descended and attacked others in the water after they landed.
Out of 1,500 troops being transported by the Kyokusei Maru, 800 were rescued from the water by the destroyers Yukikaze and Asagumo. These two destroyers, being faster than the convoy since its speed was dictated by the slower transports, broke away from the group to disembark the survivors at Lae. The destroyers resumed their escort duties the next day. The convoy, without the troop transport and two destroyers, was attacked again on the evening of March 2, with one transport sustaining minor damage.
PBY Catalina flying boats from No. 11 Squadron RAAF continued to trail and occasionally bomb the convoy over the night of March 2, and at about 03:25 on March 3, when the convoy was within range of the air base at Milne Bay, Bristol Beaufort torpedo bombers from No. 100 Squadron RAAF took off. However, because of bad weather only two Beauforts found the convoy, and neither scored any hits.
The convoy was rounding the Huon Peninsula, bringing it into clearer conditions. A force of 90 Allied aircraft took off from Port Moresby and headed for Cape Ward Hunt; simultaneously 22 RAAF Douglas Bostons set off to attack the Japanese fighter base at Lae, reducing the convoy's air cover. Attacks on the base continued throughout the day.
At 10:00, 13 B-17s reached the convoy and bombed from medium altitude, causing the ships to disperse and prolonging the journey.
Then 13 Bristol Beaufighters from No. 30 Squadron RAAF approached at low level, to give the impression they were Beauforts making another torpedo attack. The ships turned to face them, and the Beaufighters were then able to inflict maximum damage on the ships' anti-aircraft guns, bridges and crews, during strafing runs with their four 20 mm (0.787 in) nose cannons and six wing-mounted .303 in (7.7 mm) machine guns.
Immediately afterwards, 13 USAAF Mitchells bombed from about 750 meters (2,500 ft). Then 12 Mitchells made a "skip bombing" attack, reportedly claiming 17 hits. By this time half of the transport ships were sunk or sinking. As the Beaufighters and Mitchells expended their munitions, some USAAF A-20s joined the attack. Another five hits were claimed by B-17s from higher altitudes.
While the attack on the ships proceeded, 28 U.S. P-38 Lightnings provided top cover, and 20 Japanese fighters were shot down for the loss of three Lightnings. Two were from the 39th Fighter Squadron: the aces Bob Faurot and Hoyt Eason were both killed in action. During the afternoon, further attacks from Mitchells and RAAF Bostons followed.
All seven of the remaining transports were sunk about 100 kilometres (60 mi) southeast of Finschhafen, along with the destroyers Shirayuki, Arashio, and Tokitsukaze. Four of the destroyers picked up as many survivors as possible and then retired to Rabaul. The fifth destroyer, Asashio, was sunk in a subsequent strike as it was picking up survivors from the Arashio.
Following orders from Kenney, reportedly in retaliation for the shot-down bomber crew being machine-gunned as they descended, from the evening of March 3 until March 5, Allied patrol boats and planes attacked Japanese rescue vessels, as well as survivors from the sunken vessels on life rafts and swimming or floating in the sea.
Aftermath
The battle was a disaster for the Japanese. Out of 6,900 troops who were badly needed in New Guinea, only about 800 made it to Lae. The Australian War Memorial states that 2,890 Japanese soldiers and sailors were killed.
"A merciful providence guarded us in this great victory," said Douglas MacArthur in one of his communiqués. He used the victory to request five additional U.S. divisions and 1,800 aircraft in preparation for his landings in northern New Guinea.
