History Remembered: March 2-4, 1943

March 2-4, 1943: In the Battle of the Bismarck Sea, land-based U.S. and Australian aircraft sink 12 of 16 ships of a convoy carrying reinforcements from the Japanese stronghold at Rabaul on New Britain to the garrison at Lae in British New Guinea.

Employing new low-level tactics with deadly effect, the attacking planes sank all eight transports and four of eight Japanese destroyers. About half of the convoy’s 6,900 reinforcement troops and all of its supplies were lost. After the devastating defeat, Japan abandoned use of convoys to reinforce and resupply its garrisons on New Guinea.

After losing Buna and Gona, the Japanese attempted to take the inland town of Wau, where a small Australian force and a prewar airstrip posed a threat to the Japanese bases at Lae and Salamaua. At the end of January, the Japanese thrust closed to within a few hundred yards of the Wau airstrip but was turned back by Allied forces that had been rushed to the scene by transport aircraft. The Japanese fell back on Lae, sorely in need of supplies and reinforcements.

As February 1943 ended, Allied reconnaissance planes discovered a convoy assembling in Rabaul. ULTRA radio intercepts indicated it was bound for Lae. The convoy was detected at sea on March 1, heading for Lae and into range of Allied aircraft. On March 2, Allied B-17 and B-24 heavy bombers attempted to bomb the convoy from medium altitude. The following day, with the convoy now closer, aircraft of the U.S. Fifth Air Force and Royal Australian Air Force staged two mass, coordinated attacks. In addition to heavy bombers, the March 3 effort involved twin-engine B-25s and A-20s using newly acquired skip bombing and masthead height bombing techniques and Australian Beaufighters. Some of the B-25s and A-20s had been modified by replacing the bombardier position in the nose with multiple machine guns, for strafing and anti-aircraft suppression.

Between waves of heavy bombers higher up, the smaller bombers and Beaufighters came in at low altitude and were so effective that initial reports said the convoy had been. The Allies claimed 60 Japanese planes destroyed and lost six. The four remaining Japanese destroyers returned to Rabaul with about 2,700 survivors. Another 1,000 or so made it to Lae. Hundreds of other Japanese, in life boats or adrift in the ocean, were killed by strafing aircraft and, after nightfall, by PT boats from Milne Bay.

The U.S. Strategic Bombing Survey concluded, “Japanese reaction to the shock was apparent along his entire chain of command. Not until the Leyte campaign, did he again attempt to reinforce or supply in force a beleaguered battlefield in range of American medium bombardment. As a result, the enemy resigned his force in British New Guinea to a delaying action. He later retired these forces by land, in stages, to the Wewak area, where they were isolated and by-passed.”

A later Air Force historian described this as “a turning point for the Fifth Air Force and in many ways the entire USAAF. The ability of airpower to shape a campaign was no longer an empty promise.”

Several days after the battle, Australian troops mopping up survivors on Goodenough Island recovered some documents in a lifeboat. Among them was an alphabetical list of all 40,000 officers in the Japanese army and their assigned units – some of them previously unknown to the Allies -- as of October 15, 1942. This intelligence treasure trove was quickly translated by MacArthur’s Allied Translator and Interpreter Section and copies were rushed to intelligence officers at every Allied command in the Pacific.