Battle of The Bismarck Sea - Allied Tactics

Allied Tactics

In the South West Pacific, "the air mission was to interdict Japan's sea supply lanes and enable the ground forces to conduct an island-hopping strategy." A conventional strategic bombing campaign was out of the question because industrial targets in Japan were well beyond the range of even the largest strategic bombers operating from bases in Australia and New Guinea. But the results of the effort against the January convoy were very disappointing. Some 416 sorties had been flown with only two ships sunk and three damaged. Clearly, a change of tactics was in order. Group Captain Bill Garing, an RAAF officer on Kenney's staff with considerable experience with air-sea operations, including a tour of duty in Europe, recommended that Japanese convoys be subjected to simultaneous attack from different altitudes and directions.

Major Paul I. "Pappy" Gunn and his men at the 81st Depot Repair Squadron in Townsville, Queensland, modified some USAAF Douglas A-20 Havoc light bombers by installing four .50 in (12.7 mm) machine guns in their noses. Two 450-US-gallon (1,700 l; 370 imp gal) fuel tanks were added to give the aircraft more range. This was successful, and an attempt was then made to create a longer range attack aircraft by doing the same thing to a B-25 medium bomber to operate as a "commerce destroyer". This proved to be somewhat more difficult. The resulting aircraft was obviously nose heavy despite adding lead ballast to the tail, and the vibrations caused by firing the machine guns were enough to make rivets pop out of the skin of the aircraft. The tail guns and belly turrets were removed, the latter being of little use if the aircraft was flying low.

The Allied Air Forces also adopted innovative tactics. In February 1942, the RAAF began experimenting with skip bombing, a anti-shipping technique used by the British and Germans. Flying only a few dozen feet above the sea toward their targets, bombers would release their bombs, which would then, ideally, ricochet across the surface of the water and explode at the side of the target ship, under it, or just over it. A similar technique was mast height bombing, in which a bomber would approach the target at low altitude, 200 to 500 feet (61 to 150 m), at about 265 to 275 miles per hour (426 to 443 km/h), and then drop down to mast height, 10 to 15 feet (3.0 to 4.6 m) about 600 yards (550 m) from the target. They would release their bombs at around 300 yards (270 m), aiming directly at the side of the ship. The Battle of the Bismarck sea would demonstrate that this was the more successful of the two tactics. However, the two techniques were not mutually exclusive. A bomber could drop two bombs, skipping the first and launching the second at mast height. Practice missions were carried out against the SS Pruth, a liner that had run aground in 1923.

The Fifth Air Force had two heavy bomber groups. The 43rd Bombardment Group was equipped with about 55 Boeing B-17 Flying Fortresses. Most of these had seen hard war service over the previous six months and the availability rate was low. The recently arrived 90th Bombardment Group was equipped with Consolidated B-24 Liberators but they too had maintenance problems. There were two medium groups, the 38th Bombardment Group, which was equipped with B-25 Mitchells, and the 22nd Bombardment Group, which was equipped with Martin B-26 Marauders, but the former was missing two of its four squadrons that had been diverted to the South Pacific Area, and the latter had taken so many losses that it had been withdrawn to Australia to be rebuilt.

There was also a light group, the 3rd Attack Group, which was equipped with a mixture of A-20 Havocs and B-25 Mitchells. The 3rd Attack Group was not just short of aircraft; it was critically short of aircrew as well. To make up the numbers the USAAF turned to the RAAF for help. Australian aircrew were assigned to most of the group's aircraft, serving in every role except aircraft commander. In addition to the RAAF aircrew with the USAAF squadrons, there were RAAF units in the Port Moresby area. No. 30 Squadron RAAF, which had arrived in Port Moresby in September 1942, was equipped with the Bristol Beaufighter. Both the aircraft and the squadron proved adept at low level attacks. Also in the Port Moresby area were two fighter groups, the 35th Fighter Group and the 49th Fighter Group, which were equipped with Bell P-400, Curtiss P-40 Warhawk and Lockheed P-38 Lightning fighters, but only the latter were suitable for long range escort missions.