World War II in the Pacific
The Battle of the Bismarck Sea -- 2-3 March 1943

Background

Papua/New Guinea was part of the defensive ring around Japanese conquests of the Dutch East Indies. New Guinea would close the door from Australia, which is closer than Cuba is to Florida.

We have seen that at the Battle of Coral Sea, the invasion convoy directed to the south coast had been stopped and the Japanese forced to make a land attack over rugged mountains. That attempt failed in the Kokoda Track campaign-- Aug'-Sep'42. At the same time, the Japanese invaded the tip of New Guinea at Milne Bay, Aug'42-Sep'42 against a larger Australian force and that too failed and troops were withdrawn. The Americans got involved in a successful effort to stop the advance along the north coast in the Buna and Gona campaign in Nov'42-Jan'43. Concurrently Japanese troops were evacuated from Guadalcanal.

The battle for New Guinea was stalled, drained by the men and material required for the neighboring campaign at Guadalcanal. The north coast cities of Lea and Salamaua needed reinforcement of men and supplies. The Japanese had a defensive action by Holding Wau -- Jan'43. With reinforcements now available for New Guinea, the problem was to get troops, artillery, ammunition and fuel from Rabaul, New Britain, to the Japanese defenders on New Guinea. Rabaul is the Japanese base that was hub for the Southwest Pacific. Several single ships or small convoys had been able to make the run from Rabaul to the north coast of New Guinea during the Guadalcanal campaign. The American Air Force strongly felt the humiliating failure suffered just a few months earlier. In January 1943 a Japanese convoy of five transports and five destroyers successfully delivered the main body of the 20th Division, almost ten thousand men, to forces fighting in Wewak, on the north coast of New Guinea.

That convoy had departed Rabaul on January 5, 1943, and sailed the shortest route south to Lae. It was halfway to its goal before it was first spotted by Allied air patrols the morning of January 6. But efforts to attack the convoy suffered from a piecemeal approach and disorganization at the top. Army Air Forces squadrons did not coordinate attacks ; units were sent out as soon as aircraft were loaded with ordnance. Of the seven missions flown against the convoy on the first day, six were single-plane sorties. The seventh mission was a sixteen-plane formation of P-38s that engaged Japanese fighters covering the convoy. That night, an Australian Catalina dropped flares at the estimated position of the convoy and then managed to score a direct hit that sank the freighter Nichiryu Maru.
The next day, January 7, the Allies launched another series of ragged and uncoordinated attacks. In all, thirteen missions, of one to twenty planes each, went out. They were a hodgepodge of available aircraft, fighters and bombers: A-20, B-17, B-24, B-25, B-26, Beaufighter, P-38, P-40. Although 78 percent of the airplanes reached their primary targets ; Allied air power sank only one transport and drove another, Myoko Maru, up on the beach where it was later destroyed. The majority of ships in the Japanese convoy made it to Lae and unloaded their cargo.

New Plans

In the summer of 1942 modified an A-20 light bomber with nose guns for strafing. The A-20's success led to tactics were developed that emphasized low-level bombing and strafing attacks to overwhelm antiaircraft opposition. A number of Fifth Air Force B-25s into so-called commerce destroyers.
  • The B-25C dash 1 installed ten .50-caliber machine guns: four in the nose, two on each side, and two more in the top turret. The 81st Air Depot Group in Townsville, Australia, produced thirty B-25C-1s in the first three months of 1943. [ pic of nose of B-25C-1 ]
    A new approach to ship bombing was developed to go with the new strafing capability : extreme low-level bombing. This "rendered a miss unlikely" but created new technical problems.
  • Bomb fuzes are normally were designed to detonate immediately on impact -— which would mean the airplane would be caught in its own bomb blast. The fuse was altered to provide a 5-second delayed-action bomb.
  • Skip bombing. With the delay, the bomb could be dropped adjacent to the ship, the bomb would skip across the water, and explode in the water next to the hull creating a mine-like effect. This did not require the pin-point accuracy of hitting the ship from the air
  • Aircrews spent weeks carefully rehearsing tactics
  • Attacking in pairs, B-25s took violent evasive action at full throttle; one plane strafed the vessel from stem to stern, firing continuously from 1,200 yards, while the other plane strafed the vessel as it came in on its beam and bombed it.

    The Setup - Japanese

    The requirement to maintain two battles, New Guinea and Gaualcanal, at the same time, caused each to suffer shortages. At first, New Guinea has the priority, then the critical element shifted to Guadalcanal. Now that Guadalcanal was lost, the effort shifted back to New Guinea.
      http://www.historynet.com/battle-of-the-bismarck-sea.htm is the best source this summary was taken.
    The Japanese were attempting to keep from losing the island and their garrisons there by sending 7,000 reinforcements, artillary, ammunition, aircraft fuel and supplies. They knew the risk and planned on moving in bad weather to thwart the observation and attack by Allied air forces. Air defenses was sought of 200 fighter planes to protect from bombers. Even so, the Leadership expect a 50% loss of shipping and were willing to accept that much loss to save the island.

    The Battle

  • Reconn aircraft had noted a buildup of shipping at Rebaul
  • On March 1, U.S. reconnaissance planes spotted 16 Japanese ships en route to Lae and Salamaua in New Guinea. They were traveling north around the island to take advantage of cloud cover.
  • March 2 at 8:25 a.m., a B-24 reconnaissance plane was able to weave through the clouds and relocate the convoy. Meanwhile, six Royal Australian Air Force A-20s from Port Moresby bombed the airfield at Lae from both medium and "tree-scraping" altitude and liberally strafed the runway and dispersal areas to suppress Japanese fighter protection. They also dropped bombs on planes they found in the open.

    Less than two hours later, twenty-nine heavy bombers hit the convoy. It was still too distant for coordinated attacks by all types of aircraft, so the burden of the initial attack rested on the B-17s. The plan called for long-range P-38 fighters from the 9th Fighter Squadron to provide an escort, but the fighters failed to reach the rendezvous point on time, and the first wave of bombers faced fierce enemy fighter attacks without protection. The low cloud deck and intermittent heavy thunderstorms contributed to the confusion. Eventually, the fighters would make it to the fight and repulse the Japanese Oscars, but not before nine of the B-17s were damaged.
    Two destroyers rescued 950 troops from the water and preceded at high speed to Lea to land the troops and returned to the convoy by morning.
  • March 3, the convoy finally arrived within striking distance of the B-25C-1. The storm had moved east, leaving the convoy in the clear as it traversed the Vitiaz Strait. 38 Allied fighters attacked the Japanese air base at Lae.
    By 9:30 a.m., all the planes in the strike package reached the assembly area.
    The Japanese ship captains assumed the low flying bombers were making a torpedo run and turned to present the smallest target. Perfect for the strafing B-25C-1 to put 50 caliber machine fire the entire length of the ship.
    Twenty minutes after the attack started, the majority of ships in the convoy were sunk, sinking, or badly damaged.
    At 3:15 p.m. the attack recommenced. B-17 bombs found the damaged and stopped ships as stationary targets suitable for heavy bombers. Simultaneously B-25s finished their strafing runs sending the damaged ships to the bottom. The day's carnage ended twenty-one minutes later.
    PTs and fighters mop up.
      Forces Engaged
      Japanese Forces
      Rear Admiral Masatomi Kimura
      Destroyers
      Arashio sunk
      Asashio sunk
      Asagumo survived
      Shikinami survived
      Shirayuki sunk
      Tokitsukaze sunk
      Uranami survived
      Yukikaze survived
      Transports
      Captain Kamataro Matsumoto
      Ship Tons Cargo Fate
      Aiyo Maru 2,716 troops,equip Sunk, 323 killed
      Kembu Maru 950 aviation fuel Sunk, 20 killed
      Kyokusei Maru 5,493 115th Infantry Regiment Sunk, 486 killed
      Oigawa Maru 6,494 51st Division Sunk, 1,229 killed
      Sin-ai Maru 3,793 SNLF Sunk, 63+ killed
      Taimei Maru 2,883 51 Div Sunk, 200 killed
      Teiyo Maru 6,870 2,000 troops Sunk, 1,915 killed
      Nojima Maru 8,125 1,800 troops Sunk, 400 killed
    Two hundred fighters were to be used to defend the convoy. Many were damaged or did not make it to the fight because of Australian Air Force attack on the principle air base at Lae.
    Allied Forces
        Allied Air Forces
    Southwest Pacific Area/US Fifth Air Force
    Lieutenant General George C. Kenney
    RAAF -- Royal Australian Air Force
    Wing Squadron Aircraft Base
    No. 73 Wing RAAF
    No. 6 Squadron RAAF Lockheed Hudson Turnbull Field
    No. 22 Squadron RAAF A-20 Boston Wards Airfield
    No. 30 Squadron RAAF Bristol Beaufighter Wards Airfield
    No. 71 Wing RAAF
    No. 75 Squadron RAAF P-40 Kittyhawk Gurney Airfield
    No. 100 Squadron RAAF Bristol Beaufort Gurney Airfield
    USAAF
    Group Squadron Aircraft Airfield
    35th Fighter Group
    39th Fighter Squadron P-38 Lightning Schwimmer Airfield
    40th Fighter Squadron P-39 Airacobra Rogers Airfield
    49th Fighter Group
    7th Fighter Squadron P-40 Warhawk Durand Airfield
    8th Fighter Squadron P-40 Warhawk Kila Airfield
    9th Fighter Squadron P-38 Lightning Schwimmer Airfield
    3rd Attack Group Strickland
    13th Attack Squadron B-25 Mitchell Schwimmer Airfield
    89th Attack Squadron A-20 Havoc Kila Airfield
    90th Attack Squadron B-25 Mitchell Durand Airfield
    38th Bombardment Group
    71st Bomb Squadron B-25 Mitchell Durand Airfield
    405th Bomb Squadron B-25 MitchellDurand Airfield
    43rd Bombardment Group
    63rd Bomb Squadron B-17 Flying Fortress Jacksons Airfield
    64th Bomb Squadron B-17 Flying Fortress Jacksons Airfield
    65th Bomb Squadron B-17 Flying Fortress Jacksons Airfield
    403rd Bomb Squadron B-17 Flying Fortress Mareeba Airfield
    90th Bombardment Group
    319th Bomb Squadron B-24 Liberator Jacksons Airfield
    320th Bomb Squadron B-24 Liberator Jacksons Airfield
    321st Bomb Squadron B-24 Liberator Jacksons Airfield
    400th Bomb Squadron B-24 Liberator Jacksons Airfield
    Motor Torpedo Boat Striking Force - 7 boats.
    PT-66, PT-67, PT-68, PT-121, PT-143, PT-149, PT-150
    Of the Japanese fighter planes that attempted to destroy the Allied bombers, over 100 were shot down. The Allies, in comparison, lost four aircraft: one B-17 and three P-38s.
    Of 6,900 troops of the Japanese 51st Division who were badly needed in New Guinea, only about 1,200 made it to Lae.  Another 2,700 were rescued by destroyers and submarines and returned to Rabaul. The Japanese made no further attempts to reinforce Lae by ship. From here on, they were forced to rely on barges, small coastal vessels, and submarines to provide a lifeline to their strategic outposts in the archipelago.

    Afterward
  • Japanese Air Retaliation , April'43. A show of resolve that would have been better administered during the Battle of Bismarck Sea.
  • Salamaua-Lae campaign , 22April - 16Sep'43.
  • Western New Guinea campaign , 1944–1945.
    The New Guinea campaign lasted from January 1942 until the end of the war in August 1945.  Approximately 216,000 Japanese, Australian and U.S. soldiers, sailors and airmen died during the New Guinea Campaign.
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