Empress Augusta Bay

Empress Augusta Bay is located south of Cape Torokina on the west coast of Bougainville. It was the location of a battle between Merrill's Task Force 39 and a scratch force under Omori Sentaro.

Battle of Empress Augusta Bay. When word reached Rabaul on 31 October 1943 of an Allied force steaming up "The Slot", Omori's Cruiser Division 5 (Myoko and Haguro) had just finished escorting a convoy from Truk to Rabaul and was promptly commandeered by Samejima (8 Fleet) to intercept. Omori missed Merrill's force, but the next day elements of III Amphibious Corps began landings at Cape Torokina on Bougainville. Omori was promptly ordered out again with every ship available from 8 Fleet, the force leaving Rabaul at 1700 on 1 November 1943. Omori's force was orginally to escort a group of five destroyer-transports with reinforcements for a counterlanding, but delays, a submarine sighting, and an attack by a scouting aircraft convinced Omori to request permission to send the transports back to Rabaul and concentrate on attacking the Allied transports. Samejima agreed and Omori raced south to the attack.

Meanwhile Merrill's force was cruising slowly near the New Georgia group while its crews rested and its destroyers refueled. The destroyers rejoined by 2315 and Merrill raced north to intercept Omori's force. Merrill sailed in column, but with greater spacing between ships than had previously been American practice, and with the van and rear destroyers well separated from the cruisers with orders to operate independently and rely on torpedoes rather than gunfire. The Americans were learning the lessons of previous costly night engagements. It was a moonless and very dark night.

At 0130 an American plane bombed Haguro and inflicted light damage. Meanwhile Japanese float planes had spotted Merrill's force, but badly underestimated it at a cruiser and three destroyers. Another float plane reported transports in Empress Augusta Bay, when in fact the bay had been cleared of transports and only a number of minesweepers were operating. Both Omori and Merrill maneuvered to intercept, Merrill at a relatively slow 20 knots to reduce the visibility of his ship's wakes. Merrill had an excellent picture of Omori's movements and had a clear mission to drive him away from the transports heading down "The Slot."

Merrill's plan was to keep the Japanese well out to sea, maneuvering his cruisers at the estimated maximum effective range of Japanese torpedoes (16,000 to 20,000 yards or 15,000 to 18,000 meters) and holding fire while his destroyers raced in to attack independently with torpedoes. One of his destroyer division commanders, Arleigh Burke, was well acquainted with these tactics, but his other destroyer division commander, B.L. Austin, was new to the theater.

Omori had decided to head directly towards the reported transports, and sailed in three columns with cruisers in the middle and destroyers on either flank. He had radar, but it was poor quality and his operators were badly trained, and he ended up relying entirely on visual sightings during the battle. This was his undoing.

The Americans sighted Omori on radar at 0227 on 2 November 1943. At 0231 Burke's destroyers broke free and raced north to make a torpedo attack against the enemy flank. At 0239 Merrill reversed course, ordering Austin to countermarch as well and attack the Japanese from the south. Shortly thereafter, at 0245, Omori received sighting reports on the Americans. He turned southwest and launched about eight torpedoes at the Americans. Merrill, receiving word of Omori's change of course and concluding he had been sighted, opened gunfire.

As was typical in these early days of radar, all of Merrill's cruisers fired at the nearest large target, which happened to be Sendai. The Japanese ship was smothered by shells, lost control, and began burning fiercely, and destroyers Samidare and Shiratsuyu collided while trying to chase salvos and withdrew from the battle. However, the Japanese maneuver meant that none of Burke's torpedoes scored hits. Merrill made smoke and changed course, which prevented the Japanese scoring any hits with either torpedoes or shells.

Omori maneuvered to avoid gunfire, turning a complete 360 degrees, while Osugi milled around ineffectually. This made an excellent target for the Americans, whose shells "walked right into the target" (Morison 1950, quoting Omori). Hatsukaze stumbled into the middle of the heavy cruiser column and collided with Myoko, suffering severe damage.

Merrill continued maneuvering furiously to confuse the Japanese fire solutions, to maintain range, and to get clear of Austin's destroyers, which were slow to clear the line of fire. Haguro took a few hits that did little damage, and returned fire that inflicted light damage on Denver. Japanese gunnery was aided by float planes that dropped a number of flares and brightly illuminated the American ships. At 0337 Omori, believing mistakenly that he had inflicted heavy damage on the Americans, ordered a withdrawal.

Burke had become disoriented and chased ineffectually after the retreating Japanese destroyers before mistakenly concluding they were friendly and reversing course. His ships helped finish off Hatsukaze before rejoining Merrill at daybreak.

Austin was unable to deliver torpedoes before the cruisers opened fire, and Foote misinterpreted signals and raced off on her own. She soon discovered her mistake, but was hit in the stern by a torpedo before she could rejoin. The American cruisers barely avoided a collision, and Thatcher and Spence suffered a grazing collision that fortunately did little damage. Spence also was hit by a shell that contaminated her fuel and forced her to reduce speed. In spite of having a nearly perfect setup, Austin failed to launch torpedoes, mistakenly believing that the targets on his radar were friendly. At 0328 Austin launched torpedoes at Sendai but failed to sink her. His ships then intercepted Samidare and Shiratsuyu and the two forces exchanged torpedoes and gunfire without effect.

At 0454 Merrill ordered all ships to rejoin his force. He circled 20 miles to the west but encountered no Japanese ships except crippled Hatsukaze. The surface action was over.

Shortly after 0800 Merrill was attacked by a Japanese raid of 98 carrier aircraft from Rabaul. The Japanese attack was badly coordinated, the American antiaircraft fire was effective, and Merrill had some fighter support; damage was limited to two superficial hits on Montpelier. The Japanese raid was slaughtered, losing every one of its torpedo bombers and all but three of its dive bombers.

Omori dispatched a submarine to rescue Japanese survivors. There were none from Hatsukaze, but survivors from Sendai included her commanding officer and Admiral Ijuin. 320 other men from Sendai were lost. Merrill suffered 19 killed and 26 wounded.

Allied order of battle

Japanese order of battle

References

Coombe (1991)

Morison (1950)

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