The Battle of Empress Augusta Bay

On the night of 1–2 November 1943, some fifteen hours after US Marines had landed at Cape Torokina on Bougainville, a Japanese force under Rear Admiral Sentarō Ōmori – two heavy cruisers, two light cruisers and six destroyers – approached Empress Augusta Bay. Its task was to repeat what the Japanese navy had achieved in August 1942 at the Battle of Savo Island: to smash the ships covering the landing under cover of darkness and cut off the troops ashore. Barring its way were four light cruisers and eight destroyers under Rear Admiral Aaron Merrill. After less than three hours of confused fighting in the dark, amid collisions, smoke and flares, the Japanese turned back for Rabaul, having lost the light cruiser Sendai and the destroyer Hatsukaze. The Americans lost no ships, and the Bougainville beachhead was saved.

Was the battle inconclusive?

War chronologies describe the engagement as an “inconclusive” clash between American and Japanese warships, after which the Japanese failed to land reinforcements. The second half of that statement is true; the first needs qualifying. Most studies regard the battle as a clear American victory: some accounts speak of a “complete victory” for the American force, and Japanese sources of a “complete defeat” for their own side. The Americans sank two enemy ships and damaged several more, suffering only one badly damaged destroyer themselves, and, above all, they achieved their aim: the Japanese force reached neither the transports nor the beaches. At most, the course of the night-time gunfight itself might be called inconclusive, since both sides made mistakes and neither made full use of its capabilities.

The Japanese response to the landing

The landing on Bougainville took the Japanese by surprise. The commander of naval forces in the South-East Area, Vice Admiral Jin’ichi Kusaka, had few ships at Rabaul: part of the force that Admiral Mineichi Koga had sent from Truk for Operation RO, and the ships of the 3rd Destroyer Squadron under Rear Admiral Matsuji Ijūin, who a month earlier, at the naval Battle of Vella Lavella, had covered the evacuation of the last troops from the central Solomons. Ōmori, commander of the 5th Cruiser Division, was ordered to lead the whole force. Under his command were the heavy cruisers Myōkō and Haguro, the light cruisers Agano and Sendai, and the destroyers Naganami, Hatsukaze, Wakatsuki, Shigure, Samidare and Shiratsuyu. It was a scratch force of ships that had never trained or fought together.

At first Ōmori was to be accompanied by destroyer transports carrying about a thousand troops, who were to land near the beachhead and attack the Americans. Their departure was delayed, so the command at Rabaul called off the counter-landing and ordered Ōmori to enter the bay on his own and destroy the American ships. The crews were already tired: on 31 October the ships had put to sea to intercept a reported landing convoy, searched for the Americans all night in vain and returned to Rabaul only shortly before noon on 1 November. After refuelling, the force sailed again that same afternoon. It was soon spotted by an American reconnaissance aircraft.

Merrill’s force

Admiral William Halsey had assigned Rear Admiral Aaron Merrill’s Task Force 39 to cover the landing. Its core was Cruiser Division 12 – Montpelier, Cleveland, Columbia and Denver, new ships of the Cleveland class. Officially they were light cruisers, but they were almost as large as Japanese heavy cruisers, and each carried twelve quick-firing radar-directed 152 mm (6-inch) guns. The eight destroyers of Destroyer Squadron 23 formed two divisions: Division 45, led by the squadron commander, Captain Arleigh Burke, and Division 46 under Commander Bernard Austin.

Like other American commanders after the painful experiences of 1942, Merrill knew that the Japanese’s greatest asset in night fighting was their long-range torpedoes. He therefore decided to keep his cruisers far from the enemy, out of reach of Japanese torpedoes, and to strike at long range with radar-directed gunfire, while leaving the destroyers free to make independent torpedo attacks on the flanks. The crews had had a hard day: on the night of 31 October–1 November the force had shelled the airfields on Buka and the Bonis Peninsula, in the morning it had bombarded the Shortland Islands, and in the afternoon it was heading back to base to refuel. On news of Ōmori’s approach it turned round and before midnight took up position at the entrance to the bay. The transports had already left, but cargo ships that had not finished unloading and minelayers were still lying off the shore.

The night of 1–2 November

The Japanese were approaching from the north-west. At around 1.30 a.m. a bomb from an American aircraft hit Haguro, forcing the whole force to reduce speed. At 2.27 a.m. Merrill’s radars picked up the enemy. Merrill split his forces: Burke’s destroyers made for the Japanese northern flank, the cruisers turned away to keep their distance, and Austin’s division was to attack from the south. At 2.46 a.m. Burke’s destroyers fired a salvo of torpedoes. The Japanese spotted the danger and turned away; at roughly the same time the ships led by Sendai launched torpedoes of their own. Both salvoes missed, but the Japanese formation fell apart.

At about 2.50 a.m. Merrill’s cruisers opened fire. Sendai, with Ijūin aboard, was soon badly hit, lost steering and was set ablaze. In the confusion, as they manoeuvred around one another and dodged shells, the Japanese ships began to collide: Samidare ran into Shiratsuyu and both had to withdraw from the fight, while Myōkō rammed Hatsukaze, slicing off part of her bow. On the American side, too, not everything went smoothly. The destroyer Foote misunderstood an order, became separated from her division and wandered among her own ships; she was hit by a torpedo, probably from the Japanese destroyers, which blew off her stern and killed 19 sailors. Spence and Thatcher scraped against each other.

Ōmori’s cruisers, lacking fire-control radar, struggled to make out the American ships and at around 3.13 a.m. opened fire, illuminating the target with star shells and with flares dropped by their own aircraft. The Japanese fire grew increasingly accurate: Denver took three hits from 203 mm (8-inch) shells, which, luckily for the Americans, failed to explode. Merrill replied with a smokescreen and constant changes of course, which made aiming very difficult. Japanese lookouts reported numerous hits and ships sunk, but all their torpedoes missed the American cruisers.

At 3.37 a.m. Ōmori, convinced that he had sunk a heavy cruiser and fearing that American aircraft would catch him at dawn, ordered a withdrawal. He had come nowhere near the transports or the beachhead. At around 4 a.m. the American destroyers fell upon the stragglers: they finished off the burning Sendai and drove off the remaining ships of the northern group. The damaged Hatsukaze sank after 5 a.m. under fire from cruisers and destroyers. In the chaos of the night American ships several times nearly opened fire on their own, and on one occasion Burke’s destroyers did fire on the damaged Spence, fortunately without effect.

Morning and the reckoning

At dawn Merrill broke off the pursuit and gathered his ships around the crippled Foote, expecting an air attack. Sure enough, more than a hundred aircraft came over from Rabaul, reinforced by carrier air groups that had only just arrived there. American and New Zealand airmen flying from land bases, together with anti-aircraft gunners, shot down up to 25 of them according to American figures; the only result of the attack was two hits on Montpelier, which left nine men wounded. Foote was towed to Tulagi.

American losses in the whole battle amounted to 19 killed and 26 wounded, with three ships damaged. The Japanese lost Sendai and Hatsukaze, while Myōkō, Haguro, Samidare and Shiratsuyu were damaged. Figures for Japanese dead vary widely, from about 200 to more than 600. Sendai lost her captain and 184 crew, while 236 sailors were picked up by destroyers; on 3 November the submarine Ro-104 rescued Admiral Ijūin and 75 other survivors, and several dozen more reached the shore on their own. No survivors from Hatsukaze were found. One of the Japanese commanders who lived through that night was Commander Tameichi Hara of the destroyer Shigure, who described it in memoirs published after the war. Ōmori was relieved of his command after the battle.

The battle was no display of precision. The American cruisers expended an enormous quantity of ammunition for a relatively small number of hits, and the destroyers struggled to keep in touch with one another and missed the chance to torpedo the main Japanese group. Yet what mattered most was decisive: thanks to radar, discipline and keeping his distance, Merrill kept all his ships, and the enemy withdrew without achieving his aim.

Consequences

Admiral Koga did not give up. He sent Vice Admiral Takeo Kurita’s heavy cruisers from Truk to Rabaul, where together with Ōmori’s ships they were to renew the attack on the beachhead. Halsey had no comparable surface forces to hand and took a risky step: on 5 November he sent Rear Admiral Frederick Sherman’s carrier aircraft against Rabaul – which had been under heavy air raids by General Kenney’s air forces since October – and they damaged several of Kurita’s heavy cruisers and forced the Japanese fleet to withdraw to Truk. On the night of 7–8 November destroyers managed to land several hundred troops at the northern edge of the beachhead, but they were quickly wiped out by the Marines.

The Battle of Empress Augusta Bay was the last major surface action of the Solomon Islands campaign in which the Japanese tried to oppose an Allied landing with warships. Throughout 1942 and as late as mid-1943, night actions in these waters had often ended in Japanese victories – from Savo to Kolombangara. By the autumn of 1943 the advantage had passed to the Americans, who had learned to combine radar, new tactics and a growing number of ships. After the battle off Cape Torokina they could build airfields undisturbed, from which in the following months fighters escorted bombers over Rabaul. The last night destroyer action of the campaign was fought a few weeks later between Buka and New Ireland, and it too ended in a Japanese defeat. The Japanese never again threatened the beachhead from the sea, and the base at Rabaul itself, ever more heavily bombed, soon ceased to matter as a fleet base.