Battle of Empress Augusta Bay

The Battle of Empress Augusta Bay, on 1–2 November 1943—also known as the Battle of Gazelle Bay, Operation Cherry Blossom, and in Japanese sources as the Sea Battle off Bougainville Island (ブーゲンビル島沖海戦)—was a naval battle fought near the island of Bougainville. The naval battle was a result of Allied landings on nearby Bougainville in the first action in the Bougainville campaign of World War II and may also be seen as part of the Solomons and New Guinea campaigns. The battle was significant as part of a broader Allied strategy—known as Operation Cartwheel—aimed at isolating and surrounding the major Imperial base at Rabaul. The intention was to establish a beachhead on Bougainville, within which an airfield would be built.

On 1 November 1943, the U.S. 3rd Marine Division landed at Cape Torokina in Empress Augusta Bay. The bay had been chosen because it was at the outer limit of Allied fighter plane range, and because the numerically-superior Japanese 17th Army was concentrated at other, more strategic sites in the north and the south. The Marines were backed by Task Force 39, composed of cruisers and destroyers, commanded by Rear Admiral Aaron S. "Tip" Merrill.

Naval battle

The Japanese responded with air attacks and a powerful naval force from Rabaul commanded by Admiral Sentaro Omori: Cruiser Squadron - heavy cruisers Myōkō and Haguro, 10th Cruiser Squadron - light cruiser Agano, destroyers Naganami, Hatsukaze, and Wakatsuki, 3rd Destroyer Squadron - light cruiser Sendai, and destroyers Shigure, Samidare,and Shiratsuyu. The Japanese formation was hastily assembled from whatever ships were on hand, many of which had never trained or fought together before.

The U.S. Task Force 39 consisted of Cruiser Division (CruDiv) 12 - USS Montpelier, Cleveland, Columbia , Denver and two destroyer divisions (DesDiv): DesDiv 45 - USS Charles Ausburne, Dyson, Stanley, Claxton and DesDiv 46 - Spence, Thatcher, Converse, Foote.

The Americans evacuated most of their landing craft and troop transports, assembled their ships to the southwest of Empress Augusta Bay and steamed slowly northward. CruDiv 12 would maneuver in a race track pattern, blocking the entrance to Empress Augusta Bay. The Japanese approached from the northwest and would try to bombard the invasion force in their transports and on the shore.

On 2 November at 0130 Haguro was struck amidships by an American aerial attack. The resulting damage necessitated a significant reduction in speed for the entire formation.

The Americans made radar contact at 0230 on 2 November. From the leading position in the American formation Commodore Burke sent the four destroyers of DesDiv 45 forward for a torpedo attack and at 0245 fired a salvo toward the enemy. Almost simultaneously, the Sendai-led division fired 18 torpedoes. Each attack was detected and both groups maneuvered away from the torpedoes. 3rd Destroyer Squadron turned southward into the path of Cruiser Division causing havoc in the Japanese formation. The Japanese fleet became separated in the confusion into three groups, north, center and south.

Admiral Merril then ordered DesDiv 46 to attack. Unprepared, Foote misinterpreted the command and was separated from the other ships. Despite her captain's best efforts Foote was unable to effectively rejoin the fight and was in some danger of colliding with other friendly ships.

Once it became apparent that DesDiv 45's torpedo attack had failed to achieve complete surprise, at around 0250, the American cruisers opened fire, quickly disabling Sendai. DesDiv 45 maneuvered north and concentrated on the northern group, DesDiv. 46 engaged the center group while the cruisers divided their fire between all three groups.

After firing her torpedoes, Samidare collided with Shiratsuyu. Samidare and Shiratsuyu were subsequently forced to retire from the battle with Samidare receiving 5-inch hits at 0300. Myōkō also collided with Hatsukaze, slicing off her bows. Myōkō had significant damage from this collision, including loss of a torpedo launcher. She was next hit by 6 cruiser shells, only two of which detonated, causing even more damage.

The Japanese ships were equipped with anti-air and surface detection Type 21 Radar, and they were forced to rely on optical tracking of their targets. With difficulty they pinpointed the American cruisers, and at 0313 they opened fire. At 0320 Cruiser Squadron fired a total of 10 torpedoes at CruDiv 12. At 0327 numerous hits on CruDiv 12 were erroneously reported to Omori – all missed their targets.

The Americans were also having problems as the Spence and Thatcher also collided but were able to continue in the battle. The Foote was struck by a torpedo which blew off the stern of the ship, leaving 19 dead and 17 wounded. Subsequently, the drifting Foote became a navigational hazard to the other ships adding to the confusion of the battle. Foote was busy for the remainder of the engagement trying to stay afloat and fighting off an enemy aircraft attack.

Without fire control radar, the Japanese depended heavily on flares to illuminate their targets. CruDiv 12 repeatedly maneuvered to avoid starshells fired by the opposing ships but was finally successfully illuminated by brilliant flares dropped by Japanese snooper aircraft.

Between 0320 and 0325 Denver received three 8-inch hits which failed to detonate. Also, while closing with a group of Japanese destroyers in the center, the Spence was hit at the waterline by a shell that failed to explode. As was common during World War II, the thin-skinned destroyers were not tough enough to detonate armor-piercing ammunition designed to penetrate heavily armored battleships. At this point the Japanese fire was heavy and increasingly accurate. In response, the American cruisers began maneuvering behind a smoke screen which successfully interfered with the Japanese gunnery.

All during the battle the American destroyers experienced difficulty maintaining contact with each other and several times came close to firing on friendly ships, underscoring the difficulty in fighting night actions even when equipped with radar and IFF (Identification Friend or Foe) systems. A later evaluation of the battle revealed that DesDiv 46 missed an opportunity to torpedo the center group of enemy ships because of uncertain identification. DesDiv 46 then turned north and concentrated fire on the Sendai.

By 0337, Omori, believing that he had sunk a heavy cruiser and worried about being caught in daylight by U.S. carrier aircraft, ordered a retreat. 10th Cruiser Squadron fired a salvo of 8 torpedoes at CruDiv 12 from extreme range at 0340 but missed. Omori received another erroneous report of torpedo hits at 0354.

Merrill's cruisers closed to bombard the retreating Cruiser Division to the south but difficulties in positive identification hampered this effort and CruDiv 12 turned away to the north allowing the Japanese cruisers to slip away in the darkness.

0400: DesDiv 45 and 46 were engaged in a confused melee with retreating Japanese stragglers - sinking the Sendai and driving off the remaining northern group ships. At 0410 Spence lost speed due to water in the fuel line and fell out of formation. The American ships reported many hits on the enemy contacts but unfortunately at 0438 DesDiv 45 fired on the limping Spence in error while causing no damage.

At 0510 CruDiv 12 and Spence engaged an enemy straggler. Unable to distinguish between the straggler and Spence the cruisers ceased fire. By 0519 DesDiv 45 came to the aid of Spence which by this time had almost exhausted its ammunition. The Japanese straggler, the heavily damaged Hatsukaze, exploded and by 0542 sank.

At daylight the pursuit was broken off and all ships, many low on fuel and ammunition, were ordered to rendezvous with the hapless Foote. The rest of the day was spent defending the landing beaches from air attack.

After the Japanese ships returned to Rabaul, they were joined by four cruisers and more destroyers from Truk for another attack on the Allied landing forces at Bougainville. On 5 November, however, two U.S. aircraft carriers raided Rabaul, heavily damaging four heavy cruisers, which had to withdraw to Truk. This ended the Japanese warship threat to the Allied landing forces at Bougainville.

External links

• Description by Vincent O'Hara
• Order of battle
• JO1 Lorraine Ramsdell (US Navy Reserve), "The Battle of Bougainville"
• WW2DB: Solomons Campaign
• Night Engagement of Empress Augusta Bay 1943 US Navy "action report film" online at FedFlix.