The battle of Vella Gulf (6 August 1943) was a clear American victory that crushed one of the last attempts by the 'Tokyo Express' to get reinforcements to the remaining Japanese garrisons in the New Georgia Islands.
On 5 August the vital airfield at Munda on the south-western tip of New Georgia finally fell to the Americans, but there were still Japanese troops elsewhere on that island, and a strong garrison on Kolombangara, the next island to the west. The Japanese were still determined to get reinforcements onto Kolombangara, and despatched four destroyers under Captain Kaju Sugiura to Kolombangara. His flagship, the Shigure, carried no troops, but the Hagikaze, Arashi and Kawakaze carried 900 troops and 50 tons of supplies between them.
The Americans were expecting the Tokyo Express to run on the night of 6-7 August. On previous occasions (battle of Kulf Gulf, 6 July 1943 and battle of Kolombangara, 13 July 1943) they had sent a mixed force of cruisers and destroyers to intercept the Japanese, but these battles had been costly draws. Admiral Aisworth lost one cruiser in the first battle and had three damaged in the second and his division had not yet been rebuilt. The other cruiser division in the area was too far away to take part in the night's operations, so the job was given to Commander Frederick Moosbrugger and six destroyers from Destroyer Division 12 (Dunlap (DD-384), Craven (DD-382), Maury (DD-401), Lang (DD-399), Sterett (DD-407), and Stack (DD-406).
Moosbrugger was confident that his destroyers would be more successful now that they had been freed from the need to operate with cruisers. Moosbrugger split his destroyers into two columns. He commanded three torpedo armed destroyers, and would lead the attack if the Japanese sent destroyers themselves. Commander Rodger Simpson commanded the other three destroyers, which had replaced some of their torpedoes with quad 40mm guns. He would take the lead if the Japanese used barges.
Moosbrugger was briefed on the possibility that the Japanese had better torpedoes than the Americans (the existence of the Long Lance torpedo, which had twice the range of its American equivalents was still only a rumour to the Americans), and was advised to concentrate on long range gunnery, but his division had practised radar controlled night torpedo attacks and he was determined to stick to that plan.
Moosbrugger's destroyers entered Vella Gulf from the south at ten in the evening of 6 August. After checking the southern approaches they turned north and sailed up the gulf. At 23.33 they picked up the Japanese destroyers on radar, ten miles to their north at the northern end of the gulf. Moosbrugger ordered his ships to turn to 335 degrees so they could close into torpedo range. At 23.41 he ordered the three ships in his division to fire their torpedoes, and twenty four weapons were soon in the water. He then ordered a ninety degree turn to the right to get out of the way of any incoming Japanese torpedoes.
Moosbrugger needn't have worried. For once the Japanese were caught out. They were convinced that the nearest American ships would be at the southern end of the gulf. They finally spotted the American destroyers just after they had turned away. The Shigure, unburdened by troops, managed to fire eight torpedoes at 23.45, but all eight missed.
The three troop carrying destroyers were all hit by American torpedoes. Hagikaze and Arashi were both hit in fire rooms, while the Kawakaze was hit in one of her magazines and suffered a devastating explosion. Within a few minutes she rolled over and sank. Simpson's destroyers now came into action, firing their guns and torpedoes at the stricken Hagikaze and Arashi. Moosbrugger soon joined in and by midnight both Japanese ships had stopped firing.
That only left the Shigure. She reloaded her torpedo tubes in 23 minutes and turned back towards the fray, but at 0.10am on 7 August she saw the Arashi's magazines explode. She also heard an American reconnaissance aircraft overhead and assumed that her sister ships were being bombed. This was enough to convince her captain to retreat, and he escaped to the north-west. Eight minutes later the Hagikaze, now the target of all eight American destroyers, also exploded.
An attempt to rescue some of the Japanese survivors ended in failure. After half an hour none of the swimming survivors had been willing to enter captivity and at 2.00am the Americans gave up the attempt. Only 300 of the 1,800 Japanese sailors and soldiers on the four destroyers survived the battle.
As always the Americans overestimated their success, believing that they had also sunk a cruiser, but their real success was impressive enough. The 'Tokyo Express' didn't attempt to land any more reinforcements and the remaining troops on New Georgia and Kolombangara were left to their own devices, until eventually the survivors were evacuated.