The Battle of Kolombangara

On the night of 12–13 July 1943, a week after the Battle of Kula Gulf, Rear Admiral Walden Ainsworth’s ships for the second time barred the way of a Japanese convoy bound for the island of Kolombangara in the central Solomon Islands. In the Battle of Kolombangara the Allies destroyed the Japanese light cruiser Jintsū, together with the force commander, within a quarter of an hour or so. Half an hour later Japanese destroyers that had managed to reload their tubes hit all three Allied cruisers with torpedoes and sank an American destroyer. The battle is usually regarded as a tactical victory for the Japanese – rightly so, although this success did little to change the course of the campaign.

Background

Since 30 June, when the landing on Rendova began, the Americans had been fighting for New Georgia and its airfield at Munda. The Japanese were strengthening the defence with reinforcements brought by night in destroyers to Kolombangara, from where they were ferried on to New Georgia. On 6 July, despite losing two destroyers, they landed some 1,600 troops at Vila, and on 9 July another 1,200 without interference. In July the Americans became bogged down in the jungle on the road to Munda, and every Japanese battalion delivered to Kolombangara meant longer fighting for them.

On the morning of 12 July another force sailed from Rabaul. It was commanded by Rear Admiral Shunji Izaki, commander of Destroyer Squadron 2, in his flagship, the light cruiser Jintsū. She was a mid-1920s ship of the Sendai class, armed with seven 140 mm guns – not the newest, but still dangerous; in August 1942 she had been the flagship of Rear Admiral Raizō Tanaka in the fighting for Guadalcanal. The escort consisted of five destroyers – Mikazuki, Yukikaze, Hamakaze, Kiyonami and Yūgure – while four older destroyers, Satsuki, Minazuki, Yūnagi and Matsukaze, carried 1,200 troops with their equipment. It was rare for a cruiser to take part in a run of the “Tokyo Express”, as the Americans called these night transports.

Coastwatchers and reconnaissance warned the Allies that the Japanese had sailed. Admiral William Halsey again sent out Ainsworth’s force. The place of the sunken Helena was taken by the New Zealand light cruiser HMNZS Leander, which together with USS Honolulu and USS St. Louis formed the core of the force. Ainsworth was also given ten destroyers in two squadrons: Captain Francis McInerney’s Destroyer Squadron 21 (five ships, most of them veterans of the fighting in Kula Gulf) and Captain Thomas Ryan’s Destroyer Squadron 12. The latter had only just been assembled, and its ships had never exercised together.

The first phase: the end of Jintsū

The Allied force left Tulagi at 5 p.m. on 12 July and, under a cloudless sky and in the moonlight, steamed north-west along the coast of Santa Isabel. It sailed in a single line: McInerney’s five destroyers in the van, then the cruisers Leander, Honolulu and St. Louis, and Ryan’s five destroyers at the rear. The slowest ship, Leander, limited the speed of the whole force to 28 knots. At 0.36 a.m. on 13 July an American Catalina flying boat spotted the Japanese force; it then appeared on the radar screens, and at 1.03 a.m. it was sighted from the deck of the destroyer Nicholas. The Japanese force was then north of Kolombangara.

Ainsworth had counted on surprise, but he did not achieve it. The Japanese ships lacked good radar, but they had recently been fitted with receivers that detected American radar transmissions, and Izaki had known of the enemy’s presence for an hour. When at 1.06 a.m. the Allied force turned to port to bring all its guns to bear, the Japanese destroyers had already fired their torpedoes.

Jintsū switched on her searchlights, illuminating the Allied ships. The searchlights, however, made her the most visible target on the whole stretch of water. The fire of the three cruisers – St. Louis fired more than 1,300 shells and Honolulu about 1,100 – was concentrated on her, and within minutes the Japanese ship was ablaze. Shattered and broken in two, Jintsū sank at 1.45 a.m. with almost her entire crew of some 480 men and Rear Admiral Izaki. Only 21 sailors were later rescued by the Japanese submarine I-180, and a few were picked up by the Americans.

At 1.22 a.m. one of the Japanese torpedoes struck Leander amidships, in a boiler room. Twenty-eight New Zealanders were killed, and the damaged cruiser withdrew from the action under the protection of the destroyers Radford and Jenkins. The destroyers of both sides also fired torpedoes, but without scoring hits.

The Japanese force split up. The destroyer Mikazuki stayed with the sinking cruiser, the four transport ships turned into Vella Gulf and proceeded unhindered to the west coast of Kolombangara, and the four escorting destroyers – Yukikaze, Hamakaze, Kiyonami and Yūgure – withdrew northwards. Under cover of a squall their crews reloaded the torpedo tubes in just eighteen minutes. It was a skill for which the Japanese were famous and which the Americans still underestimated.

The second phase: the salvo at 2.08

Ainsworth set off in pursuit to the north-west with his two remaining cruisers and Ryan’s destroyers; McInerney’s ships chased the Japanese destroyers separately. At 1.56 a.m. radar detected four ships heading back towards the Americans. Ainsworth hesitated, unsure whether they might be detached ships of his own Squadron 21, and held his fire. Several precious minutes passed before it was confirmed that these were not McInerney’s ships and before, at 2.03 a.m., star shells revealed the silhouettes of Japanese destroyers. At 2.08 a.m., while the Americans were only preparing to open fire, the Japanese torpedo salvo reached its target.

A torpedo struck St. Louis in the bow. Honolulu was hit in the bow, which was almost torn off, and a second torpedo struck her stern but failed to explode. A third hit the destroyer USS Gwin amidships – the same ship that a week earlier had taken 88 of Helena’s survivors off the shore of New Georgia. Manoeuvres to avoid the torpedoes also led to a collision between the destroyers Woodworth and Buchanan. The Japanese ships withdrew without loss. Gwin’s crew could not save their ship; the men were taken off, and at 9.30 a.m. the destroyer Ralph Talbot finished her off with a torpedo. Sixty-one sailors were killed in Gwin.

The cruisers, their bows smashed, limped by day through “the Slot”, the channel between the islands, exposed to air attack. Ainsworth requested fighter cover and was given a strong group of fighters from the Russell Islands. On the morning of 13 July it beat off a raid by 18 Japanese dive bombers escorted by 20 fighters. All the damaged ships reached Tulagi under their own steam.

Meanwhile, by 3.40 a.m., the four transport destroyers had landed 1,200 troops at Sandfly Harbour on the west coast of Kolombangara and left for Buin. The Japanese had thus achieved the purpose of the run.

The balance: who won?

Victory here depends on the yardstick. The Allies lost a destroyer and 89 men killed, including 28 New Zealanders from Leander. The Japanese lost a cruiser and the squadron commander, and more than five times as many of their men were killed. Yet the Japanese force had accomplished its mission, and three Allied cruisers were out of action for many months: Honolulu and St. Louis returned to service in November 1943, while Leander spent the rest of the war under repair combined with modernisation and never returned to combat. This is why the tactical victory is credited to the Japanese. The American naval historian Samuel Eliot Morison, however, summed up such successes with the remark that a string of such victories adds up to defeat. American industry had no difficulty replacing damaged cruisers, whereas the Japanese were unable to make good the ships they lost.

The battle was one of the Japanese navy’s last successful night actions in the Solomon Islands. At the same time it ended the era in which the Americans sent cruisers in close line ahead against night convoys. Halsey and his officers drew their conclusions: against the “Tokyo Express” it was better to use forces made up solely of destroyers, operating independently, attacking by surprise with torpedoes and not tied to a line of cruisers.

Place in the war

The battle was fought in a week in which the war was passing a turning point on every front. In the east the German offensive against the Kursk salient was under way, and on 10 July the Allies began the landing in Sicily. In the Pacific the fighting for New Georgia was part of Operation Cartwheel, which was intended to encircle and isolate the Japanese stronghold of Rabaul.

Despite appearances, the victory at Kolombangara did not reverse the course of the campaign. The reinforcements did not stop the Americans at Munda, and the Japanese, losing one destroyer after another, stopped sending large ships through Kula Gulf. Increasingly they moved troops in landing barges and sought a route through Vella Gulf and Blackett Strait, along the west coast of Kolombangara. The Americans, for their part, following a decision by Admiral Chester Nimitz, concluded that cruisers were too exposed in the confined waters of the Solomons and handed the task of intercepting convoys to destroyers, PT boats and aircraft.

On the night of 15–16 July American ships, in an operation postponed from 12 July because of Japanese fleet movements, took off from Vella Lavella the survivors of Helena who were being hidden by the islanders. The change of tactics soon bore fruit. The destroyer Yūgure, one of those that had torpedoed Ainsworth’s cruisers, was sunk by American aircraft as early as the night of 19–20 July. And on the night of 6–7 August six American destroyers under Commander Frederick Moosbrugger, operating independently without cruisers, surprised four Japanese destroyers carrying troops in Vella Gulf and sank three of them with torpedoes without losing a single ship. On 5 August the airfield at Munda fell. The Americans decided to bypass Kolombangara, where the Japanese had meanwhile assembled some 10,000–12,000 troops: in mid-August they landed on the more weakly defended Vella Lavella, and in September and October the Japanese evacuated Kolombangara. The effort they had put into its defence in the July night battles proved to have been in vain.