The Solomons Campaign: The Bougainville Invasion, November – December 1943(Part I)

The next four posts will cover the invasion of Bougainville and are provided via guest author CINCLAX.– SJS

The Last Spoke in the Cartwheel

Strategic Progress

Before the Guadalcanal operation (Watchtower) even began in August 1942, it had been decided to neutralize the Japanese bastion of Rabaul by moving up the Solomons one step at a time until Rabaul could be pounded from the air on a daily basis. Operation Cartwheel—as it was to be called—had begun inauspiciously with strong Japanese responses by sea and air, and by the early fall of the year some people were even calling for a strategic retreat and the evacuation of Gen. Vandegrift’s First Marines. The Navy was having great trouble stopping IJN surface attacks on Henderson Field, and the “Tokyo Express” reinforcement runs from Rabaul could not be effectively stopped. Japanese night surface tactics and superior torpedoes were not yet understood by American commanders, and the soon-to-be-famous “Cactus Air Force” was often reduced to a handful of operational aircraft left to handle the daily Japanese air raids.

Rabaul continually haunted Allied leaders. No operation in the Solomons or New Guinea could be considered complete as long as Rabaul remained strong and served as a hub for aggressive Japanese troops to attempt the re-conquest of Guadalcanal or even eastern New Guinea.

Then the always aggressive VADM Halsey took over SOWESPAC and things slowly began to change for the better. By the summer of 1943 the Allies had moved into the Central Solomons, eventually capturing the Russell Islands, New Georgia, Rendova and finally Vella Lavella. Along with each conquest had come new air bases ever closer to Rabaul, relentlessly hacked out of the jungle by the seemingly tireless Seabees. Henderson Field had been some 560 miles from Rabaul; Munda (New Georgia) was some 200 miles closer, while Barakoma on Vella Lavella was only 320 miles from Rabaul. The ring was closing.

Moreover, Halsey’s campaigns had also worn down Japanese air and naval forces to the extent that they no longer had the upper hand in the Slot. Their surface warships had been sorely depleted, and many of their veteran IJN pilots had been lost in combat and operational accidents. The Cactus Air Force on Henderson Field had now grown into AirSols, one of the best small air forces in the world and a true “joint” command of Navy, Marine, USAAF and New Zealand planes operating out of multiple strips all over the Central Solomons. Masters of improvisation and scrounging since the dark days of Operation Watchtower, AirSols would take the unsuccessful P-39 and P-40 fighters (rejected for European service) and make them effective low-level fighter bombers. When they needed floatplanes, they snatched them off of damaged cruisers heading home for repair. Similarly, the vulnerable Lockheed Ventura patrol bomber was turned into a night fighter. Meanwhile new arrivals like the P-38, the F4U Corsair and F6F Hellcat would rule the higher altitudes against the Zero. Now AirSols “Black Cat” PBYs patrolled the nights over water and their “Dumbos” rescued hundreds of downed flyers who lived to fly and fight again.

Meanwhile Gen. Mac Arthur’s forces in New Guinea had slogged their way from Port Moresby to Buna and beyond, establishing a large air base at Dobodura (near Buna). There, Gen. George Kenny’s Fifth Air Force had established itself as the terror of the Bismarck Sea. On the last day of February 1943, Gen. Imamura (8th Area Army CO in Rabaul), sent out some 6900 troops to reinforce his garrison at Lae; eight destroyers and eight transports carried the load. Kenny attacked the convoy with 335 aircraft, and in two days the Japanese lost all eight transports, four destroyers and about 3500 soldiers. With the disaster of the Bismarck Sea battle, Imamura and his Rabaul Navy cohort Adm. Kusaka (11th Air Fleet) would dare no further reinforcement attempts in New Guinea.

So Bougainville would be the next—and virtually last—target of the Allied Solomons campaign. In the summer of 1943, Halsey’s staff in Noumea joined with VADM Aubrey Fitch from the New Hebrides, LTG Alexander Vandegrift, and RADM Theodore “Ping” Wilkinson at Camp Crocodile on Guadalcanal to complete their planning. If Bougainville was to be the logical target, the question remained as to where? It was estimated there were about 40,000 Japanese Army troops, plus 20,000 Navy personnel on Bougainville and its adjacent islands. Most of these were in the south: Kahili, Buin, and the Shortlands; there were also 6000 in the north on or around the Buka Passage. All these locations featured airfields which the Japanese could be expected to defend tooth and nail—as they had at Munda.

What the Allies needed was a relatively lightly defended location where they could build their own airstrips, and one far enough away from existing Japanese strongholds so that speedy overland reinforcement would be difficult if not impossible. After deliberating, they decided on Empress Augusta Bay, in the middle of Bougainville’s west coast and equidistant (about 50 miles) from Japanese strongholds. About 16 miles wide from Cape Torokina to Mutupina Point in the south, the Bay was not a well-protected anchorage from westerly storms, but it would have to do.

In many respects, Bougainville would be a repeat of Guadalcanal: establish a perimeter against initially weak resistance, construct several airstrips and defend them against counter-attacks, then go about the business of continuing to reduce the stronghold of Rabaul—only 220 miles distant. Unlike New Georgia or Vella Lavella, there would be no need to occupy the entire island.

Another Difficult Battlefield

Bougainville is the largest island of the Solomons, some 130 miles long (including the nearby island of Buka in the north) and 30 miles wide. It is a mountainous island, dominated by two central ranges reaching nearly 10,000 ft. and two active volcanoes. The lower slopes and coastal plains are covered in some of thickest jungle in the world. As is the norm in this part of the world, heavy rainfall, high humidity, poisonous snakes and insects, malaria and dengue fever contribute to man’s misery.

Near Cape Torokina, on the northern end of Empress Augusta Bay, the west side is mostly a swampy plain where it borders the coastline; there are few clear landing zones, and the beaches are only 15-20 yards wide. But Cape Torokina’s environs had one big advantage: the local coconut plantations were relatively flat and suitable for airstrips.

As with all the Solomon Islands, Bougainville’s interior is covered with a dense, triple canopy rain forest; combined with the rugged mountain ranges, it makes overland travel extremely difficult. In 1943 only two reasonably well-cut tracks crossed the interior. One cut across the mountains from Numa Numa on the east coast to Empress Augusta Bay, where it connected with the East-West trail to Buin in the south. Skirting the coastal swamps, this path would be the principal Japanese reinforcement route from their bases in the south.

Bougainville had been a German colony until the end of WW I, when it passed into Australian control. Unfortunately the island’s estimated 43,000 natives were still under the influence of German missionaries, and by spring 1943 the coastwatchers had been forced to evacuate by submarine, depriving the Allies of the timely local intelligence they had enjoyed elsewhere in the Solomons.

Command Structure

This would be a truly “A Team” operation, with only experienced leaders involved. While ultimate authority resided with Halsey, effectively the operation was under the overall tactical command of Theodore “Ping” Wilkinson, who had already proved his mettle with the bypass of Kolombangara for the successful capture of Vella Lavella. An extraordinary man, Wilkinson had been a classics scholar since high school days (St. Paul’s School, Concord, NH), graduated at the top of the USNA Class of 1909 and had won the Medal of Honor for his actions at Vera Cruz in 1914. Most important, Wilkinson actually listened to subordinates of all paygrades, and had an easy informality about him. Wilkinson would go on to command amphibious operations at Palau, Leyte and Lingayen Gulf.

The cruiser commander, “Tip” Merrill (TF 39) had been one of the Navy’s best tactical minds in dealing with the Japanese, whose vaunted night operations had worried so many American’s for so long. The IMAC (First Marine Amphibious Corps) commander was none other than LTG Alexander Vandegrift of Guadalcanal fame.

On the downside, Nimitz had committed most of his resources to the upcoming operation in the Central Pacific (Tarawa and Makin), and had left Halsey the bare minimum of support and transport ships. In fact Wilkinson had been allotted only 12 APAs and AKAs, most of them hard-working veterans of Guadalcanal and after.

One of these which bears special mention was the Alchiba (AKA-6), the ship that refused to sink. On late November 1942 Alchiba was anchored off Guadalcanal in Lunga Roads when she was torpedoed twice and caught fire. Given that her cargo was gasoline and ammunition, the crew could have been forgiven had they jumped overboard, swam to shore and let the vessel blow up.

But her skipper, CDR James Shepherd Freeman would have none of it. He slipped his anchor cable and set the engines at full ahead to run the ship ashore. After five days of continual fire fighting the ship—and most of its sorely needed cargo—was saved. Hauled off the beach by salvage tugs from Tulagi, Alchiba was torpedoed again on December 7th. But the determined CO and his crew didn’t give up. They saved their ship and eventually made it to Espiritu Santo for jury repairs sufficient to get to Mare Island shipyard—and eventually back to service in the Solomons.

In WW II the Presidential Unit Citation was awarded 12 times, 11 of them to warships. Alchiba was the only transport ever to be so-awarded. Freeman received the Navy Cross for his actions.

Wilkinson had only one carrier group immediately at his disposal (TF 33), as well as only a single cruiser-destroyer squadron (TF 39) with only four light cruisers and eight destroyers. Additional carrier and cruiser groups were on their way, but wouldn’t arrive until a week after D-Day.

Most important, Wilkinson understood the capabilities and liabilities of his beaching craft. He realized that if the slope of the landing beach was not something close to 1 in 50, that ponderous vessels like LSTs could not ground enough of their keel to avoid possible broaching. Conversely, if the slope were too steep, the bow doors could not open. In most WW II amphibious operations the only way to ensure efficient LST unloading was to put bulldozers ashore first, then have them build artificial piers where the LSTs could ground.

MARINE COMMANDERS — LTG Alexander Vandegrift (left), formerly 1st Marine Division commander on Guadalcanal, was on his way home to Washington to become 18th Commandant of the Marine Corps when, on the sudden death of Gen Barrett on October 8 , he was recalled to the Pacific to resume command of IMAC and lead it in the Bougainville operation. He, in turn, was relieved by MG Roy S. Geiger (right) on November 9. Geiger had long experience on land and in the air, and would be the first Marine general ever to command an Army (Okinawa 1945).

October Preliminaries

• The Treasury Islands are only some 17 miles from the Japanese-held Shortlands. For unknown reasons they had never occupied them in force, so the New Zealanders of the 8th Brigade Group of the 3rd Division were assigned to capture them. The Kiwis landed on October 27th on both Mono (the larger of the two) and Stirling, and by November 12th had eliminated the last defenders. Immediately Seabees went to work building an airstrip on Stirling, to keep AirSols within instant striking range of Shortlands and Bougainville bases, from which counter attacks against Cape Torokina could be anticipated. Eventually a PT base was also set up.

• A diversionary raid on Choiseul was carried out by the 2d Parachute Battalion, 1st Marine Parachute Regiment, FMF, landing at Voza on October 27th. Choiseul’s large size and position could suggest its use as a base against Shortland or Bougainville, and if Bougainville, U.S. seizure of a base on Choiseul would indicate a landing on the east rather than the west coast.

DIVERSIONARY RAID on Choiseul by Marine 2nd’ Parachute Battalion, led by LTC Victor Krulak.

• On the night of October 31st-November 1st, a cruiser-destroyer force under RADM Aaron “Tip” Merrill bombarded Japanese installations in the Buka-Bonis area, then raced south to perform similar work in the Shortlands. After that, they would furnish cover for the Torokina landings.

• Throughout October Air Sols made some 3259 sorties against Japanese airfields at Kahili, Kara, Ballale, Buka and Bonis. Keeping these fields cratered and their aircraft in short supply would greatly reduce enemy response to the initial landings.

• On October 23rd, 24th and 25th Kenney’s Fifth Air Force raided Rabaul’s Simpson Harbor. On the 29th he dropped some 115 tons of bombs on Vunakanau, one of Rabaul’s five air fields. Greatly inflated claims were made of ships sunk and aircraft destroyed, but the truth proved to be far less. Still, it put Rabaul on notice that it could expect almost daily bombings and helped divert attention from Bougainville.

D-Day

The landings at Cape Torokina began with the 3rd Marine Division on November 1st. Most of the landing force came ashore on beaches between Cape Torokina and the Laruma river to the north. Small detachments were assigned to seize Torokina and Puruata Islands.

The landings were extremely well organized and the first assault waves hit the shore at 0726, just 41 minutes after the transports anchored. Nearly 8,000 Marines were ashore before noon.

The only enemy concentration of any strength in the Empress Augusta Bay area was estimated to be 1,000 troops at Mosigetta. These appeared to be, for the most part, engaged in cultivating rice fields, as delivery of food to Bougainville was increasingly hampered by U.S. Navy planes and submarines.

Rabaul was very quick to respond, and at 0735 nine Val dive bombers escorted by 44 Zeros showed up but did no damage. At 1300 a second raid arrived, composed of 100 carrier-type aircraft from the 11th Air Fleet—recently stripped from three carriers (Shokaku, Zuikako and Zuiho) at Truk. Damage was negligible, and the attackers paid a substantial price at the hands of AirSols.

To get his transports in and out of the landing beaches as soon as possible, Wilkinson had them “short loaded” to only 25-30% capacity. It proved to be a master stroke. The cargo ships were lightly loaded, not more than 550 tons apiece, to ensure quick discharge of their supplies. By 1730 eight of the ships were fully unloaded, putting just over 14,000 men and 6200 tons of supplies ashore. All transports withdrew at 1800, but four with vital cargos still aboard were detached to return and finish unloading. These ships retreated once again the following evening when an AirSols scout reported Japanese warships leaving Rabaul, then returned following the Allied victory in the Battle of Empress Augusta Bay (see below).

Plans for the 3d Marines began with a simultaneous landing by four landing teams on beaches from Cape Torokina to the Koromokina River to the northwest. the 1st Battalion landing on Cape Torokina (Beach BLUE 1), the 2d Raider Regiment (less the 3d Battalion) landing west of the 1st Battalion (Beach GREEN 2), the 2d Battalion to the west of the Raiders (Beach BLUE 2), and the 3d Battalion between the Koromokina and the 2d Battalion (Beach BLUE 3). The 9th Marines scheduled landings of its 1st, 2d, and 3d Battalions from left to right in that order on Beaches RED 3, RED 2, and RED 1, and provided for simultaneous landing of the 3d Raider Battalion (less Company L, which landed on Beach GREEN 2) on Beach GREEN 1, Puruata Island, in order to destroy all anti-boat defenses which might be emplaced there.

Plans called for the immediate construction of an airstrip, so the 71st Naval Construction Battalion began to reconnoiter the coconut plantation just east of Cape Torokina as the site for the airfield. They would begin work as soon as the Marines established a perimeter.

The Japanese defenders of Cape Torokina consisted of the 2d Company, 1st Battalion, 23d Infantry plus 30 men from the Regimental Gun Company—or about 270 officers and men. This force was also equipped with a single 75mm gun emplaced in a log and sand bunker on the shoulder of Cape Torokina near Beach GREEN 2, and was clearly served by an expert crew. Before being knocked out, it destroyed four LCVPs and damaged about 10 others. There were also prepared positions consisting of 18 pill-boxes, solidly constructed with coconut logs and dirt, and connecting trenches and rifle pits. Of this force, one platoon was stationed on Puruata Island and one additional squad on Torokina Island. All other beaches were undefended, indicating the Japanese had anticipated a landing east and not west of Cape Torokina.

Unloading supplies onto the beachhead of the 3d Marine Division and subsequent distribution of those supplies to beach dumps was a major task on D-day and those immediately following. Transports and cargo vessels all supplied men to assist in this unloading. The 3d Defense Battalion brought ashore most of their bulky anti-aircraft equipment, and managed to establish antiaircraft defenses on November before unloading of equipment and supplies was completed.

Although the landings had been made with comparatively small loss in men and material, some confusion still existed on several beaches due to circumstances which had arisen after boats had left their line of departure. Because of the steep pitch of the shoreline, it proved impossible to land equipment on the three western beaches. This required boats originally destined for the western beaches to unload at points farther east. Nevertheless the job was completed within the first week.

The daylight hours of 2 and 3 November were given over to sending out patrols to the flanks and front for the purpose of insuring security and reconnaissance. Meanwhile Torokina and Puruata Islands were finally cleared until no further Japanese resistance could be found. Initial resistance to the Marines’ landing had come to an end and the beachhead was established to a depth of some 2000 yards.

Next up: Part II – Pressing Inward

(Cross-posted at USNIblog.org)