December 1943 - April 1944
by Eric Hammel
Copyright © 2008 by Eric Hammel
The campaign by the 1st Marine Division to seize Imperial Japanese Army airfields and bases in western New Britain was unique because it was undertaken by Marines entirely under U.S. Army command in an area considered the province of the U.S. Army. The Cape Gloucester campaign, in fact, was an offshoot of the New Guinea campaign and not an extension of the Solomons campaign.
The impetus for the landings at Cape Gloucester, New Britain, was the need to deny the Japanese an opportunity to mount air strikes against the open right flank of Royal Australian Army units advancing along the New Guinea coast within combat range of Cape Gloucester airfields, especially between Finschafen and Saidor. By the time of the invasion, AirSols assets operating from Bougainville would be in a position to relieve the New Guinea-based U.S. Fifth Air Force and elements of the Royal Australian Air Force of the burden of neutralizing Rabaul, and those Fifth Air Force and Australian bombers and fighters—including those to be based at Cape Gloucester—could then assist in speeding the ground advance in New Guinea. Likewise, Vitiaz Strait, the sea passage between Cape Gloucester and New Guinea, would be firmly under Allied control and would thus provide clear passage for shipping along the continuing route of advance up the New Guinea coast as well as toward the Philippines.
The 1st Marine Division was selected for the main role on New Britain because it had recuperated and retrained in Melbourne, Australia, following its harrowing ordeal at Guadalcanal; it happened to be ready to return to combat at a time when General Douglas MacArthur’s Southwest Pacific command needed an amphibious-capable infantry division for the Cape Gloucester job. Final training and rehearsals took place in New Guinea.
Cape Gloucester is among the rainiest regions on Earth, and the landings were to take place at the height of the northwestern monsoon season. Moreover, as was the case at Cape Torokina on Bougainville, the landing area was filled with largely unmapped swampy lowlands, high ridges, and rugged rain forests with few trails and waterways to aid in movement through the region. On a typical day, temperatures stood at an extremely humid and strength-sapping 90 degrees, and 72 degrees at night.
The key objectives were two airfields just back of Cape Gloucester, but hundreds of square miles of terrain had to be secured to deny access to the airfields by nearly the equivalent of an Imperial Army infantry division deployed in western New Britain. Thus the New Britain operation contemplated the rehabilitation of existing airfields and the development of a stout defensive cordon around them, as well as the pursuit and annihilation of Japanese ground forces across a vast area in which only a few known axes of advance existed. The advantages on the side of the invaders were air supremacy, freedom to move amphibiously at the periphery of the battle zone, and the deterioration of Japanese command and control following more than a year of intense ground war in New Guinea.
The first Marines to get into action on New Britain were crews from Company A, 1st Amphibian Tractor Battalion, who took part in landings at Arawe by U.S. Army troops on December 15, 1943. Two of the company’s new LVT-2 amtracs took a direct part in overwhelming a Japanese strongpoint.
The net result of the Arawe landing was the dispersal of the Japanese garrison and the dispatch of a thousand veteran troops from Cape Gloucester toward Arawe only days before the Marine landings at Cape Gloucester.
The main prelanding bombardment at Cape Gloucester was undertaken by Fifth Air Force bombers and fighter-bombers over a period of months under conditions of total air supremacy. The target airfields were no longer operational by late November, and the garrison was utterly demoralized. Beginning on December 18, many air sorties were mounted against prepared defenses in the immediate invasion zone, which were nearly destroyed.
Beginning at 0743 hours on December 26, two infantry companies of the reinforced 2d Battalion, 1st Marines (2/1) went ashore aboard LCMs almost without incident east of the main beaches. The mission was to block trails leading from the airdromes to the main landing beaches. This landing is notable in that it was preceded at the last moment by the first-ever rocket bombardment mounted by amphibious vehicles, in this case U.S. Army DUKW amphibious trucks bearing multiple launchers. The Marines uncovered a system of trenches and bunkers, but no Japanese troops were encountered. The remainder of 2/1 landed without incident from LCIs and LCTs, and the entire force got to work on defensive measures to a distance of 500 yards from the beach.
In advance of the main landings at Cape Gloucester’s Beach Yellow, two Royal Australian Navy heavy cruisers and two U.S. Navy light cruisers opened fire at 0600 hours against beach targets with a 90-minute bombardment that mounted to 3,605 8-, 6-, and 5-inch rounds. Five squadrons of Fifth Air Force B-24 heavy bombers attacked a feature known as Target Hill between 0700 and 0720; then, as naval gunfire ceased at 0730, a squadron of B-25 medium bombers unloaded 8 tons of white phosphorous bombs, also on Target Hill. While the smoke from fires on Target Hill certainly obscured the landings from Japanese observers, as intended, it also enshrouded the beaches to a distance of 3,000 yards to seaward just as landing craft were bearing down on them.
On schedule at 0745, a pair of LCI rocket ships fired last-minute salvos at the beachhead area. Between 0741 and 0748, the leading elements of 1/7 and 3/7 hit their respective beaches in a dozen LCVPs. There was absolutely no one home. The biggest problem the assault troops faced was the twisted wreckage of hundreds of trees blasted by the prelanding bombardment. Indeed, the first casualties resulted from undermined trees that fell as advancing Marines brushed by them.
The first Japanese opposition was long-range machine gun fire that tracked Company I, 3/7, as it hacked through dense jungle and emerged on the coastal trail after its LCVPs went astray in the smoke and dumped it 300 yards beyond the beachhead boundary. As the reinforced 1st Marines (less 2/1) came ashore aboard LCIs behind the 7th Marines, 3/1, which was to lead the drive on the airfields, was ordered to attack the bunkers from which this fire originated, which happened to be on the way to 3/1’s D-day objective.
Except for the occupants of the bunkers, the landing force met no human opposition, but a deep, unmapped swamp directly behind the beach, as well as other natural obstacles rearranged by the preinvasion bombardment, made for extremely slow progress toward D-day objectives. Almost as soon as it started its move toward the bunkers on a two-company front, 3/1 had to contract its formation to a column of companies.
As 3/1’s vanguard passed through Company I, 3/7’s blocking position before the bunkers at 1010 hours, it came under heavy fire. The battle did not go well for the Marines. An ad hoc bombardment by new 2.36-inch rocket launchers (bazookas) and 37mm antitank guns was ineffective because the spongy logs from which the bunkers were constructed absorbed the impacts; 3/1 was unable to advance in the face of concentrated fire until an LVT carrying supplies from the beach drove over one of the bunkers and collapsed it. This allowed the infantry to penetrate the defensive zone. Thereafter, a platoon of five Sherman M4 medium tanks arrived to help seal the fate of the defenders. In all, seven Marines and twenty-five Japanese were killed and seven Marines were wounded. Then 3/1 advanced to its D-day phase line and dug in.
On the left, 1/7 met only light opposition on its way to Target Hill. This high ground was seized against light opposition, and 1/7 also dug in.
In the center, 2/7 advanced through a deep swamp to the coastal track; seized an abandoned Japanese supply depot; and attacked into a dense, swampy forest through spotty opposition. The battalion reached its D-day phase line in the late afternoon and dug in on rising ground without being able to tie in with adjacent units on either flank.
During the afternoon, 3/7 advanced through a swamp to its objective and also dug in. When 3/7 was ordered to shift to its left to link up with 2/7, alert Japanese soldiers attempted to infiltrate via the abandoned position, so the Marine battalion was called back to defend that ground.
Behind this screen of four infantry battalions, 1/1 landed as the force reserve and set up in the Japanese supply depot, and 2/11 set up its 75mm pack howitzers on dry ground along the edge of the coastal trail that ran through the beachhead. Two other artillery battalions—1/11 with 75mm pack howitzers, and 4/11 with 105mm field howitzers—had a much harder time getting ashore across swampy ground. The 75s were moved to dry sites aboard amtracs, but the 105s were too heavy for that. In the end, amtracs blazed trails by crashing through dense growth so that artillery tractors and troops using blocks and tackles could move the guns, of which only three (of twelve) were set in by nightfall.
Faced with the problem of unmapped swamps sitting on proposed dump sites, the division pioneer battalion (now designated 2d Battalion, 17th Marines, or 2/17) faced problems identical to those encountered at Bougainville for the same reasons, including a 4-foot tidal surge. The landing of supplies—many of them aboard preloaded U.S. Army trucks driven by U.S. Army artillerymen—became increasingly unglued as D-day progressed. The unprocessed supplies and long lines of trucks made for a glaring target when eighty-eight Rabaul-based Imperial Navy Zero fighters and D3A dive-bombers attacked in the afternoon. One destroyer was sunk and another was severely damaged, but so many Japanese planes were shot down by antiaircraft guns and two squadrons of P-38 fighters that the invasion force was never again molested during the day.
The 1st Marine Division forward command post moved ashore right in the wake of the assault, and it oversaw the approximately eleven thousand Marines who got ashore by nightfall. D-day operations—a complete success—cost twenty-one killed and twenty-three wounded. That night, the division commander requested that his force reserve—two reinforced battalions of the 5th Marines—be landed as soon as it could be lifted to Cape Gloucester from Cape Sudest, New Guinea.
The Japanese also sent all available forces toward Cape Gloucester. Most were on the move by the evening of December 26, and at least one Imperial Army infantry battalion arrived opposite 2/7 during the late evening. As the Japanese filed into a firing line opposite 2/7, individuals opened fire on whatever targets they could perceive on a dark, moonless night. Eventually Japanese scouts figured out that 2/7 was in an isolated position with a swamp at its back and tied into no friendly units on either flank.
As Marine carrying parties maintained a flow of ammunition through the swamp, 2/7 held the developing counterattack at bay with remarkably accurate fire coupled with iron-willed fire discipline. The Marines fired only at clear targets and, for the most part, only when fired on. It rained all night, but the rain subsided at dawn, just as Japanese troops assaulted toward a break in the line. At that moment, troops from a 1st Special Weapons Battalion 37mm antitank battery that had left its guns behind to haul ammunition through the swamp arrived to plug the gap. The day was saved in a heart-stopping seesaw battle in which the Marines finally prevailed.
The Japanese doggedly threw in progressively weaker attacks for three days, while the Marines built up their line with all manner of troops. In the tradition of “every Marine is a rifleman,” the line in the center of the beachhead was lengthened, bolstered, and filled in by 37mm gunners, pioneers, and other special troops acting as infantry. As the battle around 2/7 progressed, each component of the regiment lengthened its line to tie in with adjacent units; as 2/7 stretched right to tie in with 3/7, Weapons Company, 7th Marines, filled in part of 1/7’s original line so that battalion could ease to its right to tie in with 2/7’s left flank. In due course, the Japanese were defeated by a continuous line of battle-tested Marines, of whom eighteen were killed, three went missing, and fifty-eight were wounded. The Japanese lost at least two hundred dead or wounded, and the battalion around which the counterattack was built was permanently crippled.
With the 7th Marines pinned in the center and many of its own troops committed as infantry, 2/17, reinforced to a strength of fourteen hundred by several hundred replacements who had been preassigned to the division en bloc, cleared the fouled beaches; the reinforced 5th Marines was made ready to land at Cape Gloucester; and the 1st Marines (less 2/1) moved on the airfields. Engineers from 1/17 and Seabees from 3/17 advanced in the infantry’s wake to put in roads and drain dump sites all across the beachhead. Whenever the roads failed, U.S. Army LCMs and LCVPs dropped supplies along the beach, opposite the troops who needed them, and the supplies were then ported inland by work details.
The vanguard for the advance on the airfields was 3/1, which, following a quiet first night ashore, moved ahead on the narrow strip of dry land supporting the coastal trail. Progress was orderly, deliberate, and steady behind a fan of combat patrols and on-demand artillery coverage.
The innovation of the day lay in tank-infantry coordination. The 1st Marine Division entered combat at Cape Gloucester with two companies of new, modern Sherman M4 medium tanks, and one sixteen-tank company was attached directly to the 1st Marines. The regimental commander, Colonel William Whaling, was a renowned woodsman who had organized and trained a scouting force on Guadalcanal and commanded several offensive operations. He took the nascent tank-infantry doctrine of the day to heart and applied it vigorously in the budding Cape Gloucester advance. In a nutshell, he teamed one infantry squad per medium tank for mutual support during the advance. The 3/1 vanguard was preceded by a twelve-man scouting force; then a column of tank-infantry teams advanced cautiously but steadily, one after another, to phase lines a half- or three-quarters of a mile apart. Between the phase lines, infantry combat patrols peeled off the left (inland) side of the coastal track to probe the dense woods and swamps as well as to secure the advance against Japanese scouts, probes, and counterattacks.
The tanks aided greatly in overcoming two belts of pillboxes and bunkers encountered along the way. Indeed, they took primary responsibility for reducing each position with their 75mm main guns. In return, the infantry stuck close to prevent the tanks from being overwhelmed by Japanese infantry. By this means, 3/1 advanced 5,000 yards to its objective by 1350 hours on December 27. Ahead lay a wide, continuous belt of bunkers, pillboxes, and trenches centered on a feature eventually dubbed Hell’s Point.
The December 28 attack was delayed to allow time for the 5th Marines to reach Cape Gloucester and get into position to support the 1st Marines. A message announcing a one-day delay in the reinforcement operation was too garbled to be understood, but the reserve regiment’s nonarrival was noted, so the 1st Marines resumed its attack after only a brief delay.
Beginning at 0800 hours, 2/11 bombarded the Japanese defensive zone, and at 0900 Fifth Air Force A-20 ground-attack bombers arrived to strafe and bomb the objective for an hour. The 1st Marines was to have jumped off as the last A-20s flew from the scene, but Colonel Whaling requested an hour’s delay to bring up more tanks At 1100 on the dot, 3/1 stepped off toward Hell’s Point in the same formation it had employed the day before. Then 1/1 moved up to cut a flanking path through the forest on the side of the coastal track.
The Japanese were ready. While the defensive zone had been constructed to repel a beach assault, many positions could be rejiggered to inland bearings and thus face the 1st Marines. An intact infantry battalion supported by 75mm dual-purpose guns occupied the defenses.
The battle was joined on the flank at 1145 when Company A, 1/1, ran into the prepared defenses 500 yards from the beach. The first shots were fired by concealed Japanese troops as Company A broke out of the forest into an area of chest-high grass. The Marines pulled back to the concealing tree line; and then the fight developed into a four-hour stalemate as forces of equal size duked it out with rifles and machine guns. The Marines beat off two infantry flanking assaults but could not overcome the steady Japanese stand by any means at hand. Eventually, under covering fires put out by 2/11, Company A, 1/1, pulled back for the night to draw ammunition at its battalion perimeter. A stronger attack force that kicked off at dawn on December 29 fell into ground that had been abandoned overnight.
In the meantime, 3/1 bored into the main defensive line, right on Hell’s Point, throughout daylight on December 28. Rain and dense foliage helped shield both sides from fire but also hampered both sides equally. Marine tank-infantry teams went up against defensive positions protected by land mines and barbed wire as well as by interlocking bands of fire from other emplacements fielding 20mm antiaircraft cannon, 70mm infantry guns, and at least three 75mm field guns. In some places, infantry-supported M4s ran right over pillboxes, smashing them in and exposing the occupants to direct infantry fire, but for the most part the infantry-supported tanks stood off from their targets and reduced one position at a time with pinpoint 75mm fire. The hellish all-out battle ended at 1630 hours, when the last beachside bunker was overcome without a fight, its occupants having withdrawn minutes earlier as part of a general retreat. There was nothing left between the Marines and the airfields. During the night, 266 Japanese corpses were counted within the Hell’s Point defensive zone. Fewer than twenty Marines were killed and fewer than fifty were wounded in the two-day battle—a testament to the effectiveness of the tank-infantry teams.
Half of 1/5, most of 2/5, the 5th Marines regimental headquarters, and assorted attachments landed on newly opened Beach Blue, just behind the 1st Marines vanguard, beginning at about 0730 on December 29. The remaining elements of the 5th Marines regimental combat team were ashore on Beach Yellow by 0935 and were sent forward.
Air and artillery opened ahead of the 1st and 5th Marine regiments at noon, December 29. The Marine assault was to be undertaken by 1/1 on the right, toward Airfield No. 2; and 2/5 on the left, toward a line of foothills that was thought to be the site of a Japanese defensive zone. Support was provided by 2/11’s 75mm pack howitzers, 4/11’s 105mm field howitzers, and a pair of rocket DUKWs.
Attacking in the rain and supported by tanks and 75mm halftracks that were obliged to remain on the firm coastal track, 1/1 reached the airfield perimeter against desultory opposition at 1755 hours and was soon joined by 3/1 to defend the area. In the meantime, 2/5 was delayed as it traversed unexpectedly deep swamps and did not really join the attack until 1500. It found Japanese defensive positions but no Japanese troops in the foothills, so it looped down to help secure Airfield No. 2, where it tied in with 1/1 and 3/1 to complete the night defensive perimeter. Still in the forest at dusk, 1/5 established an all-around night defensive position.
On December 30, two reinforced companies of 2/5 marched across Airfield No. 1 while 1/5 moved up to Airfield No. 2. In going back over what had been abandoned defenses on a feature dubbed Razorback Hill, scouts from 2/5 ran into Japanese troops, possibly the advance guard of a battalion that was to have occupied the vital terrain a day or two earlier. A platoon of Company F, 2/5, was sent to mop up the Japanese, but it was attacked by a larger force as it reached the summit of one of the hill’s knobs. Reinforcements poured in from both sides. The Japanese attacked to dislodge the Marine platoon, but mortar fire held them at bay, and the rest of Company F arrived in time to drive them off. Tanks were called forward; then Company F attacked the Japanese. By 1130, thirty prepared positions had been overwhelmed by Marine tanks and infantry. More than 150 Japanese bodies were counted against the loss of 13 Marines killed and 19 wounded.
In the meantime, 1/5 ran into prepared defenses east of Razorback Hill, but 3/1 and supporting medium tanks attacked through 1/5 and overcame the defenders. By that evening, the 1st and 5th Marines controlled both airfields and all the important high ground overlooking them.
The strategic objectives of the operation were and remained firmly in American hands. An informal flag-raising was held on Razorback Hill by Company I, 3/1, on December 30, and the formal flag-raising was held at the airdrome on December 31.
The main objectives of the Cape Gloucester campaign were in Marine hands following a mere five days of combat, but the campaign in western New Britain ground onward into March 1944, taking elements of the 1st Marine Division into several amphibious landings, long trail chases, and a few hard fights as they expanded the beachhead, absorbed several Japanese countermoves, hunted down Japanese forces of every size and description, and rolled up bases and encampments throughout the western end of the island. The main purposes of the ongoing and spreading offensive were to prevent attacks on the Cape Gloucester airfields and to so dominate the equivalent of a Japanese division as to keep it from ever taking part in a meaningful operation against Allied forces. All missions were accomplished in spades, and many hundreds of Japanese were killed or dispersed.
Alas, advances in early 1944 by the Southwest Pacific Force in New Guinea and islands off New Guinea were swifter than anticipated in the 1943 run-up to the invasion of western New Britain, and the importance of the Cape Gloucester base receded even while engineers and Seabees improved and expanded the Cape Gloucester beachhead and rehabilitated the airfields. Neither airfield was on particularly good ground, and Airfield No. 1 was soon abandoned altogether. The first landing on Airfield No. 2, on January 28, 1944, was that of the personal plane of the 1st Marine Division commanding general. Two Fifth Air Force fighter squadrons were briefly based there, but both were withdrawn when the ground war left them far in the rear.
By the end of April 1944, the entire 1st Marine Division had been relieved by U.S. Army units and withdrawn to a new training base on Pavuvu, in the Russell Islands. A total of 310 members of the division died on New Britain, and 1,083 were wounded in action.