The Hollandia Tactical Plan- WW II End

While the problems of logistics were being solved, the tactical plans for the Hollandia and Aitape assaults were being drawn up. Limited knowledge of the terrain at the objectives was a major obstacle to detailed planning, but by early April the ground, air, and amphibious force commanders, in cooperation, had solved most of their problems and had published their final tactical plans.
Humboldt Bay
Two regimental combat teams of the 41st Division were to start landing at Humboldt Bay on 22 April at 0700, high tide time in the Hollandia area. Simultaneously, two regimental combat teams of the 24th Division were to go ashore at Tanahmerah Bay. After securing their beachheads, the two divisions were to drive inland through successive phase lines to complete a pincers movement aimed at the rapid seizure of the Japanese-held airfields on the Lake Sentani Plain.
It was intended that the main effort should be made from Tanahmerah Bay by the 24th Division, since known and suspected Japanese defenses seemed concentrated at Humboldt Bay. While the RECKLESS Task Force Reserve (the 34th Regimental Combat Team of the 24th Division) might actually be more needed by the 41st Division at Humboldt Bay, General Eichelberger, the task force commander, planned to land the reserve at Tanahmerah Bay in an endeavor to exploit expected enemy weaknesses there. Task force headquarters and most of the reinforcing units and service organizations were also to land at Tanahmerah Bay. The 41st Division was to be prepared to drive inland from Humboldt Bay, but its role might be limited to containing Japanese strength which could otherwise move against the 24th Division. Nevertheless, the 41st Division's plans were made to take advantage of whatever weaknesses might be found in enemy defenses at Humboldt Bay.
The Humboldt Bay landing areas selected for the 41st Division, WHITE Beaches 1-4, presented complex problems of coordination and control. From the northwestern and southeastern shores of the inner reaches of Humboldt Bay ran two low sand spits, divided one from the other by a narrow channel leading from Humboldt Bay southwestward into smaller Jautefa Bay. Narrow, sandy beaches lined the Humboldt Bay side of the two spits, but the Jautefa Bay shore was covered with tangled mangrove swamps.
WHITE Beaches 1-3 were located on the two sand spits. None was ideally located in relation to division objectives, but the beaches were the best in the area. Access to the mainland from the spits could be obtained by movement along the Humboldt Bay side to inland ends of both peninsulas. The northern spit was flanked inland by an open-topped height called Pancake Hill, which was suspected of containing Japanese defensive installations. North of Pancake Hill, toward the town of Hollandia, lay wooded hills rising to a height of over 1,000 feet. The southern spit opened on marshy ground along the southeastern shore of Humboldt Bay.
WHITE Beach 1, about 800 yards long and 70 wide, ran along the northern spit south from the point at which that peninsula joined the mainland. WHITE Beach 2 was at the outer end of the same spit, while WHITE Beach 3 was located at the northern end of the southern peninsula. WHITE Beach 4 was on the western shore of Jautefa Bay and was situated just north of Pim, a native village at the eastern terminus of a motor road running inland to Lake Sentani and the task force objectives.
Close air support for the landings of the 41st Division was the responsibility of planes aboard the carriers of Task Force 58. These aircraft were to maintain combat air patrols over enemy airstrips in the Hollandia area from earliest light on D Day until H plus 60 minutes (0800), or until such patrols proved unnecessary. Fighter planes engaged in these patrol missions were to have freedom of action over the entire Hollandia region until H minus 30 minutes, after which they were to confine their operations to targets two or more miles inland from the landing beaches at both Humboldt and Tanahmerah Bays.
At Humboldt Bay, from H minus 15 minutes until H minus 4, or until the 41st Division's leading landing wave was within 800 yards of the shore, carrier-based aircraft were to hit enemy antiaircraft batteries and other known or suspected defensive positions around Humboldt Bay, especially on hills near WHITE Beaches 1 and 4. At H minus 4 minutes, carrier-based bombers were to drop their bombs on the beaches in an attempt to detonate possible beach mines. At H minus 3, when the first wave was scheduled to be 500 yards from shore, antipersonnel fragmentation bombs were to be dropped on WHITE Beach 1.
Naval fire support at Humboldt Bay was to be provided by three light cruisers and six destroyers of the U.S. Navy, firing to begin at H minus 60 minutes. Principal targets were Hollandia, Pim, heights north of WHITE Beach 1, Cape Soedja at the northwestern end of Humboldt Bay, and the four landing beaches. Two rocket-equipped landing craft, infantry (LCI's), were to accompany the leading boat waves, one to fire on Pancake Hill and the other to bombard high ground north of Pancake. A single destroyer was to accompany the first waves to bombard Capes Pie and Tjeweri (the tips of the two sand spits) and to support movement of amphibian tractors (LVT's) from WHITE Beach 2 to WHITE Beach 4.
The first landings to take place on WHITE Beach 1, at H Hour, were to be executed by the 3d Battalion, 162d Infantry. After landing, the battalion was to push rapidly north along the beach to the mainland and make ready to descend into Hollandia from hills south of that town. One company was to move west from the main body to establish a block across a road connecting Hollandia and Pim. The seizure of the northern section of the Hollandia-Pim road was assigned to the 2d Battalion, 162d Infantry, which was to follow the 3d ashore on WHITE Beach 1. The 2d was to push up the road toward Hollandia and assist the 3d Battalion in securing that town. The 1st Battalion, 162d Infantry, was to land at WHITE Beach 1 still later and assemble inland as division reserve.
WHITE Beach 2 and Cape Pie were to be seized at H Hour by a reinforced rifle platoon from the 1st Battalion, 162d Infantry. The beach was to be used by the 3d Battalion, 186th Infantry, which, aboard LVT's, was to move across the spit, push through the backing mangrove swamp, and land on WHITE Beach 4 across Jautefa Bay. Then the battalion was to clear neighboring hills and advance south toward Pim along the Hollandia-Pim road. The rest of the 186th Infantry was to land on WHITE Beach 1 after H Hour and move inland around the upper end of the spit. The 1st Battalion, 186th Infantry, was to move to Pim while the 2d Battalion assembled in division reserve.
Seizure of WHITE Beach 3 on the southern sand spit was designed as a security measure, and the beach was to be occupied by a rifle company of the 3d Battalion, 186th Infantry, at H Hour. This unit was then to secure Cape Tjeweri, at the northern tip of the spit, and patrol southeastward from the peninsula along the shore of Humboldt Bay to ward off or delay any Japanese counterattacks from that direction.
Artillery landing on D Day was to take up positions either on the northern spit or near the Hollandia-Pim road and from those positions provide support for infantry advancing inland and toward Hollandia. Antiaircraft artillery was to be grouped initially on or near WHITE Beach 1. The first duties of engineers were to unload ships, construct or improve exit roads from WHITE Beach 1 to the Hollandia-Pim road, and improve the latter track. The 41st Reconnaissance Troop was to scout along the shores of Humboldt Bay as far as Tami Airstrip, eight miles southeast of Hollandia, and to Imbi Bay and Cape Soedja at the northwestern limits of Humboldt Bay.

Tanahmerah Bay - Sentani
Landing points chosen for the 24th Division at Tanahmerah Bay were designated Red Beaches 1 and 2 and the principal thrust was to be made over the latter. Situated on the east-central shore of Tanahmerah Bay, RED Beach 2 ran north and south about 800 yards, boasted clear approaches from the sea, and was steeply inclined. It was known to be narrow and backed by a swamp, the nature of which could not be ascertained before the landing. RED Beach 1 was located at the southern end of Dépapré Bay, a narrow southeastern arm of Tanahmerah Bay. The narrow approach to RED Beach 1 was flanked on each side by hills only 600 yards from the central channel, and the landing area was fronted by a coral reef, the characteristics of which were unknown before D Day.
Red Beach 1 opened on a small flat area at the native village of Dépapré, near the beginning of the only road between Tanahmerah Bay and the inland airfields. Little was known about this road, but it was believed to be extensively used by the Japanese, passable for light wheeled vehicles, and subject to rapid improvement. West and south of RED Beach 1 lay a swamp backed by heavily forested hills. To the north was more difficult terrain, dominated by three prominent hills overlooking both RED Beaches. The division expected to find a road running along the sides of these heavily forested hills over the two miles which separated the beaches.
H Hour at Tanahmerah Bay was the same as for Humboldt Bay, 0700, and carrier-based aircraft from Task Force 58 were to support the landings of the 24th Division in much the same manner they were to support the 41st Division's assault. Naval fire support at Tanahmerah Bay would be provided by two Australian cruisers and by Australian and American destroyers. Targets and timing of naval support fires were similar to those to be used at Humboldt Bay. Most of the fire at Tanahmerah Bay was to be directed at RED Beach 2 and its environs and, prior to H Hour, only one destroyer was assigned to fire on RED Beach 1. After H Hour all fire support ships would be available to fire on targets of opportunity or objectives designated by the forces ashore. One LCI was to support the leading waves to RED Beach 2 with rocket and automatic weapons fire, which was to begin when the carrier-based planes finished their close support missions (about H minus 4 minutes) and continue until the first troops were safely ashore.
On the northern half of RED Beach 2 the 19th Infantry (less one battalion in division reserve) was to land. The two assault battalions were to secure half the beachhead, establish left flank security for the rest of the division, prepare to assume responsibility for the protection of the entire beachhead, and undertake mopping up north of the beach. Simultaneously two battalions of the 21st Infantry were to land on the southern half of RED Beach 2. After securing their sectors of RED Beach 2, these battalions were to push overland and south toward RED Beach 1. The division planned to improve the road which supposedly connected the two beaches or, if necessary, construct a new road between the two.
Initial landings on RED Beach 1 were to be undertaken by three reinforced rifle companies of the 1st Battalion, 21st Infantry, and were to begin at H plus 25 minutes, 0725. The primary missions of this force were to start rapidly inland over the road leading to Lake Sentani and the airfields and to report the size and condition of possible additional landing points in the Dépapré area. Movement inland was to begin before the Japanese could organize defenses along that portion of the road which wound snake-like over rugged hills south and east of Dépapré.
The Allied Naval Forces originally objected to a landing on RED Beach 1 and by arrangement with General Eichelberger had had this plan canceled. But General Irving, who wished to provide for every contingency in a landing area where terrain conditions were practically unknown, wanted the RED Beach 1 landing to remain in the plan, even if naval fire support for the assault could not be obtained. He considered it possible that failure to secure quickly the entrance to the Dépapré-Lake Sentani road might have disastrous consequences were it found impracticable to build a good road from RED Beach 2 to RED Beach 1. Seizing an opportunity to reopen the discussion of a landing on RED Beach 1, General Irving made personal pleas to General Eichelberger and Admiral Barbey, and succeeded in having the landing reinstated in the plan. This proved one of the most important tactical decisions of the Hollandia operation.
Preliminary Operations and the Approach
Intelligence Operations
Early in 1944 General MacArthur's G-2 Section had noted that the Japanese were increasing their activities in the Wewak area and near-by Hansa Bay. As D Day for the Hollandia-Aitape operation approached, it was discovered that the bulk of the Japanese 18th Army was withdrawing from forward bases at Madang and Alexishafen and was moving rapidly westward across the Ramu and Sepik Rivers to Wewak and Hansa Bay. These activities seemed to indicate that the Japanese probably expected the next Allied attack to be aimed at the Wewak-Hansa Bay area.
Every effort was made to foster in the mind of Lt. Gen. Hatazo Adachi, commanding the 18th Army, the growth of the idea that a major assault in the Wewak sector was imminent. During March and early April, Wewak was heavily bombed by the Allied Air Forces, not only to prevent the Japanese from using their airfields there but also to lead the enemy to believe that the usual aerial softening-up process preceding an amphibious operation was taking place.
Minor naval bombardments of the Wewak and Hansa areas were carried out in March and early April, and PT's of the Allied Naval Forces patrolled actively along the coast north from Madang to Wewak. By various means propaganda was spread to convince the 18th Army that a landing was soon to be made at Wewak, and dummy parachutists were dropped in the same vicinity. Allied Naval Forces submarines launched empty rubber life rafts along the coast near Wewak in an endeavor to make the Japanese believe that reconnaissance patrols were active in that area.
One effort was made to obtain terrain information and knowledge of enemy troop strength and dispositions in the Hollandia area. About two weeks before the landing a Seventh Fleet submarine landed an Allied reconnaissance patrol at Tanahmerah Bay. The venture proved completely abortive. Local natives betrayed the patrol to the Japanese, and the members were killed, captured, or dispersed. A few men of the original party eluded the enemy and were found alive after the Allied landings.
Air Operations
The scheduled strike by Task Force 58 against the Palaus, designed both for strategic support of the Hollandia operation and the destruction of enemy air and surface units, was carried out on 30-31 March. Other islands in the western Carolines, including Yap, Ulithi, Ngulu, and Woleai, were hit during the same two days or on 1 April. The raids resulted in the loss for the Japanese of almost 150 aircraft either in the air or on the ground. Two enemy destroyers, four escort vessels, and 104,000 tons of merchant or naval auxiliary shipping were sunk and many other ships, of both combat and merchant classes, were damaged. In addition, airfields and shore installations at all objectives were damaged and the main channels into the Palau fleet anchorage at least temporarily blocked by mines.
Unfortunately, Task Force 58 had been sighted by Japanese search planes prior to its arrival off the Palaus, and many enemy combat ships and a number of merchant vessels had fled from the area. The desired results were achieved, however--the enemy naval units at Palau were removed as a threat to the Hollandia-Aitape operation and driven back to more westerly bases. Task Force 58 lost twenty planes, but its ships suffered no damage.86
The efforts of Task Force 58 had been supplemented by South and Southwest Pacific aircraft which, from bases in eastern New Guinea and the Admiralties, bombed islands in the eastern Carolines and undertook many long reconnaissance missions. Meanwhile, Southwest Pacific aircraft had been neutralizing enemy air bases in western New Guinea and eastern islands of the Netherlands East Indies. Most of the strategic support missions flown to western New Guinea were undertaken by U.S. Fifth Air
Force planes while the Royal Australian Air Forces Command assumed responsibility for the majority of the strikes against the islands in the eastern Indies. These operations were intensified about six weeks before the landings at Hollandia and Aitape. From Wewak to the Vogelkop Peninsula of western New Guinea, and from Biak to Timor, the Allied Air Forces destroyed Japanese planes and airfield installations, rendered many air bases at least temporarily unusable, and hindered enemy attempts to fly air reinforcements to New Guinea from the Philippines.
Spectacular results were achieved by the Fifth Air Force at Hollandia, where the Japanese 6th Air Division had recently retreated from Wewak and received strong reinforcements. The air unit conserved its planes, apparently waiting to see where the Allies would strike next. The Japanese waited too long.
The Fifth Air Force shifted the weight of its attack from the Wewak area to Hollandia, and, during the period 30 March through 3 April, destroyed or damaged over 300 Japanese aircraft, most of them on the ground. On 30 March, when over 100 planes were destroyed at Hollandia, the Japanese were caught completely unprepared. Faulty intelligence, resulting partially from insufficient radar warning facilities, found many Japanese planes on the ground refueling after early morning patrols. Others had been left unattended upon receipt of reports that a large Allied air formation had turned back eastward after bombing Aitape. Finally, earlier Fifth Air Force attacks had so cratered runways and taxiways of two of the three enemy fields at Hollandia that there was little room to disperse the planes. The Fifth Air Force, in a series of low-level bombing attacks, covered and aided by newly developed long-range fighters, found enemy aircraft parked wing tip to wing tip along the runways. By 6 April the Japanese had only twenty-five serviceable aircraft at Hollandia. They made no attempt to rebuild their air strength there and, after 3 April, Fifth Air Force raids were met by only a small number of enemy fighter planes which made but desultory attempts at interception.
The Japanese did build up a small concentration of air strength farther west, at Wakde-Sarmi, and continued airfield development at still more westerly bases. The Fifth Air Force and Australian aircraft increased their efforts against these latter installations,while planes of Task Force 58 effectively neutralized Japanese air power at Wakde-Sarmi just prior to 22 April.
Task Force 58's efforts at Wakde and Hollandia on D minus 1 and D Day bagged an estimated thirty-three aircraft shot down. Damage to planes on the ground at either objective was difficult to assess because of the degree of destruction previously achieved at both places by the Allied Air Forces
Attack Force Preparations
Meanwhile, Allied ground and amphibious forces had been engaged in final preparations and training for the coming assault and, on 8, 9, and 10 April, had undertaken last rehearsals. The 24th Division's rehearsal at Taupota Bay, on the coast of New Guinea south of Goodenough Island, was incomplete. Little unloading was attempted, and the area selected did not permit the employment of naval gunfire support. The 41st Division had a more satisfactory rehearsal, with realistic unloading and naval fire, near Lae, New Guinea.
Final loading began on 10 April. LCI's of the RECKLESS Task Force left their loading points on 16 April in order to allow the troops aboard to disembark at the Admiralty Islands for a day of exercising, resting, and eating. Other vessels of Hollandia-bound convoys left the Goodenough Island and Cape Cretin staging areas on 17 and 18 April. Ships carrying the PERSECUTION Task Force moved out of the Finschhafen area on 18 April and on the same day rendezvoused with the vessels bearing the 41st Division toward the Admiralties.
All convoys moved north around the eastern side of the Admiralties and, at 0700 on 20 April, the various troops assembled at a rendezvous point northwest of Manus Island. Moving at a speed of about nine knots, the massed convoys steamed westward from the Admiralties all day and at dusk turned southwest toward Hollandia. At a point about eighty miles off the New Guinea coast between Hollandia and Aitape, the PERSECUTION Task Force convoy--the Eastern Attack Group---broke off from the main body and swung southeast toward Aitape. The ships bearing the RECKLESS Task Force proceeded to a point twenty miles offshore between Humboldt and Tanahmerah Bays. There, at 0130 on D Day, this convoy split. The Central Attack Group, with the 41st Division aboard, turned southeast toward Humboldt Bay and arrived in the transport area at 0500. The ships of the Western Attack Group, carrying the 24th Division and the remainder of the RECKLESS Task Force, moved into Tanahmerah Bay at the same time.