Operation Cartwheel

Markham Valley and the Huon Peninsula

Plans: US and Japanese

by James Miller, jr.

While South Pacific troops had been so heavily engaged in New Georgia, General MacArthur's Southwest Pacific forces were executing Operation II of the ELKTON plan--the seizure of the Markham Valley and the Huon Peninsula of New Guinea--aimed at increasing the Southwest Pacific Area's degree of control over Vitiaz and Dampier Straits. (Map 12)

Map 12: The Huon Peninsula
Jumbo Map: The Huon Peninsula (monstrously slow: 611K)

This operation had actually started in January 1943 with the Australian defense of Wau in the Bulolo Valley, and was furthered by the Australian advance from the Bulolo Valley toward Salamaua and the 30 June landing of the MacKechnie Force at Nassau Bay.

(The subsection is based on ALF, Rpt on New Guinea Opns: 4 Sep 43-26 Apr 44; GHQ SWPA Warning Instns 2, 6 May 43, in GHQ SWPA G-3 Jnl, 6 May 43; GHQ SWPA 01 34, 13 Jun 43, and subsequent amendments, in CHQ SWPA G-3 Jnl, 14 Jun 43; Craven and Cate, The Pacific: Guadalcanal to Saipan, pp. 183-86; Kenney, General Kenney Reports, pp. 273-87; Morison, Breaking the Bismarcks Barrier, Ch. XIV; Memo, ACofS G-3 GHQ SWPA for CofS GHQ SWPA, 14 Jul 43, no sub, in GHQ SWPA G-3 Jnl, 14 Jul 43; Ltr, Adv Hq ALF to GHQ SWPA, 16 Jul 43, sub: Opns CARTWHEEL, in GHQ SWPA G-3 Jnl, 16 Jul 43; Ltr, Brig Gen Donald Wilson, CofS AAF SWPA, to CINCSWPA, 20 Jul 43, sub: Supporting Plan, GHQ 01 34, same file; LHQ [ALF] 01 54, 30 Jul 43, in GHQ SWPA G-3 Jnl, 31 Jul 43; NGF 01 95, 25 Aug 43, in GHQ SWPA G-3 Jnl, 25 Aug 43; Memo, Gen Chamberlin, ACofS G-3 GHQ SWPA, for CofS GHQ SWPA, 25 May 43, sub: Control of Opns Of 2d ESB, in GHQ SWPA G-3 Jnl, 25 May 43; ANF Opn Plan 5-43, 19 Jul 43, in GHQ SWPA G-3 Jnl, 20 Jul 43; AAF SWPA 01 37, 18 Jun 43, in GHQ SWPA G-3 Jnl, ig Jun 43; Ltr, Comdr ANF to CINCSWPA, 16 Aug 43, sub: Air Support for Troop and Sup Overwater Movements During POSTERN Opn, in GHQ SWPA G-3 Jnl, 16 Aug 43; Memo, Gen Kenney for Gen Chamberlin, 25 Aug 43, sub: Opn Plan, Adv Ech 5th AF, POSTERN Opn, same file; G-2 Est POSTERN, 20 Aug 43, in GHQ SWPA G-3 Jnl, 20 Aug 43.)

Plans

The Allies

The ground forces in Operation II (or POSTERN) were under command of the New Guinea Force.

General Blarney arrived at Port Moresby and assumed command of the New Guinea Force on 20 August 1943, and General Herring went to Dobodura, where as general officer commanding the I Australian Corps he exercised control over tactical operations. General Blarney was responsible for coordination of ground, air, and naval planning. In the actual conduct of ground, air, and naval operations, the principle of co-operation rather than unity of command appears to have been followed.

The operations involved in the seizure of the Huon Peninsula and the Markham Valley were complex. The Southwest Pacific lacked enough ships for a completely amphibious assault, and had too few aircraft for a completely airborne attack; there were enough ground troops, but New Guinea terrain precluded large-scale overland movements. To bring sufficient power to bear General MacArthur and his subordinates and staff therefore employed all available means-amphibious assault, an assault by parachute troops, an airlift of an entire division, and the shore-to-shore operation already executed at Nassau Bay.

MacArthur, in operations instructions issued before the invasions of Woodlark, Kiriwina, and Nassau Bay, and followed by a series of amendments, ordered the New Guinea Force to seize the LaeMarkham Valley area by co-ordinated airborne and overland operations through the Markham Valley and amphibious operations (Including Nassau Bay) along the north coast of New Guinea. The Markham Val ley operations were to be based on Port Moresby; the north coast operations on Buna and Milne Bay. MacArthur directed the seizure of the coastal areas of the Huon Gulf, including Salamatia and Finschhafen, and initially ordered the New Guinea Force to be prepared for airborne-overland and shore-to-shore operations along- the north coast of New Guinea as far as Madang on Astrolabe Bay. The immediate objectives were Lae and the Markham and Ramu Valleys.

The two river valleys form a tremendous trough between the Finisterre and Kratke Ranges. Starting at the mouth of the Markham River at Lae and running northwesterly for 380 miles to the mouth of the Ramu, the trough varies from 5 to 25 miles in width. The rivers flow in opposite directions from a plain in the level uplands of the trough some 8o miles northwest of Lae. Both valleys contain extensive flats of grass-covered sand and gravel, and thus there were many excellent sites for air bases. Already in existence were several emergency strips that had been used by Australian civil aviation before the war.

Lae, a prewar sea terminal for air service to the Bulolo Valley, had a developed harbor and airfield, and was the key to Successful employment of airfields in the valleys. Once it was captured, ships could carry supplies to Lae, and roads could be pushed up the Markham Valley to carry supplies to the airfields. The New Guinea Force was ordered to construct airfields in the Lae-Markham Valley area as specified by General Kenney. They were eventually to include facilities for two fighter groups, some night fighters, two medium and two light bombardment groups, one observation squadron, one photo-reconnaissance squadron, and four transport squadrons. MacArthur wanted Madang taken in order to protect the Southwest Pacific's left flank during the subsequent landings on New Britain. Salamaua was not an important objective, but MacArthur and Blarney ordered the 3d Australian Division with the MacKechnie Force attached to press against it for purposes of deception. They wanted the Japanese to believe that Salainatia and not Lae was the real objective, and so to strengthen Salamatia at Lae's expense.

The commander in chief ordered Kenney and Carpender to support the New Guinea Force with their Allied Air and Allied Naval Forces. Allied Land Forces could make the necessary troops available.

U.S. Army Services of Supply and Line of Communications units of Allied Land Forces would provide logistical support. From thirty to ninety (lays of various classes of supply was to be stocked at intermediate and advance bases. General Marshall's U.S. Army Services of Supply would be responsible for supply of American forces in the Huort Peninsula and Markham Valley, and would provide all items to the Army and Navy. MacArthur ordered Marshall's command to aid Allied Naval Forces in transporting, the 2d Engineer Special Brigade to the coinbat zone, and to prepare to relieve Allied Naval Forces of the responsibility for transporting supplies to Lae and to Woodlark and Kiriwina.

Some of the plan's outstanding features were the ways it proposed to use air power. The impending assault by parachute would be the first tactical employment of parachute troops as such by Allied forces in the Pacific. (The 1st Marine Parachute Battalion fought well at Guadalcanal and Tulagi in 1942, but it fought on foot as an infantry battation. It made no tactical jumps.)

The combination of airlifted troops and parachute troops in co-ordination with amphibious assault had also not been used hitherto by the Allies in the Pacific. The year before, General Whitehead had sold the Aussies on the scheme of an airborne show at Nadzab to take Lae out from the back," and General MacArthur had liked the idea too, but there were not enough transport planes in the area to carry it out at that time. (Kenney, General Kenney Reports p. 128)

Generals MacArthur and Blarney had planned to operate overland from the Lakekanni River to the Bulolo Valley and thence to the Markham Valley in conjunction with a parachute assault by one battalion. Delays in building the mountain road from the Lakekamu to the Bulolo Valley made necessary a decision to land an entire parachute regiment at Nadzab, a superb airfield site in the Markham Valley where a prewar Australian airstrip already existed, and to fly an entire division from Port Moresby to Nadzab immediately afterward.

The third unusual feature of the POSTERN air operations was made possible by General Kenney's enthusiastic willingness to try any experiment that offered a hope of success and by the fact that both Allied and Japanese forces were concentrated in small enclaves on the New Guinea coast, with the highlands and hinterland available to whichever force could maintain patrols there.

On General Kenney's recommendation, MacArthur ordered the development of two grass strips, one in the Watut Valley west of Salamaua and the other in the grassy plateau south of Madang where the Markham and Ramu Rivers rise. These strips could serve as staging bases that would enable Kenney to send fighters from Port Moresby and Dobodura as far as the expanding enemy base at Wewak or over the western part of New Britain, and to give fighter cover to Allied bombers in the vicinity of Lae. Thus the Allied Air Forces would be using inland airfields to support and protect a seaborne invasion of a coastal area.

D Day was set for planning purposes as 1 August, but was postponed to 27 August and finally to 4 September to permit the assembly of enough C-47's, more training for the 7th Australian Division, and the relief of the VII Amphibious Force of its responsibilities for Woodlark and Kiriwina. The precise date was picked by General Kenney on the basis of weather forecasts. He wanted fog over western New Britain and Vitiaz and Dampier Straits that would keep Japanese aircraft away while bright clear weather over New Guinea--a fairly common condition--permitted the flight to and jump into the Markham Valley. The fourth of September promised to be such a date and was selected. (In his book Kenney tells how the American and Australian weather teams kept altering their forecasts and disagreeing with one another. Finally the American team picked 5 September; the Australians decided on 3 September. General Kenney "decided that neither one of them knew anything about weather, split the difference between the two forecasts, and told General MacArthur we would be ready to go on the morning of the 4th for the amphibious movement. General Kenney Reports, p. 288.)

The final tactical plans were prepared by New Guinea Force and by the various higher headquarters in the Allied Air and Allied Naval Forces under the supervision of General MacArthur, General Sutherland, MacArthur's chief of staff, and such subordinates as General Chamberlin, the G-3 of GHQ. (GHQ supervised the preparation of the plans for operation II more closely than, for example, those for Woodlark-Kiriwina. The staff at GHQ felt that New Guinea Force and subordinate headquarters were slow in preparing plans, tended to prepare plans for initiating operations rather than for carrying them through completely, failed to provide for co-ordination of forces, and (lid not thoroughly appreciate logistics. See Memo, Chamberlin for CofS GHQ SWPA, 28 Aug 43, no sub, in GHQ SWPA G-3 Jnl, 16 Jul 43.)

Final plans, issued in August, called for the employment of two veteran Australian divisions, the 7th and the 9th, the U.S. 50,3d Parachute Infantry Regiment, and elements of the U.S. 2d Engineer Special Brigade, as well as the American and Australian troops already pressing against Salamaua in their deception maneuver. The 9th Australian Division was to be carried by the VII Amphibious Force, with elements of the 2d Engineer Special Brigade, attached, from Milne Bay to beaches far enough east of Lae to be beyond range of enemy artillery.

Early plans had called for the 2d Engineer Special Brigade to carry the 9th Australian Division to Lae and support it thereafter. But closer study showed that an engineer special brigade could carry and support but one brigade in reduced strength--about 3,000 men, or not nearly enough to attack Lae. Therefore the VII Amphibious Force was ordered to carry the 9th Division, and the 2d Engineer Special Brigade was attached to Barbey's command for the initial phases.

Two brigade groups, totaling 7,800 men, plus elements of the amphibian engineers, were to land starting at 0630, 4 September. (A brigade group was similar in strength and composition to a U.S. regimental combat team.)

That evening 2,400 more Australians would land, and on the night of 5-6 September the VII Amphibious Force, having retired to Buna after unloading on 4 September, was to bring in the 3,8oo men of the reserve brigade group. The time for H Hour, 0630, was selected because it came thirty minutes past sunrise, by which time the light would be suitable for the preliminary naval bombardment.

Admiral Carpender organized his Allied Naval Forces into almost the same task forces that he had set up for Woodlark and Kiriwina and assigned them similar missions. Admiral Barbey organized his VII Amphibious Force into a transport group Of 2 destroyers, 4 APD's, 13 LSYS, 20 LCI's, 14 LCT's and 1 AP; a cover group Of 4 destroyers; an escort group of 2 destroyers; an APC group of 13 APC's, 9 LST's, and 2 subchasers; and a service group of 1 tender, 3 LST's, 10 subchasers, 5 minesweepers, 1 oiler, and 1 tug. The attached engineer special brigade elements possessed 10 LCM's and 40 LCVP's.

Allied Air Forces' plans for support of the invasion called for General Whitehead to provide close support to ground troops, to provide escort and cover for the amphibious movements, to establish an air blockade over Huon Peninsula, to specify to General Blarney the air facilities to be constructed in the target areas, and to prepare to move forward to the new bases.

But again there was an argument over the method by which the air forces would cover the VII Amphibious Force. Admirals Carpender and Barbey had no aircraft carriers and thus were completely dependent upon the Allied Air Forces for air support. They pointed out that the amphibious movement to Lae would involve over forty ships, 7,800 soldiers and 3,260 sailors. This represented all suitable vessels available, with none retained in reserve. Losses to Japanese air attacks would seriously jeopardize the success of future operations, and therefore they argued that only a fighter umbrella providing continuous cover for the VII Amphibious Force would be adequate. The airmen, who were planning to use over three hundred planes in the Markham Valley parachute jump, were willing to provide air cover for Barbey's ships over Lae itself on D Day, but argued that the movement of the convoys would be amply protected by maintaining fighter squadrons on ground alert at Dobodura and the staging airfield in the Watut Valley.

The argument, a heated one, went tip the chain of command to General MacArthur himself, and was finally settled by Kenney's agreement to use a total of thirty-two planes to give as much cover as possible over the VII Amphibious Force during daylight and to maintain fighter squadrons on ground alert.

There remained the problem of fighter control. One fighter control unit was stationed at Dobodura, and another at the staging field in the Watut Valley, but radar coverage over the area was far from complete. Japanese aircraft from Wewak or Madang could fly south of the mountains to Lae, or from New Britain across Dampier and Vitiaz Straits, and radar would not pick them up until they were almost over Lae. And as Brig. Gen. Charles A. Willoughby, MacArthur's G-2, pointed out, Allied experience at New Georgia showed that the Japanese air reaction might be violent.

An Australian airman suggested that the difficulty be alleviated by posting a radar-equipped destroyer between Lae and Finschhafen. This was accepted, and the U.S. destroyer Reid, which was part of Barbey's antisubmarine screen, was selected as picket with orders to steam in Vitiaz Strait some forty-five miles southeast of Finschhafen.

Markham Valley plans called for the 503d Parachute Infantry Regiment, flying from Port Moresby in C-47's, to jump onto Nadzab airstrip on the north bank of the Markham River on 5 September, the day after the amphibious assault. Nadzab was not believed to be occupied by the Japanese, but this seizure would block the valley and prevent the enemy's sending troops overland from Wewak.

Once captured, Nadzab airstrip was to be quickly readied for airplanes by the 503d and by a force of Australian engineers and pioneers. The Australians were to paddle in boats from the staging airfield in the Watut Valley down the Watut River to Nadzab-a distance of about thirty- two air miles, but actually twice that far for anything but crows and airplanes. Then one brigade of the 7th Australian Division, plus engineers and antiaircraft units, having been flown to the Watut Valley previously, would fly in. The next brigade would come in directly by air from Port Moresby.

Once adequate strength had been assembled, the 7th Australian Division would march eastward down the Markham River against Lae, and at the same time the 9th Australian Division would drive westward from the landing beaches.

Seizure of Nadzab would have a threefold effect: it would provide Allied forces with one more air base with which to increase their control over the Huon Peninsula, the straits, and western New Britain; it would provide a base for the 7th Division's eastward march against Lae; and an Allied force at Nadzab could forestall any attempt by the Japanese to reinforce Lae from Wewak by marching through the Ramu and Markham Valleys.

The Enemy

Japanese strategic intentions were not changed by the Invasion of the Trobriands or of Nassau Bay. In August 1943 Generals Imamura and Adachi were still resolved to hold Lae and Salamaua as parts of the outer defenses of Wewak and Madang, and were still planning to move into Bena Bena south of the Ramu Valley. (This subsection is based upon 8th Area Army Operations, Japanese Monogr No. 110 (OCMH), pp. 22-34, 36-85; 18th Army Operations, II, Japanese Monogr No. 42 (OCMH), 27-54; USSBS, Allied Campaign Against Rabaul, p. 84.)

There were about ten thousand men in the Lae-Salamaua area, with somewhat niore than half of these defending Salamaua. Many of the ten thousand, reported the Japanese after the war, were sick. Some estimates run as high as 50 percent.

At Lae, General Shoge, temporarily detached from his post as infantry group commander of the 41st Division, led a force consisting of a naval guard unit, elements of the 21st, 102d, and 115th Infantry Regiments, and artillerymen and engineers. In addition to defending Lae, Shoge was responsible for patrolling up the Markham River and for protecting the southern approaches to Finschhafen on the east coast of the Huon Peninsula.

In the months following the Bismarck Sea disaster the supply systems for Lae and Salamaua had almost broken down. The Allied aerial blockade of the Huon Peninsula prevented the use of large ships to carry suppl les forward to Lae. Until June, six submarines helped carry supplies, but then the number was cut to three and the bulk of supplies had to be carried on barges.

Supply of the ten thousand men for the five months preceding September would have required 150 bargeloads per month, while 200 more barges were needed for transport of reinforcements and ammunition. But there were far too few barges. Only 40, for example, were making the run to Lae from the staging base at Tuluvu on the north shore of Cape Gloucester. The sea and the tides in Dampier Strait damaged many, and several fell victim to Allied aircraft and to nocturnal PT's which, like their sister boats in the Solomons, prowled the barge lanes.

Imperial General Headquarters, meanwhile, had paid heed to Imamura's request for more planes. On 27 July ImPerial Headquarters ordered the 4th Air Army, commanded by Lt. Gen. Kumaichi Teramoto, from the Netherlands Indies to the Southeast Area. Teramoto's army would include the 7th Air Division, the 14th Air Brigade, some miscellaneous squadrons, and the 6th Air Division, which was already based at Wewak.

The 4th Air Army headquarters arrived at Rabaul on 6 August, whereupon Imamura ordered Teramoto and his planes to proceed to Wewak with the mission of escorting convoys, destroying Allied planes and ships, and co-operating with the 18th Army. The move was made at once; the Allies were well aware that the Japanese were building up strength on the four Wewak airfields.

More Markham Valley and the Huon Peninsula

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