The problems of logistics proved as serious as had those of procuring information about enemy strength and dispositions. Preparations began before the intelligence section had completed its work and before the final tactical plans were prepared. The logistical plans were based upon General Vandegrift’s organization of the division for combat. On 29 June he organized the division into two regimental combat groups each of about 4,500 men. Each group was organized into a headquarters and support group and three battalion combat teams. Every combat group consisted of one infantry regiment, one artillery battalion, one company each from the tank, engineer, pioneer, amphibian tractor, and medical battalions, and scout, special weapons, and transport platoons. Each combat team was originally composed of one infantry battalion, one field artillery battery, and platoons of engineer, pioneer, and amphibian tractor personnel. Scouts, signal, medical, and other service personnel were added to the combat teams prior to the invasion.
Combat Group A, commanded by Colonel Le Roy P. Hunt, was composed of the 5th Marines and supporting troops. Combat Teams Nos. 1, 2, and 3 of Combat Group A consisted of the reinforced 1st, 2nd, and 3rd Battalions, respectively, of the 5th Marines. Combat Group B, Colonel Clifton B. Cates commanding, was made up of the 1st Marines and supporting troops. Combat Teams Nos. 4,5, and 6 of Combat Group B consisted of the reinforced 1st, 2nd, and 3rd Battalions, respectively, of the 1st Marines. On 9 July the division support group was organized. It consisted of about 3,500 men under Colonel Pedro A. del Valle organized into four subgroups made up of headquarters, communications, medical, artillery, special weapons, pioneer, engineer, and amphibian tractor personnel and the 1st Parachute Battalion. The parachutists, fighting as infantry, were later assigned to the assault on Gavutu. The rear echelon, 1,729 men from all divisional units, including the 4th Battalion, 11th Marines (155-mm. howitzers), was to remain in Wellington when the division departed.
[NOTE: 1st Mar Div Opn Ord No. 5-42, 29 Jun 42, in 1st Mar Div Rpt, I, Annex B. The terms in the operation order differ from present day usage. The combat groups would now be regimental combat teams. The combat teams would be battalion landing teams.]
As each combat group was to be embarked in a transport division consisting of three transports and one cargo ship, every transport in each division was assigned to carry one combat team, three units of fire, thirty days’ rations, and quartermaster, ordnance, engineer, chemical, signal, and medical supplies. Supporting troops, heavy equipment, seven units of fire, thirty days’ rations and other supplies, and clothing stocks were “assigned to each cargo ship. The logistical difficulties did not stem from shortages of materiel, for the division had come overseas with nearly all its equipment and supplies. The shortages were in dock space, time, and shipping. In late June there were just seven ships of the Amphibious Force in Wellington Harbor—five transports and two cargo ships. More vessels had been assigned, but it was apparent that there would not be enough cargo space to combat-load all the division with its supplies and equipment. To embark the maximum number of troops, General Vandegrift ordered that “all units . . . reduce their equipment and supplies to those items that are actually required to live and fight.”
The division was ordered to embark bulk supplies, including rations and fuel, for sixty days instead of the ninety days then considered necessary. The ammunition allowance was reduced by one-half. Office equipment, cut to a minimum, included no more than two typewriters per battalion headquarters and four per regimental headquarters. Mess equipment was limited to water bags, vacuum food carriers, camp kettles, coffee mills, and stoves. The order directed that all the division’s motor transport would be embarked; all sandbags, rubber boats, outboard motors, camouflage and chemical warfare equipment, all engineering materiel, water purification equipment, sixty days’ clothing replenishment (shoes, socks, and green utility suits), and thirty days’ post exchange supplies (tobacco, matches, soap, and razor blades only) were to be embarked. Officers and enlisted men were ordered to take with them all their individual equipment but to reduce their baggage to a minimum. Each officer was allowed one bedding roll, clothing roll, or handbag, while enlisted men were limited to what they could carry in their packs.
Loading the division’s weapons and supplies on board the ships was a difficult matter. Aotea Quay in Wellington was small and could berth only five ships at the same time. Combat Group A had already landed, unloaded, and been established inland in base camps prior to 29 June. To clear the quay for the second echelon, it was decided to begin the embarkation of Combat Group A and its equipment and supplies on 2 July. The division supply officer organized the embarkation and combat loading, exercising control through transport quartermasters on the ships and through field officers in charge of the 300-man working parties assigned to each ship. Organized into three reliefs, the working parties labored around the clock in 8-hour shifts. Except for a few skilled civilian operators of loading machines, cranes, hoists, carriers, and stacking machines, marines performed all dockside labor. All divisional motor transport plus eighteen 10-wheeled trucks of the 1st Base Depot and thirty flat-bedded New Zealand Army lorries moved supplies, equipment, and ammunition from their depots to the dockside. By 13 July Combat Group A and its gear had been embarked. A few shortages were made up by local purchases in Wellington, and others were alleviated by materiel carried by the second echelon. After embarkation Combat Group A practiced landings in Wellington Harbor.
The second echelon—largely troops of Combat Group B and the Support Group—encountered much greater difficulty. It arrived at Aotea Quay on 11 July, while Combat Group A was completing its embarkation. As it had not been anticipated that the division would be tactically employed after its arrival in New Zealand, the ships had not been combat-loaded before leaving the United States. Most of the troops had been carried across the Pacific aboard passenger vessels, while cargo ships carried their supplies and equipment. The second echelon was forced to unload, sort, and classify stores and equipment on the limited dock space, and to reload for combat by 22 July. The weather had been clear while the first group had embarked, but, during the entire period of the second echelon’s unloading and re-embarkation, cold, driving rains typical of a New Zealand winter made the task miserable. The morale of the troops, working in the rain, was low. Many of the supplies had been packed in cardboard cartons, which, becoming soggy from the rains, burst and strewed their contents over the docks. Other cardboard cartons, stacked inside the warehouse, were crushed.
Lack of cargo space prevented the division from loading all its motor transport aboard the twelve available ships. Nearly all the quarter-ton and one-ton trucks were put aboard, but 75 percent of the heavier vehicles were left behind in Wellington with the rear echelon. The engineers expected that the Lunga Point airfield would perhaps be almost complete by D Day, but put earth-moving equipment, in addition to bridging equipment and a portable dock, aboard the cargo ship Fomalhaut.
Medical preparations for the campaign had not been difficult. Those medically unfit for foreign service had been left behind in the United States. The standard of health remained fairly high, except for troops on board one transport of the second echelon. Among those marines rotten food on the voyage to New Zealand had caused a loss of weight varying from sixteen to twenty pounds per man, as well as a diarrhea epidemic. Exposure while loading in Wellington had resulted in some cases of colds and influenza, and a few sporadic cases of mumps broke out en route to the target area. The medical plans provided for medical care, under combat conditions, of 18,134 men for ninety days. By 22 July reloading had been completed, and the division was ready to sail from Wellington.
On 20 July, when logistical preparations had been almost completed in Wellington, General Vandegrift issued tactical orders for the landings. The grouping of forces for Tulagi and Guadalcanal was based upon the premise that of the 8,400 Japanese which the intelligence section believed to be defending the objectives 1,400 troops, including one infantry and one antiaircraft battalion, were in the Tulagi area. One reinforced infantry regiment, one antiaircraft battalion, one engineer battalion, pioneers, and others—7,000 in all—were thought to be on Guadalcanal. The major part of these were expected to be at Lunga Point, with a smaller force at Koli Point. These estimates greatly exaggerated enemy strength. In early August there were about 780 Japanese in the Tulagi-Gavutu-Tanambogo area, and 2,230 on Guadalcanal. Admiral Ghormley’s original estimate of 3,100 had been correct.
As it was anticipated that the invasion of the Tulagi area, involving direct assaults against small islands, would be the most difficult, the most experienced battalions were assigned to this attack. To protect the flanks of the units landing on Tulagi and other islets, small forces were to land first on near-by Florida. One battalion would then land on Tulagi, followed quickly by a second. A third battalion would land on Gavutu at H plus 4 hours to seize Gavutu and Tanambogo.
The Guadalcanal landing presented a simpler tactical problem than did the landing on Tulagi. The large number of undefended beaches on the north coast would make it possible for the remainder of the division to land unopposed at some distance from the Japanese. The area selected for the landing lies between the Tenaru and Tenavatu Rivers, about 6,000 yards east of the Lunga airstrip, well away from both Lunga and Koli Points. Having landed and established a beachhead, the Guadalcanal Group of the division under General Vandegrift could then attack west to capture the airfield. This maneuver would require the troops to cross both the Tenaru and the Ilu Rivers, but the Tenaru and the Tenavatu Rivers, on either flank of the beach, would help to protect the beachhead if the Japanese counterattacked while men and supplies were coming ashore.
The orders issued on 20 July utilized the previous organization of the division into combat groups, combat teams, and the support group. The orders also organized the reinforcing units—the reinforced 2nd Marines, the 1st Raider Battalion, and 3rd Defense Battalion—which had not then joined the division. The In the early maps, the names of the Tenaru and the Ilu Rivers were transposed. The Ilu lies about 2¾ miles east of the Lunga. The wide part of the river is also known as Alligator Creek.
2nd Marines, Reinforced, commanded by Colonel John M. Arthur, included the 2nd Marines, the 3rd Battalion of the 10th Marines (75-mm. pack howitzers), and engineer, pioneer, amphibian tractor, tank, medical, and other service troops—a total of 4,840 men. This reinforced regiment was organized like the others into a headquarters and support group and three combat teams of about 1,300 each. Combat Teams A, B, and C were composed of the reinforced 1st, 2nd, and 3rd Battalions, respectively. The 1st Raider Battalion, totaling 828 men, was commanded by Lt. Colonel Merritt A. Edson. The 3rd Defense Battalion, Colonel Robert H. Pepper commanding, totaled 872 men. These reinforcements, when they arrived, increased the division strength to over 19,000.
The 20 July orders prescribed eight groups of varying strengths: Combat Group A, Colonel Hunt commanding, 4,398 (to be subsequently reduced by about 1,100 by the assignment of Combat Team No. 2, one reinforced infantry battalion, to the Tulagi attack); Combat Group B, Colonel Cates commanding, 4,531; the Support Group, Colonel del Valle commanding, 3,537; the Tulagi Group (the 1st Raider Battalion and Combat Team No. 2 of Combat Group A), Colonel Edson commanding; the Gavutu Group, Major Robert Williams commanding, 395 of the 1st Parachute Battalion; the Florida Group, Major Robert E. Hill commanding, 1,295 of Combat Team A (1st Battalion, 2nd Marines, Reinforced); the 3rd Defense Battalion; and the Division Reserve—the 2nd Marines, Reinforced (less Combat Team A)—Colonel Arthur commanding, 3,545.
These forces were to attack and destroy the hostile garrisons on Guadalcanal, Tulagi, Gavutu, Tanambogo, and Makambo by landings on D Day, and then to organize the defense of those islands. There were not enough landing craft, however, to execute all landings simultaneously. At H minus 20 minutes, one rifle company and one machine gun platoon of Combat Team A (1st Battalion, 2nd Marines, Reinforced) were to land at Haleta on Florida, just west of Tulagi, to cover the Tulagi landing. At H plus 30 minutes the remainder of Combat Team A would seize Halavo, the peninsula on Florida just east of Gavutu, and support the Gavutu assault by fire.
The Tulagi Group, led by the 1st Raider Battalion, would land on a 500-yard front on Tulagi at H Hour and seize the northwest part of the island. Having reached the first phase line about 1,500 yards northwest of the southeast shore, the assault troops would signal for a 5-minute air and naval bombardment upon the defense positions in the hills and ravines around Government House, the cricket field, the hospital, the prison, and the radio station, then attack and capture that area. Once taken, the island was to pass to the control of the commander of Combat Team No. 2 (2nd Battalion, 5th Marines, Reinforced, less E Battery, 11th Marines) of Combat Group A. The 1st Raider Battalion would then prepare to re-embark for further operations. Combat Team No. 2 was to embark enough troops to seize Makambo, northeast of Tulagi, and also was to relieve the 1st Parachute Battalion after it had captured Gavutu and Tanambogo. The 3rd Defense Battalion was to land one-third of its antiaircraft strength on Tulagi.
The 1st Parachute Battalion was to land on the east coast of Gavutu at H plus 4 hours, seize it, and then take Tanambogo, the small island connected with Gavutu by a concrete causeway. The firing of a green star cluster would be the signal for five minutes of naval gunfire on Tanambogo from the Tulagi Fire Support Group. After the capture of the islets the battalion was to be prepared to re-embark for employment elsewhere.
While operations were being conducted against the northern islets by air squadrons, the Tulagi Fire Support Group, Transport Group Y, and the Marine units under General Rupertus’ command, the rest of the force—air squadrons, the Guadalcanal Fire Support Group, Transport Group X, and the majority of the Marine division under General Vandegrift—would be operating against Guadalcanal. Combat Group A (5th Marines, Reinforced), less Combat Team No. 2 (2nd Battalion, Reinforced, less E Battery, 11th Marines), was to land at Zero Hour on a 1,600-yard front with combat teams abreast to take the beachhead.
Combat Group B (1st Marines, Reinforced) was to land in column of battalions at Zero plus 50 minutes, pass through Group A, and attack westward toward the “grassy knoll” (Mount Austen) which was erroneously believed to be only four instead of six miles southwest of Lunga Point. This course, it was hoped, would prevent the Japanese from escaping southward into the mountains. The 1st Marines was to maintain contact with the units advancing on its right. The formation would be a column of battalions echeloned to the left and rear to protect the left flank. Group A, after Group B had passed through, was to send Combat Team No. 1 (1st Battalion, 5th Marines) west along the shore to seize the Ilu River line. In the order the Ilu was mistakenly called the Tenaru.
Combat Team No. 3 (3rd Battalion, 5th Marines) was to seize the line of woods running southeast from the Tenavatu River, thus covering the east line of the beachhead. The division’s light tanks, landing with the combat groups, were also to cover the east flank of the beachhead but were not to be committed to action except on orders from General Vandegrift. Platoons of A Battery of the 1st Special Weapons Battalion were to land on the flanks of the beach to provide antiaircraft defense with automatic weapons. They were to revert to control of the 1st Special Weapons Battalion of the Support Group upon the landing of that battalion’s headquarters.
The artillery battalions of the combat groups were to land with their groups, but to pass to control of the headquarters of the 11th Marines of the Support Group upon the landing of that headquarters. The Support Group, including elements of the artillery, engineer, special weapons, and pioneer battalions was to land on orders from division headquarters, and to co-ordinate the artillery support for the attacks of the Combat Groups as well as the antiaircraft defense of the beachhead. The 3rd Defense Battalion (less one-third of its antiaircraft units) was to land on divisional order, pass to control of the Support Group, and assist in the defense of the beachhead.
Combat Team A of the division reserve (2nd Marines, Reinforced) had been released to General Vandegrift for the Florida landing, but the remainder of the reserve was to remain under Admiral Turner’s control for the occupation of Ndeni if it was not required for Guadalcanal and Tulagi. General Vandegrift ordered the reserve, however, to be prepared to land Combat Team B less its reinforcing elements at H plus 4 hours, and to be ready to attach Combat Team C minus its reinforcing units to the Tulagi Group.
While the division was making ready for combat, the other units which were to make up the invading force were sailing toward their respective rendezvous areas. The carrier Wasp came from the Atlantic Ocean through the Panama Canal. On 1 July she sailed from San Diego, escorting the five ships bearing the 2nd Marines, Reinforced, across the Pacific. On 7 July the carrier Saratoga, with Admiral Fletcher on board, and her supporting warships departed from Pearl Harbor, followed by the carrier Enterprise and her supporting ships. The destroyer-transports, which had helped to escort the Enterprise, left the carrier at sea and sailed to New Caledonia to embark the 1st Raider Battalion. The ships from the Southwest Pacific left Brisbane, Australia, on 14 July and arrived at New Zealand five days later to come under Admiral Turner’s control. On 21 July Admiral Fletcher, commanding Task Force 61, ordered all units to rendezvous southeast of the Fiji Islands at 1400, 26 July. The 3rd Defense Battalion, on board the Zeilin and Betelgeuse, escorted by two destroyers, did not leave Pearl Harbor until 22 July and did not join die task force until 3 August.
The twelve transports and cargo ships of the Amphibious Force, carrying the 1st Marine Division together with their escorts, sailed from Wellington on 22 July under Admiral Turner’s command. On 26 July the entire Expeditionary Force (Task Force 61), except the Zeilin and Betelgeuse and their escorts, assembled southeast of the Fijis, and on the next day sailed to Koro for the rehearsal.
From 28 through 31 July the Expeditionary Force rehearsed with carrier air groups participating. The rehearsal was far from being a success. One of the most serious handicaps was the necessity for maintaining radio silence which made ground-to-air communication impossible and impeded the co-ordination of ground force attacks with close air support. Two complete landing exercises simulating the scheme of maneuver had been planned, but coral reefs made the beaches impracticable for landings. General Vandegrift, who firmly believed in the necessity for complete rehearsals, later wrote that the advantages gained from the Koro rehearsal were “dubious” when compared with the loss of “priceless time.” The rehearsal had some value, however, for the force received practice in debarkation procedure and in the conduct and timing of boat waves. The forces supporting the ground troops had an opportunity for firing and bombing practice. Since McCain, Fletcher, Turner, and Vandegrift all attended the rehearsal, they seized this first opportunity for close personal conferences during which they discussed their plans in detail.
Since the performance of landing craft at the rehearsal led the commanders to expect numerous mechanical break-downs, a boat pool was organized. It was at Koro that the decision was made to land first at Tulagi and later at Guadalcanal on D Day. The transport Heywood, carrying both the 1st Parachute Battalion and elements of the Guadalcanal Support Group, would have to unload the Parachute Battalion in the Tulagi area and then cross the channel to land tanks on Guadalcanal.
The landing craft carried by the ships of the Amphibious Force amounted to 480 1942-model boats of various types,54 in addition to the vehicles of the 1st Amphibian Tractor Battalion of the 1st Marine Division. There were 8 30-foot landing craft. 308 36-foot LCP(L)’s and LCP(R)’s, 116 36-foot LCV’s, and 48 45-foot LCM’s. The 30-foot boats and the LCP(L)’s were the old fixed-bow type without ramps. The LCP (R)’s, the LCM’s and the LCV’s were equipped with movable bow ramps. The LCV’s, each with a 10,000-pound cargo capacity, could carry 75-mm. and 105-mm. howitzers or 1-ton trucks, but heavier equipment (90-mm. and 5-inch guns and heavy trucks) would have to be carried in the LCM’s. The LCP(L)’s could carry troops and portable supplies, but all supplies brought ashore by the LCP(L)’s would have to be lifted over the gunwales by hand at a considerable expense of time and manpower. The amphibian tractors (LVT’s), about to make their first appearance in action, were an early, unarmored type mounting two machine guns.
The final details of organization of the boat pool, including all boats from the ships of the Amphibious Force, were completed during the rehearsal. Ten boat groups, varying in size from sixteen to sixty-four boats of various types, were organized. Nearly every group included one craft assigned as a repair boat. Four groups, including 103 craft, were assigned to the Tulagi area to unload Transport Group Y, and the remaining six groups were assigned to unload Transport Group X at Guadalcanal. The assaulting combat teams would be brought ashore by ninety-one craft—sixty-three carrying Combat Team No. 1 and Headquarters and supporting troops of Combat Group A, and twenty-eight carrying Combat Team No. 3. Combat Group A’s tanks would be brought in by sixteen LCM’s. Forty-one boats would carry the next waves—Combat Team No. 4 and Headquarters, Combat Group B. Following the landing of the first elements of Combat Group B the forty-one boats would join an additional fifty-one to carry Combat Team No. 5. Combat Team No. 6 would be borne ashore by fifty-seven craft.
After the landing of the assault troops, the LCM’s of the boat groups, in general, were to continue unloading heavy equipment from certain specified ships, while the other boats returned to their mother ships to unload them, bringing in supporting troops and supplies on the second, third, and succeeding trips to shore. General Vandegrift also ordered that amphibian tractors be used wherever possible to haul supplies. Although not a tactical vehicle, the unarmored amphibian tractor could sail from ship to shore, surmount the beach, and carry supplies overland directly to regimental and battalion dumps, with a resulting economy in both time and labor.
Those troop commanders who were to be responsible for the complete unloading of the ships were to assign enough men to work all ships’ holds twenty-four hours per day, for all ships were to be unloaded in the shortest possible time. Supplies were to move over the beaches in accordance with the following priority: ammunition, water, combat transport, rations, medical supplies, gasoline, other transport, and lastly, miscellaneous supplies.
All men, as originally planned, were to wear green utility suits and to carry head nets and cot nets for protection against mosquitoes. Each man was to carry two canteens of water if enough canteens were available. The men of the task and landing forces were to initiate the first Allied offensive in the Pacific, one of the largest amphibious operations in the history of the United States up to that time. The tactical plans were hastily prepared, but they had a broad and well-established base in the doctrines governing landings on hostile shores which had been developed during the years preceding the outbreak of war. It is significant to note that whereas plans for the landing operations proper were detailed and comprehensive, there was no reference to systematic re-supply of the 1st Marine Division which carried sufficient supplies for sixty days. Although on 14 July Admiral Ghormley had directed the 7th Marines in Samoa to be ready to embark on four days’ notice with ninety days’ supply and ten units of fire, no Army units for reinforcing or relieving the division were alerted.
Source: Guadalcanal: The First Offensive ; BY: John Miller, Jr. (United States Army Center of Military History)