World War Two: Guadalcanal (1-2); Plans for Invasion

Admiral Turner’s Plan: Like General Harmon, the officer assigned to command the Amphibious Force, Rear Admiral Richmond K. Turner, was also an aviator, but he had taken up flying at a comparatively late date. In 1908 when Turner was graduated from the U. S. Naval Academy as a passed midshipman, he held fifth place in a class of 201. Commissioned an ensign in 1910, he studied naval ordnance and engineering in the years prior to World War I. During the war he was a gunnery officer aboard several battleships, and in 1925 and 1926 he was on duty with the Navy Bureau of Ordnance. He completed naval aviation pilot training at Pensacola in August 1927, and commanded air squadrons for nearly two years. From 1929 to 1931 he served in the Plans Division of the Bureau of Aeronautics, and in 1932 he was a technical adviser to the United States delegation at the General Disarmament Conference at Geneva. He then served aboard the carrier Saratoga, and after graduation from the Naval War College in 1936 he served on the staff there for two years. In 1939 he commanded the cruiser Astoria when she carried the remains of Ambassador Hirosi Saito to Japan. In 1940 Turner became Director of the War Plans Division of the Office of the Chief of Naval Operations, and in early 1942, a change in the organization of the Office of Naval Operations gave him the title of Assistant Chief of Staff to the Commander in Chief of the U. S. Fleet. He held that post, which was also concerned with war plans, until he was ordered to the Pacific in the summer of 1942, at the age of fifty-seven.

Admiral Turner, who after conferring with Admiral Nimitz at Pearl Harbor had reached Wellington on 15 July, issued Operation Plan No. A3-42 to the Amphibious Force on 30 July. He divided his force into eight groups: Transport Group X, Transport Group Y, the Guadalcanal Fire Support Group, the Tulagi Fire Support Group, the Minesweeper Group, the Screening Group, the Air Support Group, and the Landing Force Group, which consisted of the 1st Marine Division, Reinforced (less the 7th Marines).

Transport Group X, assigned to the Guadalcanal landing, consisted of four transport divisions. Two of the divisions were each composed of three transports and one cargo ship; the third, of two transports and one cargo ship; and the fourth, of one transport and three cargo ships. Transport Group Y, assigned to the landings in the Tulagi area, consisted of two transport divisions—one made up of four transports and the other of four destroyers previously converted to troop carriers (APD’s). Four more ships, the Zeilin and the Betelgeuse and their escorting destroyers, were to transport the 3rd Defense Battalion from Pearl Harbor.

The Guadalcanal Fire Support Group consisted of three fire sections composed of one heavy cruiser and two observation planes each, and of two fire sections of two destroyers each. The Tulagi Fire Support Group consisted of one light antiaircraft cruiser and two destroyers. There were five minesweepers in the Minesweeping Group.

The Amphibious Force’s second-in-command, Rear Admiral V. A. C. Crutchley, R.N., commanded the Screening Group. It consisted of three Australian cruisers, one U. S. heavy cruiser, nine destroyers, two fighter squadrons based on the aircraft carriers, but detached to the Screening Group on D Day, and eight observation seaplanes from the cruisers. The Air Support Group was made up of one fighter and one dive bomber squadron, plus one additional fighter and one additional dive bomber squadron for the initial mission, all drawn from the carriers.

The Landing Force was led by the commanding general of the 1st Marine Division. It was divided into two groups—the Guadalcanal Group directly under the division commander, and the Northern Group under the assistant division commander. Six observation planes from the cruisers Astoria and Quincy were assigned to the Guadalcanal Group, and two planes from the cruiser Vincennes were assigned to the Northern Group.

Admiral Turner, in his analysis of enemy strength against which the Amphibious Force would have to contend, estimated that at least 150 Japanese planes were based in the Bismarck-New Guinea area, and that 11 Japanese cruisers, 13 destroyers, 15 submarines, 12 patrol bombers, 15 or 17 transports, and a number of motor torpedo boats were available. The Amphibious Force was to expect attacks by the planes based at fields from Rabaul to Salamaua.

Admiral Turner warned his force that submarines, motor torpedo boats, cruisers, destroyers, and transports might be met around Tulagi. The Guadalcanal-Tulagi garrison was estimated to total 7,125, a figure more than double Ghormley’s. It was believed that 1,850 men constituted Tulagi’s garrison, whose armament included antiaircraft and coast defense guns, seaplanes, and picket boats. The rest of the troops were supposed to be in the Lunga area on Guadalcanal, which was protected by antiaircraft and coast defense guns.

The Amphibious Force was to assume attack dispositions on D minus 1 and to arrive in the transport areas off Guadalcanal and Tulagi before sunrise of D Day. The main landings were to be made on the center of the south coast of Tulagi, and on a 1,600-yard-long sandy beach between the Tenaru and Tenavatu Rivers on the north coast of Guadalcanal, about 6,000 yards east of Lunga Point. H Hour, the time of the Tulagi landing, was set for 0800 for planning purposes. Zero Hour, the time of the Guadalcanal landing, was originally set for 0830. Admiral Turner’s flagship, the cargo ship McCawley, was the site of the 1st Marine Division’s floating command post. Admiral Crutchley flew his flag aboard the Australia.

 The majority of the Amphibious Force—Transport Group X, the Guadalcanal Fire Support Group, one fighter squadron and one dive bomber squadron, and about two regimental combat teams of the 1st Marine Division—was assigned to the assault on Guadalcanal. Transport Group Y, the Tulagi Fire Support Group, one fighter squadron, one dive bomber squadron, and the balance of the Marine division, except the reserve, were assigned to the northern attack. Air attacks by the planes directly supporting the Amphibious Force were to inaugurate operations on D Day. Communication and control between the Amphibious Force and the air squadrons were to be effected through an air support director group from the carrier force stationed aboard the McCawley. An alternate director group was to be aboard the Neville.

 Fifteen minutes before sunrise of D Day, while the transports were approaching their unloading areas, one fighter squadron was to destroy any aircraft at Lunga or Koli Points on Guadalcanal, and any seaplanes, motor torpedo boats, or submarines operating near the island’s north coast. At the same time a second fighter squadron would strike similar targets near Tulagi. Two dive bomber squadrons, assisted by the fighters, were to hit antiaircraft and coast defense guns on Guadalcanal, Tulagi, and Gavutu. Dive bombers were also to cover the assaulting landing craft as they moved toward the beaches. Beginning one hour after sunrise on D Day, fighters and dive bombers were to maintain stations overhead to protect the transports.

Admiral Turner ordered the fire support warships to fire at all antiaircraft and coast defense guns, to cover the minesweepers, and to be on the alert against torpedo boats and submarines. Warships were to take care to avoid interfering with landing craft formations, and for the safety of the American troops were to use percussion instead of time fuzes against shore targets. The warships were to provide naval gunfire liaison teams, equipped with radios, to go ashore with the troops.

The naval gunfire support problem in the Tulagi area was more complicated than that for Guadalcanal. Numerous near-by islets and promontories of Florida Island lie within artillery and even small-arms range of Tulagi. The ships’ gunfire plan called for supporting fires to be placed, prior to the landings, on all the islets as well as on parts of Florida and on Tulagi. The ships were also to put fire on the radio station on the southeastern part of Tulagi, and on Tulagi’s antiaircraft positions. Starting at H plus 30 minutes the party on shore was to designate targets. The Tulagi Fire Support Group and the air squadrons were also to bombard the southeast portion of Tulagi when the troops, advancing southeast from the landing beach, had reached the first phase line, about two-thirds of the way down the island. The signal from the troops for this bombardment would be a green star cluster flare.

The cruisers of the Guadalcanal Fire Support Group were to cover the area between Lunga and Koli Points with fire starting at daylight of D Day. The four destroyers were to take stations at Zero minus 30 minutes to serve as control and salvage vessels by the landing beach; they were to mark the line of departure for the initial boat waves 5,000 yards north of the beach. All ships of the group were to close in by Zero minus 10 minutes to give direct support to the landing. From Zero minus 10 to Zero minus 5 minutes, they were to put fire to a depth of 200 yards on an area extending 800 yards on either side of the beach, using 135 8-inch and 1,400 5-inch rounds. Starting at Zero plus 5 minutes, the ships were to put fire ashore to assist the advance of the combat teams from the landing beach west to the Lunga airfield.

The liaison planes assigned to the landing forces were to mark the flanks of the beaches with smoke at H minus 20 and Zero minus 20 minutes, respectively. Starting at H plus 1 hour, one plane was to assume station over Guadalcanal for observation duty for the field artillery. If ground-to-air radio communication failed, communications between the ground forces and the liaison planes were to be maintained by message drops and ground panel codes. Transport Groups X and Y were to land the troops, equipment, and supplies of the 1st Marine Division on Tulagi and Guadalcanal in accordance with that division’s plans. The destroyer-transports of Group X would act as control and salvage vessels for the boats landing at Tulagi.

The minesweepers were to sweep the shallows south of Tulagi from H to H plus 1 and a half hours. Three minesweepers were then to sweep the waters from the Guadalcanal landing beach east to Taivu Point, while two cleared the area off the beach itself. The Transport Group commanders were authorized to move their ships in close to the landing beaches once the waters were proved safe. On D plus 1, the minesweepers would clear the Kukum Beach area just west of Lunga Point.

The Screening Group would guard the Amphibious Force against surface, air, and submarine attacks. One fighter squadron was to cover the transport areas during daylight while the ships were unloading. Control would be exercised through a fighter director group from the carrier forces aboard the Chicago-During enemy air attacks the fire support warships would come under Admiral Crutchley’s control to screen the transports with antiaircraft fire, and, in the event of surface attack, would also support the Screening Group. On the completion of their shore fire missions the fire support warships were to pass to Admiral Crutchley’s command. During the amphibious phase, one observation plane from the Vincennes was to conduct antisubmarine patrols, reporting results to the Screening Group.

Admiral Turner intended to establish Amphibious Force headquarters ashore once the objectives had been captured and the amphibious phase ended. Communications with the area commander would be maintained through the 1st Marine Division’s radio. A small naval force, including a boat repair section, boat crews, and twelve LCM’s (landing craft, mechanized), twenty LCP(L)’s (landing craft, personnel) and thirty LCV’s (landing craft, vehicle), was to be established at Guadalcanal and Tulagi.

It was estimated that the transports would be unloaded and could withdraw from the forward area by the night of D plus 1. They were to retire under the command of Rear Admiral Norman Scott, the commander of the Tulagi Fire Support Group. The cargo ships were to be unloaded by D plus 4, and were to retire under command of Admiral Crutchley.

The force for the Santa Cruz operation, consisting of one cruiser, four destroyers, four transports, one cargo ship, and the 2nd Marines, Reinforced, having formed an integral part of the Amphibious Force for the Guadalcanal-Tulagi invasion, was to depart from the Guadalcanal area about D Day to occupy and defend Ndeni.

On completion of the entire operation the air squadrons were to revert to Task Force 61. The Amphibious Force organized for the invasions was to be dissolved on orders from Admiral Fletcher, but the South Pacific Amphibious Force proper would remain in existence.

Landing Force Plans

The 1st Marine Division, which was to make the landings, had been moving overseas while the Joint Chiefs of Staff were discussing the attack against the Solomons. Brought to war strength at New River, N.C., between 7 December 1941 and 1 May 1942, it had then been organized around two infantry regiments, the 1st Marines and 5th Marines, and one artillery regiment, the 11th Marines. The 7th Marines, the third infantry regiment, had been detached for service with the 1st Provisional Marine Brigade in Samoa. The division had engaged in field exercises and combat firing at New River, and during March and April each battalion landing team of the 5th Marines and one of the 1st Marines engaged in 10-day landing exercises at Solomon’s Island, Md. The division was commanded by a 55-year-old veteran of Caribbean and Chinese expeditions, Major Gen. Alexander A. Vandegrift. After attending the University of Virginia for two years, Vandegrift had been commissioned a 2nd lieutenant in the Marine Corps in 1909. He served in Nicaragua, Mexico, and Haiti, and in 1916 began two years’ service with the Haitian Constabulary.

After a brief tour of duty in the United States, he served again in Haiti from 1919 to 1923. Upon completing the Field Officers’ Course at Quantico, Va., in 1926, he became Assistant Chief of Staff at the Marine Base at San Diego, Calif. Vandegrift then served for over a year as Operations and Training Officer on the staff of the 3rd Marine Brigade in China. Returning to the United States in 1928, he held various staff positions, including one with the newly founded Fleet Marine Force, until 1935. He served in Peiping, China, for two years, and from 1937 to 1941 was at Marine Corps Headquarters in Washington.

Ordered to the 1st Marine Division in 1941 as a brigadier general, he was promoted to major general and took command of the division in March 1942 with Brigadier General William H. Rupertus as his assistant division commander. Vandegrift had not believed that his division was sufficiently well trained for combat when he was notified in April that it was to be sent to New Zealand as part of the South Pacific Amphibious Force to establish bases and train for “minor landing offensives and counter-attacks to be designated at a later date”. He had not expected that any combat missions would be assigned before January 1943. Division headquarters and the 5th Marines reached Wellington, the capital city of New Zealand, on 14 June, but the second echelon did not arrive until 11 July.

The second echelon was still at sea when Admiral Ghormley called Vandegrift to Auckland on 26 June to announce the plan to use the 1st Marine Division (less 7th Marines), reinforced by the 2nd Marines, the 1st Raider Battalion, and the 3rd Defense Battalion, in the Solomons about 1 August 1942. The division’s plans had to be prepared semi-independently, for Admirals Fletcher and Turner had not yet arrived in the South Pacific. According to Vandegrift, “there was no time for a deliberate planning phase, and in many instances irrevocable decisions had to be made even before the essential features of the naval plan of operations could be ascertained“; there was “an absence of meeting of minds of commanders concerned.” General Vandegrift’s plans were based upon the assumption that the Allies would firmly control the air and sea routes to the Solomons.

In a little over one month the division, hiding its preparations under the guise of preliminaries for amphibious training, had to prepare tactical and logistical plans, unload part of its ships, reload for combat, sail from Wellington to the Fijis, rehearse, and sail to the Solomons, in addition to gathering data on the islands and on Japanese strength and dispositions there.

Terrain and Intelligence

The 1st Marine Division’s intelligence section, on receiving Ghormley’s orders., immediately began to gather data on terrain, landing beaches, climate, and the natives, from U. S. Army and Navy monographs, extracts from the Pacific Islands Year Book, and reports of the British Navy and Colonial Office. There was no opportunity for ground patrols to reconnoiter the islands prior to the invasion. Colonel Frank B. Goettge, the intelligence officer of the 1st Marine Division, and his section interviewed former Solomons residents, civil servants, and merchant ships’ officers in New Zealand. On 1 July Colonel Goettge flew to General MacArthur’s headquarters to collect information. Spending one week in Melbourne and several days in Sydney, he interviewed former residents of the Solomons in those cities. Eight of these men were given commissions or warrants by the Australian forces and were attached to the 1st Marine Division as guides, advisers, and pilots. They reported to division headquarters on 15 July to interpret maps and aerial photographs.

The Solomons, with their green mountains, forested shores, low-hanging clouds, and coral reefs, are beautiful when viewed from the air or from the calm interisland channels, but they present difficult terrain for military operations. They are covered by heavy, tropical rain forests. Mountains, deep rivers, swamps, heat, humidity, heavy rains, and mud, combined with the jungle, make all movements extremely difficult. Except along the sandy beaches vehicles cannot move until roads have been built. At the opening of the campaign there were few vehicular roads. Tulagi had some trails, and a trail had been built through the coconut groves on the north coast of Guadalcanal, but the only inland passages were native footpaths. There were no bridges suitable for artillery and heavy equipment.

The islands are unhealthful; malaria as well as dengue fever is common. The malarial (Anopheles) mosquito breeds in swamps, lagoons, sluggish streams, and puddles, and has seeded the natives heavily. In addition, fungus infections and sores were to plague all the troops. Only the utmost efforts at the prevention of disease would keep troops healthy, but living and combat conditions on Guadalcanal were to make systematic malaria control difficult.

Guadalcanal, which is shaped like a Paramecium, is ninety miles long and averages over twenty-five miles in width. A backbone of forested mountains and quiescent volcanoes, rising in some places as high as 7,000 feet, runs the length of the island. Coral reefs and sharply rising mountains make the south coast inhospitable for ships. The north coast has no harbors, but Sealark Channel is calm. Many sandy beaches on the north coast are free of reefs and provide suitable landing areas for amphibious operations. From Aola Bay to the Matanikau River, between the mountains and Sealark Channel, there is a flat, narrow, grassy plain. Coconut, plantations line most of the beach, and there are some stretches of high, tough kunai grass. The plain is cut by many rivers and streams. They are generally deep and swift, and are frequently flooded by rains. Stagnant pools have formed at most of the river mouths through the accumulation of silt which, massing cones and sand bars, blocks the flow of water.

The coastal plain ends east of the Matanikau River; between the river and Cape Esperance at the northwest tip of the island a narrow corridor lies between the coastline and the high ground on the south. Steep ravines and abruptly rising ridges cut laterally across the corridor. Lunga Point, where the Japanese were building their airstrip in July and August of 1942, is dominated by Mount Austen, a 1,514-foot-high series of ridges and knolls about six miles southwest of the point.

Colonel Goettge returned from General MacArthur’s headquarters with its intelligence estimate of enemy strength and dispositions in the Solomon Islands, New Guinea, and the Bismarck Archipelago. This estimate, supplemented by aerial reconnaissance and reports from coastwatchers, was the basis of the division’s estimate of enemy strength and dispositions in the Solomons. On 20 July division headquarters believed that 8,400 Japanese were on Guadalcanal and Tulagi, a figure which, like Admiral Turner’s, much exceeded Admiral Ghormley’s.

The 1st Marine Division continued to receive radio reports from the coastwatchers, which were monitored and transmitted by the American radio at Efate, even after the division’s departure from Wellington. During the week preceding D Day, the Solomons coast-watching net broadcast reports three times daily in a special code. The reports were to have been relayed directly from Efate to Admiral Turner’s flagship at sea, but as the code had not been properly intercepted they had to be relayed through Australia and New Zealand, a process which sometimes delayed them for three days.

On 17 July two officers of the Marine division were taken by a B-17 on a reconnaissance flight from Port Moresby over Guadalcanal and Tulagi. They saw no evidence of any airfields, except for burned-off areas at Lunga Point and Tetere, nor any extensive beach defenses on the north coast of Guadalcanal. Returning to Wellington by way of Townsville, Australia, they brought back aerial photographs of Tulagi and a strip map of the Guadalcanal coast between Koli Point and the Matanikau River.

There were no good maps of Guadalcanal, a deficiency that was, in fact, never remedied throughout the campaign. During the planning phase the division’s intelligence section never received what it considered an adequate number of aerial photographs of Guadalcanal, although it received a large number of the Tulagi area. The intelligence section used two U. S. Navy Hydrographic Charts as the bases for its maps. Chart No. 2658 of Tulagi and Gavutu, on a scale of 1/12,000, was fair, showing approximate elevations. Chart No. 2916 of Guadalcanal and Florida was enlarged to a scale of 1/108,643 but was inaccurate and lacked recent corrections. A crude sketch which had been prepared by colonial officials before the war aided in locating some trails and buildings but lacked contour lines and elevations. The division’s base map for the Guadalcanal landing was a 9-sheet strip drawn and reproduced by the photolithographic section from aerial photographs which Colonel Goettge had brought from Australia. The map, based on photographs taken in late June, covered a narrow coastal strip on Guadalcanal from Lunga Point east to Aola. A rough, uncontrolled sketch showing rivers, plains, plantations, and forests, it was reproduced before the Amphibious Force’s sortie from Wellington. No more photographs reached the division until 2 August, when Admiral McCain forwarded photographs which had been taken by a B-17 and had been developed aboard the Enterprise. These pictures of Tulagi and Lunga Point showed that the airstrip was nearly complete.

Source: Guadalcanal: The First Offensive ; BY: John Miller, Jr. (United States Army Center of Military History)

World War Two: Guadalcanal (2);

World War Two: Guadalcanal (1); Plans for Invasion

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