Chapter 10: Strategic and Tactical Significance of the Gilberts Operation
Strategic Consequences
Writing some six years after the event, General Holland Smith posed the question, “Was Tarawa worth it?” “My answer,” he said, “is unqualified: No.” General Smith continued:–
From the very beginning the decision of the Joint Chiefs to seize Tarawa was a mistake and from their initial mistake grew the terrible drama of errors, errors of omission rather than commission, resulting in these needless casualties. ... Tarawa had no particular strategic importance. ... Tarawa should have been by-passed. Its capture ... was a terrible waste of life and effort. ... [We] should have let Tarawa “wither on the vine.” We could have kept it neutralized from our bases on Baker Island, to the east, and the Ellice and Phoenix Islands, a short distance to the southeast.1
General Smith was alone among high-ranking officers to voice this opinion. Admirals King, Nimitz, and Spruance, as well as General Julian Smith, were all in agreement that the capture of Tarawa and Makin was a necessary prelude to the invasion of the Marshalls.2
The strategic value of the Gilberts lay in their geographic proximity to the Marshalls and therefore in their utility as air bases for the forthcoming operations in the Central Pacific. Before launching the Gilberts campaign, the United States had no airfields within range of the Marshalls, the closest being at Funafuti in the Ellice Islands and at Canton—1,300 and 1,600 nautical miles from Kwajalein, respectively. The occupation of Baker Island and Nanomea, which was incident to the capture of the Gilberts, closed this range somewhat and allowed American planes to operate from bases about 1,020 and 1,050 nautical miles from Kwajalein. But even if these islands could have been held without the elimination of the Japanese air potential in the Gilberts, which is in itself doubtful, Baker and Nanomea were still too distant from the Marshalls to allow steady
bombing and photographic reconnaissance. The capture of key islands in the Gilberts halved the distance between American airfields and Kwajalein and made possible the effective employment of land-based aircraft against that target. Almost immediately upon completion of infantry fighting in the Gilberts, naval Seabees and Seventh Air Force engineers commenced work on airfield construction at Tarawa and Makin. By 18 December the field at Makin was well enough along to base its first planes. Less than a week later two fields at Tarawa (one on Betio and one on Buota) were ready to fly and service bombers. By mid-January a field at Apamama was in operation.3
The completion of these airfields in the Gilberts changed the entire character of operations against the Marshall Islands. The long-distance raids with light bomb loads now gave way to shorter flights with heavier loads, and allowed flights of planes with shorter ranges. Medium bombers, attack bombers, and fighters were brought into the attack. Army Air Forces B-25’s (medium bombers) were based at Tarawa and Apamama; A-24’s (fighter-bombers) and P-39’s (fighters) were based at Tarawa and Apamama; A-24’s and P-39’s were brought to Makin; and P-40’s (fighters) were based on Makin and Apamama. Most of the B-24 (heavy bomber) squadrons that had been bombing the Gilberts and southern Marshalls were moved to Tarawa by the first week in January. Advance headquarters of the VII Bomber Command and of the VII Air Service Command were set up at Tarawa by 7 January.
During November the B-24’s, which were then carrying the entire load alone, had totaled 237 sorties against the Gilberts and Marshalls. In December these planes, able to stage through Tarawa late in the month, flew 365 bombing and photographic sorties against the Marshalls alone. They were augmented by the B-25’s that were brought to Tarawa on 28 December and the A-24’s based at Makin.
The Gilbert bases allowed the use of land-based fighters for the first time in the Central Pacific. The two P-39 squadrons and the one P-40 squadron based at Makin and Apamama accompanied bombing sorties over the Marshalls from the day they arrived in the Gilberts. In addition to protecting the heavier planes, the fighters also bombed and strafed Japanese installations and shipping. No longer did B-24’s have to assume sole responsibility for land-based photographic and bombing missions against the Marshalls. Those of shorter range could be turned over in part to medium bombers and fighters based in the Gilberts. Also, the shortened distances between the new forward bases and the B-24 targets in the Marshalls allowed the heavy bombers to fly with still heavier loads and more frequently.4 Finally, as Admiral Spruance pointed out, the superior photographic techniques of land-based aviation made possible a more accurate picture of terrain, hydrographic conditions, and enemy defenses in the Marshalls than could otherwise have been obtained.
Tactical Lessons Learned
The Gilberts operation, especially the invasion of Tarawa, was the first instance in the Pacific war of a large-scale amphibious assault against a well-fortified shore line. Before the outbreak of the war the
United States armed forces, chiefly the Navy and the Marine Corps, developed a systematic doctrine for landing waterborne troops on hostile shores, supporting them both before and after the landing by naval guns and carrier-based air, and providing the necessary logistical support by overseas shipping. This doctrine had been set forth in abundant detail in a series of military manuals published by the two services.5 Yet, until Tarawa, it had never been put to a severe test in the Pacific. The landings in the Solomons, New Guinea, and the Aleutians had all been conducted against light opposition or no opposition at all. Tarawa was the first occasion in the Pacific war when the enemy had heavily fortified the beachhead that had to be seized if the attacking force was to achieve its objective.
The fact that the atoll was captured with acceptable casualties (about 20 percent) provided incontestable proof that American amphibious doctrine was sound and that the most formidable island fortress could be taken even with the relatively slender means then available to Allied forces in the Pacific. Just as significant, however, as the ultimate success of the invasion were the various deficiencies in equipment and techniques and the errors in execution that the operation revealed. It was the experience gained in the Gilberts, coupled with a tremendous expansion of all U.S. arms in the Pacific, that made the more nearly perfect execution of subsequent amphibious operations possible.
Naval Support
According to the later testimony of Admiral Hill, the “first and foremost” among lessons learned during the Gilberts operation was “that naval task forces accompanying the assault forces had the power to move into an area, obtain complete naval and air control of that area, and remain there with acceptable losses throughout the entire assault and preliminary consolidation phases.” “This,” he continued, “is a lesson which had never been demonstrated before the Gilberts operation and which formed the basis for all subsequent operations in the Central Pacific Area.”6
Just as the invasion of Tarawa demonstrated that naval task forces could seize control of the air and sea long enough to support a successful landing, so did it indicate that a period of preliminary naval fire, much longer than a few hours, was necessary if all beach defenses were to be eliminated or effectively neutralized. The consensus among observers at Tarawa was that the three hours allotted for preliminary naval bombardment was insufficient.7 Any hopes that had been pinned on the ability of naval gunfire and aerial bombardment to “obliterate” the target proved false. In spite of the more than 3,000 tons of explosives thrown at or dropped on the island of Betio immediately before the landing, the majority of Japanese weapons there were still in operation when the troops reached shore.
The difficulty was that there were too many targets to be destroyed for the time allowed. Naval ships had time to deliver pinpoint destructive fire only against such well-defined targets as coastal defense weapons and heavy antiaircraft batteries. If the beach preparation had been spread over a longer period of time, with slower fire to allow ships to observe their targets and determine the effectiveness of that fire, it would have been far more effective. As it was, with the limited time available, ships’ guns had to resort to mere area bombardment, or neutralization fire, long before it could be accurately determined how many of the enemy’s guns had been actually knocked out of action. Neutralization is not destruction, as the marines who went ashore soon discovered. One solution for the deficiencies of naval gunfire at Tarawa was clear. For naval ships effectively to support landing operations they would have to deliver slow, deliberate, pinpoint fire against selected targets and maintain constant observation of the damage actually done by their salvos. This would require time—more time than was allotted to the support ships at either Tarawa or Makin.
Another conclusion in respect to naval gunfire support that emerged from the Tarawa operation was that an insufficient proportion of major-caliber armor-piercing shells was employed by the firing ships. Against the steel-reinforced concrete pillboxes found on Betio, 5-inch antiaircraft and 6-inch bombardment shells had little effect. For future operations against well-fortified positions of this sort, it was recommended that greater reliance be put on the heavy guns of battleships and that a larger proportion of armor-piercing shells be employed.8
Still another deficiency in both the plan and the execution of preliminary naval gunfire at Tarawa was the rapid shifting of fire from one target to another. This was based on the principle of keeping the enemy guessing as to where to jump next by placing fire into areas in an unpredictable sequence. Experience at Tarawa showed that although this type of bombardment was useful for neutralization, it failed to achieve the degree of destructiveness desired. Destructive fire called for accurate control, which was rendered impossible by sudden, large, and frequent shifts of fire. For future operations, it was recommended that less radical shifting be employed, and that naval fire be laid directly toward or away from, and right or left of an established reference point. Thus, it was believed, more accurate fire control could be maintained and greater damage be done to well-covered enemy emplacements.9
Also at Tarawa, naval gunfire on the beaches was lifted too soon. One reason for this was to permit a last-minute aerial strafing and bombing run along the shore line, but the precaution was unnecessary. Actually, the planes did not fly low enough to be endangered by ships’ gunfire. The desirability of a last-minute naval barrage, more effective than aerial bombardment, was clearly demonstrated. At Makin this had been partially provided for by equipping some of the leading amphibian tractors with 4.5-inch rockets, which were fired to good effect on Yellow Beach.10 At Tarawa only two small support craft (LCSs)
were furnished with rockets. These were fired from the flanks of the leading wave with indeterminate effects. An alternative to a last-minute rocket barrage would have been the employment of armored amphibians (amphibian tanks) in the first wave. These could be equipped with 37-mm. or 75-mm. guns and would have provided excellent close support fire for the assault waves. Another device that was clearly suggested by the landing on Betio was the continued employment of destroyer fire in support of the leading waves until just before the landing. In the one instance where this was done, on Red Beach 3 at Tarawa, casualties to the troops in the ship-to-shore movement were reduced to a minimum. In the opinion of General Julian Smith, close support fires by destroyers should have been maintained all along the beach until the troops were within a hundred yards of the shore line.11
These various deficiencies in both the quantity and quality of naval preparatory fire at Tarawa pointed up a corollary lesson—the desirability of an early landing of artillery on islands adjacent to the main target to assist the attendant naval ships and aircraft in laying down a heavy bombardment preliminary to the principal landings. The configuration of Central Pacific atolls was such as to make this tactic feasible, other conditions permitting. In every case the larger islands, which were invariably the most heavily fortified, were separated by only short distances from smaller neighboring islets within easy artillery range. During the invasion of Tarawa it was not thought practicable to emplace artillery on the islets adjacent to Betio well in advance of the main landing for the same reason that it was not believed wise to provide for a more prolonged preliminary naval bombardment—the fleet should not be exposed to enemy action any longer than could possibly be helped. By the time that the Marshall Islands were invaded this danger was no longer so acute, and it was possible for the planners of those operations in each case to make provision for placing artillery on the smaller islets of the atolls some hours before the initial landings on the main islands.12
Close Air Support
Clearly, the most disappointing aspect of the entire Tarawa operation was the execution of air support for the landing. The inadequacy of air support was attributed in about equal measure to poor communications, poor coordination, and the poor training of the carrier pilots.
The plans called for a dawn strike on the beaches from 0545 to 0615. This strike was twenty-five minutes later than was expected by the ground troops and naval surface forces present. Admiral Hill’s support aircraft commander aboard the flagship Maryland was unable to establish communication with the striking groups to determine their status. Maryland’s main batteries were firing and the concussion apparently disrupted her radio communications. The majority of planes attacked between 0610 and 0620.
The H-Hour air strike was scheduled for the period from H minus 5 to H plus 15 minutes, with H Hour set at 0830. At 0820 the air groups were informed that H Hour would be delayed until 0900. This change of plans was either not received or was disregarded by the planes, and fighters commenced strafing the beaches at 0825 as originally scheduled. At 0842 they were
finally reached and directed to cease firing. At 0855, on the anticipation that H Hour would be 0900, surface ships were directed to stop firing and fighters were ordered to strafe the beaches. In fact, the fighters did not arrive to strafe until just before 0910, and by that time the first troops were coming ashore and the mission had to be canceled.13
In addition to the poor coordination of air support with the other arms, it was evident that the carrier squadrons were not fully enough trained to provide efficient air support of amphibious operations. One carrier commander reported that carrier flights operated over the target area on D Day with little semblance of orderly procedure. Serious confusion resulted when dive and glide bombing and strafing was carried out to the taste of the individual leaders.14 Pilots experienced considerable difficulty in locating and striking targets as requested, both before and after the troops landed. It became apparent that the pilots had not been thoroughly briefed and that they lacked sufficient knowledge of the general techniques employed by landing forces in an amphibious operation. One solution to the problems thus raised was suggested by General Holland Smith—to assign at least one Marine aircraft wing specifically to give direct air support to landing operations. The wing, he recommended, should make direct air support a specialty, should train specifically for that purpose, and should be given a complete background of amphibious operations and a period of thorough training in the problems peculiar to air support of landings.15
Communications
The failure of communications aboard the battleship Maryland on several critical occasions during the landing on Betio served to point clearly to the need for specially constructed and equipped headquarters ships in future amphibious operations. The simple fact was that no battleship was suited to perform the duties imposed on Maryland. Her transmitters, receivers, and antennae were too close together and caused mutual interference. Several of her radio communications installations were so damaged by the shock of her own naval guns as to be completely inoperative. Furthermore, if a situation had arisen where the vessel would have had to leave the immediate area of Tarawa to engage in a surface fleet action, the ability of both Admiral Hill and General Julian Smith to exercise command would have been seriously impaired.16
All of these shortcomings were well recognized before the operation. Specially equipped headquarters ships were already under construction, but none was ready in the Pacific in November 1943. The ships would make their appearance in the Marshalls operations, but until they were completed the only alternative was to make the best of the means available. The experience with Maryland at Tarawa merely confirmed what had already been realized—that the battleship was inadequate as an amphibious command ship.17
The other outstanding communications deficiency revealed in the Gilberts operation was in tank-infantry liaison. On Tarawa as at Makin the communications equipment carried by the tanks broke
down completely. Tanks could communicate neither with each other nor with the infantry units they were supposed to be supporting. On Betio not a single member of a tank crew was killed inside a tank, but several became casualties getting out of their tanks in an effort to communicate with infantrymen. This deficiency could only be remedied by the installation of improved radio sets.18
Weapons
At Tarawa the 37-mm. gun, which was mounted on the light tank, proved virtually useless in knocking out pillboxes and various other enemy emplacements. However, fire delivered from the light tank was effective for holding the enemy down while infantry advanced. Whatever its merits in this connection, the light tank was generally incapable of the duties imposed on it. The consensus among most commentators was that in future operations against the Japanese the light tank be replaced by the medium tank mounting a 75-mm. gun.19
Perhaps the most valuable weapon at Tarawa proved to be the flame thrower. The greatest obstacle facing the troops in their advance was the extensive layout of Japanese pillboxes and heavy emplacements. Against these, flame throwers firing through ports and pillbox entrances proved invaluable. However, not enough had been assigned to the 2nd Marine Division, and it was recommended that for future operations at least one per rifle platoon be issued. Another suggestion made as a result of this experience was that tanks be equipped with large-capacity flame throwers.20
Logistics
The plans for unloading supplies and equipment on Betio followed the standard doctrine as set forth in current naval manuals on the subject.21 Control over small boats was vested in the commander of the naval transport group and priority in unloading was given to the assault transport division on which were embarked the assault troops. Each assault landing team had a shore party that was to function on its own beach, the 2nd Marine Division shore party commander coordinating the activities of the separate shore parties. Parallel to the division shore party commander was a naval senior beach-master whose job was to coordinate the activities of three platoons of naval personnel assigned to unloading duties on the beach and to advise the transport group commander on the best methods of getting supplies and equipment from ship to shore.
As events worked out, none of these plans could be put into effect until late on the second day of the operation. During most of the first two days of fighting, the beachhead was neither deep enough nor safe enough to allow shore parties to function normally. Boats, on returning to parent ships, were loaded and dispatched to various beaches without awaiting the call of shore party commanders. Direct requests placed by the troops to the ships did not give adequate information and therefore many boats were loaded with nonessential material. Finally and most important, there was an insufficient number of control stations established off the beaches
to regulate the traffic of boats returning to the beach after their initial trips.
Much of this confusion was of course unavoidable, given the extreme difficulties of establishing the beachhead. The whole concept of the shore party in amphibious doctrine presumes the establishment of a protected area along the shore line sufficient in depth to permit the physical unloading of boats and the dumping of supplies and equipment on land in a relatively orderly fashion at places where troops can get what they need when they need it. None of these conditions obtained during the first two days of fighting on Betio. Yet this was not all that was amiss. Even had a comparatively safe beachhead been established, the offshore control system was inadequate to meet the requirements imposed on it.
Hence, it was recognized that in future operations control boats should be stationed at or near the line of departure for the purpose of directing traffic to and from the beach. After the initial assault, only such equipment and supplies as would probably be immediately required ashore should be boated and the boats should then be dispatched to a central control vessel offshore for assignment to separate beaches. The control vessels, it was recommended, should be under control of a senior naval officer assisted by an officer representing the landing force. In this manner, it was hoped, much of the confusion evident at Tarawa could be avoided.22
One final logistical lesson that was pointed up by the Gilberts operation was the desirability of pallet loading in amphibious landings. Pallets had been used extensively at Makin and with excellent results.23 None had been made available to the 2nd Marine Division for Tarawa and the lack had been noted. Holland Smith’s headquarters concluded, “pallets are unquestionably necessary in landing operations,” and set forth immediately to provide Marine divisions with the requisite number for future landings.24
The Amphibian Tractor
Of all types of amphibious equipment used in the Gilberts operation, the amphibian tractor was the most indispensable. “Without the amphibian tractor,” reported Holland Smith, “it is believed that the landing at Tarawa would have failed.”25 Speaking from his experience at Makin, General Ralph Smith concurred. “The use of amphibian tractors in this type of operation,” he said, “is considered mandatory to insure success and reduce casualties. ... Their necessity cannot be over-emphasized.”26
Yet if the presence of these vehicles spelled the difference between success and failure in the Gilberts, it remained true that there were not enough on hand, at least at Tarawa. The 125 amphibian tractors assigned to the 2nd Marine Division were not enough. Only the first three assault waves could be initially carried ashore by amphtracks. Subsequent waves boated in standard Navy landing craft were stopped at the reef, and the troops had to wade into the beach or await transfer to LVTs. Thus, the momentum so necessary to amphibious assault against a well-defended shore line was halted. The
result was only short of disaster for the attacking troops.
General Julian Smith recommended that in the future no less than three hundred troop-carrying LVTs be furnished each Marine division, plus an additional twenty-five for cargo-carrying purposes.27 Admiral Nimitz concurred.28 Never again in the Pacific war would the assault troops be so handicapped as they had been at Tarawa for lack of these essential vehicles.
Conclusion
Strategically speaking, the Gilberts operation was not a turning point in the Pacific war. It was only a prelude to the invasion of the Marshalls, which in turn was a prelude to more decisive naval and land victories in the Carolines and the Marianas. The chief strategic significance of this operation is that it was the beginning of the Central Pacific drive against Japan. It had been decreed by the Joint Chiefs of Staff that the Central Pacific drive would constitute the “main effort” in the Pacific war.
Largely because of the limited means available to Admiral Nimitz’ forces, the drive was initiated not against the geographic center of Japanese power in the mid-Pacific, but against the perimeter. Yet victory in the Gilberts certainly paved the way for the relatively easy conquests in the Marshalls that were to follow. Air bases were obtained without which adequate bombardment and photographic reconnaissance of these more important targets would have been difficult if not impossible to obtain.
Tactically speaking, the Gilberts landings, especially that on Tarawa, were chiefly important as a testing ground of established amphibious doctrine. Never before in the Pacific war had such an experimental opportunity presented itself. After Tarawa there was no doubt that the techniques, tactics, and procedures set forth in the basic U.S. manuals for landing operations were workable even under the most difficult conditions. Some shortcomings and deficiencies in the execution of the landings were revealed. The most serious deficiencies stemmed from shortages of amphibious equipment and from lack of sufficient naval power or previously emplaced artillery to permit as prolonged a period of preliminary bombardment as was desirable. These could only be corrected as production of the necessary arms caught up with the needs of the Central Pacific drive. Meanwhile, avoidable errors and omissions in execution were carefully noted and studied by all echelons concerned in the Gilberts operation. And, what is more important, steps were immediately taken to avoid their repetition in the future.