The Fruits of Victory
The conquest of the Marshalls was a far more significant victory than the previous success in the Gilberts. FLINTLOCK and CATCHPOLE represented a shattering of the line of outposts that protected the inner defenses of the enemy homeland. As far as the Japanese were concerned, the Marshalls themselves were not indispensable, but the speed with which the American forces moved robbed the enemy of the time he needed to prepare for the defense of the more vital islands that lay nearer to Japan.
THE ENEMY SITUATION1
Among the victims of FLINTLOCK was the Japanese naval base at Truk. On 10 February, immediately after the loss of key islands in Kwajalein Atoll, the enemy decided to withdraw his major fleet units to prevent their destruction by American air power. The carrier raid that preceded CATCHPOLE made Truk a rattlesnake without fangs. Nimitz concluded that no amphibious assault would be necessary and abandoned a plan that called for the employment of five divisions and one additional regiment. Once Truk had joined Rabaul and Kavieng in the backwash of World War II, the 1st, 3d, and 4th Marine Divisions, the 4th Marines, and the 7th and 77th Infantry Divisions were freed for service elsewhere in the Pacific. American planners could now look forward to the Marianas.
The loss of the Marshalls and the resultant neutralization of Truk caused the enemy to revise his strategy. Early in March, Admiral Mineichi Koga, commander in chief of the Japanese Combined Fleet, established still another zone in which interception operations could be carried out against the American fleet. Patrol planes, submarines, and picket boats were charged with detecting any attempt by Nimitz to penetrate the Central Pacific Front, an area stretching from the Kuriles past Honshu, through the Bonins, Marianas, and Carolines, and terminating in New Guinea. Should the United States fleet venture into the area, land-based planes would blast the carriers to enable surface ships to close with and sink the troop transports. The Japanese admiral urged his men to destroy as many of the invaders as possible while the expedition was at sea. The survivors, in keeping with current tactical doctrine, were to be annihilated at the beaches. This was the gist of Koga's proposed Z Operation. Admiral Koga was killed in a plane crash before his plan could be executed,
but his successor in command of the Combined Fleet, Admiral Soemu Toyoda, had ample time to modify this basic strategy before the Americans struck. This revised plan, dubbed A-GO, also called for strengthening the island defenses along the Central Pacific Front. Toyoda, however, established two "decisive battle areas," the Palau Islands and the western Carolines. If amphibious forces should attempt to seize outposts in either the western Carolines, the neighboring Marianas, or the Palaus, the defense forces already posted in the threatened sector were to hold fast. The bulk of the Imperial fleet, now based at Tawi Tawi off Borneo, would stream northeastward to crush the Americans.
CATCHPOLE, following so closely after FLINTLOCK, made it inevitable that Japan would have extreme difficulty in completing the preparations necessary for A-GO. The decision to bypass Truk left Nimitz with enough well-trained troops, many of them combat veterans, to deliver a sudden blow at the Marianas. The enemy wanted to reinforce these islands before they were attacked, but in order to move the necessary men and their supplies, the Japanese had to place a heavy strain on an already weakened merchant marine. By the beginning of March 1944, the available enemy merchant shipping, almost 6½ million tons at the outbreak of the war, had been reduced to about 4 million. American submarines had wrought most of this destruction. Now, thanks to the Marshalls operations, these undersea raiders would be able to operate from a base 1,200 miles closer to the Marianas.
This second part of the Central Pacific campaign had come to a close with the capture of bases some 800 miles within enemy territory. The Japanese had been driven back to their inner defenses. American amphibious forces demonstrated beyond question that they had absorbed the lessons offered by the assault upon Betio.
Besides securing bases from which to mount further operations, the Pacific Fleet, by seizing certain key objectives, had succeeded in neutralizing the more powerful Japanese bastions in and near the Marshalls. The "unsinkable aircraft carriers," in which the enemy had placed so much confidence, remained ready to receive planes, but none could be sent them. American carrier task forces had driven the Japanese from the skies over the Marshalls, and land-based planes from the recently captured atolls stood ready to maintain this mastery of the air. The careful selection of targets coupled with a skillful use of the available air, ground, and sea forces meant a saving in lives as well as time.
In addition to these strategic gains, the Americans amassed additional experience in atoll warfare. Although the Marshalls operations represented some improvements in tactics and techniques over previous efforts, planners as well as troop leaders were well aware of errors that thus far escaped correction. Only by coldly assessing the campaigns just completed, noting weaknesses, and making the necessary corrections could Nimitz' amphibious forces lay the groundwork for future victories.
Like the Gilberts expeditionary force, the organizations formed for FLINTLOCK and CATCHPOLE did not include replacement pools. Planners had decided that casualties in the brief but intense Marshalls actions would not be severe enough to impair the effectiveness of the landing forces. At Kwajalein Atoll, no serious difficulties were encountered by the assault divisions, but the Roi garrison had to call for an emergency draft of 27 men to replace casualties suffered during the 12 February Japanese air raid. At Eniwetok, however, a series of relatively brief fights gradually wore down Tactical Group 1 to such an extent that General Watson ordered rifle units formed from among elements of his garrison forces.
The staff of Tactical Group 1 had been hard pressed to keep an accurate tally of casualties. What was needed, General Watson decided, was a single center for compiling such data, a clearing house that would be located in the flagship of the attack force commander. VAC pointed out that directives then in force called for just such a system of accounting. The fault lay in the various commanders, who seldom reported accurately or on time.
American intelligence concerning Kwajalein Atoll was accurate, but General Smith's staff desired more extensive coverage by oblique aerial photographs and wanted the pictures delivered at least 90 days prior to D-Day. General Watson, whose Parry Island assault troops had been confused by a redesignation of the beaches, noted that the arbitrary designation of "color" beaches by higher headquarters was not always advisable. He believed that the attack force commander should have additional leeway in designating the area to be stormed. Looking back on the Eniwetok operation, Watson also called for the marking of known defenses on maps as small in scale as 1:20,000, a more careful delineation of the coastline and of all landmarks upon which the tractor waves might guide, and photographic coverage of every island within the atoll to be attacked. JICPOA had done an accurate job in placing the bulk of the 1st Amphibious Brigade at Eniwetok Atoll, but photographs taken prior to D-Day did not indicate the type of defenses that the enemy had prepared. By the time of the main landings, General Watson was aware of the enemy's strength and probable dispositions. The extent of the Japanese underground defenses, however, was not known until the Americans actually encountered them.
Neither of the Marshalls operations represented any departure from the established command structure for amphibious operations. Although the position of the corps commander was clarified for the Kwajalein landings, the nature of the undertaking prevented General Smith from exercising close tactical supervision. Essentially, FLINTLOCK consisted of two distinct series of
RIFLEMEN of 22d Marines advance toward the last Japanese-held area on Parry. (USMC 74488)
MARIANAS INVASION FORCE assembled in the lagoon at Eniwetok Atoll on 9 June 1944. (USN 80-G-248207)
landings by widely separated divisions. Admiral Turner, however, later noted that "all Central Pacific amphibious operations in which I was concerned needed at least a corps command of expeditionary troops."3 The principle, then, was already accepted. As soon as VAC attacked a suitable land mass, its commanding general would direct more closely the actions of its assigned divisions.
As far as planning was concerned, the staffs of both VAC and Tactical Group 1 voiced the same complaint--not enough time. Indeed, every agency involved in the planning of FLINTLOCK and CATCHPOLE was working against a rapidly approaching deadline. For this reason, final versions of certain annexes of the basic plans were late in reaching the assault units. The most conspicuous victims of this situation were the LVT and LVT(A) battalions, which had not received their orders for the Roi-Namur landings in time for rehearsals. ln particular, this fact hampered their communications, since radio frequencies had to be set en route to the line of departure.4
If nothing else, the Marshalls fighting proved the value of sound training climaxed by realistic rehearsals. The shortcomings of Marine amphibian tractor crews at Roi-Namur and of Army infantrymen on Eniwetok Island were blamed on a lack of indoctrination and practice. VAC headquarters could account for the poor quality of the amphibious rehearsals staged for Tactical Group 1. Watson's command completed its training while the FLINTLOCK expedition was being mounted, so the assault units rather than the reserve had first call for the limited number of DUKWs and LVTs then available. The 10th Amphibian Tractor Battalion had completed its final exercise before the plan of attack was ready for distribution. As General Smith went on to point out, there would be times when speed was so essential that rehearsals were certain to be inadequate.
In the case of the Marshalls operations, speed denied the enemy time to convert the objectives into fortresses as powerful as Betio Island had been. Firepower helped the American landing forces to succeed in spite of the minor defects in their training and employment. The prolonged naval bombardment of targets in Kwajalein Atoll was supplemented by the effective fires of artillery units emplaced on islands off the principal objectives. The quality of naval gunfire, and of air support as well, had improved since GALVANIC. General Schmidt, for example, estimated that between 50 and 75 percent of the Roi-Namur garrison was killed by either naval shelling or aerial attack. At Eniwetok Atoll, neither planes nor warships were as deadly, for the planned bombardment was based on an incomplete knowledge of the nature of the Japanese defenses. The troops fighting ashore at Eniwetok, however, benefited from the first heavy use of night illumination shells by supporting naval vessels.
The landings, screened by the fires of
LVT(A)s, LCI gunboats, and warships, were hampered by poor communications. In Kwajalein Atoll, where the sea was rough, many of the radios carried in LVTs were drowned out by spray, thus insuring a confused advance toward the beaches. Once again, Marine officers renewed their appeal for communications equipment that was adequately waterproofed.
Ashore the Marine troops fought well. What mistakes they did make were those expected of men entering combat for the first time. The unauthorized sprint across Roi, for example, upset the prearranged scheme of maneuver, although it undoubtedly kept the enemy off balance. This advance was traceable to the Marines' desire to excel in their first battle. Although the 22d Marines had trained ceaselessly during its stay in Samoa, this unit, too, needed the experience of actual warfare. During CATCHPOLE, unnecessary firing decreased in volume as the troops became used to fighting at night. In addition, the men of the regiment learned to avoid leaving weapons scattered about the battlefield where Japanese infiltrators could find them. In attacking enemy emplacements, whether concrete bunkers or underground spider webs, flamethrowers, demolitions, and hand grenades proved most deadly. The division of rifle squads into fire teams, as practiced by the 22d Marines, was a successful innovation, for these elements were especially effective in dealing with enemy positions that were located in wooded or overgrown areas.
Most aspects of the logistical plans for FLINTLOCK and CATCHPOLE represented improvements over GALVANIC. The DUKW justified the confidence that General Corlett had placed in it, and the "hot cargo" system, as practiced by the 7th Infantry Division, proved a reliable method of getting priority cargo ashore during the early hours of an amphibious operation. Generals Schmidt and Watson also had critical items of supply pre-loaded in amphibious vehicles, in their case LVTs, ready to be landed at the request of the units ashore. Corps observers were convinced that the amphibian truck was better suited for carrying supplies than the tractor, for the DUKW had a larger cargo compartment and was easier to repair.
During the Marshalls fighting, the LST performed several important duties. Except for those units which seized the islands adjacent to Roi-Namur, all the Marine assault forces boarded their assigned tractors before the LVTs were launched by their parent landing ships. Thus, the troops were spared the ordeal of transferring in the open sea. Besides carrying LVTs and providing enclosed transfer areas, this same type of ship participated in the logistical plan. Certain LSTs carried food, water, and ammunition, others served as hospital wards, and still others carried tools and spare parts with which to repair damaged tractors.
The amount of supplies carried to Kwajalein Atoll proved, in some instances, more than sufficient, but the troops at Eniwetok Atoll endured shortages in concussion grenades and demolitions fuzes. Fortunately, the men had enough ammunition. One item that was habitually discarded as soon as the troops landed was the gas
mask, which General Watson considered a "distinct nuisance."5
The limited area available prevented the proper dispersal of supply dumps, but otherwise the movement of cargo to the troops inland was well executed. Pallets permitted the rapid landing of bulk cargo, and a permanent beach party organization assumed responsibility for controlling boat traffic and the evacuation of the wounded. After observing these beach parties in operation, Admiral Turner's headquarters recommended that a permanent shore party similar to that used in the Southwest Pacific be organized. A well-trained nucleus could be reinforced as necessary by labor contingents and garrison units, so that the handling of supplies no longer would depend on men borrowed from the assault battalions.
The role of Marine aviation in the Marshalls was little changed from the previous operation, for General Smith's recommendation that Marine pilots based on carriers support future landings had not been accepted. The performance of Navy airmen, however, was improved, thanks to better planning and careful briefing. During FLINTLOCK, aircraft had attacked in conjunction with the preliminary naval bombardment. Since the experiment had proved successful, VAC recommended that similar aerial attacks be carried out in forthcoming landings. General Watson's command had not benefited from this kind of coordination. Rather than suspend naval gunfire to enable the planes to make a final strafing run, he urged that this last-minute strike be omitted in future landings.
Immediately after the capture of bases in Kwajalein and Eniwetok Atolls, Marine fighter planes arrived to help defend these conquests. Between 15 and 23 February, elements of two Marine fighter squadrons (VMFs-224 and -532) began flying combat air patrols from Kwajalein. VMF(N)-532, using radar-equipped F4Us, was responsible for patrolling the night skies. Although ground crews landed on Engebi while that island was being mopped up, Marine fighter craft did not make their appearance there until 27 February. VMF-113 operated during daylight, and a detachment from VMF(N)-532 took over after dark. On 14 April, the Engebi-based night fighters made their first kills of the war, destroying two Japanese planes and probably shooting down a third.
During the critical hours after the landings, the antiaircraft units from defense battalions were employed to protect the beachheads. Scout bombers also assisted indirectly in the aerial defense of the Marshalls bases by helping neutralize the bypassed atolls. In short, Marine aviators played a slightly larger role in FLINTLOCK and CATCHPOLE than they had in GALVANIC, but support of the landings remained the responsibility of the Navy. In addition, naval aviators operating from carriers prevented the Japanese from launching aerial attacks against the expanding beachhead, a task which they shared with Marine and Army antiaircraft units.
In summing up the FLINTLOCK operation, General Smith noted that the lessons learned in the Gilberts had
proved invaluable. "In the attack of coral atolls," read his report, "very few recommendations can be made to improve upon the basic techniques previously recommended and utilized in FLINTLOCK. However, there is still much to be desired to improve planning, improve coordination of efforts, and prepare for the attack of more difficult objectives."6 As the Central Pacific drive moved westward, the enemy's island defenses seemed certain to improve.
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 Unless otherwise noted, the material in this section is derived from: Hattori, Complete History, v. 3, p. 5; Isely and Crowl, Marines and Amphibious War; USSBS, Campaigns of the Pacific War.
 Unless otherwise noted, the material in this section is derived from: TF 51 AR; TF 53 AR Roi-Namur; VAC AR FLINTLOCK (including rpts of staff sections, Encl. C-H) ; VAC Rpt of LogAspects; VAC Cmts on TG 1 SAR, dtd 1Apr44; TG 51.11 OpRpt; 4th MarDiv AR; TG 1 SAR; ComInCh, Marshall Islands; Sherrod, Marine Air History.
 Turner ltr.
 The radio frequencies received in the plan could not be set up within the LSTs, consequently units had to struggle to establish them once they were launched for the landings. Metzger ltr.
 TG 1 SplRpt, p. 15.
 VAC AR FLINTLOCK, p. 11.