Part VI
Saipan: Employment in Mass

The Combined Chiefs of Staff shaped the final strategy for winning the Pacific War against Japan during the Casablanca Conference of January 1943. They decided that the decisive route of advance toward Japan would be the Central Pacific through the Marshalls, Truk, and then to the Marianas Islands. MacArthur's advance through the Southwest Pacific via the Solomons, New Britain, New Guinea, and the Philippines would provide flank security for the main Central Pacific operations. The next objectives after the capture of the Marshalls in February 1944, were among the toughest--Truk and the Marianas.

Truk had long been regarded as the anchor of Japanese strength in the Central Pacific area and was listed as a prime objective along the route of advance. It contained air fields, naval repair and staging facilities, and a sizeable garrison of ground troops, and with such strength any attempt to bypass it would create a threat in the rear of American units moving forward to other objectives. The Marianas also contained sizeable forces and would offer the United States a new set of important advanced bases for the final operations against Japan. The position of the Marianas, 1,200 miles south of Japan, became a key factor in early 1944 when the United States produced the B-29 bomber which, with a combat range of 3,250 miles, could span the distances to Japan. Bases developed for the B-29 in China began operations on 5 June 1944, but they were

--151--

Figure 24. B-29's delivering their payloads over Japan
Figure 24. B-29's delivering their payloads over Japan

--152--

considered insecure because there were doubts the Chinese could hold them against Japanese attacks.1 The Marianas offered the United States the first secure base for commencement of strategic bombing of the Japanese homeland with a heavy land-based bomber.

The strikes against Truk conducted by Naval carrier aircraft on 17 and 18 February, simultaneous with the Eniwetok landings, disclosed how weak Truk Atoll actually was. There were 365 planes caught on the ground by the 17 February raid and of the approximately one-hundred undamaged aircraft, none rose the next day to oppose the second raid of Navy fighter-bombers, apparently due to lack of pilots.2 By the end of the second day of air attacks, two cruisers, four destroyers, nine auxiliary craft, and twenty-four cargo and transport vessels had been sunk.3 The Navy had hoped for a decisive fight during the operations against Truk, but although none developed, the raids demonstrated just what a hollow shell the former bastion had become. The Japanese had withdrawn.

Original planning by Admiral Nimitz had included an attack on Truk and the date for operations against the Marianas was then set for 15 November 1944.4 The Joint Chiefs of Staff, however, were looking for ways to accelerate the pace of the Pacific War and the rapid capture of the Marshalls coupled with the weakness of Truk created the opportunity they sought. On 12 March 1944, they issued a directive setting 15 June as the target date for the seizure of the Marianas Islands to secure secondary naval facilities and a potential B-29 air base.5

The Marianas Islands are fifteen islands stretching 425 miles in a north-south direction, in the West Pacific Ocean. They were former German possessions which the Japanese received as part of the League of Nations Mandate in 1921, with the exception of the American possession of

--153--

Map 13. The Marianas
Map 13. The Marianas

--154--

Guam, won by the United States in the Spanish-American War. Only those islands in the southern portion had military significance including Saipan, Tinian, Rota, and Guam. During the first days of World War II, Guam had been seized by the Japanese despite the valiant stand of the few American military personnel on the island. Because the Japanese kept their activities cloaked in secrecy during the pre-war years, little was known of the islands until they became amphibious objectives during World War II.

The first target was the island of Saipan, the administrative headquarters for Japanese forces in the Marianas and location of several large airfields. It had ample room for construction of maintenance facilities and placement of artillery to fortify the later assault on Tinian, three miles to the south. The selection of Saipan as the first objective in the Marianas was therefore a logical one that lowered the risks in the attack against Tinian. It should be noted that the 2nd and 4th Marine Divisions were scheduled to attack Saipan as well as conduct the shore-to-shore operation against Tinian; three days after the landings on Saipan, the 3rd Marine Division and the 1st Provisional Marine Brigade would attack Guam. The reserve for the overall attack of the Marianas was the Army's 27th Infantry Division.

Saipan is an irregularly-shaped island with a length along the north-south axis of approximately 14.2 miles by 6.5 miles wide or a land area of about seventy-two square miles, far larger than the tiny atolls that Central Pacific forces had been attacking in the Gilberts and Marshalls. In contrast to the maximum elevation on Eniwetok of twenty feet above sea level, the highest point on Saipan is 1,554 feet on Mount Tapotchau, located near the center of the island. The northern and eastern sections

--155--

are rolling hills and plateaus which drop sharply into the sea in well-defined cliffs. The only exception to this is Magicienne Bay on the east coast with a usable beach and a coral reef, the only one on the east coast. The southern part of the island features a low-lying plain on which the Japanese built Aslito Airfield with a 3,600 foot main runway. The west coast has a coral reef along almost its entire length which narrows to between five-hundred and 1,300 yards in width.6

The beaches on the southern part of the west coast of Saipan offered the best entrances into the inland portions of the southern plains. This area was chosen as the landing beaches for the 2nd and 4th Marine Divisions on 15 June 1944. The presence of the coral reef dictated the use of LVTs in this landing and with two combat divisions landing abreast, each with 17,465 personnel, they were to be employed on a scale not seen up to this point in the war. Six battalions or six-hundred troop LVTs would be used and two battalions (or about 136 armored amphibians) would precede them to the beach. This massive application of the LVT on Saipan featured the use of the latest modifications off the production lines, and these changes represented significant improvements in LVT design.

The new cargo model was the LVT(4). The design was developed by the Food Machinery Corporation which utilized many of the basic components of the LVT(2) but included the much-needed ramp in the rear. The numbering system in this case appears out of sequence because of the concurrent attempt of Borg-Warner to develop a ramped LVT. Borg-Warner, it will be remembered, developed the Model A as the first armored amphibian but its design was rejected in favor of the Food Machinery models which became the LVT(A)(1) and LVT(2). After its initial failure, Borg-Warner continued development and next produced a prototype ramped LVT, the Model B, which

--156--

was to be called the LVT(3). Production difficulties delayed its completion and so the Food Machinery designed LVT(4) was the first ramped LVT to see action.7

The design changes in the LVT(4) were built around the requirement to incorporate a. ramp feature into the cargo LVT, a feature recommended almost from the first operations involving LVTs in the Solomons. With both the LVT(1) and (2), it was necessary to hoist all cargo, personnel, and weapons over the side of the vehicle to load into the cargo compartment. This cargo compartment was in the middle of the LVT with the driver's station forward to provide visibility, and the engine was in the rear. Food Machinery Corporation maintained the driver's position forward, but also moved the engine forward to a position just behind the driver which allowed the rear area to become the cargo compartment with the back side hinged and lowered. The hinged portion became the loading ramp into the vehicle and eliminated the need, to hoist the load over the side. Cargo could now be rolled, pushed, and generally man-handled far faster than ever possible using the old over-the-side method with earlier LVTs. Despite the extensive re-design to obtain this ramp, much of the vehicle used time-proven components including substantially the same track, engine, and transmission as the LVT(2). In order to give the rear loading ramp strength, substantial reinforcement was necessary. This, combined with the manually operated winch necessary to lower and raise the ramp, added about 2,600 pounds of weight to the vehicle and reduced land speed from thirty-one mph for the LVT(2) to twenty mph for the LVT(4); the water speed remained nearly the same for both vehicles, about six mph. Despite its added weight, the recommended maximum cargo for the LVT(4) was 2,500 pounds more than that for the LVT(2) due mainly to the

--157--

Figure 25. The LVT(4) and LVT(2) in a floating comparison.
Figure 25. The LVT(4) and LVT(2) in a floating comparison. Note that the LVT(4) floats about one foot higher.

Figure 26. A rear view of the first ramped LVT showing the massive ramp
which formed a separate watertight compartment.
Figure 26. A rear view of the first ramped LVT showing the massive ramp which formed a separate watertight compartment. This vehicle is at the LVT Museum, Camp Pendleton, California.

--158--

increased size of the cargo compartment, no longer cluttered and obstructed by the drive line. Both the LVT(2) and LVT(4) had the same ninety-four inch wide cargo space, but the LVT(4)'s space was longer at 150 inches versus 129 inches for the LVT(2). Production started on the LVT(4) during December 1943, too late for the Marshalls, but in time for Saipan. The following is a summary data table for comparison of the LVT(2) and the LVT(4):

  LVT(2) LVT(4)
Length 26'1" 26'1"
Width 10'10" 10'8"
Height 8'1" 8'1"
 
Crew 3 to 6 2 to 7
 
Weight: empty 24,400 lbs. 27,400 lbs.
Weight: loaded 30,900 lbs. 36,400 lbs.
 
Ground Clearance 18" 18"
 
Engine: make Continental Continental
Engine: type/model Radial-Gasoline
W670-9A
Radial-Gasoline
W670-9A
Engine: horsepower 250 250
 
Fuel Capacity 110 gallons 140 gallons
 
Radius: land 200 miles 150 miles
Radius: water 60 miles 75 miles
Sources: War Department Technical Manual 9-775, February 1944, and Robert J. Icks, "Landing Vehicles Tracked", in Armored Fighting Vehicles in Profile, ed. by Duncan Crow (New York: Doubleday & Company, Inc., 1972), p. 162.

The ramp feature allowed for the first time, loading a military jeep into an LVT or, with the muzzle elevated, a 105 mm howitzer. This ability to carry small vehicles and artillery pieces up to 105 mm greatly expanded the variety of applications for the LVT as the battle for Saipan approached.

The new armored amphibian was designated the LVT(A)(4). The origin of

--159--

Figure 27. Side view of the LVT(4) with a 105mm howitzer loaded
Figure 27. Side view of the LVT(4) with a 105mm howitzer loaded. The LVT(4) was the first LVT capable of carrying this artillery piece.

Figure 28. Inside view of the 105mm howitzer load
Figure 28. Inside view of the 105mm howitzer load. The tube is near full elevation.

--160--

the skip in numbering from the LVT(A)(2) to the LVT(A)(4) is obscure, But plans appear to have been made to build an armored version of the LVT(4), to receive the designation LVT(A)(3), which would be armored with a heavy gun, but without a turret. Although these plans were never completed, Food Machinery's new armored amphibian received the designation LVT(A)(4).8 This vehicle retained definite similarity to the basic configuration of the LVT(A)(1) but used a different turret and gun. The basic change in this case was more than just a heavier gun, in fact it replaced the LVT(A)(1) tank gun with an artillery howitzer. Since the capabilities of the gun determine the tactical usage of such a fighting vehicle, the new LVT(A)(4) moved away from the attempt to make the armored amphibian a tank and towards the role of an artillery weapon and an assault gun. A detailed comparison of gun performance will be useful:

  LVT(A)(1) LVT(A)(4)
Caliber 37 mm 75 mm
Muzzle Velocity 2,900 feet per second
(Armor piercing ammunition)
1,250 feet per second
(High explosive ammunition)
Max. Range 12,850 yards 9,610 yards
Source: E. F. Hoffschmidt and W. H. Tantum IV, United States Military Vehicles, World War 2 (Old Greenwich: W.E. Inc., 1970), pp. 56, 89.

The prime mission of the 37 mm gun in the United States arsenal of weapons was to defeat enemy armor. This called for a high-speed, armor-piercing round of ammunition with a flat trajectory. While valuable in some limited applications against light fortifications, the 37 mm rounds did not have either the penetration power or explosive charge required to damage heavy Japanese fortifications. The heavier explosive charge packed in the 75 mm howitzer of the LVT(A)(4) capitalized on the demonstrated

--161--

Figure 29. Side view of the LVT(A)4
Figure 29. Side view of the LVT(A)(4). A machine gun mount is on top of the turret.

Figure 30. Overhead view shows the open-top construction of the turret
Figure 30. Overhead view shows the open-top construction of the turret.

--162--

effectiveness of 75 mm guns used on Tarawa, Roi-Namur, and Eniwetok. However, as seen from the table above, the howitzer uses high explosive ammunition which gains its effect through blast rather than penetration, as in the case of the armor-piercing round of the 37 mm tank gun. Because howitzer rounds are larger, slower, and travel in an arching manner or high trajectory, targets shielded from the direct fire of the 37 mm tank gun may be reached by the 75 mm howitzer since its rounds fall more from above than those of the flat-shooting tank gun. The 75 mm howitzer mounted in the LVT(A)(4) represented a definite break with previous gun and mission thinking with respect to armored LVTs.

Another significant difference was that the new armored amphibian's turret did not provide for gyro-stabilization of the main gun. Gyro-stabilization is a system that maintains the gun in a constant elevation set by the gunner, despite the rolling, pitching, and lurching of the vehicle. The LVT(A)(1) had this system in its turret for the 37 mm main gun. Without gyro-stabilization, accurate shooting on the move is impossible. The best technique for firing the main gun of the LVT(A)(4) was a form of snap-shooting or firing as the target appeared to be nearing the cross hairs of the sight and not waiting for an ideal or perfect sight picture prior to firing.9 The reason the LVT(A)(4) lacked gyro-stabilization stems from the military approach to use standardized and time-proven components of tank and armored vehicles to achieve quick and workable solutions to a problem. Thus, when the turret of the M3 light tank was used on earlier LVTs, gyro-stabilization was included because it came as standard equipment with the turret and gun. In contrast, in searching for a larger 75 mm gun for an improved armored LVT, the turret of the M8 self-propelled howitzer was considered to be the satisfactory

--163--

answer, but this turret did not come with gyro-stabilization because the mission of the M8 was to fire from a stationary position as artillery.

Saipan's planning called for troop LVTs and LVT(A)(4)s of the 4th Marine Division to penetrate inland to capture high ground dominating the beach. It was hoped to capitalize on the armored mobility and fire power of the LVT and the armored amphibian combination to cover ground rapidly at the outset. The high ground was designated the O-1 line and required a movement of 1,500 to 2,000 yards inland.10 This plan had the definite side benefit of clearing the narrow beaches which averaged only twenty to thirty yards wide and allowing the large number of troops in succeeding waves room to land. Initially, the plan to penetrate inland was to apply to both the 2nd and the 4th divisions but General Watson, Commanding General of the 2nd Marine Division, took strong exception to using this method in his zone of action because heavy woods lay just behind the narrow beaches and he feared loss of control of the troops over an extended period of time while they continued inland in LVTs. Also, he felt the grouping of men into the vehicles would expose them unnecessarily to fire as they moved inland.11 In his zone, General Watson secured permission from General Smith to have movement no more than 200 yards inland to a tractor control line marked by a railroad line. The troops were to disembark at this point while the armored amphibians (LVT(A)(1)s and a few LVT(A)(4)s of the Army's 708th Amphibian Tank Battalion) delivered overhead support fire from the vicinity of the beach. Troop-carrying LVTs were also to deliver overhead support fire from their machine guns until the next wave reached the control line. They were then to return to the LVT pool for further use as directed by the control vessel at the line of departure.12

--164--

The plans thus formed did not differ substantially from earlier use of the cargo LVT or armored amphibian except that a deep penetration was to be attempted to high ground by General Schmidt's 4th Marine Division. Subsequent use of the LVT(A)(4) was to be reinforcement of the artillery or to support infantry by direct fire. In contrast to earlier landings, two full tank battalions, the 2nd and 4th, supporting their parent divisions, would land and assume the missions appropriate for tanks, thus preempting this role for armored amphibians. Saipan's plans therefore moved the armored amphibian more towards artillery fire support and direct fire support as an assault gun--that is, from behind a screen of infantry--rather han attempting to lead infantry as was frequently done by tanks.

The plans laid for the LVT, particularly in the 4th Marine Division zone, were not based on the comprehensive knowledge of the terrain needed for operations across such an extensive land mass. Intelligence gathering for the Saipan landing suffered from problems stemming from too few aircraft for too many concurrent missions in the various theaters of war in the Pacific. Aerial photo coverage fell far short of ideal considering the size of the objective and the complexity of the terrain. Intelligence officers had little knowledge of the island until carrier planes attacked Saipan on 22-23 February 1944. Aerial photos were taken of certain portions of the islands during these raids, but these photos were mad.e by attack planes whose targets did not always coincide with areas required for proper landing force intelligence. Also, enemy anti-aircraft fire made it unhealthy for attacking aircraft to linger over areas that needed photo coverage. General Smith's Intelligence Officer wanted coverage ninety, sixty, thirty, and fifteen days prior to 15 June but the demands on carrier aircraft caused Admiral Spruance to deny further photo runs

--165--

from carrier aircraft.13 Between 17 April and 6 June, seven additional photo runs were finally made by high level Navy bombers, but these photos were not available to the landing force when it left Hawaii. They were delivered to the force when it staged at Eniwetok Atoll for some transfer of troops among the shipping, but the slower elements in the LSTs had already set sail by the time the photos arrived and only the division headquarters had access to this latest update. Map makers, working with the photos taken during the 22-23 February carrier raid as well as other scanty information, developed maps where slopes were assumed to be uniform unless shadows indicated a sharp rise or depression. Clouds, trees, and the angle at which the photo was taken sometimes helped to hide the true nature of the terrain and the maps were in error. Many cliffs, for example, were mapped as gentle slopes. While the 2nd Marine Division was aware of the difficulties for LVTs due to the presence of a heavy forest in their zone, the 4th Marine Division's plans, based on the erroneous terrain maps, would be frustrated by the rugged terrain that would prove more than a match even for LVT mobility. Intelligence further failed to establish an accurate count of the Japanese forces on the island. The final estimate was 15,000 to 17,600 Japanese consisting of 9,100 to 11,000 combat troops, 900 to 1,200 aviation personnel, 1,600 to 1,900 Japanese laborers, and 400 to 500 Koreans. The actual count was about 30,000 soldiers and sailors plus hundreds of civilians.14

As the task forces churned towards Saipan, preliminary bombardment commenced with carrier aircraft attacks on 11 June, which surprised the Japanese and destroyed 150 Japanese aircraft on the ground and in the air, and heavier aircraft bombing runs on 12 June.15 On 13 June a group of fast battleships arrived to begin shelling the beaches and other island

--166--

targets. These were newer battleships, built since 1939, and the Missouri and the New Jersey were among this class of powerfully armed ships. Despite their modern equipment, their bombardment was not as effective as it could have been. It was not certain if the waters off the west coast of Saipan had been mined by the Japanese, and, because the fast battleships had arrived before the slower minesweepers, the area close to shore had not been officially "swept" or cleared. As a result, the battleships were required to stand off at ranges over 10,000 yards to fire rather than the 2,000 yards normally employed to achieve pinpoint destruction. The spotters and crews of the fast battleships were not as well trained as the old battleships which up to this point had been the mainstay of the naval bombardment; many targets remained intact. In addition, the fire tended to be area fire rather than the methodical point-by-point destruction required to clear the way for a landing. The fire of these ships, however, was not intended to replace but rather to supplement the close-in work by the veteran gunfire crews of the older battleships scheduled to arrive the next day.16 On 14 June, the old battleships arrived and began their short-range destruction of targets around the beaches, however, Japanese use of camouflage was excellent with many mobile guns enabling them to move out to shoot, then duck under skillfully constructed natural covers in caves or hillsides. Other factors mitigated the effect of the bombardment. Naval ships were required to conserve ammunition for the bombardment of Guam, scheduled three days later, and on D-Day no naval gunfire was to fall more than 1,000 yards inland, leaving only aircraft to attack inland targets. The latter order was issued to conserve precious time required to coordinate fires but in fact resulted in many targets escaping fire from the weapon

--167--

best suited to destroy them.17 Overall, there was also the basic problem of insufficient time. The destruction by the experienced naval gunfire ships was scheduled for one day only, hardly adequate to do the job. There would be many more Japanese on the beaches than expected.

The gunfire plan for the approach of the LVTs to the beach was a product of amphibious experience and represented tightly coordinated fire support. The line of departure for Saipan was 4,000 yards offshore. When the LVTs reached a point, 1,000 yards from the beach, the main batteries of the old battleships were to cease fire on the beaches and shift inland. Aircraft would start their final neutralization runs when the LVTs were 800 yards from shore, flying over the path of the naval shells. Five-inch guns were to continue to fire until the LVTs were only 300 yards from shore. Aircraft were to continue to attack the beach right up to the point of landing.18

The task forces approached the island and went into positions seaward of the line of departure on the morning of 0-Day, 15 June 1944. There was considerably less shuffling of troops to load LVTs than previously in the Marshalls because during the staging at Eniwetok, six days earlier, assault troops had been transferred to the LSTs carrying the LVTs that were to land them. After six days in a cramped LST, the marines were mean enough to attack anybody.19 Other lessons learned in earlier engagements were now applied. LVTs at Saipan were supplied with bundles of wooden plugs to pound into holes punched in the hulls by gunfire or coral to seal them until they could be welded.20 Cargo LVTs in the lead waves were given two sand bags, partially filled with sand, which were placed on the rear of the cargo compartment, with instructions to the crew to throw the bags over any grenades landing inside the vehicle. The

--168--

Map 14. D-Day at Saipan
Map 14. D-Day at Saipan.

--169--

operation orders gave further grim instructions, "If you can't get a sand bag, place your helmet over it. If at all possible throw it out. You may lose your hand, but that's better than your life."21 The crew chief's position was behind the driver to enable him to observe the front and sides and assist the driver in steering by the "hand tap" method. The operations orders cautioned, "Remember, this boy has little or no vision. The crew chief is his eyes."22 All cargo LVTs were loaded with certain assault supplies to assist in immediate supply of the infantry and to keep their own machine guns firing. This included four expeditionary cans of water for the infantry, four cases of belted machine gun ammunition, two cases of rifle ammunition, two cases of carbine ammunition, two cases of grenades, and about four rounds of either 81 mm or 60 mm mortar ammunition.23

The plans for the formation of armored amphibians and cargo LVTs resembled the tactics of the Marshalls on a massive scale. The outer flanks of troop-carrying LVTs were protected by six armored amphibians and the gaps between the battalion-sized landing teams were filled with a wedge-shaped formation of six more armored amphibians. This allowed firing by both the first wave of cargo LVTs and the armored amphibians simultaneously. Following waves were only to fire if they were attacked by aircraft. Three LCI gunboats were to precede each battalion landing team. LVT(2)s comprised the first three waves with the last wave consisting of LVT(4)s because these vehicles were better suited to carrying the heavier loads of headquarters elements, including wheeled vehicles.24

The forty-seven LSTs carrying the armored amphibians and LVTs reached their assigned positions 1,000 yards seaward of the line of departure at

--170--

about 7:00 A.M., on the morning of 15 June and began unloading at 7:00 A.M. Some LSTs were late in starting because the armored amphibians, positioned ahead of the LVTs on the main or tank deck, were difficult to debark.25 This and other minor problems caused the task force commander, Admiral Kelly Turner, to postpone H-Hour ten minutes from 8:30 to 8:40 A.M. Navy guide boats led the LVTs to their lines of departure where most of the waves were formed around 7:30 A.M., but some as late as 8:00 because one LST could not get its bow doors open.26 The signal to cross the line of departure was given at 8:05 A.M. and the leading waves composed of ninety-six LVTs, sixty-eight armored amphibians, and twenty-four LCI gunboats churned towards the line of old battleships pounding the beaches at ranges of 2,000 yards.27 The interval between the LVTs varied but averaged forty yards, although that of the lead wave was a little less due to its additional armored amphibians. The time interval between the waves varied slightly but ran generally at three minutes between the first and second waves, five minutes between the second and third waves, and eight minutes between the third and fourth waves. The compressed timing of the early waves was to land men and guns rapidly to secure a foothold. The early part of the 4,000 yard run from the line of departure to the beach was uneventful, only scattered Japanese fire falling near the line of departure. As the tractors closed on the barrier reef (about 1,000 to 1,500 yards offshore) however, Japanese fire became more intense and increased closer to the beach. There was high surf at the reefs edge, estimated by one battalion commander to be from twelve to fifteen feet, and one to two tractors per battalion were lost by overturning in the rough water. Mortar and antiboat fire increased as the LVTs moved from the reef towards the shore,

--171--

although the first two waves suffered only light losses from this fire. The third and fourth waves came under more accurate fire and losses increased to about one to two LVTs per battalion. Despite the efforts of the Japanese, the first waves hit the beach between 8:38 A.M., and the following three waves of LVTs came in five to nine minute intervals. The relatively light losses were due in part to the spot armoring of the cargo LVTs with 1/4 and 3/8-inch armor on the hull, and 1/2-inch armor on the cab and bow. Although some did penetrate, many rounds as well as much shrapnel were turned.28 Control craft guiding the LVTs were unable to cross the reef and the LVTs were on their own from the reef to the beach. The deadly fire of the Japanese and a strong northerly current made it difficult for the LVT drivers to maintain direction and many battalions were landed 400 to 600 yards too far left in their zones. This caused troop concentrations that were vulnerable targets for enemy fire and losses were particularly high in the 2nd Marine Division's zone of action.

As the tractors hit the beach, the cost of the poor intelligence and aerial photography became more apparent. Terrain assumed to consist of uniform slopes now was seen to be sheer cliffs. Dense woods blocked the tractors in the 2nd Marine Division and they were unable even to reach the tractor control line, 200 yards inland; most could not go more than thirty yards from the beach.29 The rugged terrain blocked the planned armored thrust to the dominant ridge in the 4th Marine Division's zone and most troops were forced to debark at the beach under fire. It was the plan of the Japanese commander, General Hideyoshi Obata, to attempt to defeat the Americans at the beach, and the rugged terrain, concealing Japanese positions which escaped the preliminary bombardment, and the overall failure of American intelligence to gauge properly the nature of

--172--

the terrain or the number of the enemy, combined to make the fight for Saipan's beaches one of the toughest in the history of the Marine Corps. Japanese mortar and artillery fire, guided by observers on the dominant ridgeline which was to have been seized by the abortive armored thrust of the 4th Marine Division, caused severe casualties, particularly among later waves of troops when the Japanese fire on the beach became extremely accurate. By 1:00 P.M., one regiment in the 2nd Division lost an estimated thirty-five percent wounded or killed.30 Artillery and mortar fire took a heavy toll among the armored amphibians which remained on the beach after landing to furnish fire support for the assault troops. Figures on the losses of armored amphibians are confused, but the earliest official history of the campaign lists three armored amphibians disabled prior to reaching the shore and twenty-eight damaged on the beach or attempting to move inland.31 LVTs returning to the line of departure were also fired on by artillery and anti-boat guns, which inflicted some losses until discouraged by the, crews zig-zagging in the water. In a number of cases, when the tractor began to zig-zag, the fire ceased.32 The LVTs gave as good as they had received, and one cargo battalion expended 50,000 rounds of caliber .50 machine gun ammunition and 175,000 rounds of caliber 30 during the run to the beach.33

Immediately after the landing, cargo LVTs returned to their control vessels for further orders, a trip made difficult by the high surf at the reef which caused a few tractors to overturn. (Their crews were rescued.) Badly needed reserves were transferred from LCVPS to LVTs at a transfer line seaward of the reef, and landed at about 10:30 A.M. As the day progressed, more LVTs were utilized in the logistical duties vital to support a major, landing of two Marine dIvisions. Generally, this, meant

--173--

some LVTs were retained by the shore party organizations of the two divisions for runs inland to dumps while others made runs between the ships and the beach carrying supplies. Outgoing LVTs were used to evacuate the casualties to hospital ships.

The armored amphibians continued to furnish assault gun fire support to the infantry. In the 4th Marine Division zone, some isolated groups were able to penetrate to the ridgeline. Eight LVTs supported by three armored amphibians, probably LVT(A)(1)s, sprinted through the Japanese defenses on the only available road beyond the town of Charan Kanaoa on the beach, and prepared a perimeter defense on a hill astride the ridgeline, a position isolated and exposed to direct small arms fire and mortar fire. The LVT(A)(1)s, fearing possible destruction from concentrated fire, remained at the base of the hill and did not provide fire support at that point. The outpost was recalled after dark to friendly lines. A similar breakthrough occurred further south in the 4th Marine Division zone involving five armored amphibians and three cargo LVTs. This breakthrough was also unsupported by the remainder of the battalion and had to be recalled or risk possible destruction by surrounding Japanese.34

At the end of the first day, it was necessary for the cargo LVTs to return to their LSTs for the night because there was no room on the beachhead for them or their maintenance shops due to the shallow penetrations of the landing forces. Darkness fell as they struggled through the high surf at the reef and some LVTs, finding it difficult to locate their "mother" ship, as they had in the Marshalls, tied up to any available ship for the night, unable to refuel or conduct maintenance.35 Although this meant the LVTs were scattered during the night, improved command and control organization was able to muster them without difficulty the

--174--

following morning. This improved control included the use of a control vessel remaining exclusively on station at the line of departure, unlike the Marshalls where the control vessel at one point left station and temporarily became a fire support ship. In addition, the 5th Amtrac Battalion used an LVT officer stationed on the control vessel who was in constant communication with the LVT battalion command post ashore. Landing force logistical requirements for which LVTs would be needed were given to the LVT battalion command post and these were relayed to the LVT officer on the control vessel who in turn had radio and visual communications by semaphore with the LVTs afloat in the LVT pool area.36 The 2nd Amtrac Battalion used a liaison officer stationed with the shore party and as missions were ordered requiring the use of LVTs in their zone, the liaison officer would radio the mission to the floating battalion command post which then used either radio message or semaphore to designate a tractor to execute the mission.37

On the second day of operations, the logistical mission included landing reserves and elements of the shore party, and hauling ammunition, water, medical supplies, and other supplies as part of the unloading of amphibious shipping. Some LVTs were attached to the attacking battalions to haul supplies directly to their dumps inland, a requirement that was continued for twenty days in the 2nd Marine Division zone.338 Also during the second day, a small boat channel was discovered which was free of coral shallows and allowed some landing craft to proceed to the beach in the 4th Marine Division zone. This eased the strain on the LVTs but the limited capacity of the channel was inadequate during the critical early days to eliminate the necessity of reef-crossing with LVTs.39 In order to avoid the difficulties in finding LSTs in the dark, LVT operations on

--175--

the second day were secured at about 6:30 P.M to allow enough daylight to locate mother ships. This procedure was successful and LVTs were able to refuel and conduct maintenance during the second night at Saipan.

General unloading continued on the third day, and the various cargo battalions were able to transfer their operations ashore because the landing force, after a stiff fight, carved out a beachhead 2,000 to 3,000 yards deep and finally controlled the ridgeline that was to have been seized on the first day. During this time the LVTs became the mainstay for movement of supplies because few wheeled vehicles had landed, a situation continued for far longer than had been planned because the Japanese main battle fleet had sortied to defend Saipan and American Naval Task Forces were redeployed between 17 through 22 June (during which time the Navy severely pounded the Japanese in the Battle of the Philippine Sea). Because the transports and LSTs were now vulnerable to Japanese air attack by being bunched so close to shore, they had to move out to sea and so their unloading operations stopped. LVTs continued as the prime cargo movers of supplies inland from the beaches for the landing force, a continuous operation which wore down the number of vehicles remaining operational each day. This strain was increased by the landing of the Amphibious Corps Reserve, the 27th Infantry Division, during the night of 17 June, a decision made by General Holland Smith because he foresaw the vicious fight necessary to secure the rest of the island, and realized that the reserve would otherwise have to stay at sea with the redeployed Navy forces and would therefore be lost to the landing force on Saipan.

With the landing of the 27th Infantry Division, the campaign for Saipan became a three-division thrust, initially fanning out east and

--176--

south, and then realigning for the push to take the northern half of the island. Although wheeled vehicles were landed after the return of the Navy from the Battle of the Philippine Sea, some LVTs continued logistical runs throughout the campaign. The majority of cargo LVTs were able to perform maintenance and repair functions as the need for their services diminished. On several occasions, LVT battalions were ordered to supply men, machine guns, and sometimes vehicles to augment beach defenses along the west coast. Also, one battalion furnished LVT crews to act as listening posts inland of some of the 2nd Marine Division's supply dumps. A variety of tasks were also completed to lend further support to the drive north to capture the remainder of Saipan. Samples of the range of missions listed by the 2nd Amtrac Battalion were:

  1. Working with demolitions teams to assist in blowing a small boat channel through the reef.

  2. Salvaging many landing craft stuck on the beach and reef by driving up to the craft and pushing it backwards off its stranded perch.

  3. Supplying LVTs for use. as fire-fighting vehicles at beach dumps.

  4. Experimenting with and constructing portable bridgehead ramps.

  5. Evacuating casualties to hospital ships.40

The LVT played a pivotal factor in the highly satisfactory unloading of Navy ships between D-Day and 25 June. During this time the majority of shipping was unloaded, and at low tides only the LVT and DUKW were usable because of the very shallow waters over the reef. The few boat channels in the reefs rapidly became congested and the narrow beach frontage was piled high with supplies, an inviting target for the Japanese. Only the LVT and DUKW were able to bring their cargoes out of the water and haul

--177--

them inland to dumps, a vital factor which reduced beach congestion which might otherwise have become a monumental obstacle in the attempt to support three divisions attacking abreast.41

The armored amphibians, despite their heavy early casualties, rendered valuable support as assault guns. The tanks of the 2nd and 4th Marine Divisions landed during 0-Day but suffered costly losses by dropping into potholes on the way to shore and drowning in the deep water. In one company, only four of the company's fourteen medium tanks made it to shore in working order.42 Other companies were more fortunate, but all suffered from the journey across the reef. Until the lost tanks could be salvaged, additional pressure was placed on the armored amphibian to provide needed close-in fire support, a service they continued to provide. Remarked one battalion commander, ". . . I shall always remember the excellent support given to my battalion by the Army LVT(A)'s."43 This was in reference to the excellent service rendered by the Army's 708th Amphibian Tank Battalion, armed predominantly with the old LVT(A)(1)s. The added power of the 75 mm gun on the LVT(A)(4) was well used because the fortifications encountered at Saipan were frequently substantial with the toughest installations concentrated near the beaches. As the medium tanks of the two Marine tank battalions were salvaged and returned to service, use of the armored LVTs diminished, although they remained in action during the push north whenever the Marines or Army were fighting along the coast. For this task the armored amtracs were used on the beach to provide fire support into the shore line cliffs which frequently harbored Japanese hidden in caves. The northward push to complete the conquest of Saipan was rugged fighting, characterized by close-in encounters as Marine and Army infantry dug the Japanese out of their caves. This cave fighting

--178--

was the singular characteristic of the fighting on Saipan. When American forces continued to pressure the Japanese and forced them into a compressed pocket in the northern end of the island, the Japanese decided to stage what was to be the largest banzai (suicide) attack of the entire war. During the night of 6-7 July, from 1 ,500 to 3,000 Japanese soldiers poured through a 300 yard gap in the line of the 27th Infantry Division and surged about 1,500 yards into the rear of American lines. They overran the batteries of the 10th Marine Artillery Regiment that was firing in support of the 27th Division from positions about 600 yards in the rear and continued until stopped by their own losses and the actions of the 27th Infantry Division Commander, General Griner, who committed his reserves.44

The tragic consequences of Japanese propaganda on local civilians became clear as the Americans closed on the northernmost tip of the island, Marpi Point. Japanese military had convinced civilians they would be tortured and killed by the Americans, and thousands leaped to their deaths from high cliffs over the sea. Mothers threw their babies ahead of them or jumped with them in their arms.45 It was a spectacle few who were there care to remember but one they can never forget. The island was declared secure on 9 July 1944. Additional mopping-up was conducted to include the attack of Maniagassa Island, a small island situated outside the main usable harbor on Saipan and thus a threat to American shipping. Although the island was tiny, 250 yards wide by 300 yards long, preparations were as complete as those for a large landing. Naval gunfire support was furnished by the 40 mm machine guns of one LCI gunboat. Fifteen minutes prior to the 11:00 A.M. H-Hour, the 10th Marine Artillery Regiment showered 920 105 mm and 720 75 mm shells on the island.

--179--

The 3rd Battalion, Sixth Marines attacked the island using 25 LVTs of the 5th Amtrac Battalion, preceded by five LVT(A)(4)s of the 2nd Armored Amphibian Battalion. It was over within an hour with twenty-nine Japanese defenders captured or killed and one Marine wounded.46

A review of the campaign leads to certain conclusions about LVT development to this point. The new LVT(4) passed its first combat test with flying colors, yet not all Marines thought highly of it. Remarked one Marine concerning the LVT(4), "You had the engine in your hip pocket."47 This referred to the forward position of the engine which made the driver's position in the cab hot and noisy. The winch for raising and lowering the ramp was placed high on the wall inside the cargo compartment, requiring a crewman to expose himself to fire to operate it; it was also considered too weak by many and repeated failures were recorded.48 Also, despite the plain lessons of the Marshalls, the LVT(4) at Saipan did not have hand-operated bilge pumps in addition to the power driven models. This failure did not create problems at Saipan because operations during the first two days were not as confused as those at the Marshalls and operations from the third day on were conducted from land bases. The sustained operations during the early days of the operation highlighted the need for greater maintenance capability within the LVT battalion. Recommendations were made to provide more mechanics and welders as well as for the design of a specialized retriever LVT that could tow other LVTs and could be equipped with a boom to lift engines and LVTs for repair.49 Communications aboard the cargo LVTs continued to suffer from lack of waterproofing. A pioneer effort was made during the Saipan operation to equip LVTs with multiple receiver-transmitter radio sets for use of command vehicles. While the operation was in its landing

--180--

and early beachhead phase, such a vehicle could provide the battalion commander with a mobile command post and sufficient communications nets to handle his needs until his full command post came ashore. This concept was to gain a firm hold in future operations, but during the landing at Saipan, these vehicles still suffered from inoperative, flooded radios.50

The armored amphibian received its share of punishment during the Saipan operation. Both the LVT(A)(1) and (A)(4) were used to support the landing and then to continue to give fire support at the beach or to move inland to spearhead a drive for quick seizure of commanding terrain. The intensive artillery fire delivered by the Japanese wreaked havoc with the armored amphibians in all zones of action once they lumbered out of the water and became vulnerable on land. While in the water, the armored LVT presented a low profile and those parts above water, principally the turret, were the more heavily armored parts of the vehicle. Once on land, the high silhouette of the vehicle and its lightly armored hull made it vulnerable to powerful anti-tank guns and direct hits from artillery. Twenty-eight of the sixty-eight armored amphibians in the lead wave were destroyed or damaged by Japanese artillery although some were later repaired. This type of attrition is eloquent testimony to the limits of use of the armored LVT against heavy resistance at the beachhead. It stands in stark contrast to the heavily armored tank which can take a great deal more punishment from artillery hits and survive direct hits up to 105 mm. The inability of the armored LVT to act as a tank did not destroy its usefulness at Saipan because it did give valuable fire support to Marines pinned down on the beach. The point raised by Saipan was that, once forces project inland, the usefulness of the armored amphibian begins

--181--

to decrease dramatically as it confronts the full range of anti-tank threats inherent in land combat. The medium tank must come ashore early to spearhead any inland drives against fairly large land masses such as those encountered at Saipan.

The damages incurred by the armored amphibians at Saipan stirred a controversy over the open-turret design of the LVT(A)(4). The LVT(A)(1) had a fully enclosed turret of a light tank while the (A)(4) had the open turret of a gun carriage used on self-propelled artillery. Many thought that the armored LVTs might have survived longer with a closed turret. The argument was not settled during World War II because all armored LVTs, the (A)(4), and the later (A)(5) retained the open turret design. General Louis B. Metzger, commander of early armored amphibian battalions in World War II, wrote in 1948:

Armored amphibians should never be employed as land tanks, but only as assault guns. The difference being that LVT(A)s should always operate behind a screen of infantry and support such infantry by direct fire. If this concept is adhered to the requirements for turret covers are reduced considerably.51

As a final highlight to this point, a review of casualties suffered by the various armored amphibian battalions and the tank battalions should prove instructive. All figures are total casualties including killed, wounded, and missing:

2nd Armored Amphibian Battalion     12 officers     136 enlisted
708th Amphibian Tank Battalion     0       184  
2nd Tank Battalion     0       18  
4th Tank Battalion     6       53  
762nd Tank Battalion     6       75  
Source: Casualty tables, Appendix III, Hoffman's Saipan.

The casualty figures show the superior ability of the medium tank to take

--182--

battle punishment.

The hard fight for the beaches of Saipan took a heavy toll on LVT crews but did not diminish the overall service these vehicles were able to render in the conquest of Saipan. The cargo LVT continued not only to act as the assault landing craft for the infantry but also as a vital logistics asset that helped to make the difference between chaos and progress in logistical support operations. Its versatility now extended to carrying artillery and the beginning was made in the use of the command LVT for communications for the commander in a mobile combat situation. Improvements were needed On the LVT(4), but its basic redesign to incorporate the ramp greatly added to its overall versatility and value to the landing force.

The armored amphibian's role was placed in true perspective by the Saipan campaign. It became clear that it was not a tank and although it could render direct fire support to the infantry, once the tanks came ashore, the LVT(A)(4) was adaptable to providing indirect fire support similar to artillery. This adaptability, however, was not extensively utilized and histories simply note that the vehicle was used to reinforce fires or tanks, artillery, and mortars. From this it is difficult to determine if the fire delivered was direct fire similar to that of the tanks, or overhead fire of mortars and artillery. The full range of capabilities of the 75 mm howitzer does not appear to have been used on Saipan. The LVT(A)(1) remained in use and due to the high velocity tank gun it mounted, it was usable only in the direct fire role. The land mobility of the armored amphibian, however, frequently did not compare with that of the tank and its failure to lead the way inland in the 4th Marine Division zone of action is partially due to this problem. The

--183--

greater power and track width of the medium tank made it the vehicle to overcome the terrain inland from the beaches of Saipan.

Within the Marianas, the fight for Saipan was the toughest test of the new LVTs. The subsequent operation to take Tinian was characterized by General Holland M. Smith as the perfect amphibious operation.52 The LVTs performed their functions with a high degree of effectiveness and their ability to continue inland from the beach was critical to the success of the Tinian landings because the tiny beach of only 200 yards in width held no room for dumps, maintenance stops, command posts or any of the normal beach activities. Given favorable terrain, the LVTs ability to project toward the center of the island with its load allowed the landing force simply to displace normal beach functions inland. This approach permitted Holland Smith to land his Marines at the rear of the Japanese who held heavily fortified lines in the south of the island near Tinian Town. The outcome of the battle against the island's 9,000 defenders was never in doubt The LVTs amphibious capability allowed the Marines to execute a classic surprise landing.

Sterner tests lay ahead for the LVT and the Marines under General Holland M. Smith. The new B-29 was taking heavy losses over Japan and there were no fighters with sufficient range to escort the big bombers from Saipan or Tinian. An intermediate stop was needed that could provide a landing site for damaged B-29s and a launch point for fighter escort over Japan. The island chosen was Iwo Jima.

--184--

Table of Contents
Previous Part ** Next Part


Footnotes

1. John W. R. Taylor, Combat Aircraft of the World (New York: G.P. Putnam's Sons, 1969), p. 455.

2. Robert D. Heinl and John A. Crown, The Marshalls: Increasing the Tempo (Washington D.C.: Historical Branch, G-3 Division, Headquarters, United States Marine Corps, 1954), p. 127.

3. Heinl and Crown, The Marshalls, p. 27.

4. Carl W. Hoffman, Saipan: The Beginning of the End (Washington, D.C.: Historical Division, Headquarters, United States Marine Corps, 1950), p. 18.

5. Ibid., p. 20.

6. Ibid., map 2.

7. Marine Corps Schools, Amphibious Operations, The LVT and LVT(A) (Quantico: Marine Corps Schools, 1948), p. 11.

8. Food Machinery Corporation, Water Buffalo (Mimeographed Historical/Technical pamphlet, no location: 1944), p. 4.

9. Lt. J.I. Williamson's letter to the Special Marine Corps Amphibian Tractor Board, 5 May 1948.

10. Hoffman, Saipan, p. 51.

11. Ibid., p. 52.

12. 2nd Amtrac Battalion, Operation Order No. 1, Forager (In the field: 2nd Amtrac Battalion, 1944), p. 2.

13. Henry I. Shaw, Bernard C. Nalty, and Edwin T. Turnbladh, Central Pacific Drive, Vol. III of the History of the United States Marine Corps Operations in World War II (5 vols.; Washington D.C.: Historical Branch, G-3 Division, Headquarters, United States Marine Corps, 1966), p. 245.

14. Ibid., p. 246.

15. Hoffman, Saipan, p. 35.

16. Ibid., p. 37.

17. Ibid., p. 41.

18. Shaw, Nalty, and Turnbladh, Central Pacific Drive, p. 250.

19. Hoffman, Saipan, p. 34.

20. 2nd Amtrac Battalion, Operations Order No. 1, Forager, Annex A, Special Landing Instruction for LVT Personnel, p. 7

21. Ibid.

22. Ibid., p. 9.

23. 2nd Amtrac Battalion, Operations Order No. 1, Forager, Appendix 1 to Annex A, Special Instructions for LVT Personnel, p. 1.

24. 2nd Amtrac Battalion, Special Action Report (In the field: 2nd Amtrac Battalion, 1944), p. 1.

25. Ibid.,

26. 715th Amphibian Tractor Battalion, Special Action Report (In the field: 715th Amphibian Tractor Battalion, 1944), p. 1.

27. Shaw, Nalty, and Turnbladh, Central Pacific Drive, p. 264.

28. 2nd Amtrac Battalion, Special Action Report, p. 6.

29. Ibid., p. 2.

30. Shaw, Nalty, and Turnbladh, Central Pacific Drive, p. 269.

31. Hoffman, Saipan, p. 50.

32. 715th Amphibian Tractor Battalion, Special Action Report, p. 3.

33. Ibid.

34. Shaw, Nalty, and Turnbladh, Central Pacific Drive, p. 273.

35. 2nd Amtrac Battalion, Special Action Report, p. 3.

36. 5th Amtrac Battalion, Special Action Report, (In the field: 5th Amtrac Battalion, 1944), p. 1.

37. 2nd Amtrac Battalion, Special Action Report, p. 3.

38. Ibid.

39. 715th Amphibian Tractor Battalion, Special Action Report, p. 2.

40. 2nd Amtrac Battalion, Special Action Report, pp. 3-4.

41. Hoffman, Saipan, p. 164.

42. Ibid., p. 60.

43. Ibid., p. 56.

44. Ibid., pp. 227-228.

45. Ibid., p. 245.

46. Ibid., p. 246.

47. Interview with Master Sergeant C.J. Peterson, USMC, 13 June 1975.

48. 2nd Amtrac Battalion, Special Action Report, Enclosure B, p. 1.

49. Ibid., p. 2.

50. 2nd Amtrac Battalion, Special Action Report, p. 6.

51. Lt. Col. Louis B. Metzqer letter to Special Marine Corps Amphibian Tractor Board, 17 May 1948

52. Holland M. Smith, Coral and Brass (New York: Charles Scribner's Sons, 1949), p. 201.



Transcribed and formatted for HTML by Patrick Clancey, HyperWar Foundation