Landing Vehicle Tracked

The Landing Vehicle Tracked (LVT, from the further additional designation amphibious tractor emerged amphtrack the widely known name, Amtrac or amtrak) was designed by Donald Roebling chain-powered amphibious vehicle, which is also mainly from the U.S. Navy and U.S. Marine Corps, as well as in smaller numbers was used by the U.S. Army and allies during World War n. The vast majority of these floating tank was used in the Pacific War.

There they were able to drive over the submerged coral reef e, the traditional boats had stopped.

In the European theater of war was rarely resorted to these vehicles (eg B. Operation Varsity). The LVTs were converted after the end of World War II and several times came during the Korean War for use. The current production from 1942 to 1945 brought a total of 18,621 of these vehicles produced in different variants.

The Amtracs were by Major General Roy S. Geiger, Commander of the III. Amphibious Corps, during the battle for Okinawa as “workhorses of the Marine Corps”.

(German: “workhorses of the Marine Corps”), respectively. Lieutenant General Holland M. Smith formulated the importance of this vehicle in 1949 as follows:

From 1953 they were replaced by the developed from scratch LVT-5 family. The service currently located 3 Generation, based on the Landing Vehicle Tracked, the AAV7 to be replaced from 2015 by the Expeditionary Fighting Vehicle.

Development history

Okeechobee Hurricane

As a trigger for the development of the LVT 16 is the Okeechobee hurricane, September 1928 arrived on the North American mainland. Previously, he had left a trail of destruction in the Caribbean. Thus, 600 people died in Guadeloupe and 300 more in Puerto Rico, where he also left 200,000 homeless. Among other things, he devastated several Boomtown s in the Everglades, which were inhabited mainly by wealthy Northerners. One of the victims was John Roebling II, a prominent businessman and philanthropist and grandson of John Roebling, the designer of New York’s Brooklyn Bridge. Its in Lake Placid, 56 km north-west of Lake Okeechobee, the winter residence was located at the time being rebuilt. The workers involved in the conversion of Roebling were summoned to the disaster area to provide assistance. When they returned a few days later, they were able to report only about the difficult conditions with which they – ultimately unsuccessful – fought for the rescue teams arrived with their boat s and wheeled vehicles sluggish on the muddy and flooded roads. One of the workers noticed Roebling over that one. Using a vehicle that both roads and marsh and deep water passages could have been overcome, many lives could have been saved

Interest in the military

John A. Roebling recognized the lucrative and this untapped market for such a rescue vehicle and commissioned in 1932, his then 23-year-old son Donald Roebling with the realization of his vision, this time with the construction of his mansion in Clearwater, close to the Lake Okeechobee, was busy. The development and production costs would take to market this vehicle Roebling senior.

The next two years spent Donald Roebling and a small staff at his estate. Erected there in the workshop, they built the first prototype, called Alligator I and led the in-house swimming pool by the first swimming attempts. This first draft corresponded in appearance and performance, however, by no means an emergency vehicle. After further work be alligator IV was able to meet all expectations.

On 4 October 1937 was published a two-page article entitled “Roebling’s Alligator for Florida Rescues” in the scientific and business section of Life magazine. Rear Admiral Edward Kalbfus, commander of the battleship squadron of the U.S. Pacific Fleet, was aware of the richly illustrated report and sent it to the Commandant of the Marine Corps General Thomas Holcomb in Washington, DC The U.S. Marine Corps under investigation at this time the trials of Colonel Earl Ellis who had two decades earlier developed the foundations of modern amphibious warfare. Since this seemed ideal vehicle for implementing these theories, Holcomb led the product on to the equipment authority of the Marines in Quantico, whose chief, Brigadier General Frederick Bradman letter asking for more information at Roebling. Other agencies responded skeptical: the “Committee for Transport and tanks” announced that the Alligator “not suitable for the uses on land,” and appeared as’m discouraged by his purchase. Similarly, it also saw the “committee boat”, only a small number of these vehicles could be used for backup tasks to water. Both bodies were in agreement that the armor is too weak and inadequate suspension would cause problems.

Roebling said the equipment authority, he enclosed by a very detailed report of its construction and pointed out that the alligator can be visited at any time. Initial tests followed in varying terrain, a financing request to the Chief of Naval Operations was granted, however, refused. Admiral William Leahy were the valuable properties of the alligator were conscious, but the required funds from the budget for landing vehicles were already scheduled for the development of modern landing craft e of the Navy. Despite this disappointment, sat Donald Roebling continued to restructure its Alligators in order to meet the expectations for the next visit to the military. In January 1939, he sent photographs and drawings of the progress of reconstruction work on those responsible of the Marine Corps. The successor to Brad Mans, General EP Moses gave very impressed, a new funding request was granted; 1940 Roebling received its first order for a military prototypes.

The prototype

On 18 October summoned Secretary of the Navy an “inspection and testing department” headed by General Moses to Florida to test the finished alligator V extensively. After completion of the inspection the vehicle was shipped to Quantico, where it regularly the Potomac River and sailed Chopawamsic Creek. A presentation to journalists, congressmen and military leaders from Army, Marine Corps and Navy was successful. After a further performance tests, the Marine Corps was on 4 November 1940 make his first real amphibious tanks in service. In December 1940, the alligator was the first Ordered U.S. Marine Brigade to Culebra, where he participated in Fleet Exercise Number 7 (FLEX No.. 7), the last fleet exercise of this kind before the entry of the United States into the Second World War.

Brigadekommendeur Holland Smith entrusted Captain Victor Krulak (father of the 31st commander of the U.S. Marine Corps, Charles C. Krulak) and his crew (Sergeant Clarence H. Raper and Corporal Walter L. Gibson) with the task to deal with the promising vehicle. They did this in great detail in any weather and highest swells, so the practicality of the alligator test successfully completed.

Start of series production

The troop testing of the alligator was considered a great success, and the Department of the Navy ordered 22 February 1941 a contract section of 200 of these vehicles worth $ 3.3 million. This was however not the current version V of the alligator. The Navy had two basic requirements: First, there should be a pure steel construction, as this would provide a much better protection from enemy fire and before coral reefs, on the other hand, the engine should be replaced by a 146-hp Hercules WXLC-third

With this order, Roebling was standing with his team before the difficult task of rebuilding the alligator so that it met the requirements of the Navy. In order to produce the required number of vehicles it needed a larger factory. For this reason, the Roebling contacted in the near Dunedin Headquartered Food Machinery Corporation (FMC), a producer of insecticide spray pumps. The contact for this company was already a few years, as these had already made quite a few parts of the original “alligators”. In the coming months Roebling’s team worked closely with the FMC engineers around James M. Hait, to ensure the new design in steel construction and timely delivery of the ordered 200 copies.

With one month’s delay in August 1941 left the first LVT-1 (Landing Vehicle Tracked, Model 1), the new name, the assembly hall of the FMC. Since the supplies were considerably limited in default and the capacity in Dunedin, funded the Department of the Navy more production lines in Lakeland, Riverside, and San Jose. The lucrative contract to build the facility in Lakeland was one of Donald Roebling’s construction companies.

When the first LVTs were completed, the Marine Corps had already set, Dunedin. On 2 May, the first Amphibian Tractor School built on site. Its first commander, Major William W. Davies, were under at that time, four more officers and 33 Marines. In September, the production was in full swing, and then the 1st Amphibian Tractor Battalion was established. With the U.S. entry into the war in the Second World War has ordered the Department of the Navy more LVTs, so that the battalion grew to six companies, four operational companies with a total of 400 LVT-1 as well as a staff and a maintenance company. On 16 In February 1942 was with this battalion from the 1st 1st Marine Brigade incurred U.S. Marine Division moved to the South Seas, where it opened the allied offensive in August. At this time the 2nd Amphibian Tractor Battalion was at Camp Pendleton, California, situated.

Development

Originally conceived as a pure van, pushed this first Amtrac in difficult terrain due to weak armor and unreliable suspension and curb chain n soon its limits. Nevertheless, the Marines recognized the potential of Roebling’s invention as an attack vehicle. During the war, heavily armored versions were introduced, as well as amtanks called varieties, which were equipped for combat support with gun s. Other key innovations for the LVTs were more powerful engines and an improved suspension, which was acquired by M3 Stuart for the most part.

After the war, resulting prototypes came no more into series production.

Volume of production

A total of 18,621 LVTs were produced in different variants.

. Besides the factories of the Food Machinery Corp. in Dunedin and Lakeland, Riverside and San José, other companies were later involved in the production of LVTs:

•Borg Warner Corporation in Kalamazoo, Michigan

•Ford Motor Company in Detroit, Michigan

•Graham-Paige Motors Corporation, Detroit, Michigan

•St. Louis Car Company in St. Louis, Missouri

Versions

Roebling Alligator

At the start of the project took place in 1933 to Donald Roebling and his staff development focused on two main problems was the realization of a versatile and robust amphibious rescue vehicle in the way:

1.The weight of the vehicle should be kept low in order to lose as little buoyancy. However, the design should be robust enough to survive in rough terrain can.

2.The drive had to be designed so that the “emergency order” was not compromised. That is, it should be simple and take little space.

The weight problem solved developers with aluminum, a revolutionary for its time material. This light and appears suitable for the task material was indeed already in use for almost 40 years, but the use in vehicle was a technical innovation and thus a risk.

The drive on water and on land set represents a greater challenge Roebling wanted to avoid from the beginning a double drive, so propeller for the water ride and a wheel or chain drive for urban driving. The requirement to build a simple construction drive that works in both environments provided turned out to be a major obstacle. The solution looked Roebling the drive of the old paddle steamer on the Mississippi from, who had almost a hundred years ago revolutionized the shipping industry: the two track n of the chain drive mounted angled plates (paddle plates; engl: “paddle cleats”) worked in the water as the paddle wheels of a steamer and on land as the chains of a conventional crawler s

After they had solved the problem of mixing drive, the question of how to best handle made of aluminum. The metal tools and machine tools then available were unsuitable for the soft aluminum sheets, as is known from the steel processing welding and riveting methods. Over time, it turned out that woodworking machinery for aluminum processing were better than those for metals. Thus, employees contributed Roebling pioneered the use of aluminum.

Alligator I, II and III

The first prototype, the alligator I was 7.3 m long and 6.5 tons. The rider sitting in a vehicle mounted on the bow, single cab while the rear sections were held flat. The 92-hp gasoline engine was built by Chrysler in the rear, where the drive wheel of the track sat.

With the first test drive of the alligator I in the spring of 1935, some deficiencies in the design emerged: While the prototype provided to land a top speed of 40 km / h but only 3.7 km / hour in water. Besides speed and maneuverability to water was poor, due in part to the vertically mounted to the direction of the chain angle plates. The paddle plates and the crawlers broke after only a few kilometers on rougher terrain, because they were too thin and made of material too weak.

Although the alligator I was a disappointment due to its performance, Roebling offered it to the Coast Guard of the United States and the American Red Cross to purchase, but as expected, were the orders.

In April 1936, the Gator II has been completed based on previous experience. The nearly 6-ton vehicle was driven by a 85-hp V8 engine from a Ford automobile. Although the paddle diagonally arranged plates and the weaker engine reduced the land speed to 29 km / h but the increased speed in the water to 8.8 km / h The twisted plates, the improved stability and control of the water.

The tested in September 1936 Alligator III was by 140 kg lighter than its predecessor. Nevertheless, the performance of the 5.8 t predominant vehicle changed less than expected. Reasons suggested in the Roebling Suspension inefficient and only slightly improved drive chain that still broke at high loads.

Alligator IV

1937 Roebling and his team completed the alligator IV, which corresponded to the ideas more than his predecessor.

The most significant change has been made to the chassis suspension. Previously an elastic suspension system was installed in the alligators, as it was used in chain driven armored vehicles. The engineers saw in them caused drag a reason for the low driving speed in the water. Instead, the chain has now been moved to a guide channel, so that it was only on the front guide wheel and mounted at the rear wheel located outside the channel. The guide took over the function of the chain tensioner and could be adjusted by the driver via a hydraulic cylinder, which was the purpose of shock absorption provided with coil spring n. The track was equipped with water-and dust-proof bearings n.

The chain material had a yield of 36 t. In order to obtain a higher strength, the paddles Alcoa 24ST sheets were extruded through a T-shaped die. The thus prepared 10 cm wide and high profile rods is bent to a radius of 30 cm and mounted on the track by means of four bolts or rivets. This driving principle for tracked vehicles in the water by gekurvter angled plates that are mounted diagonally on the chain, settled patent-ming Donald Roebling in 1938. A few years later, during the Second World War, he wrote his patent (No.) from patriotic motives of the government of the United States

The streamlined vehicle hull was mainly riveted duralumin sheet metal plates. As the bottom plate was bolted to facilitate maintenance. Attached to the front of the vehicle cab was 1.9 m wide and 1.7 m long and high, and had room for three persons including the driver. The three fixed front windows and two sliding side windows were made ​​of Plexiglas. The back door located closed the watertight cabin from the cargo space.

The vehicle was controlled by two hand levers, which worked on the brakes of the two chains and two pedals for clutch and gas. To control the direction a chain was slowed down with a lever, could be slowed by synchronous activation of both levers. On tap enbrett the driver itself speedometer, compass, thermometer, oil pressure and battery
indicator and switch for ignition, starter, choke and both headlights were.

The cabin located behind the passenger and cargo space measured 2.74 × 1.93 × 1 m and had a payload of 3.15 tons. In the 30 cm high space between the floor of the cargo compartment and the bottom plate there were two 152 liter fuel tanks, as well as the control linkage and harnesses for vehicle control.

The engine room located at the rear measure 1.67 × 1.35 × 1.93 m and housed the mercury liquid-cooled V-8 gasoline engine, which produced a power output of 95 hp at an engine speed of 3600 min -1. The 3-speed manual transmission with two forward gears and one reverse gear, a bevel gear with helical gearing (ratio 1:1), two spur gears with helical gearing (Translation 7:1) and making the necessary couplings were responsible for the transmission of power to the drive sprockets. The gear housing were cast in aluminum for weight reasons. The two drum brake 8 n of the brand Packard were hydraulically operated.

The curb weight of the alligator IV was 3.95 t, which he was to 2.5t lighter than the alligator I of 1935. These weight savings and the revolutionary drive allowed a top speed of 13.8 km / h on the water and at 29 km / h the country.

Alligator V

The current delivered to the U.S. Marine Corps in October 1940 Alligator V was a suggestion on Major Kalufs improved Alligator IV. Considered as the first military variant of the previous alligator family. Instead of the Mercury engine, a 120-hp Lincoln Zephyr was fitted with a standard transmission from Ford. The total weight was further reduced by 450 kg to 3.4 t. With the same cargo capacity, the same chassis and the same track the alligator V reached a top speed of 47 km / h on land and 16km / h on water. In a contemporary brochure it said even:

LVT-1 Alligator

The first LVT-1 was completed in August 1941 by the Food Machinery Corp.., And 13 months later underwent its baptism of fire during the Battle of Guadalcanal. It was during the battle for the Solomon Islands, as well as the liberation of Tarawa – and Makin Atoll during Operation Galvanic in use. By 1943, a total of 1225 vehicles of this type were built. The main customers were the U.S. Marine Corps with 540 units and 485 units of the U.S. Army. The remaining 200 LVT-1 decreased during the Lend-Lease Act it to the Allies.

Technical details

•Chassis: The three sections consisting of the cab, engine compartment and cargo hull was constructed of steel panels with a thickness of between 2 mm and 5 mm, which were connected by arc welding. The bumper extending from the rear to the front bottom plate had a thickness of 4.7 mm, 4 mm, and the side walls of the cab 3 mm.

•Suspension: The Alligator IV, well known from the rigid chassis design was retained. In addition to on each track (width: ~ 260 mm, Weight: 295 lbs) mounted bearings were installed to make sure the chain guide roller n.

•Maneuverability: The tracked vehicle was floating contact on the spot by the current directions of the two chains were connected opposite. Due to its weight, this LVT sank about 10 cm in sandy soil, the resulting averaged 7.8 psi ground pressure. Although he had excellent handling characteristics in the water and on the beach, the LVT-1 was not suitable for long transport journeys into the interior. Added to this was the most expensive maintenance, which often had to be done daily.

LVT-2 Water Buffalo I

The use of the LVT-1 was a complete success, although engineers at BorgWarner found significant deficiencies in Roebling construction in October 1941. These were on the one hand fixed and on the other hand, the suspension chain itself

Other deficiencies of the vehicle also questioned the U.S. Army during the 30th April to 20 July 1942 the current test phase fixed at Aberdeen Proving Ground in the U.S. state of Maryland. In its investigation report criticized mainly to the poor performance. Thus, a propeller-driven watercraft with a streamlined hull is (→ Higgin’s Boat) with the same displacement and power output by more than half faster than the LVT. Reasons for the Army looked to the high flow resistance of the hull and in the weak driving power.

All these problems are related, regardless of the improvements on Roebling Alligator IV, of which the LVT-1 was descended. Thus, the U.S. Navy commissioned next to the Food Machinery Corp.. Was that of the previously Amtracs responsible for the production, the Borg-Warner Corp.. Trying to develop a more powerful successor to the LVT-1. Furthermore, the order also provided for a more armored and armed variant of the LVT. The criteria set by the Navy provided for a minimum speed of 24 km / h on land and 13km / h on water, and a maximum weight of 12,250 kg.

BorgWarner renounced the development of a pure van and concentrated his forces on the construction of a swimming tank combat-capable (amtank), while FMC both set a goal. Borg Warner completed his Model A completed including testing after only six months, and thus created the LVT (A) -1 the world’s first modern-combat swimming tank.

FMC worked closely with specialists from the University of California and the California Institute of Technology, and was able to present the first draft for the transport tanks at the beginning of 1942. In this design, in contrast to the LVT-1 moved the cab closer to the bow and equipped with two windows made of Plexiglass. Criticized the teething problems of the first Amtracs have also been revised significantly:

•Suspension: The rigid chassis suspension caused the previously used compared to other tracked vehicles slower driving speed and the limited off-road capability of the swimming tank. Which is based on the chassis of the Stuart tank innovation consisted of eleven, mounted on rubber springs suspension waves per page with vulcanized rubber. In addition four gimbal e are inserted in order to uncouple the gear from the engine between the engine and the suspension. When connecting the drive gear with the suspension set to a flexible couplings, which allowed a small amount of hull deformations without compromising driving performance or the power transmission elements were affected. These innovations allowed in addition to a softer and more stable ride and the improvement of the defective handling.

•Chain: The steel link chain was widened to 362 mm and had a pitch of 203 mm. The connecting bolts of the individual members had a permanent lubrication and were hermetically sealed, so that no water or sand could penetrate, creating a potential blocking could be excluded. The ground contact length amounted to 3.2 m. Increased chain guide prevented the ejection of the chain at high speeds and when turning on solid ground. A larger and far better off-road driving was achieved with 73 W-shaped paddle plates that were riveted with reinforced gussets on the track. The ground pressure caused by the weight of the vehicle amounted to 8.6 psi.

The resulting certified driving him a good report. So he had a gradeability of max. 60%, could overcome obstacles wide trenches 91 cm high and 1.5 m. The LVT-2 had a turning radius of 9 m and 14.6 m on land to water, and could even in up to 30% sloping terrain to operate without losing the balance.

These modifications meet the demands made ​​by the Navy, which the LVT-2 Water Buffalo I became the official successor of the LVT-1.

The Water Buffalo I was first used in the Battle of the Gilbert Islands, where he and his predecessor, the LVT-1 was operating the first and only time. The current production from 1942 to 1943 brought forth a total of 2963 such vehicles. The production facilities were next to the factories of FMC also those of Graham-Paige Motors Corporation, Borg-Warner Corporation and the St. Louis Car Company. The Marine Corps received in 1355, the Army in 1408 and 200 copies of the Allies (British designation Buffalo II).

LVT (A) -1

It was this proposal from the Food Machine Corp. the LVT-2 very close. He had been merely added a reinforced armor and based on several machine gun armament s.

Launched by the Borg Warner Corp.. A model was designed for a comprehensive review of Roebling Alligator V and the LVT-1: The only similarity to the LVT-1 was the paddle plates. The rollers of the chain were increased in diameter and installed in the bottom of the side panel. Which were stored by Timken roller bearings with double neoprene – seals and leather, which ran on chromed shafts. Larger idler rollers and drive gears that were associated with a fully automatic suspension, allowed for a smooth transition of the vehicle drive by water on solid ground. The fuselage consisted of mainly high tensile strength and corrosion sbeständigen steel sheets that could withstand the highest loads in scalloped shape and because of the weight loss thereby incurred contributed positively to the overall work.

The outstanding feature of the Model A was its conversion capability: the basic vehicle, a 7.7-tonne and up to 2.3 tonnes loadable transport vehicle, a ton battle tanks without additional design effort could be converted into an approximately 10x. The use of the turret used in the M3 Stuart was s than the actual innovation that reduced the production cost and the model A gave a far greater firepower than the FMC model. In addition, the Gyrostabilisation the 37-mm gun was taken over by Stuart, who uses the gyroscopic effect to stabilize the barrel in the position indicated by the gunner. The Gyrostabilisator offset the movements of the vehicle, resulting in a high shot accuracy could also be achieved at full speed.

The Model A was powered by an eight-cylinder internal combustion engine, which generated an output of 141 hp.

In the immediate comparison between the prototype BorgWarner FMC and the Model A was found to be too weak. The suspension did not have the desired harmonic as well as the drive chain for causing the same problems as LVT-1. The speeds were almost the same, while the Model A with its 27 km / h on land could not stand in the water. The van variant of Borg-Warner could only carry 2.3 tonnes of cargo, up to 7.7 tonnes of FMC. In contrast, the Model A was able to score with his firepower.

The Navy finally considered the installation of the Model A-armament in the FMC Amtrac. The primary weapon of the LVT (A) -1 consisted of a 360 ° rotating turret which was armed with a 7.62 mm height adjustment range of +25 ° to -10 ° with a 37 mm gun and a coaxially mounted machine gun caliber. The tower with a maximum outer diameter of 1.19 m had a rotational speed of 24 ° per second and a 51 mm thick of frontal armor rolled steel. The side walls and the rear wall of the tower had a thickness of 12.7 mm, 6.4 mm, the cap. The cab is from 6.4 to 12.7 mm, the side walls of 6.4 mm thick steel plates welded together, while the bottom of the fuselage of a 5 mm was measured steel plate. The driving characteristics of this variant differed only slightly from those of the LVT-2.

The LVT (A) -1 (“A” for armored – “armored”) called float tank went into production in April 1943 and was first used on Kwajalein. The current production until 1944 brought out the 510 units were built exclusively by the Food Machine Corp… The U.S. Marine Corps and the U.S. Army received 182 238 amtanks such.

LVT (A) -2

The Battle of Tarawa provided not only for the war strategists, but also for the development of a watershed LVT dar. The 2nd Marine Division in the landing supportive “2 Amphibian Tractor Battalion “recorded at the end of the battle only 19 of 75 initially deployable LVT-1, 16 of the former 50 LVT-2. The loss of personnel totaled 323 fallen, wounded and missing soldiers from the former 500, including its commander. Initially it was assumed that a variety of material losses due to machine damage could come about as frequently occurred when LVT-1 in particular. Further investigation did not confirm this hypothesis, because only four per LVT LVT 1 and 2 were lost due to this fact, while the remaining Amtracs artillery bombardment, land and sea mine or the coral reef had fallen victim. Also, most LVTs had already been up to 400 hours of operation before the battle, at the manufacturer’s specified average life of 200 hours. The greatest weakness of all Amtracs used at Tarawa was the barely existing armor of the hull and the cabin. The two mounted next to the engine fuel tank exploded after a prolonged bombardment with a heavy machine gun or by a piece of shrapnel that had drilled through the side walls.

That’s just the demand for more security through increased armor was the main focus for the future LVT (A) -2. Unlike the first armored amphibious vehicle LVT (A) -1 this version had no primary armament in the form of a gun turret. The body, engine and armament they took over from the LVT-2, so that (A) -2 and the Water Buffalo looked very similar at first glance. Only the cab stand next to the additional armor the difference dar. Instead of the plexiglass windows used steel doors were installed, the fire was close to the driver. In order not to compromise the operational capability, two 360 ° rotating periscope e were installed.

The armoring was made 6.4 mm (fuselage rear of the cab) and 12.7 mm (front) thick steel armor plates were also welded or fixed by bolts. Thus, the transport capacity is reduced by up to 1.1 tons. The first combat missions on New Britain showed, however, that the party so affected cargo capacity was too small to be used effectively. So you decided to screw the armor plates only when needed to the hull. This was done mainly to fight beginning when the first assault troops were brought to the beach. If the beach was no longer under enemy fire, the self-protection could be removed, thus increasing the transport capacity increased to the LVT-2. This system of removable armor should be used in addition to the periscope also in all future Amtrac and amtank variants. The installation of a self-sealing fuel tanks of Goodrich Corporation represented a more significant change that took place in all other LVTs use.

With the start of series production of LVT (A) -2, the then SecNav Frank Knox created on 30 In October 1943 the “Continued Board for the Development of the Landing Vehicle Tracked”. This committee of the Bureau of Ships was concerned with the monitoring of the entire LVT program. As an official complaint to the Commission was therefore “meaningful” responsible development of these amphibious vehicles.

The produced in the years 1943 and 1944 amphibious tank was built a total of 450 times, of which 250 units by the U.S. Marine Corps, and 200 were operated by the U.S. Army. This was manufactured by the Food Machinery Corp. amtank., And the Ford Motor Company in Detroit, Michigan.

LVT-4 Water Buffalo II

The exclusively designed by FMC LVT-4 presented an improvement of the LVT-2 dar. In contrast to this, the engine was installed behind the cab, which the increased cargo space and the installation of a rear ramp was urgently required permits. The loading ramp weighed approximately 1.18 t together with the necessary reinforcements of the rear fuselage and the manually operated winch for opening and closing of the ramp. As a result, the speed of the LVT-4 decreased compared to its predecessor on a solid surface, while the top speed in the water remained approximately the same. Despite this additional burden on the overall design which negatively reflected on the increased total mass, more cargo could be transported by up to 1.14 tonnes. The 2.4 × 3.8 m (LVT-2: 2.4 × 3.3 m) measured cargo compartment floor the first time enabled the transport of small cars such as the legendary Willys Jeep and even a 105-mm howitzer with a maximum muzzle elevated.

In addition, could be grown at the expense of transport capacity separate armor. The load capacity reduced by up to 1,36 t if the tanks with 13 mm front and the two sides have been retrofitted with 6.4 mm thick steel plates. The cabin had two glass windows and two skylights, which were provided with periscopes. Their armor was mainly ensured by 13 mm thick steel armor plates.

Production began in December 1943, whereby the LVT-4 came too late for the Marshall Islands campaign, but was ready in time for Operation Forager. By the end of production before the war ended in 1945 leaving a total of 8351 LVT-4, the factories of Food Machinery Corp.., Graham-Paige Motors Corp.., And the St. Louis Car Company. The U.S. Army was the main buyer with 6083 units, followed by the Marine Corps (1765) and the British armed forces (503). The Buffalo IV called British LVT-4 was fitted instead of the 12.7-mm machine gun with a Polsten-20-mm rapid-fire cannon Oerlikon and came especially during the Battle of the Scheldt estuary, Operation Plunder and the crossing of italy European River Po used.

LVT-3 Bushmaster

Concurrently with FMC also developed the Borg-Warner Corp.. a swimming tank with rear ramp. After the defeat of the Model A, making it intensified working to develop a more powerful amphibious chain mail that should be which of the competing Food Machine Corp. Superior. The said alluding to the Model A Model B prototype was completed and tested before the LVT-fourth

The model B should be different from all its predecessors FMC by a single detail: the engine. Borg-Warner drove his two 300 mm wide, equipped with a 140-mm scale crawlers on with one motor. The two V8 engines from Cadillac were installed in the fuselage side walls and corresponded to the drive assembly of the M5 tank, the improved successor of the M3 Stuart. With this innovation, the cargo could be extended to 5.1 m, but had to be reduced to a width of 1.9 m. However, since the cabin was located closer to the bow, the cargo area from the last third could be widened to 2.5 m. Thus, Model B had the largest cargo space of all built up to this point Amtracs. Despite this advantage, the bus master only measured 7.5 m in length, but 3.4 m in width and 3 meters in height.

A considerable relief for the driver turned dar. the built automatic transmission This also coming from the M5 transmission was characterized by its reliability, as well as the automatic shifting to a lower gear in the transition from water to firm sandy bottom where conventional manual transmission often failed due to operator error. The suspension corresponded to the suspension based on the Stuart tank and now successfully tested in combat principle. The propulsion was provided by 103 W paddle plates in proven design. Nevertheless, Model B was the land speed of its immediate competitors, the LVT-4, does not achieve what was later attributed to the built-in 9.5-mm armor (hull, cabin, engine and tank), thus increasing the potential cargo capacity of 1.3 t to 4.1 t reduced.

The Continuing Board for the Development of Landing Vehicle, Tracked in April 1944 gave the green light for the production of the now-called LVT-3 model. The Bushmaster was the first LVT with a rear ramp that should facilitate the loading and unloading especially significant. Due to production delays and long-lasting training of tank crews and mechanics of the LVT-3 was only in April 1945, only a year after the start of production, participate in the battles of the Second World War. During the Battle of Okinawa, this proven such that it long after the war, together with the LVT (A) -4 formed the backbone of the U.S. Marine Corps.

Overall, between 1943 and 1945 left 2,964 Bushmaster factory halls of Borg-Warner Corporation and the Graham-Paige Motors Corporation. The Marine Corps was 2262 copies with primary user of the LVT-3, while the Army received only two pieces for testing.

LVT (A) -3

The third amtank based heavily on the LVT-fourth The main armament was to consist of a heavy gun of greater caliber, but should not be mounted in a rotating turret. (A) -3 never came out on the stage of the project.

LVT (A) -4

The LVT (A) -4 was similar in shape again more the LVT (A) -1, but instead had his new job corresponding to the 37-mm gun of the tower and the 75-mm Howitzer M8 Scott.

This had two reasons: on the one hand, the armor of the LVT (A) had to be too weak for direct combat on the front line proved, on the other hand, the 37-mm gun was good to combat armored vehicles and lightly fortified positions suitable, but against the heavy Japanese bunkers were their projectile s virtually ineffective. They developed neither the necessary power, enough explosive action to prevent damage to the frontal attack, especially against well-armored bunker.

The Marines, however, had a positive experience with 75-mm howitzers in the battle for Tarawa, Roi-Namur, and Eniwetok. Although the howitzer projectiles had a lower muzzle velocity, but a high explosive effect and met its target because of its high, arched trajectory from above, where the bunkers were armored weaker. In addition, you could also shoot away and objectives outside the direct line of sight because of the high trajectory over their own troops. Only the smaller projectile at 3 km range of the howitzer can be seen as a disadvantage.

Another difference with the previous (A) -1 is the absence of a gun stabilizer. Due to the parabolic projectile trajectory and the possible Höheneinstellbereiches from +40 ° to -20 °, the LVT (A) -4 was like the M8 self-propelled gun designed for remote support, resulting in a stabilization during full speed appeared to be unnecessary.

The armor of the LVT (A) -4 was that of (A) -1 similar. The hull was mainly due to 12.7 mm (cab, front), 6.3 mm (hull sides and rear) and 5 mm (bottom panel) thick reinforced steel plates. The tower had a maximum outer diameter of 1.38 m and a front armor of 38 mm. Rear and side walls were backed with 25.4 mm thick steel plates, while the tower roof as the M8 and similar self-propelled Artilleriehaubitzen remained open. The original secondary armament of a tower placed at 12.7 mm machine gun was replaced by three 7.7 mm machine guns.

The produced in the years 1944 and 1945 exclusively at FMC LVT (A) -4 reached a total number of 1890 units. The U.S. Army has received 1307 and the U.S. Marine Corps 533 copies, while 50 as part of the Lend-Lease Act went to the other Allies. His baptism of fire experienced the LVT (A) -4 it. Together with the LVT (A) -1 in June 1944 on the island of Saipan, Mariana Islands Subsequent operations were carried out on Tinian, Peleliu, Iwo Jima and Okinawa. The Marine Corps replaced the howitzer in small numbers by flamethrowers or rocket launcher.

Summary of technical data

Post-war development

After the Second World War, the production and development of the Landing Vehicle Tracked was adjusted. The U.S. armed forces unified their Amtrac – and amtank fleet so that only the LVT-3 Bushmaster and the LVT (A) -5 improved LVT (A) -4 formed the backbone of amphibious landing forces of the U.S. Marine Corps.

All other versions were sold or given to the armed forces of friendly countries in the course of development aid, and doing the then still partially decades their service in the armed forces of Great Britain (as a replacement for Terrapin Mk I), Spain’s, Brazil’s, the Netherlands and France, see France continued its LVT-4 and (A) -4 still in the Indochina War and during the Suez crisis of 1956. Until the commissioning of the LVT-5 family in 1953, which was the first redesign of the LVT family, the LVT-3C was next to (A) -5 in the arsenals of the U.S. Marine Corps.

LVT-3C

From 1949, approximately 1200 of the Marine Corps LVT-3 at Long Beach Naval Shipyard on the new LVT-3C standard (“C” stands for covered; German: “roofed”) brought. Here, a hinged and provided with deck plates aluminum “roof” over the cargo was confiscated, the protection offered against breaking waves and shrapnel. The armament consisted of M1919 Browning machine guns of the type that have been installed in an armored and 360 ° rotating tower, and beside the driver. In addition, the armor has been reinforced. In order to increase the buoyancy of the water, the bow had to be extended because these tags t fell into negative weight with additional 2.7. The LVT-3C has been successfully used in the Korean War, where he was primarily used on land as the amphibious landing operations only limited to the landing at Incheon. Unlike its predecessor, the majority of the LVT-3C fleet suffered no major damage to the engine because the machine maintenance could be carried out within the prescribed intervals.

LVT (A) -5

The only difference from his predecessor showed the installation of a Gyrostabilisation for the gun, which allowed a high shot accuracy while the water and land travel. The Food Machinery Corp.. Built from April 1945 only 292 pieces of this tank, but in the Pacific War were no longer used. After the Japanese surrender, the returning from the theater of war were LVT (A) -4 upgraded to this new standard or given to other nations.

Subsequent generations

With the foreseeable end of the Korean War in the U.S. Marine Corps sought a complete replacement of their LVT fleet (A) -5 unified since the Second World War to the LVT and LVT-3C. In 1951 began the development of the LVT-5 generation. In addition to the previously known species use as a troop transport or fire support vehicle, and special command, were pioneered in 1956 – and anti-aircraft put into service models. Of this family were built in 1124, which were mainly used during the Vietnam War.

With the end of the Vietnam War, the second by a newer generation of amphibious assault vehicles was replaced. The LVT-7 was renamed in 1987 Amphibious Assault Vehicle, to meet the changing requirements. This is after several modernization programs today in the service of the U.S. Marine Corps and is mainly used by the amphibious assault ships of the Tarawa – used and Wasp-Class. Due to numerous losses in the Iraq war, the Expeditionary Fighting Vehicle as its successor was determined. Vehicles of this type should be made officially into service from 2015. Early January 2011, announced the Department of Defense to cancel the EFV project cost reasons. In return, the existing AAV7 vehicles are to be modernized and in a not yet specified time in the future a cheaper alternative to be purchased.

Despite all the changes in the use of spectrum, and the naming of the Landing Vehicle Tracked even these vehicles still bear the nickname Amtrac.

United States Marine Corps

APC

IFV

Floating tanks

American military vehicle

Historic Mechanical Engineering Landmark

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