Originally intended solely as cargo carriers for ship to shore operations, they evolved into assault troop and fire support vehicles.

The United States Marine Corps, which had been developing amphibious warfare doctrine based on the ideas of Lieutenant colonel Earl Hancock Ellis and others, became interested in the machine after learning about it through an article in Life magazine and convinced Roebling to design a more seaworthy model for military use.

Impressed by the second prototype, the Bureau of Ships placed a contract for production of 100 units of a model using all-steel construction, for a more rugged and easily produced design, and the first LVT-1 was delivered in July 1941.

[3] The contract to build the first 200 LVTs was awarded to the Food Machinery Corporation (FMC), a manufacturer of insecticide spray pumps and other farm equipment, which built some parts for the Alligators.

[4] Originally intended to carry replenishment from ships to shore, they lacked armor protection and their tracks and suspension were unreliable when used on hard terrain.

As early as January 1940, Roebling had prepared preliminary sketches of an LVT with a gun turret to provide fire support to the landing waves.

Among other upgrades were a new powerpack (engine and cooling accessories), also borrowed from the Stuarts, and a rubber "torsilastic" suspension which improved performance on land.

Interest in the LVT was enough that the Secretary of the Navy formed the Continued Board for the Development of the Landing Vehicle Tracked on 30 October 1943.

2nd Amphibian Tractor Battalion LVTs took part in the first, second, and third waves of landings and carried the continuous supply of ammunition, reinforcements, and ferrying back of the wounded.

Of 125 vehicles used (50 new LVT-2s and 75 LVT-1s), only 35 remained operational by the end of the first day, continuing to ferry men and supplies across the coral reef and through the shallows to the beach.

Most of the troops had to disembark from LCVP "Higgins boats" and wade across the reef in chest-deep or higher water while under heavy enemy fire.

Armed with a 75mm howitzer, the latter was introduced in 1944 just before the Marianas campaign and was especially effective in this role as it was capable of destroying Japanese fortifications as it came ashore.

However, the LVT(A)-4 had an open-topped turret which left the crew vulnerable to artillery and infantry attack, especially to the latter, as it lacked any sort of machine gun armament.

The lack of machine gun armament was eventually rectified, though the open-topped turret remained in order to save weight.

In the campaign for the Marshall Islands, the full range of the LVT models became available, including armed Amtrac LVTs based on the proven LVT-2 with a tank gun turret.

[7] 54 LVT(4) tracked amphibious assault vehicles of the 672nd Amphibian Tractor Battalion as part of the raiding force on 23 February 1945 forged across Laguna de Bay and crashed the gates during the liberation of Los Baños Internment Camp.

[citation needed] The US Army 826th Amphibious Tractor Battalion provided Company A to land 43rd Infantry Division troops in first wave of this first American return to the Philippine Islands.

Following the landing Company A "amphibs" were utilized to transport dead and wounded, carry supplies inland and provide support throughout the invasion and subsequent taking of Leyte.

Ashore, the LVTs were used to rescue wheeled vehicles that could not navigate Iwo Jima's soft volcanic ash and steep terraces.

As mud was expected to hamper the Sherman DD tanks, some LVTs were armed with a 20 mm cannon and two machine guns to give fire support until bridges could be constructed across the river.

The "Specials" were under the 79th Armoured Division (which operated and coordinated the use of all specialist assault vehicles), that also provided Buffalos fitted with "Bobbin" carpets to create temporary roadways over the mud.

Five LVT-4s were supplied through Lend-Lease to the Soviet Red Army, which used them when assaulting the well-defended west banks of the Oder and Danube rivers.

In 1947 a dozen Buffalo LVTs were used by the British Army to fix a breach in the flood defenses at Crowland in Lincolnshire fens following the terrible winter that year.

It was powered by a Hercules WXLC 146 bhp (109 kW) six-cylinder petrol engine, mounted in a housing in the rear cargo hold.

It featured a new powertrain (to save time and to simplify production it was the same Continental radial 7-cylinder engine as that in the M3A1 Stuart light tank) in the rear of the hull with a propshaft along the centreline to the transmission at the front, and torsilastic suspension.

Rails for mounting machine guns ran round the sides and rear of the cargo space and across the back of the cab.

LVT-2s participated in more campaigns than any other LVT variant, including Tarawa, Roi-Namur, Cape Gloucester, Northern Kwajalein, Saipan, Guam, Tinian, Peleliu, Iwo Jima, Okinawa and in some parts of Europe, such as the Rhine crossing of Operation Plunder.

These would have been used by the "flame battery" of the 34th Amphibian Support Regiment, Royal Marines in any assault on the Japanese mainland but the war ended before they were used.

The twin 148 brake horsepower (110 kW) Cadillac V-8 petrol engines were connected by driveshafts to the transmission (the same as the M5 light tank) in the front of the hull.

[citation needed] There are two surviving LVT 1s in United States Marine Corps Museums, one at Camp Pendleton in California another at Quantico in Virginia.