Factfile

The outbreak of World War I in Europe in 1914 encouraged US companies to privately develop armored cars for potential export. The Autocar Company in Ardmore, Pennsylvania, manufactured armored machine-gun carriers for Canadian forces in small numbers. The US Congress funded the first US Army armored cars in 1915. In July 1916, the two prototype armored cars were sent to Texas to support Gen. John Pershing’s Punitive Expedition into Mexico. They saw little or no combat but were used to patrol the border. Early experiences with these primitive armored cars exposed their tactical shortcomings. The added weight of the armor placed enormous stress on their suspensions and engines. The narrow tires had such high ground pressure that the armored cars were road-bound in most circumstances. Nevertheless, armored car construction continued on a small scale around the United States, funded by local donations for National Guard units.

The first efforts in American tank design can be traced to America’s prosperous agricultural tractor industry. Companies such as Holt, Caterpillar, and C. L. Best manufactured a wide range of tractors for industrial and agricultural use. As the war in Europe coagulated into muddy trench warfare, European armies began to buy more and more tractors from the United States. These were used for military tasks such as towing heavy artillery. American tractors were instrumental in early European tank designs since they were at the forefront in track and suspension technology.

The US entry into World War I in April 1917 accelerated US Army interest in tanks. The US Army had very little detailed technical information about French and British tanks. In July 1917, the Army issued two work orders to the Peoria branch of the Holt Company to build technology demonstrators. Both were armed with a single 75mm M1916 pack howitzer, based on the Vickers 2.95-inch mountain gun. These guns were fitted in a ball mount at the front, and there were additional machine guns in barbettes on the side. The tanks were protected by ⅝-inch boiler plate rather than steel armor due to their experimental role.

Vehicle A Model E, later called the Gas-Electric Monitor, was based on the Holt 75 tractor along with a new armored body. It was powered by a Holt 90hp gasoline engine that was linked to a General Electric Company generator that powered two electric motors on either side of the tank. The layout resembled contemporary French tanks such as the Schneider CA 1 rather than British tanks.

Vehicle B Model E, later called the Steam-Driven Three-Wheel Monitor, was less conventional. This was based on Holt wheeled agricultural tractors, but with the large 8-foot, sieve-grip tractor wheels in front and the steering wheel at the rear, the reverse of the usual layout. Propulsion was provided by the Doble-Detroit Steam Motors Company, consisting of two steam engines with a combined output of 150hp.

Both of the Holt Monitors were completed in late 1917 and subjected to Army trials at Aberdeen Proving Ground in early 1918. Neither Monitor displayed acceptable mobility or trench-crossing capability. By the time testing was complete, further development was canceled.

In the late summer of 1917, Gen. John J. Pershing, commander of the American Expeditionary Force in France, established a committee of officers to examine the AEF’s needs for tank warfare. The report was issued on September 1, 1917 and recommended that a force of 20 infantry divisions would require five heavy and 20 light tanks battalions totaling 375 heavy and 1,500 light tanks.

On September 18, 1917, Pershing telegrammed the War Department that France wished the United States to manufacture 2,000 Renault FT light tanks in addition to the tanks needed by the AEF. Renault sent a representative to Washington in early November along with an initial set of manufacturing drawings. A sample of the Renault FT tank arrived in the United States on November 28, 1917. It was subsequently sent to the Maxwell Plant in Dayton, Ohio, which had been selected to head the program. Due to the scale of the production requirements, the Van Dorn Iron Works of Cleveland and the C. L. Best Company of Dayton were also invited to join the manufacturing effort. Due to the secrecy of the effort, the American-manufactured Renault FT was given the cover name 6-Ton Special Tractor.

Engineering work on the 6-Ton Special Tractor began on January 1, 1918. The initial effort was to adapt the manufacturing drawings from their original metric measurements to American manufacturing standards. In addition, Ordnance decided to substitute an American Buda engine rather than trying to reverse-engineer the Renault engine. Contracts were issued to the three
Ohio plants for 4,440 tanks at an average cost of $11,500 each.

In February 1918, the War Department informed the AEF headquarters that they could expect to receive 100 American-built 6-Ton tanks in April, a further 300 in May, and 600 per month in subsequent months. This estimate proved wildly optimistic. The original plan had expected that the French engineering drawings would be ready by December 31, 1917, when in fact they were not completed until nine months later in September 1918 due to the numerous changes that were necessary. As a result, the AEF had to turn to the French Army to supply French-manufactured Renault FT tanks for its light tank battalions. The production program ran into numerous hurdles due to the novelty and scale of the tank program.

The first three 6-Ton Special Tractors were completed in July 1918 using soft steel rather than armor plate. By September 1918, 12 had been partially built but without turrets, speedometers, tools, or accessories. The first complete 6-Ton Tractors were finished in October 1918. At the time of the armistice on November 11, 1918, 64 tanks were ready. The first two tanks arrived at the Langres tank school in France on November 20, 1918, a week after the war ended. Eight more arrived in France in December. At the end of the war, the production contracts were curtailed. Eventually, some 952 6-Ton tanks were completed, consisting of 372 gun tanks, 526 machine-gun tanks, and 50 radio-command tanks.

Due to the slow pace of the 6-Ton Tractor program, Ordnance held meetings with Ford Motor Company in March 1918 in the hopes of manufacturing tanks using large automotive facilities. Ford began work on two designs: the small 3-Ton Special Tractor, and the larger Mark I tank. The 3-Ton was a turretless tankette with a two-man crew and a single machine gun. It was powered by two Model T automobile engines that gave it a top speed of up to 8mph. The 3-Ton was expected to cost only $4,000 each, and a contract was issued for 15,000 tanks with production expected to reach 100 per day by early 1919. A test batch of 15 tanks arrived in France shortly before the end of the war. The AEF Tank Corps in France was not at all enthused about the puny tank and recommended that it be converted instead into an artillery tractor. In the event, only the first test batch of 15 tanks was ever completed, and the contracts were canceled after the war.

The Ford Mark I tank was based on the Renault FT configuration, but larger. Ford was awarded a contract for 1,000 tanks, but only a single prototype was completed after the armistice. The contract was canceled along with plans for the Mark II, a Ford-built copy of the Renault FT with a Hudson 60hp motor.

In Pictures

The Vehicle A Model E, later called the Holt Gas-Electric Monitor, was armed with a 75mm mountain gun in the bow and a water-cooled .30 cal machine gun in sponsons on either side.

The strangest American tank of 1917 was the Vehicle B Model E. Photos of this tank are rare, and this one shows it on display in a hangar at Aberdeen Proving Ground in 1925 with its 75mm M1916 pack howitzer seen in the lower left.

The Holt Steam- Driven Three-Wheel Monitor at the Aberdeen Proving Ground, Maryland, in 1918. (Artwork by Felipe Rodríguez © Osprey Publishing)

The 6-Ton Special Tractor was the Americanized version of the Renault FT. This example is fitted with the early mount for the 37mm gun. None of these tanks reached France before the end of the war.

The US Army ordered 15,000 3-Ton Special Tractors from Ford in 1918. Fifteen were shipped to France shortly before the armistice, but the production contract was canceled after the end of the war.

If you enjoyed today's feature you can find out more in US Battle Tanks 1917–1945