WW1 US Prototypes

Holt Caterpillar G-9

United States of America (1916-1917)
Tank Mock-up – 1 Built

Tanks first came to the public consciousness with the British unleashing them at Flers-Courcelette on 15th September 1916. It was some time before pictures of them started to appear in the media and, in the meantime, various artistic renderings of this new weapon of war came out as well. Being tracked and with a complicated development, many claimants put themselves forwards as being the inventors or, at least, the inspiration for the design. The most obvious of these was the American firm of Holt with their ‘Caterpillar’ vehicle. Indeed, the name Caterpillar is now synonymous with tanks and other tracked vehicles in general, but they were not the vehicle on which the British based their tanks in WW1, despite numerous books and television programs repeating this again and again over the decades. There were, in fact, numerous tracked armored and unarmored Caterpillar vehicles used in WW1, and one which received widespread attention was the G-9. If the attention it garnered from the media of the time was impressive, then its ignominious fate did not. Since WW1, it has largely vanished into obscurity. Even the movie ‘Patria’ in which it featured has disappeared from the public consciousness. The Caterpillar G-9 was one of the first American ‘tanks’, a rather poor vehicle built at a time of little or no knowledge of armored vehicle development, but undoubtedly an important one in the history of US vehicle development.

The ‘Tank’

The body of the vehicle was rather crude. Consisting of a slab-sided superstructure that taped slightly towards the roofline, with multiple loopholes or vision slots in the side. At the front, the shape of the body followed the shape of the tractor underneath, curving around the circular mount for the leading wheel and then angling upwards to a large rectangular hatch on the front. At the rear, the slab sides, as well as taping towards the roof, also taped in slightly at the back and there was another large rectangular hatch. Poking out from the rear hatch was a tube for a fake gun and presumably the same from the front hatch. However, with the tractor radiator directly behind it, the option for even a movie extra to stand there and play make-belief is doubtful. 

In the film and in some of the photos of it being observed by the US troops, it can clearly be seen to have a pair of turrets, one right at the front of the cab, directly over where the engine was, and a second directly over the rear. Some photos, however, only show a single turret in that second position, with the front one missing.

Given that the structure, other than the tractor underneath, was made of just wood, it is easy to assume that the front turret either fell off, became damaged, or was otherwise removed from the vehicle shortly after filming. Popular Science June 1917 reported that examination by the US military took place straight after filming had finished and this front turret was in a terrible position. Not only would the turret be directly over the engine and all its heat and noise, but it would also obscure any field of observation or fire from the rear turret. On top of that was the small matter of the exhaust. Images of the G-9 with just a single turret show clearly the exhaust from the vehicle exiting the roof right where turret 1 had been, implying that turret 1 simply sat over the exhaust for the film, something likely to have caused exhaust fumes to come back into the vehicle. 

Scene from the final battle in Patria with the ‘tank’ advancing.
Source: American Falls Press 28th September 1917

The height of the vehicle seems to be a function of the tractor underneath having a large canopy over the top. Building a framework for the ‘armor’ on top of this canopy would also allow someone sitting on top of it to operate the rear turret, making it move for the camera. If this was a real attempt at a design, then this extra height was utterly unnecessary and would only serve to make it a bigger target and more top-heavy. Underneath the turret/turrets and the ‘armor’ was a standard Holt 75 tracked tractor.


The Holt 75 tractor normally weighed 10,432 kg (23,000 lbs.), but was reported as being a ‘13 ton’ (US short tons) at the time of its crash in 1917. Thirteen US short tons is 11,793 kg, meaning an added weight from the ‘tank’ body and turret of just 1,360 kg. This confirms that the body was not truly armored. Were the vehicle to actually carry real and effective armor, such as something not less than 8 mm thick, it would have added substantial mass to the tractor, in the region of 10 – 20 tonnes. This meant that the 75 hp engine would not have been very effective. The maximum loading capacity of the tractor was just 21,350 lbs. (9,684 kg), so it is doubtful that, without a substantial change in the design of the G-9, any worthwhile armor could be carried on the vehicle.

The Holt ‘Caterpillar’

The Holt tractors, sold under the name ‘Caterpillar’, were effective and reliable tracked tractors. Indeed, the Holt design had been, to a degree, one of the reasons behind the impetus behind some of the British push for tracked vehicles in 1915 by men like Robert Macfie. It had some shortcomings too, such as poor speed and an underpowered engine. Even without any armor added, the machine was slow. Cladding several tonnes of extra weight would raise the center of gravity, making it unstable and even slower or utterly immobile, as well as making it hard for the driver to see where he was going.

As a farm vehicle or tractor for hauling guns, these were less problematic but not ignorable. The driver, sitting at the back on the right-hand side, had to try and see forwards over all these obstructions. Even when the vehicle was open and unarmored, his view was obscured by the engine to his front left. With armor, he stood no chance of seeing out of a small slot in the front. Instead, he would have to be guided by at least one other man, probably sat or stood right next to the noisy and hot engine. At least two men were therefore needed to control a vehicle with terrible visibility and, with the problems of communication between them caused by the engine, this was not a recipe for success. 

Holt had been successful even before the ‘tank’ appeared, having sold the US Army 63 of its Model 60 tractors with a 60 hp engine. The Model 75, however, was an order of magnitude more successful than the Model 60, staying in production until 1924 at the plant at Peoria, Illinois. Some 442 Holt Model 75s were even manufactured by Messrs. Ruston and Hornsby Ltd. in Lincoln, England. Combined, 4,620 Model 75s were made, of which more than 2,000 entered military service. 


In 1916, at the time of the Patria movie, the Holt 75s available would have been US-built examples using the Holt M-7 7 ½” (190 mm) bore, 8 inch (203 mm) stroke ‘valve-in-head’ engine delivering 75 hp, originally known as the Holt 60-75 (A-NVS), if they were made since production began in the Stockton plant in 1913. Some 16 Peoria-built tractors made between 1914 and 1915 used the Holt M-5 ‘Ellhead valve layout’ (T-6 series) engine. Due to problems, this was quickly changed to the Holt 75 (T-8 series) engine being fitted at the Stockton plant in California. Given that the film was also shot in California, it is most probable that the Holt used was a Stockton-made one rather than a Peoria-made example. 

The engine was considered perfectly adequate for its normal duties and remained the standard engine until 1921 when it was improved with a new radiator. The T-8 series Holt-75 engine was a 4 cylinder water-cooled unit that ran on paraffin with a capacity of 22.9 liters (1,400 cubic inches), delivering 75 hp at 550 rpm. This power was carried to the drive sprockets moving the tracks via a multiple disc clutch made from 5 plates made from bronze and cast iron, along with a simple reversing gearbox. The gearbox provided for 2 forward and a single reverse gear. Forward speed was limited to 2.13 mph (3.4 km/h) in 1st gear, 3.5 mph (5.6 km/h) in second (top) gear, and 2.13 mph (3.4 km/h) in reverse. The fuel tank held 53.5 Imperial gallons (243.2 liters) which, along with 5 Imperial Gallons (22.7 liters) of oil, and 67 Imperial gallons (304.6 liters) of water, provided the fluids required for the engine to operate.

The Holt tractor itself used cast iron wheels running on heat-treated axles on Hyatt roller bearings. The track itself was connected by case hardened steel pins linking pressed steel plates 24” wide (607 mm), although 30” (762 mm) wide tracks could be fitted. All of the links had pressed corrugations 1.5” (38 mm) deep acting as spuds for traction in soft ground. The load was carried on four double-coil helical springs springing the track along its 80” (2.03 m) ground contact length.

The steering was managed via a single wheel at the front, controlled via a long steering control shaft from the steering wheel and driver’s position. This was located roughly in line with the center of the track units. The steering wheel controlled a non-reversible worm and wheel gear.

Side elevation of the Holt 75 hp tractor. Source: LeGros


An article in Popular Science June 1917 makes it clear that both the body and guns were made of wood, but also that there was a wire cutter built for the front of the vehicle. The G-9, therefore, was completely unarmed, although it is possible that pyrotechnics, like blanks, could be used to simulate gunfire.

The Movie

With the tanks of Britain and, later, France seeing combat and appearing in the press, it is no shock that, when William Randolph Hearst made a war movie in 1916, he would need a ‘tank’ of his own. Hearst was a very wealthy man and a media tycoon owning numerous newspapers and an animation studio called ‘International Film Service’ (I.F.S.). In 1916, filming of the first episodes began at Wharton Studios in Ithaca, New York, on a movie for I.F.S., all funded by Hearst and very much pushing a political agenda of military preparedness.

To an audience of 1917, the script had lashing of patriotism of dedicated Americans organizing for collective defense against a foreign foe, which culminated in a pitched battle in which, obviously, the ‘good’ side would prevail. In the modern world, it is impossible to see the film without cringing at the blatant jingoism as well as the overt racism of the movie, with stereotyped Japanese villains. However, what is unacceptable now was simply grist for the mill of the overall desire of many for the US to enter the war. It is perhaps odd then that the Japanese were the ‘enemy’, given that, in 1916, Japan was aligned with British interests and actively opposed German ones having already fought the Germans over Tsingtao in 1914. Nonetheless, the rather cartoonish plot involved a secret Japanese cabal of spies in league with nefarious Mexican interests gathering arms and gold in preparation for war in the US. This is perhaps the only time such an alliance has ever been contemplated on film. The Mexican angle was the more reasonable topic of the time, given the invasion of the US in March 1916 by Pancho Villa. Villa’s raid had sacked the city of Columbus, New Mexico, sparking a punitive retaliatory expedition by the Americans.

The shooting of the first episodes of the film took place on the site of Greystone Manor, which is now part of Cornell University. It starred Irene Castle (as Patria Channing) in her screen debut, along with established actors Milton Sills (as Captain Donald Parr), and Warner Oland (as Baron Huroki), an actor most famous later for his portrayal of Fu Man Chu and Charlie Chan. 

Patria was a massive work made in no less than 15 separate episodes, costing a phenomenal US$85,000 (over US$2 million in 2021 values). The first 10 episodes were directed by Theodore and Leopold (Ted and Leo) Wharton, but the film was a little too jingoistic even for the day, particularly in its anti-Japanese portrayal.

After the first 10 episodes had been shot, allegedly, President Woodrow Wilson intervened with an appeal to the wealthy Mr. Hearst, requesting that the anti-Japanese sentiment be toned down. The result was that the leading villain, Baron Huroki, was changed from a Japanese character to that of ‘Manuel Morales’. However, the motion picture press coverage of the film at the time makes no mention of such an intervention and Huroki is both clearly villainous, Japanese, and referred to as Baron Huroki. Interplayed with this fiendish Japanese fifth columnist (although the term was not even coined at the time) plot was a criminal Mexican connection on the southern US border playing on the problems there at the time. 

The wafer-thin plot of Hurki was contrasting with the glowing, alluring, and wealthy Elaine ‘Patria’ Channing (‘Patria’ means homeland in Latin, i.e. Elaine as the personification of the noble country defiled) working with handsome and dashing Secret Service agent Captain Parr. Together, these two would try to thwart the insidious threat to national security from the invaders and insurrectionists in the form of Huroki, the Japanese, and the Mexican soldiers. 

Advertising Poster for the serial-movie Patria. Irene Castle is billed as ‘Mrs. Vernon Castle’ (her husband, Vernon Castle, was a pilot with the Royal Flying Corps on the Western Front at the time). The man next to her is Milton Sills. Source: IMDB

The final 5 episodes were to culminate in stopping the invading Mexicans at the border. The filming for these episodes was moved from New York to the West Coast and were shot in Los Angeles by director Jacques Jaccard. No doubt, California offered a better landscape to match ‘Mexico’ or the Southern USA than New York did. 

The film was published for release on 1st January 1917 and premiered on 6th January. It did not receive general release until 14th January 1917 in the USA. By the time of the final episodes being released, the political situation was changing. This culminated in the US declaring war on 6th April 1917, making it an ally with one of the main villains of the film, rendering many of the sentiments of Patria immediately and woefully redundant.

Sadly, the original serial episodes have suffered from the ravages of time and only the first 10 episodes are known to survive. They were pieced back together in 2012 by Serial Squadron. Only limited stills of episodes 11-15 are known to survive and, unfortunately, it is in these final episodes in which the ‘tank’ appears. 
Patria movie (10 episodes)
Source: Serial Squadron

Although these final scenes are missing from the film, there are both clues and a few photographs of what the ‘tank’ was that appeared. In fact, the correspondent for Moving Picture World reported that there was not a single ‘tank’ but ‘tanks’ in the final battle.

“…we have used every known appliance of modern warfare, including tanks, dirigibles, machine guns, gas bombs”. Source: Moving Picture World 24th March 1917

No footage or stills of the climactic battle are currently known to survive, although one syndicated photograph was thankfully printed in several newspapers at the time. In the photo, a twin-turreted ‘tank’ can be seen ahead of a line of US troops, heading towards what appears to be men either standing or running and with a cloud of smoke or ‘gas’ rolling across the battlefield.

Scene from the final battle in Patria with the ‘tank’ advancing. Note that it has two turrets. Source: American Falls Press 28th September 1917

Further to the single image was a long explanation of the action in the scene, which, in the days of silent movies like this one, was fairly common. An audience could read up on the action before watching it and thus be fully informed as to nuances not easy to convey in the occasional slide of words during the film.

Two excerpts from the account of the ‘battle’. Source: American Falls Press 28th September 1917

Here, in this account, it very clearly states once more that ‘tanks’, plural rather than ‘tank’ singular, were used. It even goes so far as to describe them vividly as “monstrous armadailloes [sic: armadillos]”. More than just two vehicles are actually mentioned, as the final charge is supported by “a fleet of ‘tanks’ – armored caterpillar tractors carrying machine gun crews”, yet this pluralization may simply be colorful reporting rather than strictly and literally correct. 

This account of at least two vehicles is somewhat contradicted by that of Lescarboura (1919), who provides actual numbers of the extras and vehicles involved in the scene. He described the use of more than 2,700 men, including 1,200 of the California National Guard, 325 horses, multiple field guns, 25 aircraft, and just “one armored tractor or ‘tank’”. His account of just a single vehicle is backed up by the fact that there is no photo of more than one vehicle at the same time and, more importantly, by a review in Current Opinion which has the same still as before but printed more clearly. From this, it is also clear that there is just a single vehicle involved. A serious explanation of the episode’s key plot points was provided by the magazine Dramatic Mirror of the Stage and Motion Pictures, which also made clear it was just a single-vehicle.

Better quality and wider framed shot of the assault scene from Patria. Source: Current Opinion Volume 63, 1917


Episode 15 ‘For the Flag’

Baron Huroki plans a night attack on Patria’s line of intrenchments, in which he hopes to surprise her troops. The Japanese advance is driven back, but an attack of liquid fire enabled them to creep up upon the trenches. In desperation, the American troops play their trump cards and send out their huge Caterpillar tank, which ploughs through the enemy’s ranks and scatters them over the border.

Amid the enthusiastic plaudits of the soldiers, Patria seeks out Donald Parr, who had been wounded in the battle, and this thrilling story of romance of war ends blissfully in love’s young dream

Dramatic Mirror of the Stage and Motion Pictures, Volume 77, Part 1 dated 28th April 1917

The Famous Photos

There is a trio of slightly more famous or well-known images of this vehicle that appeared in the media at the time, outside of the stills from the battle scene. The shooting of Patria had finished before January, as the episodes were rolled out into cinemas and the film-prop ‘tank’ which had been made was still around afterward. In April 1917, images of the tractor appeared in various newspapers and magazines as a ‘tank’ being evaluated by US officers for potential use.

More curious than those April photos was not that the images would be repeated even into September that year or that they even appeared as rather fanciful art, but that the vehicle appears to have predated all of those and the movie. 

The first outline of the vehicle appears in the November 1916 issue of Popular Mechanics magazine, although it is important to note that the image is not a photograph but an artist’s impression of a tank. This is an important distinction as, although tanks were used on 15th September and news of their success captured the public’s imagination – images did not appear until 23rd October 1916. In this intervening gap, various fanciful depictions appeared and the November edition of Popular Mechanics is no different. Obviously, November is after October, but the November edition would go out in October and prior to the 23rd. Thus it missed the reveal of the real tank and was out of date almost immediately. Nonetheless, this was likely one of the first proper conceptions of what a tank actually looked like, which many Americans may have seen.

The British ‘tank’ in action according to Popular Mechanics November 1916. Note the twin turrets. Source: Popular Mechanics 1916

It is obviously not possible for the artist to have copied the vehicle from the film, as filming had not yet begun, yet the two vehicles are virtually identical, meaning they are assuredly connected. If one can imagine a wealthy man like Hearst trying to fund a great ‘patriotic’ movie at exactly the same time and not having access to an actual image of a tank but needing one in his film, it is not hard to imagine a situation where the film copied the design from this depiction. In the Popular Mechanics’ depiction, there is a clear explanatory note stating that their artist has rendered the drawing based on reliable data and on photographs of the Holt tractors which were already known to be in British use and purchased for the war. If a soldier at the time described a metal machine clad in armor and with two turrets, this drawing would indeed be a fair conclusion based on the common assumption of the turrets being mounted on the top of the tank rather than on the side as, in fact, they were on those first British machines. In the still image from the film, the vehicle can be seen still using a pair of turrets, as it is in the promotional images published in April 1917 and afterward.

Front view of the vehicle with the front wheel off the ground with a pair of soldiers and a civilian in the foreground looking on. Note that this image, like others, was issued by I.F.S. rather than an independent photographer. The top of the rear turret is also visible at the back, as is the ‘wire cutter’ on the front, which appears as nothing more than a large slightly curved blade. Source: Literary Digest New York 7th April 1917
Front cover of the periodical Le Miroir (English: The Mirror) from 29th April 1917 with the caption announcing the vehicle as a ‘tank’ of the US Army. Note that this is a wider framed and uncropped view of the same image as appeared in Literary Digest earlier that month. Source: French National Library

In those April images, one thing is very clear –  namely that the vehicle had a pair of turrets. Other images of the vehicle, purported to be taken during evaluation by the US Army, are also known and these feature just a single turret at the back. This change has led to speculation that there were, in fact, two different vehicles and that this is backed up by some of those film reports of multiple tanks in the final scene of Patria. However, not all of the film reviewers agreed that more than one tank was seen. It was, after all, just a prop for a single scene and those tractors were expensive. 

This particular image, cropped from a slightly wider framed one, has appeared captioned as both being evaluated by the US Army at Sandy Hook, New Jersey (by Icks in 1975, quoting Wilson) and by contemporary sources as taking place in Los Angeles. Source: Clark.
Wider left-framed version of the same photograph which appeared in Literary Review. Source: Alexander.
The following shot showing the rear of the vehicle as it climbs a steep slope under the watchful eyes of soldiers. The vehicle can be seen leaning dangerously over to the right on this side grade. Also visible sticking out of the front is the exhaust stack for the motor, under where the lead turret used to be. Source: NARA Photo Ref: 165-WW-313-A-59.

Whatever interest the US military may have had in this beast is unclear. By the time they were allegedly looking at it, in the spring of 1917, the British tanks were already seen in the press and, unlike this ungainly machine, were fully tracked. Despite the structure being made out of wood and sheet metal (with wooden pegs inserted to imitate rivets) to simulate armor, the vehicle was still top-heavy and this helped to bring it to grief sometime in March 1917, at least a month or so before photos of it being ‘evaluated’ were shown. When the vehicle rolled over down a bank, it was utterly wrecked and thus it would have been unable to be evaluated, leaving just two possibilities. The first, that there was a second vehicle all along, or second, that the photographs were released after the crash.

Published in June 1917, this image shows the collapsed body of the G-9 tractor fallen onto its right-hand side. Note the entire side section with the word ‘CATERPILLAR’ on it has come off and is lying to the front right of the picture.
Seen in the March 1917 edition of Illustrated World, the G-9 is toppled over onto its right-hand side off the road. Source: Motor Age.

Motor Age magazine, reporting on the crash in March 1917, also used the single-turret image and was clear that the photos were both taken in Los Angeles. With the different publishing dates distinct from the dates on which events happened, the reporting of multiple ‘tanks’ during filming, and the removal of one of the mocked-up turrets, it is not hard to see why it can be confusing as to whether there were two vehicles. Clearly, having crashed no later than March 1917, it could not be trialed in April or June, but the publishing dates are misleading, as they are not necessarily reporting events happening at that time, but events that had happened. I.F.S. owning the images is the first clue that option 2 is more likely the answer, as they could release the images to help promote the vehicle and, by default, their own film.


The design was somewhat awful. Impractically large, the tractor itself was solid and reliable and had been seen as helping to inspire some of the British tank development, but it was still not a tank by any interpretation of the word. The vehicle was simply a movie prop for Patria and not much more. The film has largely vanished from the collective consciousness and no full reel of it even exists anymore. 

It might, however, be worth remembering the movie a little more. Not for its racism and xenophobia, but because it is likely to be the first ever representation of a tank recorded on film in the United States. In the post-unveiling of the tank by the British in the previous September, the world had come to see this new weapon of war as making a sea-change in the dynamics of land combat. America had clearly been languishing without. America would produce other imitations of foreign designs, eventually putting into production its own version of the French Renault FT. The G-9 design was clearly never a seriously considered tracked vehicle concept and, with the accident destroying the vehicle, it was quickly forgotten. In the century since, however, the appearance of soldiers next to it has led many to believe and claim that this was a real project considered for the US Army. Holt and Caterpillar did not suffer from this. Holt took over the firm of C.L. Best, a rival tractor firm, some years after the war, and together, the brand of Caterpillar went ahead to become a world-renowned brand in all manner of heavy plant equipment, surviving to this day.

Author’s Note: The author would like to thank the Wharton Studio Museum, New York, and Serial HQ for their help in preparing this article.

Side illustration of the Caterpillar G-9 mock-up tank that starred in the Patria movie. Illustrated by Yuvnashva Sharma, funded by our Patreon campaign.

Specifications Holt Caterpillar G-9

Crew: 2+ (driver x 2)
Armor: None
Armament: None
Engine: Holt M-8 series paraffin engine delivering 75 hp
Speed: <3.5 mph (5.6 km/h)


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