Overview
The Boirault machines were French experiments in crossing the obstacles of the First World War battlefield. Instead of conventional tracks running along either side of a hull, the first machine used a large articulated frame surrounding a central powered unit. The frame was intended to lay a broad path over wire and broken ground. Sources
The accounts distinguish two experimental machines. No.1 emphasized a large open frame, while No.2 brought the frame closer to an enclosed central body. Neither became a production tank or an operational combat vehicle. Their significance lies in the problems they attempted to solve and the limits exposed by trials. Sources
Development and trial chronology
Louis Boirault's approach addressed a pressing obstacle problem: moving through wire and across trenches rather than merely carrying armor along a road. Accounts associate the first design with 1914 and construction with 1915. It identifies French archival photographs and film as particularly useful evidence for the machines' appearance and experimental use. Sources
The source material describes multiple demonstrations or trials. February 1915 and July 1915 appear in identified photographic records, while later accounts describe further assessment and abandonment. These references remain unconfirmed. Sources
No.2 introduced a more enclosed arrangement. Its chronology requires separate attention: a film catalog's production year is not automatically the date the vehicle was designed or first tested. The same caution applies to a photograph reproduced in later press coverage. Published accounts describe a postwar bridge-related patent lead, which does not represent another production tank. Sources
No.1: the large articulated frame
No.1's defining feature was its surrounding frame-track. The central motorized unit moved within an articulated structure whose sections successively met the ground. This was a different solution from two narrow caterpillar tracks beneath a conventional armored hull. Its very large dimensions are visible in the photographic record. Sources
The account reports a machine commonly described as about 30 tonnes, with engine output around 80 hp. It also preserves uncertainty in precise dimensions, speed, and steering performance. Such figures remain attributed estimates unless tied to a specific trial record. Sources
The technical difficulty was not simply whether the machine could flatten wire. Useful movement also required steering, manageable dimensions, and the ability to continue across varied terrain. The published assessments emphasize slowness, steering limitations, and the material burden of the structure, rather than claims of demonstrated combat usefulness. Sources
No.2 and the limits of visual evidence
The second machine brought an enclosed central cabin and the surrounding frame into a more compact relationship. Photographs can support discussion of its visible form, but an opening in a cabin is not by itself proof of an installed weapon. Published accounts describe detailed armament, armor thickness, crew, and some mechanical specifications as uncertain. Sources
The evidence for the two machines is uneven. No.1 has a more readily described experimental record; No.2 cannot inherit No.1's power, weight, or performance automatically. Sources
A later film associated with No.2 includes a ramp or bridging demonstration. Its interpretation belongs with the particular recorded test and object, not with an invented combat-service history. Sources
Family structure, production, and service
The two Boirault machines were distinct experiments, each with its own modifications and test history. A revised test arrangement does not necessarily mean that another full-size vehicle was manufactured. Likewise, a patent, film, or later press image is evidence about a machine, not a variant in its own right. Sources
There was no series production or operational deployment. French military and technical bodies in the cited accounts are evaluators, not field operators. Published accounts describe no basis for assigning combat engagements or a service crew history to either machine. Sources
Comparisons with other French tank precursors can explain different answers to the obstacle problem, but related development context cannot establish a direct descent or influence relationship without evidence. Sources
Legacy and the photographic record
The Boirault experiments show why crossing one battlefield obstacle was not enough to establish a successful tank design. The work explored a striking mechanical solution, while Published accounts describe the combination of maneuverability, practical construction, protection, and useful military employment that it failed to deliver as an operational system. Sources
The gallery can be unusually informative if it separates the two machines, identifies test views, and preserves the distinction between a photograph's date and the date of its later reproduction. Sources
Photographs and image credits
Background reading and references. Each photograph has its own source and credit.
Sources and further reading
Background reading and references. Each photograph has its own source and credit.
- S1 — ECPAD / ImagesDéfense, “Expérimentation de l'appareil Boirault sur terrain, février 1915”
- S2 — ECPAD / ImagesDéfense, “Appareil Boirault. Expérience de Maisons-Laffitte du 22 juillet 1915”
- S3 — CNRS Images, “Boirault No.1 anti-barbed-wire machine,” reference 6672
- S4 — CNRS Images, “Boirault No.2 anti-barbed-wire machine,” reference 6673
- S5 — Tank Encyclopedia, Andrew Hills, “Boirault Machine”
- S6 — Wikimedia Commons, Category: Boirault machine
- S7 — Wikimedia Commons, File:Appareil Boirault 1914.jpg
- S8 — Photograph of No.1 underway, dated 1915, unknown author; public-domain tag on Commons
- S9 — Wikimedia Commons, File:Second Boirault machine.jpg / II.jpg
- S10 — Wikimedia Commons / BnF / Agence Rol, “Visite de tanks à Souain (Marne)” files btv1b530164880, btv1b53016497z, btv1b53016523n
- S11 — The Tank Museum, “French First World War Tanks”
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