How the Tank Began

Fosters Of Lincoln

The relevance of these products to William Foster & Co Ltd of Lincoln, whose pre-war products included threshing machines and steam powered portable and traction engines, may initially seem to be remote, but the firm had been brought in to the Ordnance field following the outbreak of War to assist in the solution of an earlier military problem: the conveyance of 15-inch howitzer units.
It was felt that Foster’s expertise in the solution of heavy haulage problems should be exploited, Fosters proposal in the form of 105 h.p. petrol – engine wheeled tractors, towing special wagons to carry the guns and their ancillary equipment was readily accepted by the government, in fact, the usual Whitehall procedures of approval was waived and an immediate order for 97 Tractors and 291 wagons was given. The first units were available by August 1914.
Incidental to the trials of these tractors was the use of a portable bridge to carry the units over a ditch. Observations by senior personnel to William Tritton the Managing Director of Foster’s that a unit capable of carrying and laying its own bridge would be a great asset in the type of trench warfare becoming established in France where seized upon as the next possible phase of war work to be carried out by Foster’s since the tractor contract was due for completion by the late spring of 1915.

William Tritton’s experience and success in bringing home pre-war orders for the products of Fosters and maintaining a flow of production and profits was doubtless of considerable influence in firing his interests. Consequently an experimental machine adapted from the howitzer-hauling tractors was built and succeeded in crossing a trench 8 ft wide utilising a portable bridge carried on either side of an extended wheeled frame which replaced the conventional two front wheels, however although this machine could cross a ditch in 3 minutes the weight of the unit, its unprotected nature and its unsuitability for the ground conditions prevailing in France causes to be abandoned as a project, another aspect of Fosters pre-war activities also came of Foster’s pre-war activities also came into play: that of manufacturing “Centipede Tracks” so-called because they featured endless-chain tracks, instead of wheels. This idea was to prove the key to success of the tank.

The Birth of “Little Willie”

The problems of crossing trenches still remained and was proving a major headache to the Government Departments on the other hand they now had the knowledge of a firm which had demonstrated initiative, engineering expertise, the ability to deliver on time and some knowledge in the area where the problem lay, What better than to give the problem to Foster’s and at the same time assign to them one of the military experts with ideas in this troublesome problem? The officer who was to work with Tritton was Lieutenant W.G. Wilson RNAS and thus commenced the association of the two men most responsible for the design and success of the tank, working much of the time at the White Hart Hotel in Lincoln. Their terms of reference were broad “to design a machine strongly armoured, carrying powerful guns, capable of negotiating reasonable obstacles in the battle area and crossing the opposite trenches”.

Technical restrictions imposed were that the useful life of the units need to be no more than 50 miles and that a pair of American caterpillar tracks placed at Tritton’s disposal should be incorporated in the design. Additionally in order to quicken production, Tritton as he had done in the case of the abortive bridge-layer, decided to utilise some existing elements and so the power unit of the Foster-Daimler tractor was incorporated in the design.

The 37 days between August 2nd and September 8th 1915 saw the designing and building to movement stage of a prototype christened “Little Willie” incorporating the specified tracks and with a simple box-type upper works and the distinctive rear wheel assembly unit, with the resources available this was an impressive achievement by any standards. A trial before official observers on September 19th failed because the specified American tracks came off whenever a manoeuvre was carried out, various alternatives were considered but once again, Tritton came up with a solution links in pressed plate; light in weight strong and designed not to leave the guides when unsupported as they passed over broken ground.

At this stage the design parameters were influenced to a very significant degree by the events in France. The German Trench systems had become more permanent, wider and deeper than hitherto. The solution appeared to be a unit of a size sufficient to cross the Trenches without diving into them and with the ability to climb fortification parapets.