The Devil's Chariots

by John Glanfield

  … it is only a question of time before some such war machine appears, and the nation which first produces it will have a great advantage… It does not seem probable that any use can be made of the Holt caterpillars that we saw recently at Aldershot. There would be difficulty in armouring them as they stand and they could not be armed but would have to pull an armed trailer.

  I think the sound plan is to let a committee build up from the egg, beginning with the requirements and the possibilities and [then] going on the design.19

  Scott-Moncrieff was also positive. He thought that to save time they should prepare designs for armouring a Holt tractor and trailer combination in advance of the trials. Holden was oddly pessimistic:

  … the difficulty of course is in making an engine of warfare of this description which is capable of doing what is required of it without excessive weight and being liable to destruction by the enemy’s fire…

  I am afraid Captain Tulloch does not appreciate the mechanical difficulties with which the problem is beset, and also that the time taken in working this out, if an entirely new design of engine is to be produced, will be so great that unless the war is going to last for many years, the war will be over before the engine is ready. It seems to me … that the only thing that can be usefully done at the present time is to experiment with such engines as are available viz: the caterpillar type and the traction engine type, fitted with some means of bridging ditches, trenches and other obstacles… The designing and building of new engines specially for this work is quite out of the question in view of the time involved.20

  Von Donop and Guthrie-Smith agreed with Holden. On 17 February 1915 a 120bhp Holt was duly tested in heavy rain on the mud flats of the Shoeburyness ranges. It hauled a chaintracked trailer representing a 4-ton fighting module laden with the equivalent of two quick-firing (QF) guns, ammunition and a crew of six. The course simulated battlefield conditions with a 24ft deep belt of wire fronting two parallel fire trenches 12ft apart and each 2ft wide. Beyond these were open and roofed trenches up to 8ft wide, and finally a sunken entanglement. Guthrie-Smith, Jackson and Holden attended. Swinton and Tulloch were not invited.

  There were serious shortcomings in the tractor and the trial. The Holt was poorly prepared. Its engine ran badly and despite the waterlogged ground conditions no track extension plates (grousers) were attached because, in the words of Maj Haynes, the superintendent of experiments, ‘they take a very long time to fit’. The Holt was also ill-matched to the more testing obstacles. Holden had proposed that the trial machine be fitted with some means of bridging trenches but no action was taken to provide the tackle. The heavy trailer was a dead weight on the drawbar whereas Tulloch’s proposal called for both units to be powered. Haynes reported:

  The wire entanglement was easily knocked down and the tractor reached the second fire trench without difficulty. The trailer was then in the first fire trench. The tractor stuck in the second fire trench and even when uncoupled a long time was spent in getting out, empty sandbags and odds and ends of timber being put under the track. At a second attempt to cross the same obstacle the tractor failed to extricate itself from the second fire trench. The tracks cut away the soft wet ground until there was no weight on the tracks, and the machine was resting on the driving chain covers. The tractor was eventually helped out by a stem sapper and winding rope, but in doing this the sapper became so bogged that it in its turn had to be pulled out by the caterpillar. The ground was saturated with water, the trenches were half full and heavy rain was falling most of the time.21

  Realizing that the project was about to sink like the Holt, Jackson tried to set it on firmer ground by suggesting to von Donop that perhaps their approach was flawed. He reminded the MGO of his original view that the machine needed more power and a longer track for trench crossing: ‘That such a machine could be designed to given conditions seems quite possible. How long it would take to design and build it is a question on which I cannot give an opinion.’22 Von Donop told Scott-Moncrieff that he had discussed the matter with Guthrie-Smith and Holden. He concluded that the project was unlikely to succeed because of the time required for design and production, the great weights involved, vulnerability to gunfire and difficult battlefield terrain. He added that he was open to persuasion and invited Scott-Moncrieff and Holden to nominate a competent designer.

  Scott-Moncrieff to Holden: ‘Can you suggest the name of any person competent to design a land cruiser, not too heavy, that will cross any ordinary country and negotiate the usual fences? I do not myself know of any, but perhaps the President of the Institute of Civil Engineering could advise.’23

  Holden to Scott-Moncrieff: ‘I am afraid I cannot. The only firm in this country who have had any experience in this line are Hornsby’s of Grantham.’24

  The leads were not pursued and with this lacklustre closing exchange the investigation ended. Tulloch had freely offered his services and had told Jackson that he could find an eminent automobile engineer, but after his initial submission in January 1915 he and Swinton heard no more. Tulloch later told the Ministry of Munitions that he had forewarned Jackson in January:

  … that he should avoid taking the opinion of a certain official, as I felt quite certain that if that official was consulted he would most certainly ‘crab’ the whole idea and throw difficulties in the way. Unfortunately … the official was consulted and he, together with another official, who had really no claim whatever to be considered an expert, joined in condemning the idea, with the result that much time was wasted. The plea put forward by these two people was that quite apart from the feasibility or otherwise of the idea, the preparation of the drawings etc. would certainly take a year, and therefore it did not seem worth while troubling about the matter.25

  The expert ‘official’ was Holden, as Tulloch confirmed to Swinton.26 Holden’s standing in military transport development was unassailable. His view proved decisive. Tulloch knew him well because the two had worked together at Woolwich where he was principal experimental officer when Holden was superintendent of the Royal Gun Factory. They continued to meet after Tulloch’s retirement through a mutual enthusiasm for motor transport – both were leading lights of the fledgling Institution of Automobile Engineers (IAE).

  Recriminations and evasions surfaced over the Holt investigation when the tank finally emerged. Scott-Moncrieff remarked that ‘Holden missed a great opportunity in declining the idea.’27 In his memoirs Maj Gen Sir Charles Callwell, Director of Military Operations at the time, blamed the system and conceded that the War Office came badly out of the business: ‘The technical branches had not been put in their place before the war, they did not understand their position and did not realize that on broad questions of policy they were subject to the General Staff.’28 As Master General of Ordnance, von Donop was responsible for all forms of military transport. His past mistrust of tracklayers when he was D of A may have influenced his thinking on the Swinton/Tulloch scheme but he was deeply preoccupied with the crisis over shell supply and relied heavily on Holden’s judgement.

  Holden remains the enigma. His belief that it would take years to produce a fighting machine probably sprang from his bitter experience of the excruciatingly slow pace and parsimony of peacetime military research. He appears to have overlooked the greater impetus of a war-driven and well-funded development project. Whereas he had vigorously defended the Hornsby system and the crawler principle when challenged by von Donop three and a half years before, his opinion of chain traction had nosedived by the beginning of the war when he spoke to veteran engineer Col Crompton. The old warrior told Holden of his concern at the complete absence of motorized cross-country gun tractors. Crompton mentioned chaintracks which, he says, Holden dismissed immediately as having no military value because of ‘the nutcracker action of the track shoes which had put them out of action when trials were made for heavy artillery at Lydd’.29 Holden was recalling a tendency for Roberts’ system to pick up stones which became trapped between the shoe
s, sometimes damaging the track. No such fault is mentioned in numerous MTC trials reports which tended to accentuate the positive, but the susceptibility was noted by others and was peculiar to Roberts’ design. By February 1915 however, Holden was sufficiently confident of chain traction to be buying Holts in quantity.

  In his evidence for the Crown at a High Court hearing in 1925 Holden offered a much more upbeat version of his thinking in 1914–15. (The action was brought by Capt Bede Bentley who claimed £300,000 for inventing the tank when, he said, he personally handed the design to the late Lord Kitchener during an alleged three-hour interview at Kitchener’s home in October 1914. The claim failed.) Holden said under cross-examination that he had been an exponent of the caterpillar since 1906. At the outbreak of war the MTC had two. Counsel – ‘Had either of them been a success?’ Holden –‘As a machine one of them undoubtedly was.’ Counsel – ‘A machine to be used in warfare?’ Holden – ‘Certainly.’30 He must have been referring to experimental Hornsbys Nos. 2 and 3. Holden added that the experiments ‘were so successful that it was decided to build another embodying all the improvements’.31 This last is unsupported by the many surviving documents but he may have been seeking to suggest, incorrectly, that the MTC’s Hornsbys formed part of the chain of causation of the tank. He made no mention of ‘nutcracker’ problems. In the light of Holden’s High Court statements it is all the more surprising that he responded so limply to von Donop’s request for a specialist engineer. His casual attitude in 1915 was at odds with his 1925 testimony.

  The War Office was involved at that time with another trench-crossing device – ‘Foster’s Portable Bridge Machine’. A spin-off from an Admiralty order for gun tractors, its sponsor was the First Lord, Winston Churchill. The origins of the machine lay in the aftermath of the first tactical surprise of the war, the destructive power of German heavy howitzers which demolished the Belgian fortresses of Liège and Namur in late August 1914. The 42cm monsters threw a half-ton shell, reducing in days defences intended to survive for months. Shortly before, Churchill had been amazed to learn from Rear Adm Reginald Bacon, General Manager of Coventry Ordnance Works Ltd, that his company had designed a 15in (38cm) howitzer which could be dismantled for road transportation. It was a remarkable claim for ordnance weighing some 60 tons. The army’s heaviest howitzers comprised a solitary 9.2in and a handful of obsolescent 6in pieces, against nearly 400 enemy guns in this class. Bacon had earlier offered the howitzer to the War Office. He was given to understand, rightly or wrongly, that it was against the policy of the Army Council to employ heavy guns in the field as they would encourage the infantry to hang back and let the ordnance do the work. When the fortresses at Liège fell, Churchill ordered 12 of Bacon’s heavy guns. This was Admiralty business because the weapons were destined for his Royal Naval Division, then in formation. He assured Bacon that if he could meet his own very tight delivery forecast, the Admiral should himself command them in France.

  Bacon approached the Daimler Company for tractors. Daimler happened to be supplying petrol engines for some giant tractors nearing completion for the South American market as a joint venture with Wm Foster & Company, agricultural machinery makers of Lincoln. Daimler referred Bacon to William Tritton, Foster’s Managing Director, and it was agreed that the Daimler–Foster ‘Agrimotors’ should be adapted. An order followed for 97 wheeled tractors at £1,866 each and 291 special wagons. It was, claimed Fosters, the largest single order ever placed for motor tractors. The machine’s acceptance trials at Lincoln on 10 December 1914 included a bridging demonstration. The big tractor of nearly 14 tons hauled two trailer-loads of bridge timbers to a broad ditch which engineers spanned in three minutes before waving the outfit across. Unfortunately a wagon toppled over the side, collapsing the deck. As the spectators waited, Tritton recalled that Bacon casually remarked to him that it would be of great value if an armed and armoured machine could be constructed which laid its own bridge. He continued to badger Tritton until howitzer tractor No. 44 was modified as a self-bridging testbed. These big machines were driven through traction-engine-type rear wheels 8ft in diameter and 2ft wide. The sleevevalve engine developed 105bhp and the machine could haul a 35-ton load. (Exactly a year later Fosters would be installing the engine and transmission into the first tank.) On His Majesty’s Service (OHMS) M44 dispensed with the usual pair of smaller front wheels. Instead a sub-frame was fitted as a forward extension to the chassis, increasing overall length to approximately 31ft. Within this frame two road wheels were fitted in tandem. Two 15ft steel bridging girders were slung beneath it, one on either side, hanging just forward of the rear wheels. The girders were secured by an endless chain enabling them to be lowered, raised or dragged.

  On reaching a trench the machine was run forward until the second of the front inline wheels was at its near edge, the leading wheel being on or approaching the further side. The bridge girders were duly lowered to span the trench and the machine was driven across, at least one of the front wheels always remaining in ground contact. The tractor then had to travel sufficiently beyond the trench to drag the girders clear before reversing over them to restore them to their travelling position. The whole operation took three minutes to clear an 8ft trench on firm ground, all the while a crewman sitting over the sub-frame furiously turning a highly geared hand wheel controlling the girder lifting chains.

  Bacon proposed to fit every machine with a pair of electric headlights plus a single light on either side, all with a 2ft-diameter glass front on which was painted the ferocious head of a Chinese warrior. At a given signal as 40 or 50 thunderous vehicles approached an enemy trench in a night attack, headlights would be switched on to further unnerve the defenders. The machines would then straddle the trench on their bridges, switch to the sidelights and enfilade it in both directions.

  The basic idea was sketched out and put to Churchill later that month. By the end of December he had ordered an experimental machine and had instructed Bacon to lay the project before Sir John French at GHQ and Lord Kitchener. Bacon recorded in his memoir, From 1900 Onwards, that Kitchener was pleased with the idea and authorized the trials. It was at this point – the beginning of 1915 – that Hankey’s Boxing Day memorandum forced the issue of tracked weapons development into the open. Bacon had no difficulty in securing military assistance and he expected to have the trials machine ready by 1 February. In the meantime, the official proof of his first howitzer was under way at Shoeburyness where it was firing its 1,400lb shells.

  The self-bridging project started to slide when difficulties in adapting OHMS 44 forced Fosters to put back trials readiness to 15 February. Churchill nevertheless gave Coventry Ordnance a production order for 30 bridgers on the 13th. The reason why he did not await the trials outcome is perhaps explained by Bacon’s departure for France the next day, where he was to command a half battery of his first two howitzers. Churchill had kept his promise. Bacon was highly regarded by him and the order was very probably a parting salute from Churchill. In any event, much drive departed with Bacon. The bridge machine became nobody’s baby.

  The abortive WO Holt trials took place on 17 February. Three days later Churchill cancelled his production order for self-bridgers, instructing Coventry’s Mr J.H. Mansell to proceed with the experimental machine only. The project languished without official direction until mid-May when von Donop enquired when the trials machine would be ready. Mansell expected to deliver it the following week, adding privately to von Donop that he could find no official order or correspondence on the project and asking whether the machine should be invoiced to the Admiralty or the War Office.

  The trial finally took place on 9 June on dry hard ground over the same course as the Holt had crossed in February. The self-bridger needed at least twice the available distance between the two trench lines in order to retrieve its girders after crossing the first before tackling the second, so it was decided in a mood of unwarranted optimism to put the tractor in top gear at both narrow trenches withou
t deploying the bridging.

  After flattening the wire hazard with ease, the machine – on full throttle – baulked at the first parapet, and on changing to the lower of its two forward gears it slewed sideways and stuck with one driving wheel in the trench itself. A Holt tractor pulled it free and grousers were fitted to the driving wheels. The trenches were then bypassed. The machine had no difficulty in laying girders over single trenches up to 8ft wide, but it was nose-heavy. Bacon recalled, ‘They dug a place 8 feet deep with 4 feet of water and filled with barbed wire… Tritton said when we looked at it that we never guaranteed to cross the Channel.’32

  Holden and Haynes acknowledged the design’s ingenuity but their findings were damning: it was underpowered, with inadequate weight distribution and an unacceptable requirement for a clear 25ft run-out after bridging to retrieve girders. The machine was a gunner’s gift and would have been blown to bits during the several minutes of shunting entailed in crossing trenches. It now looks an obvious non-starter but one must never forget the state of the art at the time. Bacon and Tritton shared the general ignorance of battlefield ground conditions. They saw the potential of the new tractors and pressed on with encouragement at the highest level. Their testbed was the first purpose-built machine to be put over trenches since the stalemate had begun eight months before. It was an honourable but inevitable failure. OHMS 44 was rebuilt for howitzer haulage at a cost of £20. Foster’s drawing office began work on a bridging machine of juggernaut size before Tritton thought better of it and turned to more promising work.