Wednesday, July 28, 2010

Fall of France, 3: On Armoured Warfare, II

Tanks, of course, were into their second war in September 1939, and it would be a mistake to think of them as having been invented in the 1914--18 war. On the contrary, the idea is apparently so obvious that inventers had been proposing them for centuries. It might be argued that they first became practical in 1914, but that's a slight mistake, too. Everyone understood that you couldn't drive a wheeled vehicle across a battlefield, so the idea of the tank in 1914 started with recent experiments with caterpillar vehicles. Lots of wheels drove a track that reduced the ground pressure levels so low that the vehicle could make way in the heaviest mud. Put it another way, and we get the concept of a locomotive that lays its own track as it goes. Running locomotives on roads is notoriously hard on the roads, but this is war, and you can't make an omelette without breaking eggs.

Only, and here's a problem, locomotives don't turn. They're more-or-less pushed around corners by banked and gently curved tracks. The wheels are forced to go different distances in the same time, even though they are rotating at the same speed, and so the inner wheels skid, and the locomotive turns. Without curved rails, one has to substitute direct speed control of the tanks track. This is how it worked on the tractors that so impressed the generals watching them in 1914. (And, contrary to myth, it impressed them a lot. Generals are men before they are officers, and men like gadgets.) The operators wrenched on a brake lever on one side while gunning the engine. The inner tracks slowed down, the outer ones sped up, and the tractor wrenched around to a new heading.

But, as Dr. H. E. Merritt explained to the Institution of Mechanical Engineers in 1946, there is no sufficiently rugged and compact mechanism for providing positive control of the speed of a track. Dr. Merritt's talk provides solutions using hyperbolic functions, so he solved the problem by setting up a partial differential equation and solving it, presumably numerically. For a 500 hp, 50 ton tank, length 16 feet, width 10ft, turning at 30 ft/sec velocity, he concluded, the motor must drive the outer track at 230hp. There's enormous waste heat, the tank slows rapidly as it turns, you need a huge engine, mainly to fight itself in the turns, and an even huger arm on the brake lever!

Merritt was employed by the great Huddlesfield gear maker, David Brown, except when he went down to the army's tank design office to urge his favoured solution to the problem, a regenerative braking system. Not surprisingly, he had a rival at the army's tank design office, Major Walter Wilson, who also dabbled in the private sector, founding Self-Selecting Gears. Wilso designed his first gear box in the 1920s. It was used first in an abortive tank design of the early '30s, the Vickers Independent while the Merritt-Brown transmission was first adopted in the Infantry Tank A22, Churchill, which entered service in the summer of 1941, just in time to great the great German invasion that never came.
Merritt reviews various possible transmission arrangements, not surprisingly concluding that his was the first that really worked. Major Wilson had an apoplexy in the audience, but the point should not escape us that the first really satisfactory heavy tank transmission appears in 1942. (The Germans even copied it in the Tiger.) Before that, there was 40 years of faking it. Tanks were hard to turn, hard to drive, and very slow in the corners.

As I've said, the British high command was very enthusiastic about them, all the same.
David J. Childs, (A Peripheral Weapon? The Production and Employment of British Tanks in the First World War [Westport, Conn., and London: Greenwood, 1999]) finds plenty of enthusiasm for the weapon. They might have been misused, as Liddell Hart used to like to argue, but looking back postwar, you can also write this off as a learning experience. The Army certainly seems to have valued the opportunity. A young but very promising officer, Lieutenant-Colonel Hugh Elles (b. 1880), was placed in charge of the Tank Corps, and his postwar ascension through the ranks was smooth and rapid, with some, although not nearly all of his appointments, related to the tanks. In 1934, as a 54 year-old Lieutenant-General, he was placed on the Army Council as Master-General of the Ordnance. This strikes me as a generous recognition of the tanks, and even a promise of greater things. As a Lieutenant-General he would have to retire at 60, but if he were promoted in the next 6 years, he could expect to serve until 1945, and as full General, he had a good chance to advance to the top professional appointment in the army, Chief of the Imperial General Staff. The last two had been artillerists, but as a strike against him, they had also come from field appointments.

There were many officers under Elles at the Tank Corps. Today we are inclined to focus on Fuller, who was a clever young staff officer seconded to his staff to do paperwork. Closer to his heart (I do not doubt; Fuller comes through his writings as a malignant narcissist and compulsive plagiarist) was a clever young engineer, Giffard Le Quesne Martel. You have probably never heard of him. For while the historian of the Tank Corps Hart cultivated close connections with many young officers, Martel was not among them. (If you find the alternating usage of "Tank Corps" and "Tank Regiment" confusing, it's because it is meant to be confusing, as near as I can tell. There is an explanation, which can be found on Wikipedia.)

So what are these smart fellows doing in the aftermatch of the First World War? They are worrying about the great tactical problem of the war, the (light) machine gun. As Colonel R. S. McClintock explained in the April 1931 number of Army Quarterly, the unlocated machine gun was the fundamental problem of modern war. (Col. R. S. McClintock, “The Last Five Hundred Yards,” AQ 22,1 [April 1931]: 128–40). A machine gun is so small, so inconspicuous, that you need to suppress it without knowing where it is. You have to saturate the battlefield with artillery. He goes on to conclude that the Field Force needs artillery more than tanks, but that is not the whole story. An analysis of successful modern battles (Unsigned review of Col Gresset, Montdidier, le 8 Août à la 42e division AQ 22,2 [July 1931]: 386–9) concludes that the attack needs "'mass;'" but also surprise and depth of penetration." Vast amounts of munitions and force must be brought up by stealth in preparation for the attack. To do this, engineer support has to be laid on, and, well, how do you manage both stealth and mass? By a very rapid concentration: mechanisation is key, because the attack force has to make a rapid approach march, and tanks --attack tanks-- are the one weapon that can do this. Another reviewer comments on a German thinker who concludes that to meet the new menace requires new weapons. Automatic rifles backed by LMGs, light mortars, anti tank guns (which are light enough to be manhandled), and “smoke producing apparatus.” This will allow infantry to do without as much artillery --but how can they possibly carry all of this? And is the weight of artillery that McClintock calls for even practical?

Giffard Martel had a chance to work these things out for himself. He was posted to the Experimental Bridging Establishment in 1920, where he contemplated his first world war experience and developed various ideas, good and bad, before being made chief engineeer commander of the Experimental Mechanised Force in the late 1927. In the way of such things, he was then put on half pay for six months, during which time he worked his notes up into a book, In the Wake of the Tank. Since it was published during his half-pay period, it maintained the illusion of not being an "official" document, the standard method by which British officers published works on the theory and practice war in those days. Next he was made an instructor at the Indian Army Staff College in Quetta, where he worked up the manuscript into a definitive second edition that was published on his arrival back in England to become the Assistant and then Deputy Director of Mechanisation. (Despite the qualifier, I think that he was the man in charge of tanks. The full director had other responsibilities as well.)

So while Liddell Hart and Fuller certainly had something to say about tanks, Martel was the guy actually in charge. Hopefully In the Wake of the Tank will have something meaty to say! And, of course, it does. We can actually go back to what another army rising star, Australian Basil Cranmer Dening, to get some insight. As winner of _Army Quarterly's_ inagural Bertrand Stewart Memorial Prize for best essay on military affairs, he should have something to say about 1924's topic, mechanisation.
As, indeed, he does. The germ of his paper is that the army needs armoured personnel carriers to go along with its tanks. Since he is pretty clearly right, and was recognised as being right, one wonders how such an insight was missed. Only, his runner-up, Lionel Dimmock, argues that since APCs are a little too expensive for the moment, perhaps tanks can pull armoured carriages full of troops as an interim substitute. Full marks for originality, if not practicality, the judges seem to be saying.

So lots of officers are saying that there need to be infantry operating in close support of the tanks. Hmm. But doesn't Liddell Hart tell us that he was practically the only person interested in the subject, along with Fuller? Doesn't he point out that while Fuller thought that a tank-only army was viable, he (Hart) thought that some "tank marines" would be needed, mainly to protect "tank harbours" at night and during refuelling?

Dening believes, like many of his contemporaries, for example E. G. Home and W. D. Croft) that tanks need close and organic infantry support to clear barriers (there are those "barriers" again) and thereby protect tanks from the antitank guns that will be picking the tanks off as they mill helplessly before them. By the same token, however, the infantry are vulnerable to light machine guns protecting the barriers. That is where the firepower of the tanks come in --it's all a finely integrated web. Practically, though, is it feasible?

Martel says that it is: provided that the tanks have tank support! And what he means by this is that there are two kinds of tanks. One is a "light" kind that conducts "cavalry" operations across country, presumably accompanied by infantry in APCs. The other is much heavier. Why, well, imagine the tactical situation as the enemy waits, ready to receive British attack. There are LMG teams and antitank gun teams. There is barbed wire, and mines, and ditches, and rivers and canals. Now, however, there is a storm of artillery falling on the enemy. This is the situation familiar from the Battle of the Somme and the like. Right now, there is no barrier to British infantry running right up and taking the field, except their own artillery (plus defending artillery firing from so far back that it is relatively safe from the "counter-battery" fire of British heavy artillery.)
Unfortunately, the moment that the artillery lifts so that British infantry can advance, the enemy machine gun teams and AT crews will climb out of their shelters, man their weapons, and mow down the advancing troops. Something must occupy the position first. And that is the tank's job: the heavy tank. It must be immune to enemy artillery and machine gun and light anti-tank gun fire. It must have a machine gun of its own with which to attack the enemy infantry. And, considering that the likely enemy counterattack force is heavy tanks of its own, it must have an antitank gun as its main armament.

We can call this weapon a "heavy" tank, or an "infantry" tank, or a "gun" tank. Heavy is the most literal description of it, in that it is going to be too big and bulky to steer properly. That means that it is going to have to be slow. It is not a question of engine power, cost or size, although these issues do arise. It is that technology can't give a tank this big proper steering, if it happens to be at all fast!

As for the lighter tank, what does it look like? What does it do? Well, it bursts through the broken line to chase the enemy defenders back and capture their guns, take prisoners, and generally convert a defeat into a rout. The infantry and guns follow behind, and advance into the enemy interior, striving to take capital cities, river crossings, air bases, whatever. Infantry marching fast into enemy-held country are at constant risk of being ambushed by rapidly-moving enemry forces, so the lighter tanks stay ahead of them, covering the approach routes, scouting the roads.

Everything I've said about "lighter tanks" above I could just as easily have said about cavalry in Nineteenth Century warfare, so let us call this tank what it is: a "cavalry tank." The APC that accompanies it is a pure abstraction as long as we cannot afford to build it, so we will leave it undefined. What does a cavalry tank look like? Ideally, it should not be too specialised. That is, it should be at least vaguely capable of doing the heavy tank's job. Not as much armour, compensated by more speed is the picture that we are imagining here. Certainly it should be able to skirmish with enemy infantry and tanks, and that means that it needs an antitank gun as its main armament. But it has to be self-sufficient, too, because it is fighting mobile "encounter battles" that develop rapidly. So it should have one of those "smoke projectors," too. If antitank guns and LMGs are the big issue, well, they can't hit what they can't see!

So let us push the argument forward into the early 1930s. Martel is off in India, giving his lectures. Dening is proceeding through the educational institutions of the army on his way towards a senior command, occasionally writing as he does so. The "Experimental Mechanised Force" has evolved into the Tank Brigade. The CIGS, an artillerist with the unfortunate name Archibald Montgomery-Massingberd, believes that cavalry cannot do the cavalry job anymore, so the entire cavalry division that is supposed to screen the BEF as it advances to contact in a European war will have to be "mechanised" in some way. The clear solution, it would seem, is that the tank brigade should in some way give issue to a new "Mobile Division," replacing the Cavalry Division.

I'll look at that thought later, because it is precisely what is not at issue. On the contrary, after the 1931 manoeuvres, Liddell Hart published an extraordinary series of articles in the Daily Telegraph that were later summarised and defended in a brutal series of exchanges with the young Lieutenant Colquhon Grant in the 1933--34 run of Army Quarterly:

He imagined an armoured brigade of 100 Vickers 11t Medium Tanks (1x47mm cannon and 2xMGs) and 130 light Tanks. It had, he proposed, more firepower than an entire infantry division, and, being more mobile, was consequently much more effective, and much cheaper. He suggested that had the BEF of 1914 consisted of this single tank brigade instead of its actual 5 divisions, it could have won the war in a summer.

Grant pretty much made mincemeat of this: but let us be clear that Hart is proposing that the BEF could be replaced by a brigade of 230 tanks with no infantry at all! It would be a windfall for his young friends of the Tank Corps, but bad news (institutionally speaking) for everyone else in the army. But, more importantly, it is clearly a huge deviation from the standard Army thinking about the future of armoured warfare. The 11ton medium tank with its 47mm gun is a long way from the necessary "heavy" tank, but it is a step in the right direction. But even this seems to be no more than a support weapon for a light tank with no meaningful military capacity at all. And it is to replace the BEF? Is Hart talking to the army at all? Or does he have another audience?

Let us be clear here. Far from being blindsided by the future, intelligent young officers can clearly visualise the armoured division as it existed in 1945. They are experimenting with APCs (in its British incarnation, we have the Bren Gun Carrier, which has its counterparts overseas) and know what the tank they need will look like --distractions like the idea of a "mobile pillbox" aside. This is not the division that gets to France in 1940, though.

Or is it? Is something else going on here?

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