The Chieftain's Hatch: The Can-Openers, America's Successful Failure

Allow me to quote from Wiki:

“U.S. Army doctrine held that tanks did not fight other tanks but supported infantry”

This is common knowledge. As a result, there was never any need to equip the tanks with a gun capable of dealing with the German tanks, the Tank Destroyer force can do that job. The end result of this policy was a woefully inadequate standard tank which was all but incapable of dealing with the opposition it faced, resulting in otherwise avoidable death. The error of this way of thinking was finally identified by the end of 1945 and the tank destroyers gotten rid of, making the Tank Destroyer Branch pretty much the shortest lived branch in Army history. Simple, really, we've all pretty much heard it.

One of the things that gets drilled into you in OCS is “Show me the regs.”  Armored Force doctrine was laid out in FM 17-10, it’s available online in PDF format. Next time someone comes back to you with the statement that “American tanks weren’t supposed to fight other tanks”, give them the link to the FM, and ask them to show you where, in the written doctrine signed and approved by General Marshall, Chief of Staff of the Army on behalf of the Secretary of War with force of direct order, it says that tanks were not to fight other tanks.

Here’s the short version. It doesn’t. He or she will be looking for a while. (Indeed, it states that both medium and (optimistically) light tanks could perform the anti-armour role)

There are other indicators as well. The creation of the stopgap M3 Medium is one. The US Armored Force were able to learn their lessons from the Europeans. The fall of France very quickly pointed out that the M2 with its 37mm gun just wasn’t going to cut it. The Germans even had mounted (gasp!) a 75mm on the MkIV! The US needed a new tank with a big gun to deal with the bigger tanks now roaming the battlefield, and it needed it now. Of course, the Tank Destroyer branch had not yet been created, but the concept of divisional anti-tank units was already fairly well sold in the minds of people such as McNair.

When the requirements for M4 Medium were laid out in Sept 1941, it specified that a variety of weapons be capable of being mounted into the tank. The 76mm gun M1 armed M4 Medium was approved in August 1942, before anyone, even the Russians, had encountered a Tiger. Indeed, up until then, there was only ever one encounter between US tankers in M3s and German tanks: On 11 June 1942, three crews claimed destruction of 9 German tanks with their Grants near Tobruk.

It seemed to indicate that the 75mm with American gunners was capable of dealing with the German tanks pretty well, but even so a -better- AP gun was approved for the tank at the known cost of HE capability. If the M4 medium was not supposed to fight other tanks, then why did the Army do this?

So, now we’ve dealt with that little issue, what –were- the can-openers for?

For that, hop on over to FM 18-5, the doctrine for the tank destroyers.

“Tank destroyer groups are intended for action against massed tank forces. As part of the mobile reserve of the high command, they are initially so disposed as to facilitate their rapid entry into action against large armored forces.

a. Tank destroyer groups which are attached to units engaged in offensive combat assist the attack by furnishing protection against large scale counterattacks by hostile tanks. They follow the attack closely, moving by bounds from one position in readiness to another. In enveloping attacks, they are usually echeloned toward the interior behind the enveloping flank.

b. Tank destroyer groups attached to units whose action is defensive are usually held in mobile reserve until the enemy's main effort is indicated and then engaged in mass against the hostile armored force. Depending on the situation, this may be prior to or after the launching of the hostile armored attack. “

Of particular note is this little passage.

“MASS.—The employment of tank destroyer units will be in mass. The battalion is the smallest unit which should be engaged separately. Employment of small tank destroyer units as independent defensive elements and their distribution with a view to covering every possible avenue of tank approach or to affording immediate protection to all echelons of the forces leads to uncoordinated action and dispersion with consequent loss of effectiveness”

In a nutshell, the TDs were anti-armour units –par excellence-, effectively to enhance the anti-armour capabilities of the supported organisations, not to replace them entirely.

Now, there were certainly failings in doctrine when it met reality. One was the belief that the 76mm gun on the M4 was sufficient to destroy enemy tanks. The reason M4 wasn’t given a bigger gun wasn’t doctrinal, the Americans just seemed to be utterly convinced that the M1 could do the job. To give an example, quoting an exasperated Eisenhower in July 1944: “Why is it that I am always the last person to hear about this stuff? Ordnance told me this 76mm would take care of anything the Germans had. Now I find you can’t knock out a damn thing with it.” Of course, by that point, it was a little late in the game. We can then go on about all the conspiracy theories as to why the Americans were so late in getting Fireflies or T26s (and we will, at a future point in time) but suffice to say, they really thought that Shermans could take on all the German tanks. Another is the fact that with few exceptions, those massed armour engagements that the TD force was designed to deal with never showed up. As a result, the TDs ended up being split up into smaller units contrary to doctrine. About the only true material concession to the concept of primacy of TDs over tanks in anti-armour combat was the allocation of HVAP ammunition in some units. But even that makes a bit of sense given the purpose of the TDs as anti-armour specialists. But as far as tank destroyers as a concept, they obviously weren’t wrong: Most every major force, German, Russian, British, used them. Granted, however, the German and Russian TDs at least were well-suited for the combat which was predominant: small-scale engagements at close range where heavy armour was of more import than operational mobility at which the American TDs excelled.

There was also one other advantage that the TD crews had over their tanker colleagues, their training specifically focused on dealing with enemy armour first of all, everything else secondary. As a result, they would be better at it than anyone else. This training could make a world of difference to the end result: One tank unit in Italy had the TD crewmen train the tankers on detailed anti-armour tactics, and they saw their kill rate go from multiple losses per kill and move to multiple kills per loss.

Indeed, that kill ratio is pretty much a common feature of the TD units. We’re used to talking about losing multiple M4s for every German tank killed. To a point, this is to be expected, as the Allies spent most of their time advancing. However, the TDs also spent most of their time advancing, and their kill ratios were usually positive. One battalion (703rd) had a 10:1 kill to loss ratio, and it’s important to note that many of those losses would not have come from armour but anything from mines, artillery, Panzerfaust or other such devilish contrivances of the enemy. 3:1 seemed to have been more common. On the occasions that the TDs did what they were supposed to do, and that was kill tanks, they proved to be very good at it. 823rd TD claimed 64 MkIVs, 27 Mk V, and 18 MkVI amongst the 113 tanks claimed destroyed. On Christmas Day at Bastogne, the 705th claimed 27 panzers for the loss of six guns. 704th claimed 39 kills at Arracourt for the loss of four guns. (figures from Yeide and Zaloga)

A secondary function was that, true to McNair's roots in artillery branch, the TDs were additional self-propelled artillery assets. Particularly so in Italy, where the terrain usually wasn’t suited much to anti-tank maneuver, and the smaller 76mm rounds didn’t do much damage to the roads. Even in France, TD units could fire some eight or nine indirect rounds for every direct round fired.

So the American TDs performed with distinction. They could knock out tanks well, they could provide fire support when there were no enemy tanks, they even performed some amount of infantry support, when there were no friendly tanks. The accurare, high velocity cannon proved particularly useful against point reinforced targets such as bunkers. M18s were even used as convoy escorts because they could keep up with the trucks. Why, then was the branch disbanded?

Well, that’s why I say ‘successful failure.’ There were two main issues. One was to do with the equipment. For example, lessons learned in North Africa indicated that towed guns could be devastating to armoured vehicles. As a result, half the US tank destroyer battalions were re-equipped with towed 3” guns.  Only problem was that by the time they were re-fitted, the war in North Africa was over, and it was time for an offensive action in Europe, for which the towed guns were ill-suited. Oops.

Another problem was that the guns the TDs were equipped with generally had difficulty with the larger German tanks, though this was generally rectified by the M36 once the shortcoming had been identified. This wasn’t a doctrinal deficiency, just a delusional one. The other issue was that the tanks were often used as TDs, and the TDs often used as tanks as the situation dictated. M10, M18 and M4(76) all had similar anti-armour capabilities, just the TDs had less ability to deal with infantry. It was an inefficient use of manpower to have multiple corps and items of equipment to do overlapping jobs. When M26 came out, that seemed to seal the fate. What could M36 Jacksons do that M26 Pershings could not?

The answer was, well, not much, really (We'll come back to this as well). Instead of having entire reserves of tank destroying vehicles sitting, waiting for the massed enemy armour attack, why not simply grab tanks and create a local reserve as required and use them as tanks the rest of the time?

Yet, though the Tank Destroyer force was disbanded, that was not the end of the tank destroyer men. We just called them something else, like 11-Hotels. Some of the TDs, like the M56 filled a role that no tank could do, such as provide interesting recoil experiences...

...but was the ITV was a tank destroyer which could not have been replaced in the role of protecting and supporting infantry by a tank? Other forces such as the Germans kept their tank destroyers, and Soviet doctrine dictated that the primary anti-tank system was a missile, not a tank. Tank Destroyers may have become a bit of a taboo term in the US, but the role was alive and well.

The irony is that the whole shebang came full circle with the introduction of the M1A1. Here was a vehicle designed with the primary purpose of the destruction of enemy armour. No ammunition other than Sabot (Anti-heavy-armour) and HEAT (anti-light armour) was provided for the main gun. Bradleys could do the infantry support role. An exact reverse of the first paragraph of this commentary. America's latest tank in 1986 was really a tank destroyer.

Hopefully that’s given you a little bit of food to stimulate a bit of discussion. Go ahead and click ‘add comment’ below to contribute.