U.S. WWII Tank Destroyer Doctrine.

[JasonC]

Redwolf -

StuGs were doctrinally supposed to work that way, but were more and more pressed into a TD role as the war progressed. The Pz Jgr formations are neither tank nor artillery.

Coe -

You might try to counter TDs with HE, but it is not terribly effective. Just staying below the turret rim is quite effective protection against shell splinters. You also tend to not know where they are until they engage, and real time arty cooperation is always going to be relatively poor deep in the enemy defended zone. If you could assure airbursts or in a forest, maybe, but not too reliable.

The main way to beat linebacker TDs is just to keep all arms coordination throughout the attack, to avoid giving the defender any large intel differential. What I mean is, stalking TDs work well on defense because they get reports on where attacking tanks are, where they are massed, how they are moving, etc. They then get ahead of them and can engage knowing that the engagement is going to happen, but often tactically stationary or hidden themselves.

The more the attacker relies on thrusting deep rapidly with pure tanks, the more of an intel differential he is likely to create. Because those reports come from the defending infantry, and are current only while the attacker is continually advancing etc. I mean, if the attackers wipe out the defenders forward of line X, and an hour or two have passed since, then the defense may have no more idea where tanks that helped do this are, that they did before the original attack.

In practice this means an attack that doesn't rely exclusively on an armor edge, but includes a local superiority in the other arms as well, is much more likely to be sustained without giving the defender a big intel edge. Similarly, if the defender has a big HE and arty edge, he can break up the attack into armor leading and not much else, and again set up good conditions for his TDs.

So the trick is to have enough and to be thorough wiping out the forward defenders. Also to be less than predictable where you go after you break in. Breakthrough forces screened on all sides aggressively, so the defenders can't tell where the schwerpunkt is. That is the recipe. The whole idea is to avoid any "we are buttoned and can't see squat, they've got 5 guys on the radio telling them our every move", defender edge.

"did it make sense for either side to have really heavy tanks"

Only because portions of either side's fleets aren't able to handle them. And they only convey a significant tactical effect, if they can isolate on enemies without their counter. That isn't easy to arrange, if he has many upgunned types and decent tactical coordination etc. But e.g. a Churchill company helping against a pure pillbox defense of dug in PAK, can make a huge difference compared to only having Shermans. Or a King Tiger company that manages to catch a group of T-34s and only T-34s.

Both of which did happen. But neither side had anything that the other couldn't counter with its best hitters. To that extent, uparmoring pays diminishing returns once your opponent has upgunned.

"Could I assume that this is because the Russian 76mm Zis or 57mm ATGs were less powerful than the 76mm U.S. cannons."

Well the 57mm was a good gun, but relatively rare, certainly so in 1943, and mostly towed. The Russian 76mm had about the power of the US short 75 on the plain Sherman (both are about 40 calibers long and medium velocity). The US 76mm, on the other hand, is a much higher velocity weapon. With plain AP is has about the tank killing power of the Russian 85mm. With tungsten ammo, significantly better.

The Russians fielded some 85mm weapons in the second half of 1943, and certainly found them highly useful. (The used a dozen 85mm AA in each tank corps as AT weapons in the summer, and added SU-85s in the fall). They were not outranged by StuGs and Panzer IVs, like plain T-34s were. And they could kill Tigers. (In CMBB, the 1943 ammo is vastly undermodeled - you only see the gun's real ability in 1944).

So naturally it would have been extremely useful to have had a fleet of TDs with such weapons in that era. Especially if they had tungsten (even if after a bit of delay). The only reliable "animal killer" the Russians had at that time, were a handful of SU-152s, with low ROF and only medium velocity (hence accuracy at range etc).

"Essentially you have two forces on the open step approaching...who has the greater max range?"

Not typically the issue. One side or the other is typically stationary with some concealment or cover (from rises and falls in the ground if nothing else). At least for long enough before the contact that the other side "doesn't see it coming". Tank fights at range between types that can kill each other, are usually decided by who gets "the drop" on the other guy, and fires first from concealment on targets long since acquired and tracked.

Once the engagement opens that way, typically the losing side disengages rapidly. They get into defilade. Then somebody may probe or not, there or elsewhere. They try to track the original shooters without giving themselves away, to reverse the process.

Only Tigers in 1943 could afford to "stand out in the open", continually seen by the enemy at range, and dare anybody to show themselves by firing. And even those could wind up paying for it, from a host of damaging rather than killing shots from annoyance weapons.

"if the guns had equal range and penetrating power you might not want to be in the TDs"

Nope, I want to be in whoever can see the other guy first, I want to be more concealed, I want to be the tactical defender or stationary while he moves (making him easier to spot). That is the critical question. Like two guys with scoped rifles on opposite ridges, each within range. I get very still and I scan. I don't worry about whether the sandbag in front of me is thicker than a rock he might hide behind; not the issue.

"As for the dug in experience at Anzio...was this a case of inability to get the first shot off?"

Mostly it was intel differential again. I mean, the Germans were on higher ground with excellent observation. The Americans could not (or at least, thought they couldn't and did not) do the usual thing and leave the TDs well in the rear, waiting for a German armored break-in to come into the layered infantry battalions ringing the beachhead perimeter. They didn't think they had room for that and, in all the mud, didn't think the TDs could come up to help where needed, quickly enough.

So they put then 400 yards behind the front foxhole lines and just dug them in, deep, in gun pits. That was supposed to be their cover - being harder to hit by being hull down, showing less than the full vehicle. But still close to the front, so soon spotted by the German infantry. And stationary (gun pits aren't very mobile). So the attackers had the intel differential. They picked them off easily. I mean, they could choose whether to engage, from where, etc.

You could have killed them with towed PAK if you were patient enough - no great thick front plate required. (Move the gun into firing position at night, camou it well before daybreak. Then snipe).

[coe]

Jason could you expand on then why the Germans still managed to get good exchanges early (when their guns stunk) and even later (note they still had Panzer IIIs 42-43 and the even late when everyone was upgunned - is this a case of T34 and IS-IIs running around blind?

I see what you mean about TDs - in general finding out where the enemy is, rushing there ahead with superior intelligence seems like the antidote for most things regardless if it is TD vs. Tank. In that sense the doctrine isn't that revolutionary.

More generaly for all...any advantages besides ammo load of having a StuG IV as opposed to a StuG III?

I have to look up the stats for the soviet 57mm but it seems like a good gun and since the barrel is smaller than the 76 or 85mm I am wondering if it is a smaller gun and therefore would be advantageous to have put that into a T-34 than the 76 (isn't it lighter too?)...

(and for you naval grogs, do you know where I can find a comparison of the Type VIIC U-boat and the Gato class (find out who can dive deeper, faster and which was more quiet).

[JasonC]

Germans did well early because the Russian mech arms was not ready for prime time. Combat service and support were non-existent, supply planning entirely inadequate, maintenance nearly nonexistent, etc. Most of the pre war fleet evaporates within days of making contact whether the Germans seriously fight them or not.

By the time of Moscow the Russians switch to a managable (read, small) brigade structure and get more use out of their tanks. The portion of modern heavy types is no more than a third, though, and the fleet is at its smallest. In early 42 the modern portion is up to 40% or so, (the rest are T-60, T-70, and some lighter LL vehicles) but the Russians are also hording production to build reserves from the summer to November. So the Germans don't have to face their full strength.

Throughout that period, the biggest edge besides early Russian technical-logistic incompetence is the string of operational successes the Germans are enjoying. Throughout the war, that always mattered more than the tech specs of tanks. (The guy with the better tanks is typically losing overall, I mean, as other factors swamp technical tank developments). They also make better use of combined arms, especially towed gun fronts to stop Russian heavies, which the Russians don't have the tank-artillery cooperation to counter effectively. So the German tanks try to hit where the Russian armor isn't, leaving defense to massed gun lines.

Note that it is precisely the success the Germans have using that approach that convinces McNair (US force structure architect) that tanks per se should have an offensive exploitation mission, not a tank killing mission, while tank defense should be left to a specialist arm with a defensive stance and force on force attrition, not maneuver, doctrine and focus.

The Russians still do get an initiative when they unleash the T-34 horde they have saved up, in larger formations (tank corps) and acting offensively. T-34s or better are around half the fleet by then (end of 1942), with the balance mostly T-70.

By Kursk, the German fleet has migrated with production exclusively of superior types to where only about 1 AFV in 3 is the old 1942 model mix (mostly 50L60, some 75L24), while 1 in 2 are long 75 vehicles that outrange the T-34s. 1 in 6 are the new heavies, which outclass anything they have.

The German tech spec edge peaks in the second half of 1943 as they field more and more Panthers and Tigers and the last inferior models leave the fleet through loss. While the Russians are adding little - SUs becoming more numerous, and SU-76s replacing T-70s in production, but there are still a lot of the latter in the field (roughly a third at Kursk).

In 1944 the Germans field tons of TDs but none truly superior to the Panther and Tiger I in any numbers, while the Russians get their T-34/85s, IS and ISU, and the German tech edge shrinks rapidly.

Note that the Germans lost the decisive battles of the war - Kursk to the Dnepr bend - while they had the greatest edge in tank fleet specs. The Germans don't have remotely enough tanks, is the largest problem. They get large exchange ratios but the production ratio is equally large, and the western allies are building up unmolested. Main reason, the German delay in ramping tank production - a story I am sure you have heard from me before.

Against the Russians, therefore, the Germans always enjoy either large operational successes and Russian doctrinal unreadiness, or superior tech specs. It is unsurprising that they rack up better than even kill ratios as a result.

They undoubtedly also had better average skill from more experienced tankers and especially tank officers, a bonus left by the string of early victories,carrying on as a momentum. I mean, the typical Russian tanker of 1941-2 was outlier lucky if he made it to 1943 in one piece. Russian tactics were wasteful at times in quite unforced ways, too. (Throw a tank army at a ready and waiting panzer corps, head on, etc).

By mid 1944 or so these advantages are evaporating. German production is finally ramped though and somewhat makes up for it, letting them sustain a higher rate of loss without the tank fleet disappearing.

On StuG IV advantages, the main one is better floatation aka much lower ground pressure, from wider tracks. Significantly better off road mobility as a result. A StuG III is as bad as a narrow tracked Sherman in ground pressure terms. A StuG IV is almost as good as a T-34.

But the reason they made StuG IVs wasn't either edge, really. They were made in the Panzer IV plants of Krupp after Pz III chassis production was disrupted by allied bombing. The parts for assembly that fed those plants existed, and to get around the bottlenecks created by repair delays and such at the III plants, they fed some of those feeder parts through Krupp. StuG IVs come out the other side.

The 57mm is not nearly as good as the 85mm, all around. In CM, the AP performance of the Russian 85mm in 1943 is so poor (ammo modeling, "shell broke up" results) that the 57mm is actually better, but this reflects CMs tendency to invent shell quality disasters for Russians more than any real difference in the guns. CM also overmodels penetration of small high velocity projectiles compared to larger ones of similar muzzle energy.

But the 57mm was a fine gun anyway it is sliced. Not better than the 85mm, but far superior to the Russian 76mm (all types). The Russians knew it well. And yes, they did put some in T-34s as a result - the T-34/57 was a specialized AT tank, some fielded as early as the battle of Moscow. But it was produced in very limited numbers. The eventual solution was instead the T-34/85, with SU use of T-34 chassis for dedicated TDs (the SU-85s, late war the SU-100) used in the meantime. The Russians believed in larger rounds of high energy, both because they thought them entirely effective in AP terms, and because they also gave more useful HE than a 57mm caliber could.

As for comparing Gatos and VIICs, the Gato is a far superior submarine in all respects but one.

It is much larger, carried almost twice the torpedo load with twice the launch tubes, was 10-15% faster (a serious edge running down freighters etc), and had about 50% longer cruising range.

The one attribute the VIIC beats it on is dive depth, being rated for a whopping 750 feet, to 300 feet for the Gato. The crush depths are much closer, though (order of 800 vs 900) - the US was much less inclined to push its subs to their depth limits.

One last edge the VIIC picks up only in the last year or so of the war - that late they could be fitted with snokels to let them run their diesels while submerged, instead of batteries only.

I hope this helps.

[coe]

well interesting response...dedicated tank destroyer -

if both sides know where eachother is, do you want to be in the tank destroyer or the tank?

If the tank is at a big disadvantage against a tank destroyer properly positioned and if a tank shouldn't get close to enemy infantry to begin with with the hand held AT stuff...what is the use of the tank (note here going on the assumption that Artillery and mortars aren't that effective against TDs. In that sense why not use turreted TDs in a shot = kill era against heavy armor...first of all you have higher turret rotation and can react better to the enemy threat.

[JasonC]

Not a coherent thought, it seems to me.

If any two AFVs that can each kill the other both see each other at the same time, then clearly the first one to hit is going to win. A slight edge may exist from crew skill or optics or gun muzzle velocity giving slightly better accuracy, but it is all going to be minutae (unless the skill thing is systematic and large).

Individually you are going to get a coin toss. An aggregate of independent coin tosses yields an entirely predictable dominance of numbers. Meaning, the sides exchange off with some fluctuations but in the end the side with more AFVs is left standing, when the other has had enough and packs it in.

But the reason this is of no great importance - and Lanchester attrition equations based on thinking it typical do not work in reality - is the premise is virtually never operative. AFVs that can kill each other with one shot are not in the situation of both knowing exactly where the other is, because in the nature of the case, that situation can barely last a minute whenever it occurs.

You might as readily ask which fighter plane is best in exclusively head on passes and try to conclude from it something about air combat. Since air combat is actually about teamwork on the one hand and surprise on the other, it is a footnote to possible tactics in specific matchups, and not anything critical to the types or arms themselves.

As for what tanks are good for, obviously their forte is attacking gun and infantry defenses where they are not expected and the guns are therefore thin on the ground. Guns aren't as mobile. If they try to cover whole frontages they are necessarily distributed in penny packets. (If the defender is smart, those are spread front to back in deep layers as well as along the line). These are enough to defend the infantry from handfuls of tanks, but not from whole battalions of them on a single kilometer.

That is how armor attacks. It overloads a narrow sector where it is not immediately expected. Trades off defending guns. (Defending AFVs too, if thin enough at the point of attack). If the tanks have strong armor and the guns are weak, they may take very limited losses, but they will get through regardless, just having tank 2 kill the gun that exposed itself hitting tank 1. The guns may be suppressed by artillery beforehand, too. The tanks defeat infantry not protected by serious gun or AFV AT hitters by using the superior range of their guns and MGs, and by "disarticulating" (slicing and dicing) the defense.

Sure infantry can hurt tanks at 50m, or with later rocket weapons, 200m. So the tanks clobber them from 400m. Infantry still can't defend itself from them, seriously speaking. At best they can curl into a shell in impassable terrain and avoid LOS. In which case they fail to hold a continuous front, the tanks drive between their cocoons, drop their own supporting infantry in rings around them (easy, since the cocoons, to avoid tank fire, can't reach back out either), and get on the radio "battery, fire mission..." You have all day. End of infantry, tanks untouched.

The solution to massed tanks is not infantry cocoons with fausts, it is a massed set of ranged AT hitters in the right spot, with an intel edge. You can't get that mass everywhere - the tanks are concentrated and the defenders don't have 5 or 10 times the weapons of the attackers. The defenders therefore have to "counter-concentrate", themselves. In theory they might do so by flat guessing where they will be hit. In practice, instead it only happens by leaving AT hitters off the line in reserve, and sliding them in front of the tank attacks as they penetrate the forward infantry and gun defenses.

[coe]

Forgive me on this but as you described a tank is supposed to stand off and pound infantry from a distance. A tank destroyer can do that too. A tank destroyer can engage gun lines too (if you put a bit more armor on it? and does it make a difference if it is open topped?) Thus I see no major difference in whether you use tanks on the attack or turreted tank destroyers. Please clarify the distinction of what would make a close topped vehicle (tank) that much more suited than some faster nimble but can be uparmored to be just as heavily armored as regular tanks?

[McIvan]

In game terms, the distinctions would be: Ammo load....more AP and less HE with the 76mm tanks. Inferior HE...the 76mm round has less effect than the 75mm round. Less MGs. Less MG ammo.

[coe]

true true but during the later part of 1944 alot of shermans were starting to have the 76mm gun.

[JasonC]

McIvan largely covers it.

The full tanks have more power against infantry because TDs are stripped down weapons dedicated to tank killing. A US TD has one 50 cal with limited ammo to be used by an exposed commander, and typically less than 20 HE shells. A turreted Sherman even a 76mm one has more HE ammo, three MGs, one of them coaxial which means turret stabilized and an optical sight, with vastly more ammo, fully protected gunner, etc.

Is it also marginally better to have a full top? Sure. To have Sherman W armor against some intermediate guns? Sure. The heavy stuff and infantry AT will be the same, though.

In practice, the US TDs were indeed used to support infantry. They were good at bunkers and valued for it. It was better to have them hang back and overwatch and advance with ordinary Shermans, but when those weren't around TDs did it themselves. They were also used as extra SP artillery firing indirect, when the fight was infantry dominated (e.g. in Italian hill country barely passable to vehicles).

You use any weapon system when you have it, for the tasks in front of you. TDs were flexible. Ordinary tanks were also flexible. Each had its stronger suits, but each can try to do the other's job when said others aren't around, and did.

I have the sense that coe is on an extended fishing expedition, but somehow can't bring himself to say what he thinks. It is getting kinda old...

[coe]

extended fishing expedition...no....but trying to formulate an opinion based on explanations which have caused a reevaluation as to some beliefs... - hesitating at this moment to say anything extreme due to lack of data but for entertainment purposes I'll say some extreme ideas that I'm starting to entertain.

Ignoring fleet mixing by the way: by late 1944-1945 on the Western front due to the effectiveness of guns, it was appearing that the heavy tank wasn't needed much like firearms did away with body armor in the 1700s. e.g. if you had enough armor to resist the recon vehicles canons (37mm - 57mm) and maybe bazookas that was enough since 76mm tungsten would get you anyways. And thus as Allied weapons became more powerful, it made less sense for the Germans to sport heavy tanks which were slow, broke down, slow to react (turret speed). i.e. if you are going to waltz around in a first to see-first to fire = first to kill environment, why bother having a big Panther tank at least if you were moving faster you'd be harder to hit? (maybe that is unfair since I am comparing a Hellcat speed)...and when you blow up you cost far more to replace than a PzIV. 1946 would have been interesting.

As for ammunition loads, a 76 mm sherman vs. a 76mm TD... I assume the TD might have less ammo capacity but all you need to do is perhaps change the ammunition ratio of AP to HE - (don't know if there's any space issues with putting a coaxial MG and maybe a hull MG if there is enough space (doubtful?) - but that aside with the ammo ratio change, I am starting to wonder why bother have tanks at all on either side and just have slightly uparmored TDs.

As for getting in close, with the infantry AT weapons, it seems as if any tank or TD you is pretty much in trouble if it is in close combat with enemy infantry (ok ok I know if the infantry runs out of Panzerfaust, schreks, or zook ammo, with a TD you can still do a nice grenade over the top - but that can be somewhat minimized with mesh covering perhaps).

again i might be presuming here that the infantry can do lots of the small arms part while the most important asset of the Tank/TD in infantry killing is its cannon - in a combined arms situation.

I guess it comes down to I'm starting to think that perhaps a slightly modified TD could have replaced both the TDs and heavy tanks at that point (on both sides) since the cannon it mounted could kill the heavies of both sides.

Still I'm starting to imagine perverse dreams of M-18 hellcats and some form of turreted Hetzers running in mass against eachother into battle. But it does seem the 76mm has some advantages over the 75mm L48 including accuracy.

As a total aside, since 75mm L/48s were having trouble dealing with IS-IIs, and to some extent late T-34/85, wonder what would have been done to up gun the hetzer.

So as in the last post, if the TD can do the similar roles as the tank, why bother with the tank...it's more expensive...

[John D Salt]

Originally posted by coe:

[snips]

- hesitating at this moment to say anything extreme due to lack of data but for entertainment purposes I'll say some extreme ideas that I'm starting to entertain.

[snips]

(turret speed). i.e. if you are going to waltz around in a first to see-first to fire = first to kill environment, why bother having a big Panther tank at least if you were moving faster you'd be harder to hit? (maybe that is unfair since I am comparing a Hellcat speed)...and when you blow up you cost far more to replace than a PzIV. 1946 would have been interesting.

The idea of concentrating on gun-power first and speed second, with armour last, is of course exactly what was done in both French and German tank design in the 1950s and 1960s.

Originally posted by coe:

[snips]

change, I am starting to wonder why bother have tanks at all on either side and just have slightly uparmored TDs.

...whereas the Swedes went for a fixed-gun tank, but very well protected indeed.

All the best,

John.

[dalem]

Hmm, one of my favorite armchair topics, this one.

Without the burden of being overly-versed in the details I generally devolve into triteness, and sum up the "tank tech" discussion by pointing out that the Germans won their early battles with relatively inferior tanks and lost their later ones with relatively superior tanks. To me, that means that the details are relatively unimportant and that battlefield and operational/strategic intel weigh more heavily than face hardening, turrets, or tungsten.

I'd rather have a company of 75mm Shermans in the right place than a battalion of Panthers in the wrong place, and I don't have much respect for the heavies on either side. I suspect I'd feel differently if I had to actually be IN one of them at the sharp end, but I have the luxury of my safe armchair.

Jason, didn't you post a decent analysis of armor casualties through the NWE summer-fall campaigns back in the CM:BO days, and pretty much prove that the attacker always lost tanks at a high rate no matter which make and model and who's flag was painted on the side?

-dale

[Broompatrol]

As I understand it as muzzle velocity increases the potential speed of a vehicle is less of a defensive factor. Except that I guess a faster AFV can break LOS sooner limitng its exposure time. But it seems to me that (remember we're talking 1940's drivetrains)That whether a vehicle is moving 26mph or 35mph won't matter that much. None of the AFV's of the time are going to spin up and take off like Nazi UFO.

An interesting book I read relating to this topic was titled "Men Agianst Tanks" unfortunately I don't remember the author. It is basically a history or tanks v anti-tank technology. By default it describes AFV evolution because of their environment. It is heavy on WWII history. If every body started using TD's then some smart alec would invent a new system to counter lightly armored fast AFV's Oh wait its called PAK.

[coe]

well not exactly...I was saying maybe things would gravitate towards tanks that weren't superly heavy just enough to resist the lighter AT guns (whether on vehicles or towed) such as 37mm, 50mm, 57mm.

At the time the 75mm and 76mm towed guns I think could still defeat the heavy tanks in the frontal aspect (they might take several more shots but they still could).

You'd want a tank/TD strong enough to force the enemy to use the less mobile AT guns I think...75mm then you have the ability to easily move around them before they can set up...I think....

Show me my errors in my reasoning.