A Quick Battle AAR: Shermans vs Pz IVs, Not Your Fathers Combat Mission

[SD Smack]

GhostRider3/3

I agree, Im sure you and all the others out there who have experience in the military would agree that a leader is very important in a team, whether it be a tank crew or a fire team, the leader's experince level (in CMx2 it would be Conscript-Elite) positively affects his subordinates....of course a more experinced crew would be (or could be) negatively affected by a weak leader.

Regardless within CMx2 its a generalization of the crew, but i think various things need to be considered or thought about when making a senario whether it be historical or not.

Steve-o

[Battlefront.com]

ShakyJake,

Thanks for doing some more in depth math. This is why games which don't simulate things down to this level have skewed expectations of wargames. There's just no way the can get the nuances like this using CRTs and randomized modifiers.

There was one specific tank matchup in this AAR that Charles looked at in depth. His conclusion was that the way the two tanks were orientated to each other the PzIV could have fired all day long and the Sherman would not have suffered a penetration if hit on its glacis. It was at this point Charles upped the TacAI variable to make the virtual tanker not try to put this to the test But that tweak was done after this PBEM game so in the AAR you guys are reading The_Capt's Shermans are a bit braver than they would be now.

Steve

[ShakyJake]

@ Bill and Battlefront.com

No problem at all. Doing this kind of calculation was truly a joy for me when I bought the book years ago, since it gave me a chance to apply my engineering math background towards something I actually enjoyed doing for a change. There is one minor point I'd like to ask, though, if that's alright? I'm assuming a flaw multiplier of 0.90 being used for hits on the glacis, from your post giving the plate thicknesses and what the game treats the thicknesses as. The charts in Rexford's book gives a more unforgiving multiplier to this specific T/D ratio and for medium flaws, and he even includes a passage with this specific gun and armor matchup illuminating the severity of the flaw. To quote page 29,

The 56° glacis on Shermans also included cast and rolled armor pieces, sometimes with equal areas of each, where cast armor would be inferior to rolled. While rolled plates on the 56° glacis would resist 75mm APCBC with about 104mm at 0° resistance, 51mm cast armor at 56° resistance with medium flaws would equal about 96mm at 0°.

Same exact ammunition against the same exact glacis as we have in this thread, so a good reference. Using the calculated 0° resistance of that plate to be 123mm from his equations, his figure of 104mm effective resistance seems to indicate about a 0.85 flaw multiplier, and this is exactly what the table for medium flaws on the previous page shows for this T/D ratio and hit angle.

It might be only a 5% difference, but that could mean all the world in some scenarios. It would mean more decisive penetrations in some cases, and in my earlier example with the 61° compound angle it would bring the plate's resistance down to a bare millimeter higher than the 75mm L/48's penetration at this range. The glacis would still be far tougher than the expectation which some people have of spitwads and hurled beer bottles punching through it, but might this be a bit more accurate? Thanks, and please forgive any presumption here.

[stikkypixie]

I was wondering the same thing. Even with a small sample size the overperformance of the gun means that the odds are really stretched in favour of the Sherman. It would be nice if Bil could explain a bit more about where these rounds were impacting.

There are two possible ways of making an angle with armor. Vertically, which was the angles in penetration charts list, but this assumes that the second angle, the horizontal angle, is at 0°. Like ShakyJake says, if the round start deviating from that angle as well the round will "see" more armor so to speak. In other words the penetration values listed are optimal values and even small deviation in flight pass horizontally, will results in less optimal performance. This probably why the field isn't littered with burning Shermans yet.

[The_Capt]

I think you might be misunderstanding the way he's using the term "marginal" here, Txema. Having a marginal advantage in penetration here means that there is slightly over a 50% chance of penetration, since the penetration value for the projectile is an average of the upper and lower range it can fall between. So, under an ideal circumstance of being directly head on to the target and at that range, it will probably penetrate, just as he has said. However, once any kind of imperfect conditions start creeping into the equation, things start to become more iffy.

Using the calculations out of my copy of "WWII Ballistics: Armor and Gunnerery", the 0° resistance of the Sherman's 51mm glacis @56° comes out to 123mm, or 110mm with a 0.90 flaw multiplier (is this what's being used?). So the 75mm L/48 APCBC with 127mm penetration at 300m and 0° will most likely penetrate in this shot. However, if the tank were to have a 20° lateral angle to the firing tank, the compound angle would become 58°. Only two degrees can't make much of a difference, right? Not so. With the flaw multiplier, the 0° resistance for the 51mm glacis @58° becomes 120mm. That's a 10mm increase in resistance from just 2°. Give the tank a lateral angle of 30° and the compound angle becomes 61°. At this angle, the plate will have an effective resistance of 136mm, and now the 75mm L/48 has become unlikely to penetrate, all from just a 5° difference in shot angle. It's hard to judge from the screenshots how much this plays in this specific AAR, even the tank being just a few degrees nose up to PzKpfw IV and with some small lateral angle can give this much additional protection.

Btw, I am very saddened to hear about Lorrin Rexford Bird. I had been very excited to find him on this board after buying his book (and the principle reason I registered!), and had wondered why the E-mails we were exchanging dried up several years ago. He was definitely an expert in this, and all the calculations I made above were done straight out of his book.

Uh, I was told there would be no math. So for guys who find a cheque book an unending mystery...what we are seeing makes perfect sense?

[Gryphonne]

Is the book by Rexford still available somewhere? I can't find it anywhere..

[PAEZ]

Wow, those Panzer IV's are really breaking apart easy!!

good AAR. ...keep it coming.

[Txema]

I think you might be misunderstanding the way he's using the term "marginal" here, Txema. Having a marginal advantage in penetration here means that there is slightly over a 50% chance of penetration, since the penetration value for the projectile is an average of the upper and lower range it can fall between. So, under an ideal circumstance of being directly head on to the target and at that range, it will probably penetrate, just as he has said. However, once any kind of imperfect conditions start creeping into the equation, things start to become more iffy.

Using the calculations out of my copy of "WWII Ballistics: Armor and Gunnerery", the 0° resistance of the Sherman's 51mm glacis @56° comes out to 123mm, or 110mm with a 0.90 flaw multiplier (is this what's being used?). So the 75mm L/48 APCBC with 127mm penetration at 300m and 0° will most likely penetrate in this shot. However, if the tank were to have a 20° lateral angle to the firing tank, the compound angle would become 58°. Only two degrees can't make much of a difference, right? Not so. With the flaw multiplier, the 0° resistance for the 51mm glacis @58° becomes 120mm. That's a 10mm increase in resistance from just 2°. Give the tank a lateral angle of 30° and the compound angle becomes 61°. At this angle, the plate will have an effective resistance of 136mm, and now the 75mm L/48 has become unlikely to penetrate, all from just a 5° difference in shot angle. It's hard to judge from the screenshots how much this plays in this specific AAR, even the tank being just a few degrees nose up to PzKpfw IV and with some small lateral angle can give this much additional protection.

Btw, I am very saddened to hear about Lorrin Rexford Bird. I had been very excited to find him on this board after buying his book (and the principle reason I registered!), and had wondered why the E-mails we were exchanging dried up several years ago. He was definitely an expert in this, and all the calculations I made above were done straight out of his book.

OK, this is a very good explanation about what can be happening in these 3 Sherman hits without penetration: perhaps the tank lateral angle is around 30 degrees and the compound angle becomes 61 degrees, making the penetration more unlikely.

However, I think that if you do the same calculations (tank lateral angle around 30 degrees) for the opposite case (Pz IV-H being hit by the M4A3 Sherman in the upper hull and in the lower hull, and therefore 96mm vs 80mm and 93mm vs 80mm respectively), then the compound angle would increase significantly and probably the penetration would become also unlikely. (Could you please do the calculations ???)

My point is that in a head to head combat between a Pz IV-H and a M4A3 Sherman at 300 meters, taking into account all of these calculations, both tanks have roughly the same probability of destroying the other. If one of them hits the other straight on (without tank lateral angle) in the turret, gun mantlet or in the upper or lower hull, then it is very likely to achieve a penetration. If the tank has a noticeable lateral angle (30 degrees or more) and is hit in the upper or lower hull (in the case of the Pz IV-H) or in the upper hull (in the case of the M4A3 Sherman) then the penetration becomes unlikely.

BTW, at this very small distance (300 meters) an experienced gunner could always aim for the turret or gun mantlet and achieve an easy penetration. Therefore, the first tank that hits should get the first penetration.

Taking into account all of these data, there should be no significant difference between the Pz IV-H and the M4A3 Sherman head to head at 300 meters. They should have roughly the same probability of destroying the other.

P.S. Why the Pz IV-H of the AAR is not aiming for the turret or gun mantlet of the M4A3 Sherman to achieve an easy penetration? Why is it hitting the upper hull 3 times?

[GhostRider3/3]

Even though I may like Axis Armor better, I still enjoy a good fight. I still beleive that between Close Quarter tank combat (500-200m) the Sherman will have a slight advantage over the Pz IVH. If you really want some good reads in conjuction with Shermans and Mk IV tanks, you really should read the Books by Frank Reynolds.

Although the Mk IV tank was a decent medium tank, by 1945 it was defenitely becoming a obsolete design.

I am truly enjoying the AAR's and the beautiful pictures... the tanks look freaking sweet!

[Wrath of Dagon]

Speaking of the angles brings up an interesting point. It seems advantageous to set the cover arc centered on the target, but to set the facing of the tank pointing slightly off the target. Would the tank eventually align it's hull to the turret anyway in this situation? I guess I could try it in CMSF.

[Krilly]

Of course we get all excited about the gameplay mechanics and we are discussing at length whether pzkwIV's should eat Shermans for breakfast or not.

Whilst we do that I wanted to give a little cheer to Bil.

Great work on the AAR's mate!

• Very nice maps that make it easy to get situational awareness.
  
• Clear write-up.
  
• Very nice screenshots.
  

Greatly appreciated and keep it up!

[Andrew H.]

Speaking of the angles brings up an interesting point. It seems advantageous to set the cover arc centered on the target, but to set the facing of the tank pointing slightly off the target. Would the tank eventually align it's hull to the turret anyway in this situation? I guess I could try it in CMSF.

I think that this could be advantageous in certain circumstances, but there are three (at least) potential flaws with this approach:

1. It makes the tank a bigger target. Tanks tend to be longer than they are wide, and by angling the tank's hull, it becomes a wider target. Meaning that some shots that would have missed wide will instead hit the tank. (Since most misses seem to be vertical misses due to range estimation errors, this may not be that important of an issue, however).

2. It exposes the tank's side hull armor, although at an angle. The side hulls of most tanks are thinner and not as sharply angled as the front. Whether this is a problem depends on the particular thickness and vertical angle of the side hull; it is probably only really an issue in tanks where the side hulls are substantially thinner than the front.

3. It makes flanking easier. If a tank is situated at a 45 degree angle to the target, it will be easier for the target to get a side shot at the tank (better than the one it already has) because the target won't have to travel as far to flank. (Although this is obviously dependent on distance - it's a lot harder to flank a Tiger firing from a range of 1500 meters than a Tiger firing at a range of 300 meters). Related to this is the issue of multiple targets, where turning the hull at 45 degrees to one target probably will give the others a more advantageous angle than they would otherwise have.

[Moon]

I may be wrong, but I seem to remember historical accounts from tankers that tried just this approach in real life. North Africa I think? Anyway, that doesn't prove that it was effective, of course (in fact, Andrew H's points above all seem perfectly plausible to me), just that perhaps they were thinking along the same lines as Wrath of Dragon

[Bil Hardenberger]

MINUTE 7

This was a fairly quiet turn. 2nd Platoon continues to move up, and for the life of me I don’t remember being so careful with their movement, but when watching the movies again I notice that I am doing overwatch movement whenever there is a potential danger area. It’s possible at this stage while playing that I was still nervous about AA1 and was keeping a careful eye on that area as I advanced.

Here is an overview of the current situation. 1st Platoon on the right, with the M4A3 that was fired on at the end of last turn called out, also the location of the M4A3(76)W and of the M-20 wreck. 2nd Platoon is on the left and still moving through the trees as shown. I’ve also called out where Tank 1 saw the infantry movement in the trees.

1st Platoon and Company HQ Element

The CO HQ tank fires and hits the M4A3 again after it pops smoke and starts to reverse. The hit didn’t appear to do much damage, but the crew must be shaken as they reverse far out of sight by the end of the turn. At this point, with Warren’s tanks not dying, but at least having their forward progress stopped I can see the flicker of a faint hope.

In this image you can just see the turrets of the Company HQ element tanks on the ridge.

At the end of the seventh minute Warren has pulled the M4A3(76)W out of the cover provided by its smokescreen and it is just sitting in the open. I assume he is going to bring up the rest of the Sherman Platoon and try to rush my three tanks all together. It could get very interesting in the next couple of minutes.

The HQ Tank (1st Platoon) is just a pair of eyes right now, but I think I might pull them out of the line next turn.

Here you can see the M4A3(76)W at the end of the turn, along with the M4A3.. this tank reversed all the way from where you can see its smokescreen through the little tree line and finally settled in this position.

Next: Minute 8

[StellarRat]

I remember reading somewhere that the Germans had a tactical doctrine of angling their tanks to face 15 degrees off the direction of enemy fire. It's worth noting that anytime you expose the side of your AFVs the chance of track damage is much higher.

[Bil Hardenberger]

Of course we get all excited about the gameplay mechanics and we are discussing at length whether pzkwIV's should eat Shermans for breakfast or not.

Whilst we do that I wanted to give a little cheer to Bil.

Great work on the AAR's mate!

• Very nice maps that make it easy to get situational awareness.
  
• Clear write-up.
  
• Very nice screenshots.
  

Greatly appreciated and keep it up!

Thanks for the feedback Krilly!

[Bil Hardenberger]

By the way a new AAR post is at the bottom of the previous page.

[Steiner14]

How about a YouTube-Video?

[Wrath of Dagon]

I think that this could be advantageous in certain circumstances, but there are three (at least) potential flaws with this approach:

1. It makes the tank a bigger target. Tanks tend to be longer than they are wide, and by angling the tank's hull, it becomes a wider target. Meaning that some shots that would have missed wide will instead hit the tank. (Since most misses seem to be vertical misses due to range estimation errors, this may not be that important of an issue, however).

2. It exposes the tank's side hull armor, although at an angle. The side hulls of most tanks are thinner and not as sharply angled as the front. Whether this is a problem depends on the particular thickness and vertical angle of the side hull; it is probably only really an issue in tanks where the side hulls are substantially thinner than the front.

3. It makes flanking easier. If a tank is situated at a 45 degree angle to the target, it will be easier for the target to get a side shot at the tank (better than the one it already has) because the target won't have to travel as far to flank. (Although this is obviously dependent on distance - it's a lot harder to flank a Tiger firing from a range of 1500 meters than a Tiger firing at a range of 300 meters). Related to this is the issue of multiple targets, where turning the hull at 45 degrees to one target probably will give the others a more advantageous angle than they would otherwise have.

But that's why I said "slightly", not enough to expose flanks, but to make the front non-perpendicular to the LOS. Certainly nowhere near 45, may be 10-20.

Edit: Just saw what StellarRat posted.

[ShakyJake]

Thanks of the AAR update, Bil!

Is the book by Rexford still available somewhere? I can't find it anywhere..

Sadly, I don't think you can find this book anymore. At one time when I'd asked, Rexford had said that if there was enough demand that another run might be made, but I don't believe that's an option anymore.

However, I think that if you do the same calculations (tank lateral angle around 30 degrees) for the opposite case (Pz IV-H being hit by the M4A3 Sherman in the upper hull and in the lower hull, and therefore 96mm vs 80mm and 93mm vs 80mm respectively), then the compound angle would increase significantly and probably the penetration would become also unlikely. (Could you please do the calculations ???)

Sure. Calculating the 0° penetration of the 75mm L/40 ABCPC against FH armor at 300m gives us a figure of 98mm. We'll look at the PzKpfw IVH's upper and lower hull only (the 50mm turret front will be easily penetrated here barring any extreme angle). I'll use a lateral angle of 0° (head on), 20°, and 30°, and show the compound angles for the hit and effective resistance for those 80mm plates.

Lateral Angle 0°

Upper hull @10° = 82mm

Lower hull @15° = 84mm

Lateral Angle 20°

Upper hull @22° = 91mm

Lower hull @25° = 96mm

Lateral Angle 30°

Upper hull @31° = 104mm

Lower hull @33° = 108mm

So at this range the average penetration of the Sherman's gun can handle about a 25° lateral angle from the PzKpfw IV before penetrating the upper hull is no longer better than average, and a 20° angle before penetration of the lower hull becomes less than ideal. At 30° lateral angle, only the exceptions at the upper range of the variable penetration should be getting through.

I remember reading somewhere that the Germans had a tactical doctrine of angling their tanks to face 15 degrees off the direction of enemy fire. It's worth noting that anytime you expose the side of your AFVs the chance of track damage is much higher.

I saw a document posted with this on another forum, so it's definitely out there. IIRC, it was a doctrine to be used solely against fixed defensive positions, though, so perhaps not to be used when it was likely flanking fire was to be received? They definitely understood slope effects enough to have made this a smart choice.

[Sergei]

I may be wrong, but I seem to remember historical accounts from tankers that tried just this approach in real life. North Africa I think? Anyway, that doesn't prove that it was effective, of course (in fact, Andrew H's points above all seem perfectly plausible to me), just that perhaps they were thinking along the same lines as Wrath of Dragon

You'd think that it would be particularly ineffective in North Africa: the biggest problem with this technique is that it relies on the assumption of only one enemy firing at you so that you can control the angle. But in the desert, if you are facing a platoon or even a company of enemy tanks or a gun battery, deployed in a line opposite to you, you will be at a different angle relative to all of them.

I also think that the driver is wiser to concentrate on being ready to move forward/backward as soon as ordered, rather than fooling around with facing.

[StellarRat]

You'd think that it would be particularly ineffective in North Africa: the biggest problem with this technique is that it relies on the assumption of only one enemy firing at you so that you can control the angle. But in the desert, if you are facing a platoon or even a company of enemy tanks or a gun battery, deployed in a line opposite to you, you will be at a different angle relative to all of them.

I also think that the driver is wiser to concentrate on being ready to move forward/backward as soon as ordered, rather than fooling around with facing.

True, but in the desert you can begin firing at maximum range so unless the enemy is really spread out for the first few minutes you can manage your facing somewhat. Personally unless there is some reason to hold the line I'd be doing a lot of reverse driving to keep my front armor toward the enemy (on defense) .

[GhostRider3/3]

True, but in the desert you can begin firing at maximum range so unless the enemy is really spread out for the first few minutes can manage your facing somewhat. Personally unless there is some reason to hold the line I'd be doing a lot of reverse driving to keep my front armor toward the enemy (on defense) .

Hello StellarRat,

I know the Pz IV F2 does not have the same armor as the IVH... and in CMAK my Pz III J faired way better then the IV F2 and G's.. especially from the front. However the Side armor is always weakest, hence the need to flank all the time.

I was still amazed at the firepower of the Early Sherman hits at 800-1000m. They were destroying the crap out of my IVF2's and (G's) and even Pz III J's, although mainly the PzIV F2's suffered the most.

That being said though, the 75mm L/43 did do its job in CMAK, although I thought I would have an advantage at longer ranges with the Sherman... it was pretty much tic for tac.

[Other Means]

I remember excellent crews in CM1 setting angle on the armour - I think it's perfectly valid. 15deg sounds about right.

[Vark]

There are countless photos of Tiger tanks showing the turret pointing toward the enemy but the hull angled at 10-15 degrees and one hull side covered by a structure or terrain feature. If somebody has the repro of the comic book manual perhaps they could see if it was a standard tactic.

Bil, see what you mean about the dropped barrels when the cover arc is activated, will vehicles with poor depression be penalised (is Soviet armour in CMSF given this weakness?).

Would it be possible to have all the statistics and maths consigned to another thread? I try to avoid such things as much as possible and now open the supposed AAR with trepidation, lest I be pounced on by numerical horrors!

Talking of commanders, although it is true that good commanders were a force multiplier it is also true to say that the effect of them being injured or killed, in action, could sometimes have a disproportionate effect on their crew, or even other platoon vehicles. I read a very touching account of a dashing AC recce crew who when they lost their commander went to pieces. They had all told themselves that if Capt X got through then they would as well, when he fell that hope collapsed, as did their morale.