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

[stoex]

There's Commander, Gunner, Loader, Driver and the fifth guy who is the radio operator.

Thanks for trying to enlighten me on the painfully obvious, Sergei. Believe it or not, I counted those pistol icons 3 or 4 times and always came out with only four in total. I didn't even get it after your answer, and wrote another long post explaining again that I could only see four. I only just realized that everything is exactly as it should be (well, except that the radio operator doesn't have his function shown on his pistol icon, but who cares?) and deleted my long-winded reply.

Man, do I feel stupid . Guess I got too giddy looking at the excellent pictures. *sigh*

[gunnersman]

Thanks for trying to enlighten me on the painfully obvious, Sergei. Believe it or not, I counted those pistol icons 3 or 4 times and always came out with only four in total. I didn't even get it after your answer, and wrote another long post explaining again that I could only see four. I only just realized that everything is exactly as it should be (well, except that the radio operator doesn't have his function shown on his pistol icon, but who cares?) and deleted my long-winded reply.

Man, do I feel stupid . Guess I got too giddy looking at the excellent pictures. *sigh*

There ARE only four names...but there are five pistols.

[Bil Hardenberger]

MINUTE 4 - An Explanation

Hailing rexford to this thread, can you read me rexford?

Funny that you should call out to Rexford, as all the data used in this game is based on his work. In fact, if anybody is going to try to dispute the numbers that I am posting here they better come with some serious documentation in hand.

When I saw this game unravelling (and believe me the fun isn't over by a long shot in this game) I started to become worried. Not about the Sherman armor, I know it isn't a super tank, I've seen it go up against Panthers, Tigers, and JgdPz IVs and come off very badly, no, my concern was that the Pz-IV gun was undermodelled.

In the following quote, the big man, the brain in a jar, the hidden one, came out of his lair and explained what's happening. So sit back with a drink and your favorite smoking jacket and enjoy.

Now, for a small glimpse behind the curtain:

All else being equal, a group of M4A3 Shermans should have a modest advantage head-to-head at 300m against an equal-sized group of PzIVH.

Here is why. While the German 75mm gun is better than the US 75mm, the Sherman has superior frontal armor. The PzIVH has an obsolete turret front and virtually no armor sloping anywhere. Further, its frontal armor is face-hardened which is a liability against the capped armor-piercing ammunition (APCBC) used by the western Allies in 1944.

Let's first examine the PzIVH shooting at the M4A3 Sherman straight on, non oblique hits:

M4A3 Sherman frontal armor:

76mm @ 30° turret (treated as 69mm due to mediocre armor manufacturing quality)

89mm @ 0° gun mantlet (treated as 80mm)

51mm @ 56° upper hull (treated as 46mm)

51mm @ 15°(avg) lower hull (treated as 46mm)

German PzIVH (75mm KwK40 L/48) armor penetration (average) at 300m at various armor slopes:

0°: 127mm

15°: 120mm

30°: 99mm

56°: 53mm

Hit results:

M4A3 Sherman turret: easily penetrates (120mm vs 69mm)

M4A3 Sherman gun mantlet: easily penetrates (127mm vs 80mm)

M4A3 Sherman upper hull: usually but not always penetrates; majority of killing energy absorbed by armor (53mm vs 46mm)

M4A3 Sherman lower hull: easily penetrates (120mm vs 46mm)

Summary:

If the Sherman is hit straight on in the turret or lower hull it's in bad shape, but if it's hit in the upper hull (aka glacis plate) it has a decent chance to survive. Not great, but decent. And the glacis plate is the largest and most central of the potential target areas so many hits will occur there.

Now let's examine the M4A3 Sherman shooting at the PzIVH straight on, non oblique hits:

PzIVH-late frontal armor (all face-hardened, which is a liability versus US APCBC shells -- this is very important!):

50mm @ 10° turret

80mm @ 10° upper hull

80mm @ 15° lower hull

M4A3 Sherman (75mm M3 L/40, firing APCBC) armor penetration versus face-hardened armor (average) at 300m at various armor slopes:

10°: 96mm

15°: 93mm

Hit results:

PzIVH-late turret: easily penetrates (96mm vs 50mm)

PzIVH-late upper hull: penetrates, some killing energy absorbed by armor (96mm vs 80mm)

PzIVH-late lower hull: penetrates, some killing energy absorbed by armor (93mm vs 80mm)

Summary:

PzIVH armor cannot withstand a straight on hit from a Sherman anywhere. Its best hope is for a hull hit where some of the energy is absorbed, but often this won't be enough to save the tank.

When oblique angles are taken into effect the picture changes. The more the shot deviates from a straight on hit the greater the chance of deflection instead of penetration. Sloped and rounded armor enhances this chance more so than vertically aligned plates. If the chance of a penetration from straight on is marginal, then a less optimal angle of impact likely means the round does not penetrate. When examining the numbers above, it's pretty clear that the Sherman is far more likely to survive a hit from a PzIV than the PzIV is to survive a hit from a Sherman.

…there are some really deeply entrenched assumptions about what German (and American) equipment should and should not be capable of. And yet when we dig down a little, it seems that these hardened assumptions are not based on anything real.

The above is a perfect example. The assumption is that PzIV = Sherman. Case closed?

Well, the assumption is wrong. These two tanks are not quite equivalent. They have significantly different strengths and weaknesses. In some situations I'd want a PzIV, and in others a Sherman. And at 300m head to head, give me the M4A3 please. The armor on the PzIV is obsolete by 1944. Even to American guns, it just can't hold up, and Combat Mission reflects this.

According to this, the Pz-IV should have a decent chance of knocking out a Sherman at these ranges. We will have to wait and see if Warren has just had an extraordinary run of good luck, if the hits are on the oblique enough to make penetrating tough, or if there could be a problem.

Next: Minute 4 - Part 3 (2d Platoon's exploits)

[hoolaman]

Steiner, there no longer is an equation, it is based off the 3D model.

I don't think that is exactly correct.

It is based off the LOS tracing height and its interaction with the terrain and the small number of different LOS heights may not allow the vehicle to do realistic hull down and turret down.

[panzermartin]

It seems Stug will once again be the armored vehicle of choice for the german player.

[Elmar Bijlsma]

I don't think that is exactly correct.

It is based off the LOS tracing height and its interaction with the terrain and the small number of different LOS heights may not allow the vehicle to do realistic hull down and turret down.

We were recently told that Tigers weren't spotting what they should because the commander was mis-aligned with his viewing thingie. So I reckon that whatever abstractions have been made in this aspect will still allow a creditable hull down approximation.

Anyway, within the context of the discussion I took Steiners question to mean what determines when a vehicle is hull down and how turret size figures in to the cover gained from hull down.

And the answer is that vehicles are no longer in a a CMx1-like "Hull Down" state, but rather that the turret and other parts may or may not happen to stick above the cover and that the vehicle may receive hits based on bullet paths, not abstract "Hull Down" bonuses. What sticks out might get hit. Ergo bigger turrets stick out more.

btw

For clarity it is important to differentiate between things that might get hit, and things that might get shot at.

If the front wheel of a tank is sticking out behind a house it may get hit by any shell whistling past but it might not be possible for it to be targeted at. The first is pretty much what you see what you get, the latter is still fairly roughly abstracted.

It would be cool to hear clarification on what goes in to determining when we can shoot at a tank that has only bits of it sticking out from cover. Maybe that was what Steiner meant all along but in hindsight his question was not very clear.

[scottie]

It would be cool to hear clarification on what goes in to determining when we can shoot at a tank that has only bits of it sticking out from cover. Maybe that was what Steiner meant all along but in hindsight his question was not very clear.

Would be interested to hear about this too. Would guess its something to do with the action zone/spot type method the software uses.

[Elmar Bijlsma]

It seems Stug will once again be the armored vehicle of choice for the german player.

Good thing is that this time we can run StuG v PzIV scenarios to settle that question.

As ever though, it depends on the situation. Fighting across large fields, yeah, give me StuGs any day. In close in fighting, certainly of the more mobile kind, I would not like to be stuck with them.

[Vark]

1. If the suggestion to have TC's use small arms, is rebuffed by the, no accounts to say they did, arguement, (though I can think of three instances), then can the super-Shermans results be backed up any historical accounts?

2. Is the probability of a hit based simply on the area it physically occupies or are other factors involved? At 300m, the commander of the PzIV should be able to give the fire order "Sherman 300m, aim for the turret", and have a reasonable chance for it to be successfully carried out. Also, is it true that turret hits were more prevalent, given the tendency of gunners to over-estimate range and the shot hit high, even though the hull was the target point?

3. What model M4 did Elvis buy, for his battle? They seemed to suffer badly at the hands of Jagd Panzer IV's, mounting the same gun as Bil's impotent Pz IV's. As a European, I am particularly sensitive of US games designers rah rahing their equipment and denigrating everyone elses. Not saying this is the case at all, but CM games live and die by their accuracy, in my opinion, and I will not purchase a game that is not able to approximate reality. As is stated in point 1, where is the combat evidence of this happening, even in late 44 one of the most common guns the US tankers faced was the 75L48 and the real flesh and blood crews seemed to have a very healthy respect for it.

[Kilgore]

Interesting stuff..

This has certainly opened my eyes a bit (and almost certainly saved me from humiliation at some point it the future). In terms of depth CMBN is looking like the Mariana Trench...

Just a quick question....How will special ammo type(s) be handled such as PzGr.40 /42 (German), APCR (British) and HVAP (US)? Will they be abstracted or appear in the load-out for each vehicle?

Cheers for the AAR..

Keep 'em coming...

[Bil Hardenberger]

Vark, did you not even read my post six posts above yours? The numbers are there for you to examine and debate.

To reiterate, their are no super Shermans in CMBN... they die well and often in this game.

[Wrath of Dagon]

The JPzIV 75 mm in the Bois de Baugin AAR seemed to work about as expected. Some Shermans got lucky, but most got knocked out easily.

Hope all the data above makes it into game text at some point.

[dan/california]

The JPzIV 75 mm in the Bois de Baugin AAR seemed to work about as expected. Some Shermans got lucky, but most got knocked out easily.

Hope all the data above makes it into game text at some point.

I seem to recall that in the Bois de Baugin AAR the JPIVs were getting something of a flank shot. Thats probably enough to make all the difference. This sort of thing will probably be more common in CMBN since there are lots more equipment match-ups that don't involve crushing advantages of one kind or another. Even the elevated position of the JPzIV may have been enough to swing the balance.

[Rocky Balboa]

Would be interesting to see how well the PZIV's survive against the standard US AP rounds (M79).

What is the Ammo load out for the Sherman's in this scenario? How many rounds of APCBC (M62) vs standard AP rounds (M79) vs HE rounds does each one carry?

[Moon]

For clarity it is important to differentiate between things that might get hit, and things that might get shot at.

If the front wheel of a tank is sticking out behind a house it may get hit by any shell whistling past but it might not be possible for it to be targeted at.

That's exactly what is going on.

Spotting is somewhat abstracted/simplified. It simply has to be, because no home PC in the world would be able to run all the necessary calculations of spotting in real time from hundreds and hundreds of individuals on the battlefield down to this fidelity. It's simply impossible. In fact, spotting is one of the main reasons for the "action spots" in the game. This alone reduces the amount of spotting calculations that are needed to a more manageable number.

Think about it... the soldiers on the battlefield are SPOTTING ALL THE TIME. Every second. Every unit spots every other unit. Friendlies and enemies. Even NOTHING has to be "spotted" (for until you run the calculation, you don't know if there is "something" or "nothing").

Shooting on the other hand can be made totally WYSIWYG since a LOT less of that is going on at any one time. So you CAN hit a wheel (or any other part of a vehicle) sticking out from behind a building (regardless if it's visible to you or not), but you may not be able to "spot" that vehicle because the spotting calculation considers it hidden within the action spot.

Martin

[scottie]

how may action spots per tile ? , how many does a vehicle fill ?

ps thanks moon.

[GhostRider3/3]

Vark, did you not even read my post six posts above yours? The numbers are there for you to examine and debate.

To reiterate, their are no super Shermans in CMBN... they die well and often in this game.

Bil is right here, there is nothing wrong with the Shermans nor PzIV. Even in CMAK, CMBB when playing the Germans I kept my PzIV at a distance... meaning... no less then about 700-800m. Most of the time the Mk IV faired well and I usually caught the Shermants or T-34's traversing etc and had great Hull shots, and some good Frontal Armor hits.

I looked up the Penetration for the 75mm L/48 and at 500m it is 96mm... I am pretty sure.

I think its tactics you use. Most Commanders at the time... good Book is "Panzer Aces" new that the Pz. IV had a great Gun, good communications, and great optics and range finder. The Armor was ok, but they new if they engaged at Range.. they had the advantage. (Relative advantage). It really depended on what you were up against.

When the Germans heard and saw the "Fire Fly" they had orders to take out those tanks first as a Priority.... So the Brits began to camouflauge their barrels, as they new there was a price on their heads...of sorts.

[stikkypixie]

how may action spots per tile ? , how many does a vehicle fill ?

ps thanks moon.

An action spot is 8x8m, you can check in the editor how small the smallest tile is you can make. I would assume tanks have a size and take the appropriate area on a the map in-game. Otherwise all the 1:1, polygon intersecting would be for naught. You're thinking too much in terms of hexes methinks .

[scottie]

You're thinking too much in terms of hexes methinks .

i think you are right , the action spot v spotting v targeting concept is lost on me without a an explanation , example i think.

[The_Capt]

Ok,

Sorry for the delay, I guess I will chime in at this point...colour commentary if you will.

At this point in the game, I am actually sitting pretty. Very nice opening bell. Bil is down 3 tanks and I am down a armoured car. It is at this point that I committed the first on what I would like to call The_Capt's Great Sin List.

Great Sin #1. Never assume your opponent has the same force structure. In the absence of any intel or recon ie in a QB one can lead oneself down the garden path of thinking you are fighting a mirror image of oneself. Do not do this.

At this point I had estimated that Bil, who of course had started 7-8 Pz IVs (a troop plus Sqn HQ) cause he spent the rest on some infantry and possibly arty, was down to 4-5 Pz IVs left. That and my Shermans were taking damage at close range a lot better than his were all left me high on the heady smell of blood and victory.

The only fly in the ointment was I knew there was at least one more Pz IV in that treeline to my front (along AA3). I decided would push up and smoke him out and then deal with whatever paltry armour he had left which I suspected was coming up my right side. I would then move my infantry onto the objective and pound any of his coming out of the treeline. Brilliant plan as usual.

A see a flurry of questions. Let me answer one wrt the JPz IV....I love this beast. You pay for rarity but it is worth every penny.

Also before everyone gets too excited, keep in mind every engagement is on a bell curve. Where you start on that probablity curve has a lot to do with the mechanics of the game. However, where it goes from there is not only based on a scary amount of modeled factors but also on just plain old Ma Luck. In this engagement, she definitely was holding me to Her sweet scented bossom in these opening minutes.

Don't get me wrong. Send Pz IVs head to head against Sherman M4A3s and you are already starting from a bad spot but the roll of the bones still play an important factor.

[Thomm]

I would assume tanks have a size and take the appropriate area on a the map in-game. Otherwise all the 1:1, polygon intersecting would be for naught. You're thinking too much in terms of hexes methinks .

If I understood correctly, a vehicle is associated with exactly one action spot at all times. It does not occupy two action spots (internally), even if parts of it clearly protrude from one into another action spot.

Best regards,

Thomm

[stikkypixie]

If I understood correctly, a vehicle is associated with exactly one action spot at all times. It does not occupy two action spots (internally), even if parts of it clearly protrude from one into another action spot.

Best regards,

Thomm

This only matters for the spotting calculation? For everything else this would not matter, no?

[Vark]

Bil, yes I did, but I have, what I regard as, a healthy skepticism to statistical 'truth'. If the M4 was a tougher tank than previously represented then there should be some historical support from either the allied crews: showing a similar set of results (multiple strikes but failure to penetrate, from 75L48's) or German crews: instructions for 75L48 gunners to shoot at turrets, not the hull. I have read none of these but if they are out there I'm sure a forum member will correct me. Upon reflection I should have put 'super'-Sherman, suggesting my skepticism, not a verifiable fact.

Does the system reflect the wider field of view of german sights, allowing gunners to engage targets quicker, and does it give a first round advantage to sights with an integrated but crude range finder? Though at the range you were fighting at I doubt any ballistic drop need be compensated for, if you had engaged the Shermans at double the range do you think there would have been a greater advantage?

Is there a mechanism by which gunners can select which area to target, tracks, turret, etc, as historically seems to have happened.

Finally, regarding the firing small arms from in side tanks, I have read that the little metal protruberance, below the sight of the MP-40 was designed to hook onto the rim of a firing port?

[Thomm]

This only matters for the spotting calculation? For everything else this would not matter, no?

Only for the spotting calculation. You could hit a part of a vehicle even though the vehicle itself has not been spotted yet.

Best regards,

Thomm

[Rocky Balboa]

Bil, yes I did, but I have, what I regard as, a healthy skepticism to statistical 'truth'. If the M4 was a tougher tank than previously represented then there should be some historical support from either the allied crews: showing a similar set of results (multiple strikes but failure to penetrate, from 75L48's) or German crews: instructions for 75L48 gunners to shoot at turrets, not the hull. I have read none of these but if they are out there I'm sure a forum member will correct me. Upon reflection I should have put 'super'-Sherman, suggesting my skepticism, not a verifiable fact.

Does the system reflect the wider field of view of german sights, allowing gunners to engage targets quicker, and does it give a first round advantage to sights with an integrated but crude range finder? Though at the range you were fighting at I doubt any ballistic drop need be compensated for, if you had engaged the Shermans at double the range do you think there would have been a greater advantage?

Is there a mechanism by which gunners can select which area to target, tracks, turret, etc, as historically seems to have happened.

I think this battle is far from over, and I'm guessing we will see evidence that the Sherman isn't the "Super Tank" that the first 4 minutes of this fight might indicate.

Sitting on the edge of my seat for this one .... Is it April yet?