Sherman in CM:AK - peeve

[Soddball]

Can anyone tell me why the Sherman's armour in CM:AK is rated as 89/0 ? I don't know the armour thickness so will take it as correct, but 0 degrees?

Take a look at photo 0110 from the War & Peace Show link - it's a Sherman Firefly. It definitely isn't a 0 degree armour slope. Certainly, some Shermans have a 0 degree slope, but not all.

Just my :mad: after losing 3 Fireflies at 1,600m to a StuGIV. A marginal armour slope or a 'curved' rating would have saved them.

Here's hoping that Shermans in CMX2 (which will be WW2, Jamoomba has spoken into my skull at night) will have a more thorough appraisal of their armour sloping.

[JonS]

Could you be any less specific?

Which part of the Sherman are you talking about?

Which link from the W&P thread (last I counted there were about 6)?

Details man, details. They make the world go round.

[Andreas]

If you were a true follower of Jamoomba (who sees all and smells all), you'd know.

[JonS]

Ha! Jamoomba told me he'd seen and smelt this thread, and it was a pestilence before his eyes and nose. He sent me on a Crusade to fix it. I was promised Cheese. Cheese and serving wenches. And some hydrogen. Cheese, serving wenches, and hydrogen.

So hurry up and fix it Soddy, that Jamoomba may bestow his gifts upon me.

[Soddball]

Originally posted by JonS:

Could you be any less specific?

Which part of the Sherman are you talking about?

Which link from the W&P thread (last I counted there were about 6)?

Details man, details. They make the world go round.

The thing on the thing with the picture. Duh.

See. I can be less specific.

The Sherman's turret armour in CM:AK (and previous iterations) is 89/0 - so 89mm with a 0 degree slope. Vertical armour, like on the Churchill, Crusader etc. And here is the photo to which I refer:

That is just not, in any way, 0 degrees.

[Andreas]

Originally posted by Soddball:

That is just not, in any way, 0 degrees.

Depends on what your basis for measuring it is.

All the best

Andreas

[Soddball]

Originally posted by Andreas:

</font><blockquote>quote:</font><hr />Originally posted by Soddball:

That is just not, in any way, 0 degrees.

Depends on what your basis for measuring it is.

All the best

Andreas </font>

[Andreas]

You have just seen me in action mate.

[JonS]

Well, perhaps if you'd have mentioned somehting about the turret in your first post I wouldn't have thought you such an idjit. And which part of the turret are you talking about - the front bit, the sides, the top, the rear?

Well done leaving Blighty Andreas. Thinking and communication skillz seem to have gone out of fashion there.

[WineCape]

Probably front turret. Who knows...murky mind of a 'pooler. Good question.

Looks like most of the front turret has some angle, as can be seen with the 1st picture posted above. A visible slope can be seen running next to the gun housing, curving more towards the top of the front turret.

A case can be made out that there should be SOME angle on the front turret? Or am I missing something?

[ August 01, 2005, 03:17 AM: Message edited by: WineCape ]

[Michael Emrys]

The turret front of the VC Firefly is 76mm sloped 30°. I am quoting from the Bellona Military Vehicle Prints Series Seven.

Michael

[Soddball]

I congratulate Andreas for being able to steal money from real people and spend it on banana-measuring specifications. When I am "Ruller Of Teh Galaxxy" there will be a special place for Eurocrats.

JonS, if I could communicate properly I wouldn't be here. I'd be sitting in an office in Paris making up rules on how all businesses should employ three-legged purple people.

WineCape, don't confuse MasterGoodale's Thread of Cheery Waffle with ....that...other...place. Ours is a place of mirth and savagery, and theirs is - just wrong.

Anyway, back to my Very Important Point.

It isn't just the Firefly. There seem to be a couple of models with this very clear slope.

There is a Sherman with a 76mm turret front included in the game, but its armour is 76/0, not 76/30.

Models of Shermans - slope very clear in some but not all.

I've got a couple of other photos which are unclear or at the wrong angle, but there's no doubt in my addled brain that 89/0 for the turret front is wrong.

Realistically, I know that there won't be a fix for this flaw this late in the game. But since the Sherman is the most common allied tank in CM:AK, I'd like it fixed for the next iteration of CM.

[Soddball]

A quick trawl through the archives throws up this thread, generated by our own beloved WineCape.

Rexford's post from there:

All of the 75mm armed Shermans had sloped mantlet and turret front armor. CMBO attempts to model the ballistic resistance of the turret front/mantlet as opposed to the thicknesses and angles. For a reason.

The later 75mm gun mount had an 89mm cast and curved gun shield spaced behind a 51mm cast and curved rotor shield, so 140mm of curved armor on the turret front mantlet area.

Now come the disadvantages, which are considerable:

1. spaced armor is not as resistant as a single plate, so 89+51 does not equal 140.

2. armor is cast so reduce resistance

3. inner 89mm shield is chock full of large openings for gun, vision devices, machine gun, etc, so reduce resistance for edge effects

4. penetrations of 51mm outer shield that fail to go completely through 89mm inner shield may result in something called "keying", where the round sticks in the outer and inner shields and prevents gun elevation changes

5. if projectile penetrates outer shield but is stopped by inner shield and the HE burster detonates, explosion is likely to mess up gun aim and other things.

We did a detailed ballistic analysis of the resistance provided by 51mm/89mm shield combo against 75mm hits, which took into account edge effects, cast armor deficiency to rolled armor, spaced armor factor and impact angle. The average resistance of the combo is 89mm vertical, exactly what CMBO uses.

Here are some of the breakdowns from our analysis of 51mm/89mm shield combo:

36% hit total effective resistance of 75mm vertical or less

43% strike effective resistance of 85mm or 95mm

13% hit 105mm to 125mm

8% hit 145mm to 165mm

NOTE:Above results do not take "keying" into account

So 79% of the impacts on Sherman 75mm gun shield area will be resisted by a single vertical plate equivalence of 95mm or less. Since CMBO does not treat the area as a complicated curved arrangement with all of the peculiarities and vulnerabilities, a single vertical 89mm plate is used, which seems reasonable for wargaming.

We use the statistical breakdown in our miniatures gaming, so the Sherman shields will occasionally defeat a Panther or Tiger hit, which is likely to stick in the shields and disrupt the gun elevation or detonate and mess up the sight and machine gun.

This refers to CM:BO. However, let me draw your attention to one sentence:

"Since CMBO does not treat the area as a complicated curved arrangement with all of the peculiarities and vulnerabilities, a single vertical 89mm plate is used, which seems reasonable for wargaming."

CM:BO didn't treat the area as a complicated curved arrangement, but CM:BB and CM:AK do have the 'curved' value for armour plate, and I can't help but feel that the Sherman would have been a logical choice for this 'curved' value.

[Michael Emrys]

Okay, here's the deal so far as I can figure it out at present. The 75mm-armed Shermans all seem to have the 76mm 30° turret front. So does the Firefly which seems to have been based on the same turret with some modifications.

When the Army introduced the 76mm gun, except for the first experimental models, they also introduced a new turret that was pretty radically different in shape. The Turret front is indeed vertical. I haven't been able to find out what the thickness of that armor was. But the mickey is that the mantlet extended all the way across the front of the turret. I don't know what the thickness of that was either, but it had to significantly increase the total armor for the front, taking into account what Rexford (where has he gone, BTW?) said about all the various openings in the turret front and their effects.

Michael

[WineCape]

The 75mm-armed Shermans all seem to have the 76mm 30° turret front. So does the Firefly which seems to have been based on the same turret with some modifications.

I assume you're referring to your Bellona prints?

[ August 01, 2005, 08:31 AM: Message edited by: WineCape ]

[roqf77]

emrys, i belive that the turret on the us 76mm shermans was from the t-23. that has 89mm of armour i believe.

[roqf77]

http://afvdb.50megs.com/usa/mediumtankt23.html

it was look here for info.

[Michael Emrys]

Originally posted by WineCape:

</font><blockquote>quote:</font><hr />The 75mm-armed Shermans all seem to have the 76mm 30° turret front. So does the Firefly which seems to have been based on the same turret with some modifications.

I assume you're referring to your Bellona prints? </font>

[Michael Emrys]

Originally posted by roqf77:

emrys, i belive that the turret on the us 76mm shermans was from the t-23.

Correct.

that has 89mm of armour i believe.

Chamberlain & Ellis list max armor for the T23 at 87mm, but they don't give details and might be off a bit.

Michael

[Michael Emrys]

Originally posted by roqf77:

http://afvdb.50megs.com/usa/mediumtankt23.html

it was look here for info.

Interestingly, that site gives 76mm for the turret front and 89mm for the "gun shield", i.e., mantlet. That would give a combined total of 155mm, which is a fair amount of armor, even given Rexford's reservations.

Michael

[Bigduke6]

From a practical, intuitive point of view, if I had to choose between:

1. 89mm of cast armor at 0 degrees vertical

or

2. 89mm + 54mm of cast armor, at some slope, and all of Rexford's reservations

AND

I knew that if I chose wrong a 75mm or 88mm AP shell would have an increased likelihood of smashing through my turret -

I would choose the thicker two-layer in a heartbeat.

Heck, it seems obvious to me 89 degrees sloped armor - which is what we see on the pictures of the tank - is preferable to 89 degrees vertical - which is how the game models Sherman fronts.

This effectively implies that CM - which is an outstanding game - not only underrates Sherman turret armor, but gives the vehicle no defensive benefits for the mantlet at all!

It literally would be more advantageous from an Allied wargaming point of view to remove the mantlet from the Sherman, because that would force the game to take into account the slope of 89mm plate to enemy fire.

As it is, the game appears to tilt that plate vertically, and to reduce the mantlet to eye candy. Maybe my logic is wrong somewhere, but that's the way it seems to me.

I personally find the justifications for this situation, i.e. in the Rexford citing above, as more than a little suspect. (Rexford, nothing personal, I'm just picking at the points that got quoted in this thread.)

To take the justifications point by point, CM decided to model the Sherman front at 89 degrees vertical because:

1. spaced armor is not as resistant as a single plate, so 89+51 does not equal 140.

To which I respond - yeah, but an 89mm plate with a 51mm in front of at least part of it has got to be better than a vertical 89mm plate with nothing in front of it.

2. armor is cast so reduce resistance

I say - This is irrelevant to how the armor slope is modeled. Armor quality is a separate rating.

3. inner 89mm shield is chock full of large openings for gun, vision devices, machine gun, etc, so reduce resistance for edge effects

My opinion - All tanks have their turret fronts pierced for that stuff. It seems to me that vulnerability is not limited to Sherman.

4. AP hits can penetrate the mantlet and jam the gun, without getting through the front turret plate.

See above. It seems to me that's an issue for most tanks, not just Sherman.

5. if projectile penetrates outer shield but is stopped by inner shield and the HE burster detonates, explosion is likely to mess up gun aim and other things.

ditto

6. We did a detailed ballistic analysis....

I strongly suspect, no, I am absolutely sure, this analysis was a mathematical analysis of slope, spacing, and thickness; rather than a statistical analysis of battlefield incidents. I apologize ahead of time if I am attacking a straw man, but like I say, I doubt that I am.

To my mind this methodology - using math and firing range date to determine your armor effectiveness modeling in a computer wargame - is risky. It carries the danger of historical errors, if your goal is always depicting historical combat accurately. The reason is sometimes weapons performed on WW2 battlefields consistently differently from our mathematical predictions.

My personal examples, would of course be the Soviet ZiS-3 gun, and the (notorious) frontally invulnerable Stuermgeschuetz. Not every one buys my arguement, of course.

That said, I have to admit overall CM does an outstanding job modeling combat, best in the world right now.

I would be interested to hear from some one smart on Shermans in battle for an impression on how effective the Sherman crews thought their turret fronts were in combat. I just don't know.

[WineCape]

...spaced armor is not as resistant as a single plate, so 89+51 does not equal 140. To which I respond - yeah, but an 89mm plate with a 51mm in front of at least part of it has got to be better than a vertical 89mm plate with nothing in front of it...

Exactly. The point raised 3 years ago from my thread - see above - and raised from the swamps again by herr Oddball.

Hopefully this issue will be looked into when CMx2 re-visits WWII

[flamingknives]

To my mind this methodology - using math and firing range date to determine your armor effectiveness modeling in a computer wargame - is risky. It carries the danger of historical errors, if your goal is always depicting historical combat accurately. The reason is sometimes weapons performed on WW2 battlefields consistently differently from our mathematical predictions.

Some of my colleagues do this for a living - using maths to predict penetration of armour - why should it be particularly suspect?

[roqf77]

because you dont actualy have a gun the ammo and the tank. therefore it will only ever be a prediction.

it will never be as good as actualy doing it.

[Sergei]

Originally posted by Bigduke6:

To my mind this methodology - using math and firing range date to determine your armor effectiveness modeling in a computer wargame - is risky.

What is the alternative? Should Einstein have refrained from predicting black holes because he hadn't witnessed them IRL?