"AFV Armor Rating Granularity" Topic

A find on the interwebs about tank armor data by Mako11 got me to thinking about this topic.

Different games have differing numbers of AFV armor ratings. At one extreme you might be limited to light, medium, and heavy. At the other extreme you might have ratings from 0 to 30 or 50. Part of this is driven by whatever game mechanic is used to figure out the chance of damaging an AFV and the type of dice used.

In general d10s and d20s will allow a broader spectrum. A d6 limits your spectrum unless you're willing to see more frequent breaks where weapons can't hurt a given target.

In your opinion, if building a scale including everything from a WWII halftrack to the latest MBT in the year 2020, what sort of granularity would you expect or want?

Is a scale that accounts for every version of a given tank model needed?

Or is something as broad as 1st Gen MBT, 2nd Gen MBT, and 3rd Gen MBT sufficient?

How much abstraction are you willing to accept when it comes to AFV "shades of grey"? Do you want to see differences between the M60 and M60A3? Or would you lump them together?

As a point of reference you might consider games such as AK-47 Republic, Fist Full of TOWs, and Flames of War.

Of these three games, AK has the lowest level of granularity (it's super abstract), FoW the greatest, and FFOT falls in between.

The latest Fist Full Of Tows uses a logrithmic scale

That's correct about FFOT. At the WWII end of their scale they lump together a lot of vehicles that FoW separates out. So the question still applies, at least for WWII gamers among us.

Does the FFOT approach provide too little granularity for WWII games? Or is it acceptable?

If acceptable for WWII, then would "squashing" the FFOT model for later years be ok too?

I would also note that FoW is still more granular at the Cold War end of spectrum.

By way of comparison, our upcoming "Rush of Battle" is somewhere between FFOT and FoW. It's not as squashed as FFOT at the WWII end of the spectrum but not as granular as FoW at the upper end of the spectrum. And we based our model on more than pure penetration vs armor (e.g. you can't armor your wheels and tracks so there's a natural cap on flank shot protection when aggregating and abstracting the chance of damaging an AFV). We also focus on the men in the machines rather than the metal and the fact that a tank needed not be penetrated and brewed up to render it combat ineffective in a tactical sense.

What is your opinion on the Jim Day series of games? Panzer and MBT, board game versions by GMT Games and miniatures by Jim's own Strikenet Games.

Here is a sample data card from GMT Games newly released MBT

A lot depends on the level of the game. If more a skirmish game with one model equal to one vehicle then would expect more detailed information on each vehicle. If playing something along the line of Panzer Korps where a vehicle equals a company and the lowest maneuver element is a battalion then would expect simpler, more abstract data.

MBT, or Tractics, and similar for me.

Challenger 2/2000, and/or Modern WRG 1950 – 2000, etc., so at the more detailed end of the spectrum.

For the record, I hate logarithmic rules, for weapons ranges, armor ratings, etc., etc..

In general d10s and d20s will allow a broader spectrum. A d6 limits your spectrum unless you're willing to see more frequent breaks where weapons can't hurt a given target.

It allows more granularity but any die can be as broad as you want if you give each pip a multiple.

logarithmic might work to cover small gun APHE and modern gun APDSFS penetration with a single mechanic or chart.

I would use a percentage variation chart but that becomes difficult math for a table top game if you want faster play.

Here is a sample data card from GMT Games newly released MBT.

That is in the mold of Panzer so each factor is .5cm. 110 = 55cms or 550mm.

The way I do it (Action All Fronts) is to have a notional value of the armour. At the moment 1 is the lowest with 23 the highest (front armour of a Tiger 2). Then the chance to do damage is modified by the power of the weapon attacking (14 for a 17pdr, 9 for a 6pdr and 5 for the 75mm in a Sherman) vs the armour value. So it is still possible for a weapon that cannot penetrate to inflict a mobility kill for example. A weapon thats power is 10 lower than the value of the targets armour, would not be able to inflict any damage on it.

VIS,
I don't lump everything together. Too generalized ratings eliminate the chance for hits on especially weak areas of ricochets on armor with a 70+ degree slope in 1:1 games.

I think taking the armor value and dividing by 2 and rounding up would work pretty well (ex 44mm = 4).

This is what I've been using for the Panther A.
link

I have ratings for various horizontal angles so no math involved. All charts are customized for the particular vehicle. The charts also show behind armor systems that can be damaged.

Armor penetration is pretty variable and should have a % variation chart like Mobius indicates.

I think modern armor is going to use a completely different method of determining strength and penetration.

Wolfhag

Really detailed ratings are great, but wargamers tend to focus WAY too much on them…
If you have very detailed armour ratings then really you should have VERY detailed everything else:
PRECISE angle of shot, PRECISE angle of vehicle in at least 3 simultaneous planes, Precise information on steel quality, ammunition quality, atmospheric conditions, any additional stowage/armour at the precise point of impact? Had the vehicle received previous hits in that area? speed of vehicle at moment of impact, Thats before we get into the minutiae of the hit roll, did the gunner have an upset stomach/dear John letter that day? How worn/clean was the gun barrel? etc etc
or you can just roll a d6
they are both pretty much as accurate, and you are fooling yourself if you believe different.

I too am kind'a from the KISS, school of thought. You need a good balance of complexity & reality with playability …

they are both pretty much as accurate, and you are fooling yourself if you believe different.

Yet, there is a large contingent that will put a value of say anywhere from 1 to 20 on unit cohesiveness (an unknowable quantity). Talk about fooling yourself.

Some D6 are more equal than others.

We went thru the D6 vs. other die types … in the end … D6 was the best of both/all worlds …

I grappled with this for a while and ended up with a system in which you have PEN/DEF.

You divide PEN by DEF. Then every 0.1 difference over 0.5 increases the roll needed on 2d6 by 1 [0.6 = 1, 0.7 = 2, 1.0 = 5 etc.. So if PEN/DEF = 1.2 you need a 7 or less to KO the target. 1.6 needs an 11 or less. Any DR of 12 is a fail but can still shock the crew.

This gets round some of the anomalies at the extremes [ like with very thin armour and ATRs/20mm autocannons] and seems to keep things about right. I made a sreadsheet with PEN/DEF for every value in my game and made it into a chart. It's pretty quick to figure out what you need to roll. Any roll 3 or better less than a KO is a BURNING WRECK. Other KOs could be recovered from if left alone. One reason to machine gun the crew as they bail out or keep blasting the hulk until it catches fire. Humanitarians can round up the demoralised crew as POWs.

We went thru the D6 vs. other die types … in the end … D6 was the best of both/all worlds …

We went through that with RoB and Age of Madness.

After trying out D10s we felt the costs outweighed any advantage, as least for our level of detail. With each model representing 2 or 3 vehicles in most cases the d6 works just fine.

It also makes things more convenient for gamers. Most already have d6s around the house. We gaming vets often have d10s but more casual gamers don't.

If I had my druthers I'd use d8s. I really liked the statistical spread when I converted some of our data for use with d8s. But very, very few people are going to have 5 to 7 d8s laying around which is the upper end for our rules in most cases (most rolls are 3 to 5 dice).

Really detailed ratings are great, but wargamers tend to focus WAY too much on them…
If you have very detailed armour ratings then really you should have VERY detailed everything else:
PRECISE angle of shot, PRECISE angle of vehicle in at least 3 simultaneous planes, Precise information on steel quality, ammunition quality, atmospheric conditions, any additional stowage/armour at the precise point of impact? Had the vehicle received previous hits in that area? speed of vehicle at moment of impact, Thats before we get into the minutiae of the hit roll, did the gunner have an upset stomach/dear John letter that day? How worn/clean was the gun barrel? etc etc
or you can just roll a d6
they are both pretty much as accurate, and you are fooling yourself if you believe different.

+1

Totally agree.

I use dice shifting and the 5 ratings for a given scenario seem to work fine.

You don't want to introduce angle measurement in a miniatures game.
Unless you want things like tanks "dancing" down a road.
Ending their move facing in some weird direction as the player hopes to maximise angle of dangle.
It's funnier in retrospect than on the table.

If you have very detailed armour ratings then really you should have VERY detailed everything else:
PRECISE angle of shot, PRECISE angle of vehicle in at least 3 simultaneous planes, Precise information on steel quality, ammunition quality, atmospheric conditions, any additional stowage/armour at the precise point of impact? Had the vehicle received previous hits in that area? speed of vehicle at moment of impact, Thats before we get into the minutiae of the hit roll, did the gunner have an upset stomach/dear John letter that day? How worn/clean was the gun barrel? etc etc or you can just roll a d6

Incorrect. You CAN have detailed armor rating and detailed gun penetration numbers as long as you have a variable penetration die roll.
The target tank will have a facing, front. side or back. It's easy to tell which. A tactical game turn will usually be between 15 seconds and a minute somewhere in that span the firer can establish which facing is a target. This may be from 15 to 22.5° of direct front/rear or side. Within that span if moving it may change precise angle back and forth or even go through a turn, as well as vertical orientation up and down 5-10° from just rough ground. Thus the compound angle will have some range. The game designer can use that to help design how broad a range. A variable penetration die roll can be made where a certain percentage of the full penetration results and this is compared to the armor facing. If equal or more the tank is damaged.

You don't really need to know the precise moment when the tank is hit as you have the results of a great variety of precise elements. They are ALL covered by a single dice roll and this precise factor nonsense falls out of the way. And this die roll can be a D6.

M/Grp does it based on an algorithm as follows.

The armour class is defined as a nominal thickness of RHA (Rolled Harmogenous Stee) defined as
= 8*1.3333^(c-1) where the thickness is in millimeters and C is the armour class).

There is some logic in this.

a)Even if we ignore armor angle on the vehicle then depending on the angle to the face the apparent thickness varies by 1.4 (sine theory). If you hit beyond about 45 degrees you are hitting the other face (i.e the side) is the assumption.
b) Actual research data gives a standard deviation of the data as about 4% mean thickness penetrated. At the extreme that is pretty much plus or minus 12% of the thickness.

Linear is just wrong. The difference between 8mm RHA just about rifle proof to 12mm (HMG proof) is critical, 12mm extra with an RHA equivalent of 1.6m is stupid.

So the value 1.3333 is somewhere near. Bit finer than simple angle but not too much. You pays your money and make your own decision between the two.

This scale lands slap bang on in the range at the bottom level where vehicles mostly have about 8mm or 12 mm plate.

As has been said more accuracy would mean assessing compound angles which is beyond where I want to be in a wargame.

It still leaves open to interpretation angled plate (apparently some new penetrators are less influenced by this and by how your armor relates to RHA. Typicaly good armor may achieve the equivalent of about 4 times its thickness against solid shot and a bit more with ERA etc.

"And this die roll can be a D6."

exactly

As far as tanks dodging down the board and always presenting their best armor I agree. That's because in most games you cannot determine the timing of an event as they are some version of IGOUGO.

The variable penetration can be a good way to handle many of the nuances of armor penetration. This is what I use:
link

As far as "precision" there is a point of diminishing returns and what you want the experience in the game to be.
Christot brings up some good points but I think they are not pertinent because they border on the ridiculous but I get your point. Even with horizontal angles on frontal shots a horizontal angle of up to 20 degrees has little or no impact on the armor thickness so in a majority of shots in a game it will not matter and can be left out. Personally I think angles in a 1:1 game are important for historical authenticity and the overall experience and that small chance of something occurring – as long as it is not painful to arrive at. It's OK to disagree with me. I don't expect people to want the same experience that I do. I'm used to being in the minority on TMP and elsewhere.

Most tanks have a weak spot I think should be modeled in a 1:1 game. A static armor value with no hit location does not work for me except in higher level games. No tank was completely invulnerable at certain ranges. I wanted to recreate the nuances of the Panther armor and mantlet weakness because my group likes when those small chance occurrences happen. One die roll also helps determine damage too.

If you study some tank armor schemes you'll see almost all of them have a surface that a round could bounce off of. In 1:1 games it can be important in the overall gaming experience. In larger scale battles a waste of time. You can just decrease the hit % to reflect that or have a hit location die roll with a small chance it will happen. I like the experience of the small chance as long as it is not a painful conclusion to arrive at. I can also understand ignoring small chances in a larger game.

Players and game designers do not "need" or are required to really do anything or include certain aspects into a game. I don't think there is any game design that is 100% historically consistent nor can it be. No matter what you do only a minority % will totally agree anyhow. In the end it's the balance of playability, detail and probably most important the experience and expectations of the players in your group being met. If the expectations are more detail then put them in. If not leave them out. There is no wrong or right way to play the game. Designers just need to make sure they can back up their description and deliver on the expectations. If you can it's a good design but people will still bash it.

For me I prefer more of a physical model rather than dice mechanics to determine results. However, I've seen dice mechanics that give historically acceptable results too but I don't like that experience. I'm too old and don't have the patience to track down and determine which modifiers are needed so I use a different method to keep it simple.

Just abstract things you feel are not important for the experience and expectations and integrate more detail into what you think is important. If you feel it's important to model an accuracy penalty for your gunner because he has the crabs or clap or a spotting penalty for your tank commander because he's crying over being dumped by Betty Lou for his buddy Jodie back home I feel sorry for you. Also if you have a negative armor modifier because the quenching phase was done early Monday morning when the workers still had a hangover you need some serious help too.

Wait a minute. I think my group would like a pre-game crew characteristic result where a gunner had the crabs. I think it does have some entertainment value or maybe I need some help.

Wolfhag

in the end whatever floats your boat…
just recognise that in the game versus simulation argument its largely pointless because (sadly) the game always wins. I wish it didn't, truly I don't, but its a fact. the sooner one accepts this the happier we are.
I stick with my original assertion:
you are fooling yourself.

For 1:1 WW2 gaming, I rate various sections of each vehicle (for front and rear there are 6 areas and roll 1d6, for flank 10 areas and 1d10 to determine which area is hit) with a defensive number where 1 equals 1cm (10mm) of armor, adjusted for angle of slope, which is compared to the penetrating power of the gun at the range, also rated in centimeters. Ranges used are 100m, 500m, 1000m, 2000m, as these are the ones most often given in test data on the weapons.

Years ago, when I had the absolute pleasure to work at a place called Chertsey, not far from a place called Chobham, I used to spend my lunchtimes down in the Library.

This wasn't your normal Library. It was the size of 2 football pitches (Brit ones). It had original copies of Churchill tank manuals, reports on 17lb'er firing trials, assessments of the 'new' German 75mm long (called an F2) from 1943. Quite a few real gems in fact, until one Monday lunchtime I went down there to find 4 librarians wandering around in a daze as over the weekend a 'couple' of Army 4-tonners had turned up and loaded the lot up and shipped it down to Bovvy. But that's another story.

The point of this little story is that there were reports in there about assessments made on the thickness and effectiveness of German armour. Brinnel hardness factors, or some such like.

The point of the assessment was that even on tanks of the same Mark, eg PzIVH, the manufacturing tolerances of the armour would mean that the effectiveness of the armour on one individual tank may be quite a bit different to the tank next to it. If you think of T-34s coming off the production line at the Tractor works at Stalingrad one wonders at the quality of the armour and whether it would have been effective at all?

That's why I had/have a problem with the original Yacquinto Panzer/Armor/88 series of games, or any games that try and measure armour thickness accurately, that measure armour to the nearest 5mm. It's pointless, as the tolerances could vary so much in production.

And you've got variances in ammo production tolerances as well.

All you can say is that someone measured a tank at some point and the tank they measured had an armour thickness of so-and-so. That doesn't mean that they all were.

For a game, like we play, all you can say is that a tank of a certain mark had an armour thickness of around this much. Add in variations to the angle at which the round strikes, the different design of thickness in different parts on the tank, eg lower hull front of so much and upper hull front a lot thicker, and rolling a d6 for any target becomes pretty close.

And 'S@ds Law' always says you hit a vision slit.

The most 'accurate' anti-tank rules I've played are FFOT3. The more you think your gun can penetrate the armour the more d6 you can roll :)

Think your Tigger is always invincible, or your M1 is all Chobham'ed up and can shrug off any hits thrown at it, think again.

Hope this helps,

B

BB,
I don't think anyone is going to disagree with you. Cast armor had even more variations than RHA.

You still need to assign some type of value to armor thickness. What do you recommend? How variable should penetration be?

Can't the Yacquinto family be somewhat fixed with a variable penetration result even if you do have a single armor value?

I take into account a modifier for cast armor before determining vert/hori angle modifiers.

As far as granularity I don't take into account hardness as it's just too much of a hassle. If a tank was known to have very hard armor (T-34) I give an increase in spall damage for non-penetrating hits. That's probably too granular for most people and I'm open to suggestions.

Wolfhag

The "Magic" of a D6 is :

1 is always a miss, 6 always a hit … regardless of modifiers.

But we preferred, if you needed to roll over a 6 because of modifiers.
You must roll a 6 then* > > > >
To Roll a 7 you must roll 4+
" " " " an 8 you must roll 5+
" " " " a 9 you must roll a 6
*(the second roll is unmodified)

That seemed to work for us …

= 8*1.3333^(c-1) where the thickness is in millimeters and C is the armour class).

Holy Cow ! WE are playing a wargame not going back to Algebra/Geometry class !

I like DP9's Silhouette system, where you have an opposed roll to hit, then multiply margin of success by weapons damage multiplier, compare that to vehicle's armor value (which is the cube root of RHAe armor thickness in MM, IIRC).

Gives even a 20mm autocannon a chance of doing ugly things to a heavily armored vehicle with an excellent to-hit roll and a crap defense roll.

Having said all that…i still prefer a d10…thats my preferred level of self delusion!

Coincidentally, dragged out WRG's 1950 – 1985 rules last night, and am considering giving them a go first, rather than using some of the others I can't find, or that need tweaking, since these are already done.

They're free, use a D6, and have a reasonable number of modifiers for the firer and target to make life interesting, but not overwhelming.

Published in 1979, so sadly, missing some of the really late Cold War types and armor/ammo values.

Still, they look to be very useful for up to the early to mid-1980s period, and only need a few RPG and ATGW stats to be looked up and added on.

Need to find the terrain, and drag out the armor, to give them a go at the local club.

Ran a paper test a while back, without minis, which I posted here on TMP – T-55s vs. M48s, which worked pretty well, and was reasonably fast.

Now, to take a look at the infantry and artillery rules, and learn how to use those.

Tank Charts graded armor and penetration in actual millimeters. Can't get much more granular than that.

Wolfhag,

I'm in favour of anything that gives a bit of 'jitter' in the results.

A good way of doing that is to use a normal distribution to get the variation. For gaming a typical way is to use 2d6 where a 7 is your normal and the 2 & 12 the limits. The tricky part is working out what the limits are.

From experience and comparing to actual results it's best if the limits aren't too extreme.

For that reason I dislike opposed die rolls – they just don't give the 'correct' results.

Hope this helps, B

But we preferred, if you needed to roll over a 6 because of modifiers.
You must roll a 6 then* > > > >
To Roll a 7 you must roll 4+
" " " " an 8 you must roll 5+
" " " " a 9 you must roll a 6
*(the second roll is unmodified)

That seemed to work for us …

I use this as well on for D6 rolls but there is no modifier on the die roll but on the number needed to be rolled.
The original idea came out of WRG armor rules.

Yes, only the original roll for a 6 is modified but the next roll is not. That is the way we do it.

But yes, this is a good system, IMO, I'm not sure where we found it. Again, a D6 system works, you just have use something like this to give it a little more detail. Because after awhile it comes down to if you hit & the effectiveness … D6 works with out using higher levels of math. And I'm not very good at math …

There are a lot of interesting game mechanics in Barker's armor/infantry rules. Always enjoyed playing them.

B

As the First Cavalry Division safety officer, I had to investigate any injury causing incidents. (The army did not like the word accident.) In one case during a night time live fire exercise, a M113 with a rifle squad in it got down range and confused with targets. The track was Swiss cheese when I got there. Every man in the squad was wounded with four being killed. It was easy to determine which holes were made by M60s, M16s and .50 cals. the 50 calibers were through and through of course.
Exposure and tactical use were key in Vietnam. I read one report about how a Sheridan unit never lost a man even though it's armor was aluminum covering a Styrofoam filling.

Legion 4

Holy Cow ! WE are playing a wargame not going back to Algebra/Geometry class ! huh? wink

Relax you do not have to do that EVERY TIME. I put it in a table for folk. UNLESS I AM FEELING MEAN, then I re-write it so you lose! Hey there has to be a point to being a rule writer.

It just show how much thought goes into things.

Christot,
The falacy is thinking that its game vs simulation. A good sensible simulation is the ultimate game. The falicy is thinking complexity of rules makes a good simulation, or a good game.

Selection of the right parameters makes a good simulation and a good game and quick and enjoyable play.

Of course armor and ammo vary somewhat, that's why, in my rules at least, there is a die-roll involved. Nevertheless, a 37mm gun is not likely to penetrate the front of a Tiger I, is it?

But yes, this is a good system, IMO, I'm not sure where we found it. Again, a D6 system works, you just have use something like this to give it a little more detail. Because after awhile it comes down to if you hit & the effectiveness … D6 works with out using higher levels of math.

It is a good mechanic. For other things I use it for D10 as well. A 'natural' 10 and then roll the d10 again. '6'=11, '7'=12 , '8'=13 … etc.
I still use the D6 mechanic in our computer game Panzer Command for penetration variation even though it's behind the scenes. Since each different number will be a percentage of the full penetration it could as well be a d10, but I haven't seen a good reason to change it. I don't however use percentage variation in my miniatures game version. Like you was said, doing math, other than simple addition or subtraction slows the game and can be mentally tiring after awhile.

A normal distribution is not a useful instrument in variable penetration as there are few things that give more effective penetration than the max. But there are many things, that can give less penetration like acute angles to the armor.