Penetration KT vs M-18 - some strange conclusions

[Jeff Duquette]

Very interesting discussion. And here I’ve been all jazzed about finding a WWII Tac Sim that finally modeled the ability of tanks to go hull-down. Sounds like the “To Hit” function is at the hart of this.

[Mr. Clark]

Man, this thread has turned heated.

First off, let me say that I apologize if any of my remarks seemed "patronizing."

Second, I want to run with the "man in an invulnerable body suit" example. I COMPLETELY agree with everything this example demonstrates. If this "soldier" hides, exposing only his head, then there will be a lessened chance to hit, but a hit will always result in a kill, and in fact, enemies will be actually AIMING for his head. However, if he stands in the open, the enemy will only be able to hurt him in the head anyway, so he may as well not worry about hiding. THIS IS ALL CORRECT! I AGREE!

Now, switch this example to tanks and it runs pretty much the same. Once again, I AGREE!

Sooooooo, a man with an invulnerable body suit would not be any better off hiding behind cover with only his head (and arms so he can shoot) exposed. However, any OTHER man (who was not bodily invulnerable) would probably like to take some cover to minimize hits.

Switch this to tanks and once again it's the same.

Is this what you've been saying all along? Because I can agree that in one particular circumstance being hull down does not give any special benefit... both in real life, and in CM.

Now that I've agreed so much, let me say that this is basically also the SAME point I've been making all along. I've simply refused to discuss the penetration aspects of tank armor, because Hull Down is only meant to reduce the chance to be hit.

My argument: Hull down is always the best way to go to AVOID BEING HIT.

If I'm correct in my understanding, then all this time no one has been saying that CM incorrectly models Hull Down (which reduces hit chance), simply that in both CM and real life, it's possible that a situation will arise where Hull Down is not a tactical advantage?

If this is correct, then I agree.

I thought that people were arguing that CM was somehow modeling Hull Down wrong...

[Treeburst155]

My latest test with the subject tank returning fire supports the "Hull Down Can Be Bad" argument too. I put a Comet armed with Tungsten only against a KT Porsche at 1000 meters. This choice was carefully selected. The Comet (with Tungsten) can easily penetrate a Porsche turret, but should have real problems against the hull at 1000 meters.

KT Porsche fully exposed:

Knocked out or abandoned- 40%

Immobilized, Gun Hit, Shock- 5%

No Damage- 55%

Lower Hull Penetrations accounted for 4 KOs above. I was not too surprised, but I was hoping for a completely impervious hull. I knew it would be close with the lower hull.

KT Porsche Hull down:

Knocked out or abandoned- 50%

Immobilized, Gun Hit, Shock- 0%

No Damage-50%

With this particular combination of units, at this range, it does indeed appear that the KT was a little better off fighting in the open. If the lower hull had been just a little thicker, or sloped a little bit more the no damage stat could have gone as high as 59%.

I'm willing to give the victory on this to Rex, Hofbauer, and friends. I don't however, think there is anything wrong with the way CM handles hull down vehicles. I'd be willing to bet that in real life it was sometimes better for certain vehicles to avoid hull down positions when facing certain enemy guns at closer ranges. In order to make a good decision though, the TC would have to know what guns he was up against, what ammo was being used against him, the penetration statistics for the gun/ammo combination, and the armor thickness/slope of his own tank. There is also the overall situation to consider. A weak turreted vehicle may still want to be hull down to minimize the chance of being spotted or to provide a quick escape from enemy LOS if things start looking real bad.

Having said all that I will admit that I will now think twice before assuming a hull down position with thin turreted vehicles with good hull armor in "stand and fight" situations at less than 1,000 meters.

I vote the game is fine like it is.

Edit: I still think it would be nice to add a few seconds to rate of fire against hull down (small) targets. This would probably not eliminate "hull down is bad" situations, and it shouldn't. It would however close the gap some and bring us even closer to reality, IMO.

Treeburst155

[This message has been edited by Treeburst155 (edited 12-16-2000).]

[Jarmo]

Wow, looks like some sort of synthesis is forming here.

The one issue remaining would be, whether the hulldown position

lowers the to-hit chance enough.

One thing I'd like to know, if being hull down gives the same "bonus"

to all tanks. I mean, does a small turreted vehicle benefit more

than one with a large turret.

[Ben Galanti]

I know this thread has gotten a bit heated at times, but I'm not sure people weren't arguing the same side I think folks were just saying that hull down isn't always the preferable tactical decision, not that CM has hull down incorrectly modeled.

I think the only thing that could be questioned is the drop in to hit chance for a target being hull down instead of not hull down, but that would be extremely hard to quantify, and even harder to back up from data, I suspect.... I think some folks were just suprised that being hull down isn't always the best option, in certain situations.

[A Arabian]

Agreed, galanti and jarno. As I see it, the "soldier" example is valid, and so a reduced to hit w/ increased chance to kill is a reasonable relationship.

Once I thought about the math, I agreed with the way the kill numbers worked out as well, but it still bugged me that sometimes it was better to be NOT hull down. The remaining indeterminate variable then is the %chance to hit. It is POSSIBLE that the impact of losing 65% of your visible surface area is insufficient, resulting in the issue at hand.

I asked a friend of mine who is wise in the ways of stats to take a look at it, but it'll be monday before I get a response, so I'll update on what I find...

A. Arabian

[Guest Big Time Software]

People are discussing the hit probabilities versus hull-down targets and how they relate to fully-visible targets. Jarmo stated that hull-down targets are roughly 30% harder to hit.

Everyone please understand this: The increase in difficulty of hitting a hull-down targets is heavily dependent on range. In other words, at short ranges (say, less than 250m) being hull-down isn't much protection at all. A tank's turret (and a portion of its upper hull too - don't forget that!) is still a very big target when the range is short - so it's not difficult to hit it. But at 1000m the difference is signficant. And at 1500m or more, the chance to hit a hull-down tank is roughly halved. That's a huge advantage for the hull-down tank. You can verify these values for yourselves right in the game editor (just draw a line of sight and it tells you the to-hit%).

As for our thoughts on hull-down in general, and why there are certain cases where being hull-down doesn't help much (at short range!) what Jarmo said sums it up quite well so I'll quote him here:

<BLOCKQUOTE>quote:</font><HR>Suggestion: hulldown should always be favourable.

The infantryman example: If the infantryman only shows his head,

all hits will hit the head.

If the whole infantryman is fully visible, the opponent will likely

aim for the torso.

Now let's suppose the infantryman has a bulletproof vest but

a no-good helmet.

From a bit longer range it's obvious you should remain down

and hope the opponent misses.

From a close range, where the enemy will hit anyway. It might be

better to show yourself and sucker the enemy to shoot at your chest,

and then pop him before he fires again.<HR></BLOCKQUOTE>

Now, just to clarify (not to antagonize because it sounds like many of you already agree with this, I just want to state it for the record):

Some have based their arguments on the assumption that hull down should always be advantageous, and because certain field tests don't show this, they feel something is wrong with Combat Mission. But the assumption that hull-down is always good is incorrect. If we assume that Combat Mission's behavior which precludes gun crews from knowledge of whether the target's turret or hull is the weaker target is correct (and therefore aim for center-of-mass) then even in the real world there will be certain circumstances when being hull-down is not advantageous, and may even have a deleterious effect - because you're forcing the gunners to shoot at your (weak) turret when they might not otherwise have done so.

There is room for debate on whether gun crews should or should not know the weak points on their targets. But it doesn't seem that anyone is arguing with this.

So if you accept that gun crews aim for center-of-mass, then logically it follows that in some cases, at short range, with a tank that has a relatively weak turret, then being hull-down is not always advantageous. That's not a quirk of Combat Mission. That's the real world (assuming gunners fire at center of mass).

Charles

[A Arabian]

Thanks, charles, for keeping tabs on this thread. I want to clarify - I suspect the BTS stance will be validated - and I COMPLETELY agree that the decrease in "to hit" isn't directly proportional to the decrease in shown SA. I just want to run some stats to convince myself the numbers work.

I fully admit this as my problem - I have a hard time thinking of 500 meters as "close", but when you're shooting a 6 kg projectile and have good rangefinding etc., its right next door.

Anyway, thanks again for addressing the issues. I've come around to the "company line" on this one I think, and I can be pretty damn hardheaded at times, so I think your case is pretty tight.

[This message has been edited by A Arabian (edited 12-16-2000).]

[This message has been edited by A Arabian (edited 12-16-2000).]

[Theron]

The tests look good. I beleive them, but I am suprised that the 1000m test didn't show that it is an advantage to be hull down. Given Steve's aiming explanation the 500m results make sense. Thanks to the members who did the tests. My computer is close to the minimal system so it takes a while to crank out a tank battle, especially when I need to do it repeatedly

Theron

[Mr. Clark]

Thanks Charles!

... and to everyone else here, I cannot believe we argued through 6 pages of posts to come to the conclusion that was stated in the opening post... and that CM is fine the way it is, as the quirk (aiming for a weak, hull down turret) is a real life one.

[Chupacabra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Mr. Clark:

Thanks Charles!

... and to everyone else here, I cannot believe we argued through 6 pages of posts to come to the conclusion that was stated in the opening post... and that CM is fine the way it is, as the quirk (aiming for a weak, hull down turret) is a real life one.<HR></BLOCKQUOTE>

Hrm, you've been on the board since September and you can't believe it?

------------------

Grand Poobah of the fresh fire of Heh.

[Mr. Clark]

Heh... Good Point Chupa!

[Guest Pillar]

The best part about CM is that the players and the developers have regular opportunity to debate, and shed light on the truth in order to make CM a better product. Of course, the fact that the developers are always right is just more tribute to the work Steve and Charles have done on the game

I'm impressed everytime I see this stuff going on. You don't see much of it in other game forums.

[Jarmo]

Charles quoted me.

[Jeff Duquette]

Shot dispersion at 500 meters should not change weather firing at a small or large target. So if a 90% dispersion pattern has a diameter of 1.5 meters over a target located at 500 meters it will still be 1.5 meters weather the target is 1 meter across or 10 meters across. Therefore if the dispersion pattern remains constant and target size decreases, a corresponding decrease in the probability of achieving a hit should result. What I seem to be reading is that even a target that is presenting a substantially reduced cross-sectional area (in the case of a hull down tank this would be reduced by as much as 60% to 80% of the targets hull-up cross-sectional area) the probability of hitting a substantially reduced cross-section is either not decreased at all – or is decreased only a cursory amount.

These are numbers collected by British Army Operational Research Sections during WWII (summarized in WO 291/180) Ranges are in yards, report indicates that the target is assumed to be a approximately the size of a Tiger Ie. Hit probability also assumes no crew error in line or range estimation.

Versus a Hull-Up static Target

6 pdr @ 500yrds…..100 percent chance of a First Round Hit (FRH: first round hit)

6 pdr @ 1000yrds…100 percent FRH

6 pdr @ 1500yrds…96 percent FRH

6 pdr @ 2000yrds…87 percent FRH

17 pdr @ 500yrds……100 percent FRH

17 pdr @ 1000yrds….100 percent FRH

17 pdr @ 1500yrds….100 percent FRH

17 pdr @ 2000yrds….98 percent FRH

17 pdr @ 2500yrds….93 percent FRH

Probability of a hit on first round, hull down static Tiger Ie sized target, assumed no error in line or range by crew.

Versus a Hull-down static Target

6 pdr @ 500yrds…..85 percent FRH

6 pdr @ 1000yrds…43 percent FRH

6 pdr @ 1500yrds…22 percent FRH

6 pdr @ 2000yrds…14 percent FRH

Versus a Hull-down static Target

17 pdr @ 500yrds…..88 percent FRH

17 pdr @ 1000yrds…51 percent FRH

17 pdr @ 1500yrds…29 percent FRH

17 pdr @ 2000yrds…18 percent FRH

17 pdr @ 2500yrds…12 percent FRH

Radical divergence in both cases from 500 to 1500 yrds

[This message has been edited by Jeff Duquette (edited 12-16-2000).]

[Guest Big Time Software]

Well, I for one still strongly disagree that Hull Down is something that should be avoided based on the turret and hull armor thickness vs. known enemy gun. The reason why is that these tests are far too clinical to carry over to the battlefield tactical assesement.

These tests assume (friendly = hull down, enemy = not hull down):

- friendly tank knows that it has been spoted

- friendly tank knows what the attacking weapon is

- the enemy tank is capable of penetrating the friendly's turret armor but not its hull armor

- friendly tank has an even or less than even chance of hitting the enemy tank before it hits it

- crew experience is either even or in favor of the enemy tank

- friendly tank will take no corrective action after being fired upon

- enemy tank is not being fired upon by any other weapon friendly to the hull down tank

- enemy tank remains in position and doesn't take any corrective defensive action

- friendly tank is incapable of shooting (in M. Hoffbauer's example at least)

- both vehicles are facing each other dead on

- enemy tank is not moving

Unless all this situations above are in place, it is statistically better to be in a hull down position REGARDLESS of armor in a real battle in CM.

To state this again very clearly...

Being hull down is NOT just about surviving a shot fired in its direction. It is all about being in an overall advantageous position. Being hull down has the following advantages

1. Avoid being detected. Easier to see a tank in an open field than in a hull down position. If you see the enemy first, advantage to friendly unit.

2. Avoid being hit. Smaller target presents a lower chance of being hit (NOT penetrated). This allows the friendly tank more chances to hit.

3. Quick cover. Quite often, hull down terrain allows the friendly unit to withdraw and instantly kill the enemy's line of sight/fire. A tank in the open has no such luxury.

A perfect REAL first hand example of this was posted a couple of weeks ago. It was a Panther in Normandy (SS div, forget which one). The commander used hull down positions to nail something like 5 Shermans which were out in the open. He utilized the three advantages above repeatedly throughout the engagement. However... at the range in question the Sherman's only chance of penetrating was the turret, not the highly sloped frontal hull armor. Yet, contrary to what some here wish to believe, the Panther commander knew that being hull down gave him the edge he needed.

So in conlcusion... it is my strong opinion that avoiding hull down opportunities, simply because of these static tests, is tactically unsound.

Steve

[This message has been edited by Big Time Software (edited 12-16-2000).]

[Mr. Clark]

I'm in agreement there Steve.

While I now understand (I think) what some others here have been saying, I will still always attempt to find a decent hull down location for my tanks whenever possible.

In actual gameplay settings (as you have described) I prefer the lessened chance to hit and other benefits of hull down positions, regardless of turret armor.

Once again using the "man in invulnerable bodysuit" example...

If the man only has two choices: hide with head sticking out, or charge enemy since only head can be hurt anyway... then it does not really matter which one he chooses.

However, since while standing in the open, he IS still vulnerable to the random head shot... it is always going to be to his advantage to use surprise, and duck and cover, and anything else he can think of to avoid being hit (or even shot at) altogether.

(I think for the next analogy I'll switch to a duck in a tea kettle... or perhaps a monkey in kevlar pajamas... maybe even a gerbil in a steel pipe... um... sorry, it's the cold medication)

[Rob Smith]

Now that I have run around the block several times screaming my frustration to the winds, I believe I may be able to discuss this topic "unemotionally".

Many of the posts in this topic have been helpful in realizing that I am not the only person suffering from the hopeless goal of obtaining a "realistic and accurate" simulation of wargaming. Although I believe CMBO to be the best example of the genre, I have once again been disappointed by the high claims of peerless realism. I was hoping for a game that would be more intrinsically driven by real world tactics than "random number generators". Even with the chaos of battle, I find the combat resolutions to be uneven and, at times, inexplicable.

I have studied Military History and hardware all my life (read NERD). I have even experienced the honor of interviewing some of the participants of the holocaust that was WWII. Infantry, Armor, Air Forces and Navy... from both sides, Axis and Allies. I currently maintain acquaintances with a few of them. I was reading specs on WWII hardware even before the first grade and have had some limited (thank God) experiences in Special Operations during my tour in the service. Enough of the knuckle dragging, macho, self-laudatory crap...

I set up a battle containing the classic Axis quality vs. the Allied quantity scenario. It pits King Tigers and Jagdtigers, with some small FJ infantry support, against nearly overwhelming Allied numbers in armor and infantry; M-18's, Sherman Jumbo 76's and T-26 Pershings. Even though I set the Allied experience at "Regular" and the Axis at "Elite", the performance of the Allied tankers in hitting AND spotting is disproportionally high. With all else being equal, i.e., unit location, terrain and distance, the performance advantage is still overwhelmingly in favor of the Allies. Even with a full klick separating the combatants, the computer will hit its target three to four times more often per unit than I can, regardless of my positioning. I can somewhat chalk this up to silouette factors, but I can tell you that if someone were shooting a cannon at me in the open, I would certainly be able to localize it after at least a couple of shots. The damage to my units is also unbalanced in comparison, especially considering the superior ballistics of the Axis' guns. Even with the gyrostabilizer on the Allied tanks, this is hard to explain.

The manual states that it is a good idea to let your units pick their own targets in most cases, yet I have watched as my KT targets a tank several hundred meters away, posing no immediate threat, while a M-18 sitting 119 yards away in the open takes three shots, killing my precious with a front turret penetration. I won't even get into how seemingly easy and consistently my units get their guns damaged.

This being said, CMBO is still the best representation in this genre by far. If I can keep from screaming obscenities at the computer at three a.m. which results in several blows to my head from my sleeping wife (maybe that's the source of my limitations), I will stubbornly continue to play it. Any suggestions, except the obvious clinical ones would be appreciated as I have only been playing this game for a short time. My apologies for the filibuster...I feel better now, really.

Thanks

[Jeff Duquette]

This is the above information from British Army Operational Research conducted during the war.

Probability of first round hit 6-pdr and 17-pdr vs. a Tiger I sized target -- real world test. Tiger assumed static and either hull-up or hull-down. There is a Radical drop off in hit probability between 500 and 1500 meters for targets that are hull-down. As can be seen there didn’t seem to be much advantage to being hull down relative to hull-up at ranges of less than 450 meters (500 yrds). Beyond 450 meters the probability of a first round hit on a static hull down target drops off radically.

As range increases the impact of real world range estimation errors will also increase radically -- something which has not been reflected in the above tables. This is further exacerbated by the relative cross-sectional area of a turret sized target relative to a turret plus hull sized target (i.e. a little slop in a range estimation for a target that is 3 meters high at a range of 1000 meters isn’t nearly as bad as a little slop in a range estimation for a 1 meter high target at 1000 meters).

It would be interesting if someone would re-run the game test at say 750 meters to determine relative advantage to being hull down. The emphasis of the tests should be collecting data on the number of hits to misses on both Hull-up and Hull-down targets.

[This message has been edited by Jeff Duquette (edited 12-16-2000).]

[Mr. Clark]

Rob, I usually (read ALWAYS) play Allies, and I can say from MUCH experience that I have had my poor Shermans KO'd time and time again within the first two or three turns by some sneaky, distant German tank or Gun or Armored vehicle.

I don't think your point was that Axis are somehow being screwed in this game, but just in case it was I wanted you to know that I've often banged my head in frustration against Axis armor.

As stated in the manual, no game could really EVER be 100% accurate to reality... because it's not reality. How can any game mirror reality, where virtually ANYTHING can happen, no matter how unlikely. However, I believe CM is definately the closest we are able to get right now.

From what I've read (not as extensive as your reading I'm sure) it seems that tank battles were often fast and furious, as found in CM... with only a few shots fired to disable or kill the enemy tank.

In A BLood Dimmed Tide, I recall an american tank gunner KO'ing 3 German tanks with 3 successive shots.

In Band Of Brothers and Curahee! I remember several accounts of Allied tanks heading out to kill a Tiger, only to be destroyed one after another by that one Tiger, even though they knew exactly where he was hiding.

I'm not sure where your frustration lies in the system, but in comparing my reading to games I've played, it seems CM comes very close to representing the kind of battles that took place. Victory could shift in a second to near defeat.

This is NOT a flame, I'm just hoping to throw some positive words at you. I'm not even sure I understood your post correctly (I'm heavily medicated right now, damn cold!)... but I'm also a reality buff, and I'm pretty darn happy with CM. It somehow reflects not only the strict stats and formulas for battle, but also tosses in an element of chaos and random luck.

[Lt Bull]

...sorry, was experimenting with inserting images in posts. Thought I was going to get a preview first

[This message has been edited by Lt Bull (edited 12-16-2000).]

[aka_tom_w]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Big Time Software:

To anyone who thinks that something is wrong with the way CM handles hull-down: please state how you would like to change things. Be very specific. I think this will help explain your points and should also help illustrate why CM is the way it is, and why we feel it's the best way.

Charles<HR></BLOCKQUOTE>

Hull down targets should take longer to acquire, perhaps after that the RoF should also be slower when attempting to continue to fire at hull down targets.

This TIME issue was mentioned earlier in this thread by Treeburst and I think it would grant the Hull Down tank ONE more slight advantage.

That is specifically how I would change the CM code, I thought I would mention that since you asked for specific suggestions.

So I would propose, if the target is hull down it takes longer to get the first shot off, and subsquent shots have a slower RoF to model the increased difficulty to aim at the smaller hull down target. Treeburst suggested this oringally and he spoke about the variable of TIME and I suspect he has REAL World ™ experience and I think the ONE additional advantage the Hull Down tanks should enjoy is the ability to the FIRST shot off, against a full exposed target, FASTER than the fully exposed (non H/D) Target can get the first shot off aginst the hull down taget.

I would suggest that if the Hull down crew was conscript and the exposed tank crew was Elite (the widest range possible in crew experinence I think) then the conscript hull down crew should still get the first shot off at least a second or two before the Elite crew aiming at the Hull down conscript crew. (or perhaps more realistically, the two crews might fire simultaneously?)

AND yes I completely agree that RANGE should be as large a variable, and play as large a role in determining the "chance to hit" percentage that it does, AND range should also be a variable in determining TIME to aim and acquire the (much smaller) hull down target at longer ranges.

This is really one of Treeburst's points so I'm just agreeing with his earlier post.

Yes I did read Steve's reply and I understand this is not do-able in the forseeable future.

I think that's unfortunate because it would really confer ONE more significant advantage on the hull down tank, making the choice to seek a hull down position much more desirable, because you should then be almost guarranteed (from the hull down position) to get the first shot off against the NON-Hull down, exposed target. That fact might then help the hull down position outweigh the "Well, I don't want to leave my vulnerable turret is exposed" issue.

Thanks again for V1.1b22

The TCP/IP pathc is GREAT and this game get's more and more addictive with every new patch and update.

-tom w

[This message has been edited by aka_tom_w (edited 12-17-2000).]

[Treeburst155]

Threads like this illustrate just how really good CM is. I would much rather debate the wisdom of a hull down position with certain units at certain ranges in certain situations than have to get on here and gripe about my tanks driving off bridges, etc.. Ya know what I mean, fellas?

Treeburst155

[aka_tom_w]

Well put Treeburst.

It is a GREAT game, and now even since the latest patch they are still working on it and updating it once again.

This is also a very informative thread, its even MORE interesting with postes here by Steve and Charles.

Great work guys

-tom w

[Jeff Duquette]

Take a look at WO 291/171 “Effectiveness of British anti-tank Guns” (British Army Operational Research, 1943ish). These diagrams basically combine REAL WORLD™ accuracy (“first round hit probability”) with weapon penetration capability. Both of these numbers are rolled into one number referred to as “Chance of Success” and compared to potential engagement ranges. In at least the case of the 17-pdr vs. the Panther REAL WORLD™ testing indicates the “Chance of Success” is higher vs. a hull down Panther than it is against a Full View Panther (hull-up) at short ranges.

The study focuses on 6-pdr and 17-pdr firing at: Tiger I, Panther, MkIVG, and MkIIIL. The Panther situation described above was the only odd ball case I could find.