Normandy: Immobilisations

[MikeyD]

I found a pict from that Marine cross country run. Doesn't unditching look like fun?

[Sgt Joch]

I found a pict from that Marine cross country run. Doesn't unditching look like fun?

plus that terrain looks fairly flat to have any problem with bogging, certainly would not be an issue in CMSF.

[undead reindeer cavalry]

No, but you're saying that B can be derived from A and I've made the case that you can not.

i'm not suggesting such derivation.

at one point it was argued that the difference in numbers would exist because most CM immobilizations would be fixed soon after battle and thus would not show in daily loss statistics. so if there was a difference of, say, 10:1 in CM immobs vs daily report losses, it would just mean that 9 out of 10 immobilizations would be fixed after the battle. it then just turned out that the difference in numbers was so huge that it would have been physically impossible there to be so many temporary immobilizations as required by that logic. this stuff probably confused you to think i was trying to speak for "B from A" derivation.

We're not even sure there is a 1:400 ratio since the data you used to come to that conclusion isn't properly documented.

i realize the docs are corps level stuff, but i doubt lower level stats give any more proper documentation unless we find studies based on log books of the individual T-34s. there are of course written remarks in Soviet unit diaries, but i can't remember reading about bogging other than losing tanks to craters, AT ditches, swamps or particularly muddy terrain (which doesn't mean that other bogging didn't happen or was rare, just that it wasn't something to be mentioned in those diaries).

then there's of course stuff like 6th GTA against Japanese in 1945, marching hundreds of km thru Mongolian desert & mountains, also during night in rain, in a couple of days -- but then again i don't have daily loss stats for 6th GTA for that period and it of course changes nothing because it wouldn't show temporary boggings (just awful terrain and weather conditions).

what comes to the CM part of the 1:400 ratio, it seems established that it's not accurate and the error was apparently caused by the huge difference in CM between dirt road and open ground immobilizations. some of Vulture's test results pretty much match 5th GTA results, though if something CM may see too few immobilizations (which itself is probably to be expected if CM does not simulate mechanical breakdowns).

the old linked CM test (apparently on open wet ground) gives 3.33% per km while Vulture's test on wet dirt road gives 0.008% per km. so CM open vs dirt road ratio on wet ground conditions would be, based on that available data, 416:1.

the other tests i talked about in the other post were CM tests i found with forum search. these non-Vulture tests don't have as high test run count as Vulture's tests so there's bound to be too much randomness in them. anyway, their 2.5% wet open ground losses give 323:1 ratio if compared to Vulture's dirt road tests.

it would be interesting to know what the dirt road:open ground ratio would be on larger test sets, and perhaps with damp or dry conditions as well. perhaps i'll try to install CMBB on a XP machine of mine so that i can run some tests myself (hopefully it won't mess the license).

needless to say the 1:300-400 ratio between dirt road and open ground is not realistic for a tracked vehicle (and T-34 is not just some vehicle what comes to cross country mobility). hopefully further tests will prove the numbers wrong.

Since better data can be got from the game by anybody caring to get it I don't find it even remotely productive to continue using questionable data.

like said, if your game would work properly on my Vista computers i would have done the tests myself.

You're saying that if a T-34 got stuck, the second that happened the crews got out and walked away? There was no attempt to do anything, even simple things, like fix a broken track link or have another tank give it a push? I find that hard to believe so I find your absolute statement to be a mischaracterization of reality. Reality may be that Soviet recovery and repair capabilities were extremely poor, but they weren't absolutely non-existent.

like said already a couple of times the Soviets were forced by circumstances to voluntarily abandon vehicles. ability to recover and repair is just one part of it -- it's as much caused by things like lack of fuel, ammo and spares.

a simplified example of the rationale is that if you have fuel for 1000 T-34 kilometers and your oders are to travel 40 km and you have 50 T-34s (so that you would need 2000 T-34 kilometers worth of fuel), instead of having all tanks run out of fuel after 20 km you simply abandon half of the tanks so that you have enough fuel to move the other half those full required 40 km. of course in the real world it's as much about other things as fuel, but the basic rationale of cannibalization is the same.

it's the result of the whole way Soviet tank industry, Red Army and Stalinist USSR were run those days. e.g. those running the factories were responsible to their life that given tank manufacturing goals were met (so they just make tanks, and care less about things like spare parts, tools etc). likewise, at the other end, a mech corps, tank corps or tank division commander would answer with his life that his unit would arrive at location X by time Y. the stuff in between the two result in recovery & repair assets to be in practice zero (as much due to simply missing equipment as missing training and general fubar caused by having untrained yes men run the show).

yeah, it may be an illogical position to reach, but what else do you do in those conditions? become a "trotskyite defeatist" shot without further questions?

anyway, it's not limited to early war Soviets. for example late war Germans at Ardennes do almost the same stuff; they could recover & repair tanks but they choose not to because they need to save fuel (at that point they also do stuff like tow fully working tanks with other tanks for the same reason).

[undead reindeer cavalry]

excellent find pamak1970! (the ORO report)

[Battlefront.com]

URC,

i'm not suggesting such derivation.

Sure you are I understood your point about saying "well, if there were x number of breakdowns that were recorded, it's hard to believe that there were hundreds more for each one of those that weren't recorded". I actually don't disagree with that sort of comparison. What am saying that you don't have valid numbers in hand to make that sort of comparison in the first place. Or put another way, the logic of the comparison is fine, the numbers (input) you're using is the part I take issue with.

First, it was a small sample and even the guy who did it can't remember what the exact conditions were. Therefore, we have no idea if the results from this small test actually portray. This invalidates the sample completely IMHO, especially because new samples can be so easily obtained. Therefore, from the very start I've been saying that the numbers you were using to compare against the Soviet figures weren't good enough to draw any conclusions from. So that 1:400 ratio is meaningless.

Second, you can not compare road march numbers to off road combat numbers at all. They simply aren't in the same class, therefore you can not extrapolate data from one set (based on KM travelled) with data from the other set (based on KM travelled). In order to do that you'd need to know such things as what is the average length of off road travel at one time? How often is maintenance performed per KM when using a vehicle off road vs. on road? Is there a difference between cutting across a field without being shot at vs. evasive maneuvers because of enemy activity? There are lots of variables here which need to be accounted for and yet we don't have that sort of data. Therefore, it is pointless to compare on road march data to off road game tests.

Third, we have to remember the differences that come about from using small samples. The example of the Marines bogging down in one battle in OIF 1 is a perfect illustration of that and I've already explained that in detail.

So it comes back to the requirement of needing to stick to apples to apples and oranges to oranges comparisons. Therefore, any conclusions (1:400 or otherwise) you try to draw from an apples to oranges comparison is going to fail to impress me because it's statistically invalid. And it's so very, very easy to show that it is.

needless to say the 1:300-400 ratio between dirt road and open ground is not realistic for a tracked vehicle (and T-34 is not just some vehicle what comes to cross country mobility). hopefully further tests will prove the numbers wrong.

Again, this is very wrong headed. You've come up with a number which is statistically meaningless and then try to hold it up as something we should benchmark against. The step you've skipped is validating the benchmark. What I've done is shown, very easily, that the benchmark you came up with is invalid. I mean that in the most strict sense of the word... you might as well produce a number at random for all the validity 1:300 or 1:400 holds.

like said already a couple of times the Soviets were forced by circumstances to voluntarily abandon vehicles. ability to recover and repair is just one part of it -- it's as much caused by things like lack of fuel, ammo and spares.

Absolutely. And the Korean numbers we just were exposed to shows the same thing for the UN forces when they were on the defensive. I don't have a problem with that at all since it's not only logical but it's a well proven historical fact that the primary benefit of a rapid advance is a disproportional negative effect on the enemy's retreat. One of the most common signs of this is the abandonment of equipment. Look at Kampfgruppe Peiper. They had to "scuttle" most of their King Tigers simply because they ran out of petrol. Or the few remaining Tigers that escaped Normandy had to be abandoned at the Seine because they didn't have time to find a bridge with the capacity to get them to the other side, nor did they have engineering assets to ferry them over.

My point is your position was rather absolute. And that is that the first 20 seconds something got bogged it would be abandoned because they would give up trying to free their own vehicle or have a buddy tank give them a shove. As high as the attrition rate might have been from breakdowns and boggings (and I agree for the Soviets in 1941 it was catastrophic), I find it impossible to believe that there was "zero" recovery in the context of bogging/immobilization as discussed in this thread. Not that it matters because this is a point which is completely irrelevant to the discussion

Steve

[pamak1970]

I found the link describing in detail the Nasiriya incident and the trafficability issues.

The only thing is that it is about trafficability issues of trucks of the 507 Maint company, but it is still a good read. We do not have combat vehicles here.

It is the following

www.army.mil/features/507thMaintCmpy/AttackOnThe507MaintCmpy.pdf

On another issue, unfortunately i do not have any indication that can link high level recovery (cause of bogging issues) statistics to low level ones which can happen at tactical level and never revealed in high level reports.

I only have a rough approximation of repair and recovery figures in general from a modern US manual.

Without having it near me , from what i recall ( i may be somewhat off for certain numbers), it categorizes repair jobs in three groups, That is low-mid and high level. The proposed time threshold for each level is , 0-4 hours (or 0-2 not sure) for accomplishing a low level job. This is the job performed by crews and up to company support personel on the frontline. The next level is for jobs between 4-12 hours and the higher level (division and up) is for jobs requiring over 12 hours .

The rule of thumb is that repair-recovery jobs are distributed about equally between those categories. One third will be accomplished at low level (and most probably will not be recorded in high level reports), another third will be accomplished at mid level support units (battalion brigade) and the last third at division and above levels.

So a high level report showing x number of repair-recovery jobs by high level support units , implies actually a total of 3*X number of repair jobs occuring at tactical level. One third of those is serious enough to be forwarded to high level recovery and repair echelons.

Now if we knew that this could apply also to number of bogging issues .......

[Battlefront.com]

Pamak1970,

More good stuff, thanks!

So a high level report showing x number of repair-recovery jobs by high level support units , implies actually a total of 3*X number of repair jobs.

All makes sense to me. We do this for figuring out distribution of casualties (light, medium, serious, and fatal) since there's pretty good data for types of wounds by cause. That's the sort of thing URC is attempt to do, but without valid data.

Now if we knew that this could apply also to number of bogging issues

IF ONLY The problem is that this sort of stuff doesn't exist, as far as I can tell, because it's not important enough to spend the energy documenting. Mechanical breakdowns, on the other hand, are critically important to document since it impacts logistics in a massive way. Also, after operations commence the documentation is automatic because at least the 2nd and 3rd classifications of mechanical breakdowns involve standardized paperwork which can be very easily tabulated at their leisure.

The problem I have with repair statistics is that they tend to be fairly broad, as the Korean figures you noted already are. It makes sense, too, because generally speaking a repair shop doesn't care if a wheel rim and axel bearing were damaged due to rough terrain, operator error, AP mine, shell fragments, etc. To the repair shop the damage is what matters, not the cause of it. However, those standardized forms do include places to explain how the damage happened because that sort of thing is utilized for other purposes. Whether it's tabulated or not is a different story.

And of course... small time boggings and crew affected repairs are just not important enough to make note of. There are practical reasons for this. One of them is, IMHO, that they are just too common to make a fuss over. Kinda like noting how many soldiers have their bowels tighten up after eating MREs for too long. As far as I know there aren't reliable statistics on the ease of "evacuation". If there is such a report, I'd actually rather not delve into it

Steve

[MikeyD]

There's also a difference between bogging along the march route and bogging at 'the tip of the spear'. In one, someone uses his buddy's winch to unditch him and he's on his way again in no time (barring breakage). In the other, it takes an act of medal-worthy heroism just to crawl out the the ditch you're hiding in! It would be tempting to leave your stuck Stryker where its sitting until after the engagement is over.

[undead reindeer cavalry]

Or put another way, the logic of the comparison is fine, the numbers (input) you're using is the part I take issue with.

i agree and it would be great to have better numbers.

what comes to historical terrain & weather conditions it's a bit hard. weather information for Kursk itself is relatively easy to find (muddy still in 6th, 7-9th mostly dry, then again shower rains on 10th). it's harder to find precise weather and terrain information on 5th GTA's march route.

i think it's fair to assume the ground conditions (on CM terms) was something between damp and muddy, possibly leaning towards wet or worse because all those hundreds of vehicles have made an impact on the march terrain.

what comes to CM, it would be interesting to find time to do extensive tests on the effect made by both weather and ground condition settings. (e.g. is damp ground + rain equal to wet ground + overcast).

First, it was a small sample and even the guy who did it can't remember what the exact conditions were. Therefore, we have no idea if the results from this small test actually portray. This invalidates the sample completely IMHO, especially because new samples can be so easily obtained. Therefore, from the very start I've been saying that the numbers you were using to compare against the Soviet figures weren't good enough to draw any conclusions from.

i installed CMBB on XP machine yesterday and did some tests. not as many as i would have liked, but still better than those available previously.

CM test setting: July 1943, wet open ground, regular T-34s. 25 x T-34, 4 km distance, all on move orders (for crews to be as careful as possible). run it three times, with 8 (32%), 6 (24%) and 5 (20%) immobilizations as a result. average loss rate was thus 6.3333% per km.

master Vulture's extensive CM tests on wet dirt road gave losses of 0.008% per km.

the ratio, based on these numbers, between CM wet dirt road and CM wet open terrain immobilizations for T-34s would thus be 1:792.

so these tests give actually twice as bad result as that earlier linked test. if this ratio can be established by further tests to be about right, i think you will agree that the ratio is not too realistic.

Second, you can not compare road march numbers to off road combat numbers at all. They simply aren't in the same class, therefore you can not extrapolate data from one set (based on KM travelled) with data from the other set (based on KM travelled). In order to do that you'd need to know such things as what is the average length of off road travel at one time? How often is maintenance performed per KM when using a vehicle off road vs. on road? Is there a difference between cutting across a field without being shot at vs. evasive maneuvers because of enemy activity? There are lots of variables here which need to be accounted for and yet we don't have that sort of data. Therefore, it is pointless to compare on road march data to off road game tests.

yes, there are a lot of variables but i don't think it's all pointless.

i'm not sure i understand the combat conditions stuff, because there is no combat going in CM tests and it seems that CM doesn't simulate stress caused by combat conditions as such (for example zero immobs on dry roads). but i'll see if i can find some worthwhile numbers about combat vs non-combat losses.

i agree that road vs cross country travel is subject worth looking at, though i don't believe at all that it could lead in real world to such differences as seen in CM tests.

i am still semi-actively looking for good Soviet data (i have a couple of good pointers already, but it's a bitch to try to find old Soviet documents about these types of marginal subjects).

i'll see if i can find some good numbers about cross country stuff in combat conditions as well. something with measurable distances and clear loss numbers.

Third, we have to remember the differences that come about from using small samples. The example of the Marines bogging down in one battle in OIF 1 is a perfect illustration of that and I've already explained that in detail.

So it comes back to the requirement of needing to stick to apples to apples and oranges to oranges comparisons. Therefore, any conclusions (1:400 or otherwise) you try to draw from an apples to oranges comparison is going to fail to impress me because it's statistically invalid. And it's so very, very easy to show that it is.

i guess you are talking about small samples in CM tests?

Absolutely. And the Korean numbers we just were exposed to shows the same thing for the UN forces when they were on the defensive.

Soviets are the ones attacking, though. all the stuff i have seen about Soviet studies would seem to indicate that it's almost totally about losses when attacking.

tank attrition not caused by enemy would be around 0.5% per km for early war (from 1941 up till early 1943). by the end of war it would drop to around 0.15% per km, mostly due to improved repair & recovery, maintenance, logistical and road repair assets.

Glantz talks about this in a number of his books, so it seems he thinks it's important. it's presented as something the Soviet higher ups spend a lot of time investigating (and learning lessons from) and the resulting changes made quite a difference for Red Army tank forces.

I find it impossible to believe that there was "zero" recovery in the context of bogging/immobilization as discussed in this thread.

yes it would not be zero, but it most likely would not be very high number either.

BTW don't take this stuff as bashing of CM. it's hands down the best game of its kind and personally i haven't been annoyed by bogging or immobilizations. if something, i have often wished there to be more of them. all too often i have driven a heavy vehicle up a relatively steep slope and frequently have made sharp high speed turns which almost certainly would have lead to throwing of a track in real world. quite often i have been forced by circumstanced to cross bad terrain with tanks and have wished, with no luck, that the tanks would get stuck.

[dieseltaylor]

Your percentages agree with mine for wet.

Incidentally I do wonder if very large number tests - 100 tanks per time actually obscure the average effect in battle. I have used dozen, tens and twenties and it seems to me that low figures record higher. Not logical but then in coding who knows what gremlins occur. : )

I also find the immobs. are front loaded. Arguably with less tanks going further into the game the problem would be less anyway but allowing for that perception it does appear front-loading exists.

Just an observation. And yes CMAK is a great game. CMBB I am not fond of!

[TheVulture]

Your percentages agree with mine for wet.

Incidentally I do wonder if very large number tests - 100 tanks per time actually obscure the average effect in battle. I have used dozen, tens and twenties and it seems to me that low figures record higher. Not logical but then in coding who knows what gremlins occur. : )

I also find the immobs. are front loaded. Arguably with less tanks going further into the game the problem would be less anyway but allowing for that perception it does appear front-loading exists.

I did notice in my tests that a fair number occured almost immediately as the tanks started moving. From memory, 3 or 4 tanks bogged wiothin the first tile, out of the 60 or so total boggings observed. Since the map was 200 tiles long, you'd expect 0.3 tanks to bog in the first tile - 10 times higher is pretty significant.

Recollection isn't great data though, so might be worth testing. But it raises the possibility that tanks have a higher probability of bogging when accelerating, or just starting a new movement order from a waypoint (or, indeed, when turning). Since precious few tank movements in game involve single 4 km fast moves along a straight road, the bog rates for tanks doing stop-start moves, multiple waypoints, turning etc. may be considerably higher.

Just an observation. And yes CMAK is a great game. CMBB I am not fond of!

Burn the heretic!

[undead reindeer cavalry]

Incidentally I do wonder if very large number tests - 100 tanks per time actually obscure the average effect in battle. I have used dozen, tens and twenties and it seems to me that low figures record higher. Not logical but then in coding who knows what gremlins occur. : )

I also find the immobs. are front loaded. Arguably with less tanks going further into the game the problem would be less anyway but allowing for that perception it does appear front-loading exists.

i actually made more tests than just the wet ground ones, but didn't find time to make enough of them just yet. when doing those tests i also felt there was something strange about how immobs and boggings happened, but didn't have time to investigate it further and just took it as my mind doing tricks on me.

i wonder if there is something in the code that is made on a turn or battle level instead of calculating all the stuf "as it happens" during any given single turn for any given vehicle.

when i was searching for old CM bogging tests i encountered a couple of posts which dealed with a bug that was apparently fixed later. the bug was that the number of boggings / immobilizations was directly tied to the number of vehicles moving at the same time (or something like that). perhaps the bogging / immobilization code works in a way that we are not expecting at all, and thus we see some "statistical noise".

[undead reindeer cavalry]

I did notice in my tests that a fair number occured almost immediately as the tanks started moving. From memory, 3 or 4 tanks bogged wiothin the first tile, out of the 60 or so total boggings observed. Since the map was 200 tiles long, you'd expect 0.3 tanks to bog in the first tile - 10 times higher is pretty significant.

Recollection isn't great data though, so might be worth testing. But it raises the possibility that tanks have a higher probability of bogging when accelerating, or just starting a new movement order from a waypoint (or, indeed, when turning). Since precious few tank movements in game involve single 4 km fast moves along a straight road, the bog rates for tanks doing stop-start moves, multiple waypoints, turning etc. may be considerably higher.

i ended up using both 1 km and 2 km tests maps because i thought something like this might be happening. so per 4 km travelled there would be either 2 or 4 orders and turns.

a bit disappointingly, but not unexpectedly, i didn't see a single bogging when tanks were rotating at place. i thought about giving rotating orders per every 100 meter travelled, or something like it, but simply didn't have time for it yet.

from my limited tests i didn't see any clear statistical evidence that results between 1, 2 and 4 km maps would be different, but i did observe the possibility.

i guess there might be something into stuff like this. perhaps it's not just statistical noise. it would be tough to find by testing though, especially if there are some counters that are set when a battle is started (so that you couldn't use save games and had to plot complex move orders every single time).

BTW in those other tests i also observed quite large differences in results between test runs (each started as a new battle, no save games used), but again took it just as statistical noise. for example i did two tests with fast orders on wet open ground and the other gave 1 immob (with subjective impression that there were barely no boggings at all) and the other 8 (with subjective impression that there were a lot of boggings).

[Battlefront.com]

URC,

i agree and it would be great to have better numbers.

You bet it would What we have to be cautious about is taking a square peg and trying to fit it into a round hole simply because the only things available are square pegs and and round holes. Which is at the heart of our debate about how to use the Soviet data.

what comes to historical terrain & weather conditions it's a bit hard. weather information for Kursk itself is relatively easy to find (muddy still in 6th, 7-9th mostly dry, then again shower rains on 10th). it's harder to find precise weather and terrain information on 5th GTA's march route.

But regardless, it's still a road march. Which I'll get to in a second.

i think it's fair to assume the ground conditions (on CM terms) was something between damp and muddy, possibly leaning towards wet or worse because all those hundreds of vehicles have made an impact on the march terrain.

Hard to tell. A few days of good, warm weather followed by a day of heavy rain doesn't do much for a packed down surface, but does HUGE things for loose soil. Worse, the differences are highly situationally dependent. No two roads are likely to be affected the same way for their entire length. Engineers routinely are called in to high trafficked areas to fix soft spots in the march route. The infamous "corduroy roads" built in your country and northern Russia are extreme examples of that.

i installed CMBB on XP machine yesterday and did some tests. not as many as i would have liked, but still better than those available previously.

Excellent! So now you can go back and test in more relevant conditions than what you did here:

CM test setting: July 1943, wet open ground, regular T-34s. 25 x T-34, 4 km distance, all on move orders (for crews to be as careful as possible). run it three times, with 8 (32%), 6 (24%) and 5 (20%) immobilizations as a result. average loss rate was thus 6.3333% per km.

master Vulture's extensive CM tests on wet dirt road gave losses of 0.008% per km.

the ratio, based on these numbers, between CM wet dirt road and CM wet open terrain immobilizations for T-34s would thus be 1:792.

so these tests give actually twice as bad result as that earlier linked test. if this ratio can be established by further tests to be about right, i think you will agree that the ratio is not too realistic.

Of course it isn't too realistic because you apparently still don't know how to compare apples to apples. There is no way, no how, that the Soviet experience (or The Vulture's approximation of it) is equal to vehicles driving off road in wet ground. Therefore, testing driving off road in wet terrain will give you a data sample that has nothing to do with the Soviet sample you're comparing to. Let me try to explain this again.

If I told you that I had data that showed a tracked vehicle of a particular size had an 20% chance of bogging within 1km in wet open ground, what would you expect the bog rate to be? 20%, correct? If the game produced the result of 20%, would that not be an accurate result? Sure it would be. So what difference does it make if you look at another sample from roads and find the ratio to be horrendously off? It doesn't make any difference at all because YOU SHOULD EXPECT THE RESULTS TO BE WAY OFF.

Look at the example from Iraq a few pages back. Look at my explanation as to why it matters, more than anything else being discussed, to compare apples to apples. If you set up a situation which duplicated that of Nassiriyah, and drove Abrams, Bradleys, Humvees, and M-88 recovery vehicles into a particular area, you should expect 100% bogging within side of 100m traveled. That's fine, right? But what happens when you take that one incident and compare it to the average immobilizations for the entire OIF Campaign? Well, you're going to find one Hell of a ratio difference, aren't you?

That doesn't mean that the game is wrong, it means the statistical analysis you're making is wrong. What the resulting data tells you is that campaign wide there was very little bogging, which is true. But looking at that one battle of Nassiriyah that wonderful low rate doesn't apply because the bogging rate there was massive. That is also true. So as long as you compare the correct things to each other the data makes sense. But if you instead try to determine the realism of the boggings in Nassiriyah based on the overall figures... well, you'll come to the wrong conclusions.

I'll say this again for the 100th time... you can not extrapolate on road march conditions to equate to off road combat conditions unless you also account for dozens of other variables. The more these variables are pulled out of an arse, the less valid the comparison becomes. Since the range of variables needed in this case are absent, or at least certainly haven't been presented here so far, there isn't any meaningful results to be had by comparing the operational Soviet data with the sorts of CM game results tested against thus far EXCEPT, to some extent, the numbers from The Vulture's road tests (which themselves weren't perfect).

Honestly, I don't understand why this is so hard to grasp. It's pretty self evident to me that you can't compare things willy nilly to each other and expect meaningful results. Especially when you CAN do better tests. For example:

Try moving a large number of T-34s off road in dry ground for long distances. Take those numbers and compare them against the Soviet figures and see what we get. Then, from there, take into consideration (to some extent) basic variables such as how many of those vehicles would be recovered before being written off as losses. We have to guess at that, but the Korean numbers do give an indication as to roughly how many of them would be.

i'm not sure i understand the combat conditions stuff, because there is no combat going in CM tests and it seems that CM doesn't simulate stress caused by combat conditions as such (for example zero immobs on dry roads).

Combat Mission assumes that all vehicles are operating in combat conditions. This means a lot of things such as lack of sufficient route recon, less than 100% attention on movement, subtle changes in direction instead of straight forward driving, more willingness to go along the best combat path rather than best travel path, etc. Driving down a road, even in a combat situation, gets rid of tons of variables. The biggest one being terrain variations which directly lead to bogging.

i agree that road vs cross country travel is subject worth looking at, though i don't believe at all that it could lead in real world to such differences as seen in CM tests.

Argh... no, it's not "worth while" it is THE CENTRAL ISSUE THAT MUST BE ACCOUNTED FOR. Until then you're just causing us to go absolutely nowhere the long way around.

i guess you are talking about small samples in CM tests?

Yes. The earlier test, which I think should just be discarded anyway, was too small to go from.

Soviets are the ones attacking, though. all the stuff i have seen about Soviet studies would seem to indicate that it's almost totally about losses when attacking.

By 1943 the Soviets had sufficient skills to recover broken down/immobilized vehicles to differing degrees dependent upon specific circumstances. To assume they had near zero recovery and repair capabilities will need a rather detailed response from you in order for me to have much faith in.

Glantz talks about this in a number of his books, so it seems he thinks it's important. it's presented as something the Soviet higher ups spend a lot of time investigating (and learning lessons from) and the resulting changes made quite a difference for Red Army tank forces.

Correct, but they still aren't out there with clipboards recording how many times a tank gets stuck for 5 minutes. That's my point... the statistics that matter are the same ones they were detailing... how many vehicles available this morning are not available tomorrow morning. THAT is very important, but it isn't the same thing that CM is concerned with.

BTW don't take this stuff as bashing of CM. it's hands down the best game of its kind and personally i haven't been annoyed by bogging or immobilizations. if something, i have often wished there to be more of them. all too often i have driven a heavy vehicle up a relatively steep slope and frequently have made sharp high speed turns which almost certainly would have lead to throwing of a track in real world. quite often i have been forced by circumstanced to cross bad terrain with tanks and have wished, with no luck, that the tanks would get stuck.

Noted and I thank you for that. However, as I've said since the start of this discussion I really don't care what the bogging rate in CMBB was since CMBB is our past. If it was too high or low it doesn't matter because we're not going to change it. We also know that it didn't affect the enjoyment of the game in any significant way, even by people like PaulAU, because they would have stopped playing the game years and years ago. What I'm trying to do here is ensure that the discussion about bogging/immobilizations is meaningful and doesn't contribute to the sort of unfounded point of view that PaulAU has that bogging is completely random, happens all the time, and makes the game unenjoyable.

This has narrowed down to me trying to keep your explorations relevant by insisting on minimum "scientific" standards. I've got more than 10 years experience with people making honest, but completely flawed, tests which lead to absolutely wrong conclusions. Now, maybe you're right that even with carefully considered tests there's a problem... but the tests thus far have been so flawed that they are meaningless for such a conclusion at this stage.

Steve

[pamak1970]

"Correct, but they still aren't out there with clipboards recording how many times a tank gets stuck for 5 minutes. That's my point... the statistics that matter are the same ones they were detailing... how many vehicles available this morning are not available tomorrow morning. THAT is very important, but it isn't the same thing that CM is concerned with.

"

Adding to this i recall in one of my books describing small unit tank actions , the case of a German attack where the company commander was forced to change four different tanks during the attack.

However, the after action report of the unit for the day reports less than four tanks out of action (total losses and damaged) ). I think it was something like one total loss and one damaged.

I do not recall the specific details but i do recall that i noticed the difference when i first read about the incident.

Obviously (since the commander was forced to change four tanks) and since the aar gives less than four casualties, some portion of those vehicles abandoned by the commander were put back into action before the writing of the AAR.

[Apocal]

Perhaps URC should try running two miles in wet sand and (after resting) running two miles on paved road for an example of just why his analysis doesn't hold merit?

[Battlefront.com]

Or just run 2 miles anywhere in Finland except a road, then 2 miles on any road in Finland. I live in an area similar to Finland (slightly less vodka) so I know that you can't go more than a few feet before getting tripped up on something. And that's not even including Reindeer

Steve

[Battlefront.com]

Oh, forgot this one from URC,

[when i was searching for old CM bogging tests i encountered a couple of posts which dealed with a bug that was apparently fixed later. the bug was that the number of boggings / immobilizations was directly tied to the number of vehicles moving at the same time (or something like that). perhaps the bogging / immobilization code works in a way that we are not expecting at all, and thus we see some "statistical noise".

I vaguely remember that one. IIRC there was a "random seed" that wasn't being properly reset. If so then the issue was a programming issue which was obviously wrong and fixed, not a design issue which was wrong and fixed.

Steve

[undead reindeer cavalry]

Steve,

i don't believe for a second that you'd think i don't realize the difference between driving on road and cross country. or that there are dozens of other variables to consider, that not all CM immobilizations would show as daily losses, not all tanks would be abandoned by Soviets in 1941, that you can't directly compare road march stats to CM stats etc etc. it's stating the obvious. it's as if you are just trying to cover the actual data in meanigless discussion about the obvious.

[undead reindeer cavalry]

Perhaps URC should try running two miles in wet sand and (after resting) running two miles on paved road for an example of just why his analysis doesn't hold merit?

har har har. ok, let's make this easier for the bypassers:

- these are T-34 tests. T-34 is universally considered to have exceptionally good cross country mobility.

- it's not wet sand, it's "open ground" CM tiles. it's not crop fields, rocky ground, soft ground, swamp, scattered trees or even just bushes.

- it's compared to dirt road, which specifically is not paved road in CM.

- ground conditions for both "open ground" and "dirt road" tests are "wet". it's not "deep mud" or "mud" or "snow" or "deep snow". for those interested, yes, T-34s were regularly and succesfully operated in worse conditions than "wet open ground in summer".

- these CM tests show that for each single T-34 immobilization on wet "dirt road" you get around 800 immobilization on wet "open ground".

- yes, difference between results is of course expected. but this kind of difference is certainly not expected.

[Ron]

CM test setting: July 1943, wet open ground, regular T-34s. 25 x T-34, 4 km distance, all on move orders (for crews to be as careful as possible). run it three times, with 8 (32%), 6 (24%) and 5 (20%) immobilizations as a result. average loss rate was thus 6.3333% per km.

Looking at something three times and basing your conclusions on that doesn't seem very representative, even if that turns out to be the general trend.

[TheVulture]

Looking at something three times and basing your conclusions on that doesn't seem very representative, even if that turns out to be the general trend.

Looking at 75 separate 4 km tank drives (which is what he did, 25 per run) is much more representative though. 19 immobilisations in 300 km - one every 15.8 +/- 3.6 km. That's enough stats to be pretty reliable.

[undead reindeer cavalry]

Looking at something three times and basing your conclusions on that doesn't seem very representative, even if that turns out to be the general trend.

yes, like i said myself in the post you quoted, i didn't have time to make as many tests as i'd have liked to. still, like i said a bit later, i actually did more than those three tests (with a bit different settings).

the trend appeared established with all the tests, so the numbers were good enough to post just to have some initial numbers. not least because my tests were still a lot larger than those tests i could find with forum search functions.

what comes to the issue itself, it hardly makes a difference if the actual numbers turned to be just, say, half or twice that of my numbers.

[Battlefront.com]

URC,

what comes to the issue itself, it hardly makes a difference if the actual numbers turned to be just, say, half or twice that of my numbers.

It makes a difference what you're comparing the number against. Since you are not comparing the wet ground numbers to relevant real world numbers (i.e. not the Soviet data), then it's numbers in a vacuum. That's what I detailed on the previous page.

So... does someone want to test on dry open ground and compare those numbers to the Soviet figures? Without further clarifications the comparison is utterly meaningless, but with some extremely rough guesswork I think we can at least have a better comparison than we've been able to have so far with bad ingame data.

Steve

[Redwolf]

- these are T-34 tests. T-34 is universally considered to have exceptionally good cross country mobility.

That is not quite true.

The T-34 had wide tracks and large diameter road wheels. That makes for an even, low ground pressure and that makes it drive well across even soft ground.

However, the Christie suspension suffers from the classic problem of plain mounted springs: they get softer as they compress. What you would want is for them to get harder as they compress. The result is that if you drive a tank with the softening springs over uneven ground, then the whole tank tilts more (it falls harder into depressions) and it tears up the ground even more.

This is also the reason for the terrible performance of the initial Shermans, which had this problem and combined it with small road wheels and narrow tracks.

This is the main reason why the Germans went through all the trouble with their fancy suspensions. As road wheels get pressured in you want resistance to stiffen, not weaken.

The T-34 also had low ground clearance which mixes very badly with that suspension characteristic which lets it fall deep into uneven ground.

%%

As a result there is no such thing as just "good" or "bad" cross-country performance. There is a huge difference between going over soft but even ground, which the T-34 is really good at, and going through complex terrain without bumping hard into everything, losing kinetic energy and tearing up the ground even more.

I think that some of the irritation about CMBB's bogging also came from oversimplifying this model. Just using weight/track-surface leaves you with an inaccurate picture.

Great discussion.