Bogging and Immobilized: is it right?

[A Canadian Cat]

Started to do some testing: map 4x1km 55 M4A3 75(W) mid Sherman tanks (since they seem to perform so badly):

drive per test 16 km with 55 tanks = cumulated 880 km

Ground: Very dry grass (as reference test)

Excellent, taking out the high risk areas shows that there is a chance to become immobilized even on good ground. So, my thoughts on this are that something is not correct. As I said before I have no evidence so it could be that this just happens Shermans IRL. But it does not feel right to me. Now under wet conditions I can see there being issues but when it is all dry grass it just seems odd.

Does anyone have any WWII sources about immobilization issues that would indicate this is OK or that it is not?

[A Canadian Cat]

I completed the fast dry tests with wheeled vehicles.

Here are the updated results (some of it repeats the first post data):

Percentage of operational vehicles when traveling 7km over the test course

[B]Vehicle	Conditions / Speed

	Dry

	Fast	Slow[/B]

Sherman	22.67%	30.67%

Panther	44.00%	37.33%

PzIV	36.00%	29.33%

Puma	25.33%

M8	17.33%

Looks like in general the wheeled vehicles did worse (Puma about the same as the Sherman)

Of the vehicles that became Immobilized; here is the break down between terrain types the immobilization occurred.

Sherman

[B]	Fast	Slow[/B]

Mud	34.67%	26.67%

Sand	 2.67%	 0%

Rocky	 2.67%	 0%

GrassXT	 2.67%	 0%

Ford	34.67%	42.67%

Panther

[B]	Fast	Slow[/B]

Mud	28.00%	26.67%

Sand	 1.33%	 0%

Rocky	 0.00%	 0%

GrassXT	 0.00%	 2.67%

Ford	26.67%	33.33%

PzIV

[B]	Fast	Slow[/B]

Mud	38.67%	28.00%

Sand	 0.00%	 0%

Rocky	 0.00%	 0%

GrassXT	 0.00%	 4.00%

Ford	25.33%	38.67%

Puma

[B]	Fast[/B]

Mud	30.67%

Sand	 0.00%

Rocky	 0.00%

GrassXT	 1.33%

Ford	42.67%

M8

[B]	Fast[/B]

Mud	30.67%

Sand	 0.00%

Rocky	 0.00%

GrassXT	 1.33%

Ford	50.67%

[YankeeDog]

Excellent, taking out the high risk areas shows that there is a chance to become immobilized even on good ground. So, my thoughts on this are that something is not correct. As I said before I have no evidence so it could be that this just happens Shermans IRL. But it does not feel right to me. Now under wet conditions I can see there being issues but when it is all dry grass it just seems odd.

Does anyone have any WWII sources about immobilization issues that would indicate this is OK or that it is not?

He had more or less a full tank battalion do a 16km march across open ground (note: open ground =/= a road) going full-out, hell-bent-for-leather speed and still experienced only 2 immobilizations. That's pretty darn good in my book.

In short; IMHO yes, there should be some chance of immobilizing on dry, good ground and the rates in this dry ground reference test don't concern me at all. I couldn't quote exact historical rates, but an average 1 immobilization/440km high-speed travel seems like a pretty generous treatment of cross country travel to me. Heck, over travel distances like this, I would expect some immobilizations due to mechanical failure even if the travel were on a good, graded road. Tracks are notoriously high maintenance.

I have seen some figures for breakdowns on road marches, but these aren't necessarily comparable, because it's hard to know the conditions these road marches were done under, and at what speed.

[A Canadian Cat]

He had more or less a full tank battalion do a 16km march across open ground (note: open ground =/= a road) going full-out, hell-bent-for-leather speed and still experienced only 2 immobilizations. That's pretty darn good in my book.

Thanks for your perspective. You are right the percentage is very low. It will be interesting to see how other tank types compare.

[winkelried]

1 Immo on 440 km at 30 km/h cross country seems low to me. The tracks in WW 2 had a lifetime somewhere at 800 km AFAIK. BTW in the test tracks don't degrade at least not in the damage tab.

And a lot of other stuff can fail - except grass is considered to be like a golf green :-)

[Erwin]

AKD: I am in the final scenarios of the HOFFNUNG Campaign, and I did have 20%-30% (ie 2-3 tanks bogged/immobilized in every prior scenario (even when moving SLOW) to the point that I became nervous about moving them at all.

Maybe I was just unlucky. But, it spoils the fun/entertainment/relaxation aspect of the game (for me).

Counter-intiuitively, the wheeled vehicles seemed to be able to move as fast as one wanted on any terrain with hardly any bogging and no immobiliizations at all.

The problem with going on about "realism" is that CM series is NOT realiistic. There are tons of abstractions and gameplay compromises that had to be made to make something fun that can be played on a PC for a reasonable COTS cost.

The latest discovery I made is that one reverse a truck with a gun up to a hedge and have the gun dismount across the hedge in the next field. I need to see if I can do the same with infantry. Does it annoy me that this is "unrealistic?" Not at all - cos it doesn't destroy the fun of the game and it doesn't irritate me.

The old saw about justifying some irritating/time-wasting phenomena because it's "realistic" just doesn't cut it. This is an entertainment product and it's full of holes and compromises like ALL entertainment products.

[winkelried]

@Erwin: i lost some tanks too due to bogging/immobilized in this campaign. i don't care too much about this since it happened usually in sitiations where i pushed the equipment too hard. What i didn't like, was that i didn't get back at least some of the bogged equipement in later battles. I am not sure if this is a issue with campaign design or with CMx2. AFAIK in CMx1 you got back the "repaired/pulled out" vehicles in the next battle or so. Maybe someone knows more.

[Erwin]

I babied them, moving them SLOW and trying to keep em on roads - hence my frustration.

I agree, if they had returned in subsequent battles I would probably not be complaining.

Even the provision of a few armor reinforcements would mitigate the issue of excessive bogging/immobilizations. Hope designers do that in future as an easy fix.

[YankeeDog]

I do think the issue of Immobilized armor not returning between scenarios in a campaign is something that needs to be looked at. Especially if said armor has immobilized from terrain factors, and not enemy fire. A vehicle that has simply thrown a track from going over a stump or something similar is going to be able to be recovered and back in action a lot quicker than a vehicle that's had part of the transmission, suspension and/or other parts damaged by enemy fire.

I'm not familiar with exactly how much control the campaign designer has over this issue, but unless it's a situation where the scenario within the campaign is intended to depict something like a fighting withdrawal where any immobilized vehicles would likely end up in the hands of the enemy, in general the chances of recovering vehicles that have been immobilized without other damage between battles should be very good, even more so if the player wins the scenario and can be assumed to control the ground between battles.

[winkelried]

So, far my testing has convinced me that Fords and Mud are not a safe place to go. I did not expect them to be that bad but it seems they are. It is still not clear if that is realistic or not. I fear it is not but I have no evidence. All I can offer is some test on how the game operates.

Fords are treacherous in RL. You're often not sure if the ground will hold below the waterline. As anecdotal evidence: In the battle for Lucherberg the Allies prepared a ford after the bridge building was disturbed by German mortar fire. The first tank which crossed got stuck and blocked the ford after the engineers had worked for hours to get the ford ready.

[winkelried]

Next Batch

map 4x1 km, 55 M4A3 75(W) Sherman

Ground: Grass, Wet

Fast ca 34km/h 72 bogged 16 immobile

Quick ca 30km/h 71 bogged 12 immobile

Move ca 13km/h 54 bogged 9 immobile

Slow ca 6km/h 39 bogged 12 immobile

The last result with the 12 immobile could be a random event. Takes ages to run this test (16 km with 6km/h) so I didn't repeat it.

[Praetori]

Next Batch

map 4x1 km, 55 M4A3 75(W) Sherman

Ground: Grass, Wet

Fast ca 34km/h 72 bogged 16 immobile

Quick ca 30km/h 71 bogged 12 immobile

Move ca 13km/h 54 bogged 9 immobile

Slow ca 6km/h 39 bogged 12 immobile

The last result with the 12 immobile could be a random event. Takes ages to run this test (16 km with 6km/h) so I didn't repeat it.

What experience level did the vehicles have?

It wouldn't surprise me if Elites didn't bog down as often as conscripts. I have no idea if that's the case though.

I've also noticed that my tanks seem to bog more often if they turn-on-the-spot which seems completely reasonable to me (and I therefore seldomly use the face command or place waypoints at too much of an angle).

[winkelried]

What experience level did the vehicles have?

It wouldn't surprise me if Elites didn't bog down as often as conscripts. I have no idea if that's the case though.

I've also noticed that my tanks seem to bog more often if they turn-on-the-spot which seems completely reasonable to me (and I therefore seldomly use the face command or place waypoints at too much of an angle).

There is no significant impact of experience level did the whole thing with crack, veteran and regular.

After 4 km all tanks turned on the spot no losses.

[c3k]

Next Batch

map 4x1 km, 55 M4A3 75(W) Sherman

Ground: Grass, Wet

Fast ca 34km/h 72 bogged 16 immobile

Quick ca 30km/h 71 bogged 12 immobile

Move ca 13km/h 54 bogged 9 immobile

Slow ca 6km/h 39 bogged 12 immobile

The last result with the 12 immobile could be a random event. Takes ages to run this test (16 km with 6km/h) so I didn't repeat it.

Winkelreid, thanks for putting in the time and effort to quantify the bog or immobilize results.

I'm confused by your table. If you have 55 tanks but 72 bogs, does that mean that some tanks bogged more than once? After they did bog, did they continue for the entire test distance? (Sorry, I forget the total distance they travelled. I know it's upstream somewhere.)

Plotting the speed vs. immobile numbers is interesting.

Thanks,

Ken

[winkelried]

Winkelreid, thanks for putting in the time and effort to quantify the bog or immobilize results.

I'm confused by your table. If you have 55 tanks but 72 bogs, does that mean that some tanks bogged more than once? After they did bog, did they continue for the entire test distance? (Sorry, I forget the total distance they travelled. I know it's upstream somewhere.)

Plotting the speed vs. immobile numbers is interesting.

Thanks,

Ken

bogging = tank bogs, but then continues. so you may have tanks which bog more than once.

immobile = tank bogs and the gets stuck (immobile) and doesn't finish the test.

the number of tanks which finish the full distance (16km) = 55 - # immobile.

[Lt Bull]

Just started reading this thread and I appreciate the tests/experiments being conducted to better understand how bogging in different terrains is implemented in CMBN.

However I will add that the design of the tests could be modified to provided much more useful, valuable, transferable and meaningful information than what is currently being provided.

ian.leslie, the results of your obstacle course are interesting but the results themselves are practically meaningless outside the scope of your tests because you are using an arbitrary multi-terrain obstacle course. The results you are producing are not a transferable metric that is of much meaning outside of your own particular tests.

To get a better understanding of how terrain affects bogging, you need to run your tests on ONE type of terrain at a time and determine an "AVERAGE KMs per IMMOBILISATION" frequency metric for moving across a particular terrain type. This is just as easy to do as running any of the tests you are currently running.

For my own curiosity, I decided to run a few of these single terrain tests myself to find out exactly ho many kms of travel it took before you can expect a bogging. Its quiet easy to do. Lining up the same vehicle along a map edge and giving them all orders to travel at a certain speed (FAST, QUICK, MOVE, SLOW or HUNT) along a length of uniform terrain. All you need to do is:

a) record the number of bogging occurances

record the number of immobilisations that eventuated from any bogging (this data needs to be processed separately, will be good to know if chances of immobilisation increase if bogged in different terrain)

c) the total distance travelled

Doing this I determined that under test conditions, travelling in a straight line, with DRY conditions on GRASSXT, ShermanM4A1 (mids) regular crews will suffer on average 1 bogging every 150 kms. Because I had 38 tanks moving at once along a 2.15km course, running the test 13 times is equivalent to over 1000km of reliability data. It takes a few minutes for them all to travel the 2.15km course.

I repeated the test for MUD terrain and found that based on just 40km of testing, the frequency of bogging seems to level off/stabilise/converge at some value just over 300m.

Just a note on the tests. It gets tricky to keep track of which vehicles have bogged/rebogged if the frequency of bogging is excessive. For example, I only let the MUD trials run for just the first minute and restarted/reloaded the test so they all start lined up again. It's just easier to see who is getting bogged. Also the graphs make it easy to determine if you have done enough tests (or taken enough samples) because you can see the results converge/flatten off as the sample size gets bigger.

Anyways, it would be good to to know the kms/bogging for every terrain type for every vehicle, for each speed, for each ground condition type. These tests are how you would do it. Very easy to run. I will see if I can be bothered doing any more (I will take requests! Name the vehicle, terrain, conditions, speed). I know that BFC probably already have this frequency data these tests expose tucked away somewhere anyway. I know they could just theoretically publish the data/tables (but I know they wouldn't for various reasons), but doing these tests essentially allow you to easily reverse engineer that data anyway to within even 1% accuracy without much fuss if you want.

PS: ah stuff it, why not...here is my scenario file that has all 38 Shermans lined up already if you are interested. Just use the scenario editor to change the terrain type to do other tests.

Bogging Test GrassXt Shermans.btt

[Erwin]

This looks impressive Lt Bull. But, what's the crayon level conclusion re bogging/immobilization rates in the game vs RL?

[Wreck]

Lt. Bull, great work. I think the best way to proceed would be to run the same sort of test for all terrain types, or at least a good sampling, using the same tank in each one. (Since you've started w/ ShermanM4A1 (mids) regular crew -- that.) Then we can at least determine relative rate of bogging for that one tank. It is likely that the relative rates are the same for other tanks.

I.e., from the above we see that the rates of bogging in mud are roughly 450x as high as grassxt. This is only true for sure of the Shermans, but it is probably true for all tracked vehicles or even all vehicles.

[A Canadian Cat]

However I will add that the design of the tests could be modified to provided much more useful, valuable, transferable and meaningful information than what is currently being provided.

ian.leslie, the results of your obstacle course are interesting but the results themselves are practically meaningless outside the scope of your tests because you are using an arbitrary multi-terrain obstacle course. The results you are producing are not a transferable metric that is of much meaning outside of your own particular tests.

I don't disagree. My goal here was to get things started. My personal in game experience did not indicate to me what terrain type would be a problem (other than Mud and Fords - I knew those could be a problem). So I was trying to find out how vehicles would perform on different terrain types. I have lost Shermans to immobilization multiple times on good sold ground so to start I was trying to find out which terrain types were the biggest problem. My idea was simply to offer a standard cross country course and try various vehicles out. I was not trying to get a km / immobilization number. My idea was to see if one vehicle was noticeably worse than others and see if that made sense. I applaud the other testing that has been done - keep up the good work.

I do not intend to find km / immobilization number so I look forward to more info from your tests. I am going to start looking at roads and see if there are any issues with going on / off roads. I am doing that because I have experienced and have read others' accounts off immobilization around roads that seemed odd. Hopefully my tests will be able to show a clear problem that can be fixed or show that there is no problem and we are just experiencing the luck of the draw.

To get a better understanding of how terrain affects bogging, you need to run your tests on ONE type of terrain at a time and determine an "AVERAGE KMs per IMMOBILISATION" frequency metric for moving across a particular terrain type. This is just as easy to do as running any of the tests you are currently running.

As I said earlier I had no idea how the different terrain types would influence immobilization so my first tests helped shed some light. The biggest issue with running tests with one type of terrain is not that it is a bad idea (note: I think it is a good idea) it is that it will take n times longer than a multi terrain course. I realize that my tests will never yield a kms / immobilization number.

Your testing contributions are welcome - good luck and have fun

[Lt Bull]

The biggest issue with running tests with one type of terrain is not that it is a bad idea (note: I think it is a good idea) it is that it will take n times longer than a multi terrain course.

Hi ian. This is not exactly a correct statement. There is no "shortcut" way to get the bogging/km travelled data. For each tank/terrain/condition combination, a minimum number of total reliability kms need to be covered. If the "obstacle course" has one type of terrain, then it will actually take less time/trial runs to get the data that determines the kms/bogging frequency for that one terrain type, than if say that terrain was one of only five other terrains on the course.

I think the best way to proceed would be to run the same sort of test for all terrain types, or at least a good sampling, using the same tank in each one. (Since you've started w/ ShermanM4A1 (mids) regular crew -- that.) Then we can at least determine relative rate of bogging for that one tank. It is likely that the relative rates are the same for other tanks

I.e., from the above we see that the rates of bogging in mud are roughly 450x as high as grassxt. This is only true for sure of the Shermans, but it is probably true for all tracked vehicles or even all vehicles.

Yes, probably best to get all the data for the Sherman M4A1 (mid) as you say. Just looked at the ground condition types possible in the game. there are quite a few! Very Dry, Dry, Damp, Wet and Muddy. I would guess that the bogging rates vary for each one. Then there is also the weather conditions: there are 11 types. I wonder if they affect things at all as ultimately weather in RL does affect the ground conditions, probably not. Note however it is possible to make a scenario with Very Dry ground conditions with Downpour weather conditions.

We are yet to determine if the bogging rates are the same for all vehicles. I would tend to think not. The ground pressure data for each vehicle that BFC already had from CMx1 probably factors in here somewhere.

[akd]

Note however it is possible to make a scenario with Very Dry ground conditions with Downpour weather conditions.

Ground condition will become increasingly wet as the scenario progresses.

[Lt Bull]

Ground condition will become increasingly wet as the scenario progresses.

Hmm...are you saying that if you start playing a Very Dry/Downpour scenario eventually you will literally see the ground conditions reported when you press the "conditions" button dynamically change from Very Dry-->Dry-->Damp-->Wet-->Muddy?

[akd]

Yes, although I can't remember if the conditions page changes.

[A Canadian Cat]

Hi ian. This is not exactly a correct statement. There is no "shortcut" way to get the bogging/km travelled data.

Oops that is not what I meant to say. I was trying to say that I was not trying to measure the bogging /km but instead trying to create a way to compare different vehicles' immobilization chances by running different vehicles over the same course.

[Redwolf]

Ground condition will become increasingly wet as the scenario progresses.

How do you know that?