Statistics on bogging: terain

[Joeri]

Hi,

There have been several threads dealing with techniques how to minimize your chances of bogging down. Types of terrain (of course roads are best in wet conditions) and type of movement all seem to have an effect on this chance. I even read some speculations that the height of the terrain has influence. Curious about this all I decided to do some test. I will discuss the first part of this test here which covers some of the different terrain types. I might also do something similar on the different movement orders later.

What I want to test is how the terrain type influences the chance of bogging. Further I want to see if height has any influence. I have approached this as follows. Have made a scenario with 4 bands of terrain. half of this bands width is high (15 in the editor) and half is low (1 in the editor). The result is 8 bands of terrain half of them high half of them low with 4 types of terrain. The types are:

Sc: Scattered trees

Wh: Wheat

Br: Brush

Gr: Grass

Weather conditions are deep mud / coverage.

Then I have placed 4 tanks (M4 Sherman) on each band making a total of 32 tanks. And gave them straight fast move orders along their band. Each turn I recorded which tanks bogged down which became unbogged again and which got immobilized. This I did for 10 turns and then repeated for another 10 turns.

In total 32 tanks where involved for 20 turns making a total of 640 tank-turns (made that up myself ). This gives quite a good basis for statistics but if anybody feels this is not enough to make a judgement feel free to do more elaborate test yourself.

The results

First some terms I'm going to use:

DT: Driving turns. When a tank is bogged or immobilized, it has no chance of getting immobilized again so I need to consider only the turns the tanks are actually driving. So if 4 tanks are driving 1 turn, this number would be 4. If one got bogged, the next turn only 3 driving turns are recorded.

B: The number of times a tank gets bogged.

U: The number of times a bogged tank gets unbogged.

I: The number of times a bogged tank gets immobilized

BC%: The chance a tank gets bogged per turn (B/DT)*100%

UC%: The chance a bogged tank gets unbogged (U/B)*100%

IC%: The chance a bogged tank gets immobilized.

Note: IC% and BC% does not have to total 100% because sometimes tanks are bogged at the end of the tests.

Ok, now the results. First the total results of all terrain type:

****** TD * B * U * I * BC% * UC% * IC% *

Total 531 * 68 * 42 * 20 * 13% * 62% * 29% *

Now a distinction between High ground (15) and low ground (1):

****** TD * B * U * I * BC% * UC% * IC% *

High 269 * 35 * 22 * 9 * 13% * 62% * 25% *

Low 262 * 33 * 20 * 11 * 13% * 60% * 33% *

Now I will make a distinction between terrain types. Note that High and low is combined again per terrain type.

****** TD * B * U * I * BC% * UC% * IC% *

Sc 153 * 7 * 5 * 2 * 5% * 71% * 29% *

Wh 145 * 22 * 18 * 2 * 15% * 81% * 9% *

Br 130 * 10 * 3 * 4 * 8% * 30% * 40% *

Gr 103 * 29 * 16 * 12 * 28% * 55% * 41% *

Discussion

Overall the results give quite a nice impression of the chances of getting bogged and unbogged again. An overall chance of 13% per turn of getting bogged in deed mud is not too high in my opinion. It seems to happen more often in the games I play . You also have approx. 60% chance of getting unbogged again which is more than I expected, again based on my experience in games .

Comparing the total group to the high and low results I think the conclusion can be drawn that height is not factored in the chances of getting bogged. So no need to avoid low country in wed conditions.

Looking at the terrain types the numbers totally surprised me (Please keep in mind that the statistics are less reliable because of the lower number of tank-turns per terrain type). Scattered trees only give a 5% chance of bogging against 28% on open terrain. I would have expected it the other way around. This also explains why my tanks get bogged so often in games because I try to go for the open terrain (if no roads are available of course). These numbers seem to imply that it's better to move your tanks through scattered trees and brush. Since I have no knowledge of tanks in any way I leave this to the experts.

The chances of getting unbogged or immobilized for different terrain types varies a lot. I think this is due to the small number of occurrences. So I don't dare to put any conclusions on that one. Actually I think the chance is not related to terrain but is something like 65% for unbogging and 35% for immobilizing for each terrain.

As I said before I plan to do something similar for the different movement commands which will be posted later. In the mean time any comments/suggestions/criticism is welcome. I also would appreciate a comment from Steve or Charles whether it looks anything like it is programmed.

Joeri

[Tris]

Very good. Thank you.

Since you seem to have both time and interest, Joeri, I would suggest you repeat each test you conduct at both regular and hunt speeds as well. You might also want to check what the correlation is between vehicle flotation ratings and various terrain routes @ x speed and tracked versus treaded vehicles.

(thatshouldkeephimbusythroughtheholiday...hesaid)

[Joeri]

And not to forget different weather conditions like damp, wet, mud, deed mud, snow, heavy snow and what's more. And not to forget all the different experience levels of the crew.

You are a funny guy Tris

Joeri

[Tris]

You know, just as I took Beamer (my German shepherd) out for a spin in the park I thought about crew experience levels and wondered if that might not be factored in as well. I kind of doubt if, but it's quite possible just the same. On second thought you'd best ask Steve.

[aka_tom_w]

This was VERY informative

Thanks for the Big Effort

I think the most relevant thing is that a fast move through scattered trees is not half as dangerous as I thought. That 5% bog figure and 71% unbogged figure are a really big surprise, I would never have beleived teh 5% bog figure wouldbe so low or the 71% bog figure would be so high,

Thanks again

-tom w

[russellmz]

why is that? are the trees sucking up the water while not preventing sunshine? are the roots holding the soil together?

are woods too shady for the sun to dry? probably the roots since the open fields are hit by sun all day.

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"They had their chance- they have not lead!" - GW Bush

"They had mechanical pencils- they have not...lead?" - Jon Stewart on The Daily Show

[Doug Beman]

joeri,

when you gave your tanks move orders, were they moving uphill, downhill, or neither? That might play a part in bogging, as tanks have to work harder to go uphill and I'd think the chances of throwing a track or whatever would increase.

DjB

[Joeri]

Doug,

The tanks were moving on level terrain.

Inclination? Yet another parameter to consider. To be honest I don't think it's factored in. If it was, the height would probably play part as well.

Maybe BTS could give us the answer?

Joeri

[Bruno Weiss]

Interesting study. And not doubting your results, I remain somewhat speculative about terrain height versus bogging percentages. Only because of experience, however that is not scientific. My experience does not represent the masses. Still, in conditions where bogg is to be expected, wet/mud, I keep bogging in low terrain, and not so or nearly as much in higher elevations. One other factor, and this also is out there. I have noted a particular tendancy for some tanks, weighing more than others, to bog. Those weighing more, being more prone to bog. Again, maybe wishful thinking here towards gravitational reality, but it surely seems to me that the heavier ones bog sooner or more often.

I'd love to see the scoop on this from BTS.

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"Gentlemen, you may be sure that of the three courses

open to the enemy, he will always choose the fourth."

-Field Marshal Count Helmuth von Moltke, (1848-1916)

[Guest kking199]

One critical piece of information to keep in mind. What is the Ground Pressure (psi), or float, of the vehicle. It is not necessarily the weight of the vehicle but the distribution of the weight over the tracks, i.e. the psi. A 14psi vehicIe should have a significantly higher bog chance than a 11psi one. I go with lower psi Tanks if I know the terrain is damp/wet/muddy.

Also water always moves downward, so lower ground should be muddier than higher ground as that is where the water flows to. Ever seen water pool on a slope?!?!

[This message has been edited by kking199 (edited 11-22-2000).]

[Sgt. Steiner]

The most important factor to consider is the vehicle's ground pressure per square inch. The higher it is, the better your chance of getting bogged. The KT's and Jagdtigers are especially prone to getting stuck, forcing them to keep to the roads for the most part (just as in real life).

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Ob's stürmt oder schneit, ob die Sonne uns lacht, der Tag glühend heiß oder eiskalt die Nacht, bestaubt sind die Gesichter, doch froh ist unser sinn, ja unser sinn, es braust unser Panzer im Sturmwind dahin

-- Panzerlied

[Joeri]

I did some test with different movement speeds with very surprising/interesting results. The setup was approximately similar to test with different terrain. This time I used only open terrain. I did a test with deep mud and a test with mud. 32 tanks total 8 on fast move, 8 on move, 8 on hunt and 8 on reverse. two sets of 10 turns recording as previously explained.

The results:

First of all, the tanks which were driving in reverse never bogged down. So They are left out the data leaving 24 tanks.

First the combined test results. These include three different movement orders (fast, move and hunt) and two ground conditions (Mud and deed mud):

*** * DT * B * U * I * BC% * UC% * IC% *

Total 309 * 67 * 34 * 28 * 22% * 51% * 42% *

The difference between mud and deep mud:

*** * DT * B * U * I * BC% * UC% * IC% *

Deep 144 * 36 * 16 * 15 * 25% * 44% * 42% *

Mud 165 * 31 * 18 * 13 * 19% * 58% * 41% *

The difference between movement orders:

*** * DT * B * U * I * BC% * UC% * IC% *

Fast 90 * 21 * 11 * 7 * 23% * 52% * 33% *

Move 95 * 23 * 11 * 12 * 24% * 48% * 52% *

Hunt 124 * 23 * 12 * 9 * 19% * 52% * 39% *

Discussion

First of all, the total numbers confirm the high chance of bogging down found in the first test for open terrain. The chances are reduced somewhat because of the different ground conditions and movements orders but they are still above 20%.

Difference between mud and deep mud is visible but not very dramatic.

Difference between the different movement commands is not large. It is also not very significant considering the limited number of tests per movement order. It wouldn't surprise me if the type of movement doesn't effect the chance of bogging at all.

As mentioned before, driving reverse removes the chance of bogging in. This must be a bug and it is also one that can be exploited quite easily in games. I would appreciate it if someone from BTS takes a look at this.

There is one more thing I noticed during these tests. The speed at which the tanks drove was exactly the same for all tanks. So it was independent of the movement order. This surprised me very much. I did the same test for dry ground conditions and there the speeds were clearly different but also surprising. Fast move was fasted of course. Next came hunt and reverse which have the same speed. Slowest is the move command??? I would expect the move command to be faster than hunt ?)

Anyway for mud and deed mud all speeds are equal. This might be a 'feature' of the TacAI. Something like the drivers knowing that they should always drive slow in muddy conditions. However it might also be a bug. I leave this up to BTS to decide.

Enough test for me for a while.

Joeri

[Vanir]

Wow. This is totally different than what has been generally accepted to be fact. I think everyone thought that moving fast and moving through rough terrain made bogging more likely. This turns bad weather tactics on their head. I bet there is a bug or 2 in there somewhere....

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You mean my Java coded Real Time Bar Fight Simulator Madmatt Mission: Beyond BiteMe ISN'T going to be published?!?

Madmatt

[Joeri]

After thinking this over for a while I have made the following assumption on how it works:

Chance of bogging is dependent on:

- ground condition (unknown how but probably just how deeper the mud/snow the more chance)

- terrain type (open terrain gives highest chance, then wheat, then brush, then scattered trees and lowest chance on roads)

Movement order has no influence because when ground conditions are bad, the driver automatically takes the slowest possible speed. Exception is reverse which removes the chance of getting bogged (this is probably a bug).

Based on these assumption best tactics in bad conditions would be (if roads are not available):

- use reverse whenever no contact is expected (and you don't mind taking advantage of a possible bug).

- use rough terrain like scattered trees and avoid open terrain when advancing to contact.

Totally different from how I used to do it.

Joeri

[aka_tom_w]

Thanks for all the bog tests

They are VERY informative

A realy big thanks from all of us

So now the big question?

I guess the answer is an unqualified YES!

Is it gamey to reverse tanks while off road to avoid bogging?

I wonder if there is time to have that one fixed in v1.1?

we'll see

-tom w

[Joeri]

I think you are right about reversing being gamey, but I also think it's something which is really hard to avoid. Sometimes it's just logical to reverse and where do you draw the line. I must say that I already reversed a little bit farther than I would normally have in one of my PBEM just to be on the safe side. (Bad I know, but I couldn't help it)

About the v1.1 fix. I think the Beta is already out the door so it would probably be to late. Maybe a fast 1.101

Joeri

[Pak40]

"I think everyone thought that moving fast and moving through rough terrain made bogging more likely. "

Actually, CM models this realistically IMO. Think about it: if you're driving your car through mud, you want to keep moving. In other words, the car's momentum will get you through the mud.

If you go too slow, then your car will sink into the mud and your tires will possibly dig a rut into the mud and get you stuck. The biggest sin would be to step hard on the accelerator and make the wheels spin.

Keep your car moving at a good constant pace and then you will never need to press the accelerator hard in order to gain speed.

Scattered trees would actually aid a vehicle. Branches, roots and debris would act as a catch for the wheels/tracks.

[Joeri]

Pak40

On the movement issue. I don't think it's really relevant since it seems that in bad conditions, the specific movement order is ignored and the TacAI will always proceed in a slow movement independent of the order. So basically the TacAI already takes your driving advice

About the terrain type. I agree with you that an argument could be made for a decreased the chance of bogging in scattered trees and brush compared to open terrain. It is just not what I, and I think many others expected. If it was intended to be like this I am the last to disagree.

Joeri

[Doug Beman]

I don't think that scattered trees would help the vehicle move. If a broken trunk got caught in the tracks it'd maybe bind the suspension, maybe cause the track to snap. Also, there's the possibility of "high-centering," in which the vehicle drives over a tree stump, and the stump raises the vehicle so one track is off the ground (if you've read Team Yankee it happened in there. Not sure how realistic, but it makes sense)

And, lastly, just having all that loose crap underfoot (undertrack?) should decrease tracion, just like loose gravel makes cars skid out.

DjB

[Pak40]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Doug Beman:

I don't think that scattered trees would help the vehicle move. If a broken trunk got caught in the tracks it'd maybe bind the suspension, maybe cause the track to snap. Also, there's the possibility of "high-centering," in which the vehicle drives over a tree stump, and the stump raises the vehicle so one track is off the ground (if you've read Team Yankee it happened in there. Not sure how realistic, but it makes sense)

And, lastly, just having all that loose crap underfoot (undertrack?) should decrease tracion, just like loose gravel makes cars skid out.

DjB<HR></BLOCKQUOTE>

Obviously, big trunks and stumps would hinder movement, but any driver could drive around those obstacles. I'm talking about branches and roots - these would definitely give some traction to a vehicle, especially roots. Leaves might decrease traction but I don't think twigs and branches will.

and BTW, if you've ever been stuck in mud or snow then you'd know that putting gravel under the tires could actually aid in getting you out. Kitty litter helps too

[Dschugaschwili]

BTS, are you aware that it seems that it's impossible to bog while reversing? (bumping this thread up)

Dschugaschwili

[M Hofbauer]

aka_tom_w: "Is it gamey to reverse tanks while off road to avoid bogging?"

yeah, you go ahead and charge into the enemy ass first. I wish you a lot of fun with that, and if you charge my positions like that I can assure you that I would not object to it and call it gamey

joeri et al, you are ignoring the absolutely correct observation made in posts by kking199 and Sgt.Steiner; ground pressure / psi is prime criteria. with what vehicles were your tests done? try the same set of tests with a King Tiger and then with a Chaffee and see if CM reflects the main factor for bogging down.

[jshandorf]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Doug Beman:

I don't think that scattered trees would help the vehicle move. If a broken trunk got caught in the tracks it'd maybe bind the suspension, maybe cause the track to snap. Also, there's the possibility of "high-centering," in which the vehicle drives over a tree stump, and the stump raises the vehicle so one track is off the ground (if you've read Team Yankee it happened in there. Not sure how realistic, but it makes sense)

And, lastly, just having all that loose crap underfoot (undertrack?) should decrease tracion, just like loose gravel makes cars skid out.

DjB<HR></BLOCKQUOTE>

I agree and disagree....

In any conditions moving through scattered trees can bog and eventually immobilize any AFV.

As for branches and the such making it slippery for a tank... Ahhhhh... no. Don't think so.

[jshandorf]

Also.. I would like to see you do a test comparing level.. up hill.. and down hill terrains.

Thanks,

Jeff

[aka_tom_w]

<BLOCKQUOTE>quote:</font><HR>Originally posted by M Hofbauer:

aka_tom_w: "Is it gamey to reverse tanks while off road to avoid bogging?"

yeah, you go ahead and charge into the enemy ass first. I wish you a lot of fun with that, and if you charge my positions like that I can assure you that I would not object to it and call it gamey

.<HR></BLOCKQUOTE>

OK,

Well obviously it would be a questionable tactic to advance to actually attack a position in an ass first orientation, BUT I would think it would be gamey to move your tanks all over the "non enemy contact" part of your back field by reversing them to get them into position to attack.

I still think it's gamey but in the "privacy" of your own rear areas it seems as though it is worth considering to get into position, because bogges tanks are a real nuisance!!

-tom w