"Heights and their effect on the battlefield " Topic

I'm working with some friends to produce a set of WWII war game rules. We've now drafted some rules for hills, heights and depressions that we think reflect the impact that height and height differentials have in battle and we're seeking feedback on the approach.
You can see the detail of the rules here at allhellletloose.co.uk.
It would be great to understand what effects you think hills and heights should have both in and out of combat.

Even a twelve inch high hummock means an awful lot to a prone infantryman.

What is your ground scale? Being able to see 6" further because you are on a hill doesn't mean much unless we know what 6" represents.

Hi deephorse, we're using 1" represents between 50 and 100 yards. So that means a hill would add between 300 and 600 yards.
(I did put that in the post honest!)

I suggest you start drawing out a series scale hills and looking at what they do. You have crests, military crests to start with. Which are you modelling?
Now you will need to simplify but almost all hills have dead ground. Some cliffs may not technically have dead ground but its hell trying to look straight down without being seen or dislodging enough material that you fall down.

You have not really defined how high a tier is. Real hills are massive and difficult to get plausible.

In Maneouvre Group we effectively admitted defeat and assumed hills were at model scale heights, for both Hexon II and our own fold Flat terrain.

We then assumed VERY crudely that the edge of the slope was a military crest. Behind the crest you could not see lower and could not see anything behind higher military crests, except slopes.

So its hard to assess your assumed geometry as you have not stated what it is.

Hull down is possible using a military crest but again it will force hull down.

A 4 ft hump will give most tanks a Hull down position provided the vehicle is relatively close to the hump so the round does not descend significantly.

Infantry walking along a hedge will be difficult to see from any height you are likely to encounter. Similarly a high hedge or sharp feature like a Sunken road say 12 ft deep is probably getting on for invisible unless its a VERY steep hill very close. Again scale drawings will help you understand and from their you can derive you model knowing what the approximations are.

Edited Thought – We play at 1:1(ish) so we considered it necessary only to have VERY low hills only so while not exactly what you se is what you get it is quite close. This makes it easier for the players to assess the ground. If its higher than a house it will behave like its higher than a house. Now big models representing very large formations the models are reall board game pieces but the players need to understand that or else it may get confusing.

This is very hard to quantify, because battlefields vary so much. Chinese Farm is completely different from the Ardennes.

Trying to figure every factor into a set of rules will quickly turn into a quagmire. Weather, supply, daily morale, fatigue, mechanical repair, etc, etc, etc will never end.
Just make rules.

I generally go with two kinds: hills and crests. Crests represent minor swells. I model them with a line of flock. They block LOS but have no other effect on game play.

Hills block LOS, have costs to go up or down. We are pretty informal. Hull down is possible with any hill, but we use a marker to show it.

Check out the old FM 34-130 Intelligence Preparation of the Battlefield. PDF link
Specifically, Appendix B has, among other useful planning factors, a chart on page B-12 that tells the maximum distance observable cross referenced to the height of observation.

Interesting. Thanks.

Thanks very much everybody for all the feedback. Very interesting thoughts.

Particular thanks streetgang6 that is an enormously useful document!

streetgang6 +1

Even any fold or depression on the ground depending on the size could provide some cover. I.e. dead space, etc. Plus even non-solid objects like crops, bushes, etc. could provide concealment. Which is different than cover. As it will block LOS, but is not solid. As cover i.e. being solid could actually stop or slow down, etc., incoming rounds.

Even infantrymen being prone will be a smaller target and harder to see and hit. E.g. the longest range target on a US Army rifle range is 300m. Without a scope, etc. at 300m a human sized target is "tiny".

At @ 200m generally most vehicles to the naked, "Mk.I" eyeball are just a "blobs" of some sort.

Most ground troops dismounted or mounted, in AFVs, etc., try to get something solid between them and incoming fires. Direct or indirect.

High ground is traditionally an advantageous location as you can generally see farther. And be able to engage targets at longer ranges before they can engage you. Or just call-in supporting firers. e.g. mortars, FA, CAS, etc.

Interesting to see 'Duffers Drift' quoted in FM 34-130, thank you for the link.

E.g. the longest range target on a US Army rifle range is 300m. Without a scope, etc. at 300m a human-sized target is "tiny".

The Marines use (or did use) a human torso size target at 500 yards prone and it was not unusual to get 10/10 hits. My son got a first round hit on a walking target 90-degree deflection with his M4 and an ACOG sight at about 700m. He said it was a lucky shot. However, before he enlisted he was part of the juniors AR-15 national championship team in the US and also shot in M1 Garand 600 yard matches.

Having the high ground is going to give you a big advantage for observation. There is a hill about 100' above ground level by my house and I can easily spot vehicles 5000+ yards away when I'm on top without optics.

Print off the Google map of your area and go to various elevations and check out how well you can observe with the naked eye and 6x binoculars.

I use a rule called "Hunker Down" where infantry units can disburse and take advantage of local cover to be immune to small arms direct fire but cannot return fire. In VN a platoon could be pinned down in a rice patty for an hour with minimal causalities while being shot at from a dike a few hundred yards away. However, any return fire was pretty ineffective.

Wolfhag

"Print off the Google map of your area and go to various elevations and check out how well you can observe with the naked eye and 6x binoculars."

Not very far.

Oh, wait … that's the haze, marine layer, and smog …

Interestingly when building my card buildings one observation was that standing on a bridge some 30 ft high looking into the built up area I could see virtually no internal roads. All blocked by the houses ans actualu little more than roofs were visible. A hill would be further away so no help at all. It may not be true for US small towns and villages as generally they are much wider spaced.

I can't get a view from the bridge but even at this height its mostly roofs and this is much higher than the bridge in the center.

link

Again the issue is all the visibility rules need to be consistent with each other.

An interesting quote form a trainer of Infantry was how hard it was to get recruits to see cover less than 6". Another quote I remembered was "its hard not to find cover except in parts of a car park".

Maneouvre Group approximates. We generally don't detail ground to 6 to 12" for obvious reasons. However we do allow a relatively easy dice roll to find Masking Terrain. This is as has been described full cover from direct fire small arms but cannot be shot from. They can be detected and shot from by grenades and mortars and its a bad place to be assaulted.

The Marines use (or did use) a human torso size target at 500 yards prone and it was not unusual to get 10/10 hits.

I've heard that before … at 500 yards it must be even smaller.

There is a hill about 100' above ground level by my house and I can easily spot vehicles 5000+ yards away when I'm on top without optics.

Yes, you can tell vehicles in the open but without binos, etc., there is generally not much "definition". Yes, you can tell a big blobby looking vehicle thing from a small blobby vehicle thing …

This is from the Army manual for target recognition ranges.

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Wolfhag

Nice ! Thanks ! I now remember seeing that ! And yes as always weather and terrain are considerations …

Thanks a lot Wolfhag. That's great.

Why are the armoured vehicles and wheel vehicles recognized at longer ranges?.

Another consideration is differences in height make for interesting artillery firing calculations, particularly with Timer fuses trying to achieve air bursts.

goblin, men are smaller, and raise less dust.

Why are the armoured vehicles and wheel vehicles recognized at longer ranges?.

It has to do with vehicle/target size. An Armored Vehicle can be either tracked or wheeled. And both can be large depending on the design. E.g. a large wheeled armored vehicle may be tall as the wheels are big. For improved cross-country mobility, etc.

Look at the Russian BTR APC, OT-64, US Stryker or LAV. All wheeled … all Big … Also note how Big a US 5 ton Truck or HEMTT are.

Another consideration is differences in height make for interesting artillery firing calculations,

IIRC when calling in Naval Gunfire you have to include the height of the target …

"IIRC when calling in Naval Gunfire you have to include the height of the target"

An old work friend of mine served as a USMC ANGLICO naval gunfire controller in I Corps during the Vietnam unpleasantness – everything from 5in DDs to 16in BBs

As I understand it, the same deal applies for any significant elevation difference exists between any firing battery and its target.

Then there is the issue of an intervening terrain feature of superior height situated between the firing battery and its target ….. where the trajectory of fire must be adjusted to clear the intervening terrain while still delivering the fire on target ….. which is why howitzers and mortars, with adjustable propelling charges, are such desirable tools to have at hand.

FWIW.

B

Yes, I was also trained to call-in mortar and FA fires. And generally we only had to give a grid and description target.

E.g. :

FO : "Fire Mission, over"

FDC : "Fire Mission, out "

FO : "Adjust Fire, Shift, grid FL348981. Infantry in the open, over" …

IIRC, etc., etc., ? …

Also while on the road yesterday. I did an exercise in ID'ing/spotting Vehicles at different ranges. The weather was overcast with light snow and rain.

Yes, certainly at 200m or 300m or less you can generally ID type, color, etc. of a vehicle. And of course it depended on size, e.g.: sedan, Pick-up, SUV, Van, Delivery Truck[e.g. Fedex, etc.], Bus, and 18 Wheeler.

And not surprisingly as the distance became greater between me and the vehicles, e.g. 200-300m +, +, +. The Smaller "targets" became harder to ID. e.g. cars, pick up trucks, SUVs, vans, became harder to discern other than a squarish "thing", that looked like some sort of vehicle.

For larger, e.g. a Delivery truck, bus and 18 wheeler still were pretty much easy to ID.

I do remember that chart from the Army FM. Of course AFVs generally are bigger than most civilian vehicles. So yes, at almost all ranges AFVs/military vehicles are certainly easier to spot/ID than others. Of course a Jeep or even HMMWV will be closer to the size of a sedan so yes, harder to spot.

Hi L4 -
Would it be sensible to assume that any firer vs target height differentials were dealt with as part of the battery's FC computations?

B

I was trained to fire 81mm mortars, run the FDC, as well as call it in as a young LT. But never remember having anything to do with elevation … ?

Generally your first shot was rarely on target. Hence " Adjust Fire, Shift …" Then add or drop the range until on target, then "Fire For Effect". This could be rapidly done by the FDC thru the FO. But sometimes you get a fire round hit followed by a salvo. Then repeat as needed.

Of course in many cases having pre-registered targets was helpful. But just saying the target number, e.g. AB1001, etc. The tubes already knew where the target was and could adjust if needed.

Blutarski, Legion 4, yes you can indeed factor in elevation differentials. Digital, vice voice, fire missions will compute them. Not to say you can't do it in voice fire missions; I've done so myself and it does greatly improve first round accuracy. Then again, I'm just a DAT. ;-)

Back when I was on active duty '79-'90 IIRC our Redlegs didn't have anything digital, AFAIK.

Then again, I'm just a DAT.

I was just a Grunt whose M113 Mech Co was frequently attach to an M60/M1IP Tank Bn … So I'm in good company DAT !

No we had gllds then but even with old fashioned grid coordinates, the grunt calling it in didn't have to worry about target elevation but the FDC sure as hell did. We looked at the map.

Yeah only our Scouts had GLLDs … But yes, I never remember having to add elevation when calling-in mortars or FA.

Like you we looked at the map and called it in from there. But again, I was Grunt, served in 4 Inf Bns not a Redleg. however, was very glad to have my FST nearby.

It matters more to the Naval gunners because their computers are assuming a target no more than about 50ft above sea level, and they probably don't have ground maps…

That makes sense …

Don't know about these days, with higher-velocity weapons, but in the ACW it was often the case that troops (and guns) on higher ground overshot their targets, as the trajectory would be different than if both shooter and target were on the same level.

No so much today … Our Tech is so much higher than in the ACW of course.

"Slope range" still matters today, but mostly at longer distances (usually beyond 300m). Your bullet only drops the horizontal range, but your eyeball (or cheap laser rangefinder) sees the distance on the angle. Takes a little trigonometry (or a LRF that measures the angle) to get the proper hold-over for the actual range.

little trigonometry

Now I'm waaay out of my league !

There is no such that as "a little" trigonometry!

There is no such that as "a little" trigonometry!

Tangent math is fun! Once you understand sine and co-sine, that is. Or so I'm told.

My understanding:

sine = "No Parking"
co-sine = "Weekdays 3 to 6pm"

Don't know about these days, with higher-velocity weapons, but in the ACW it was often the case that troops (and guns) on higher ground overshot their targets, as the trajectory would be different than if both shooter and target were on the same level.

No so much today … Our Tech is so much higher than in the ACW of course.

"Slope range" still matters today, but mostly at longer distances (usually beyond 300m). Your bullet only drops the horizontal range, but your eyeball (or cheap laser rangefinder) sees the distance on the angle. Takes a little trigonometry (or a LRF that measures the angle) to get the proper hold-over for the actual range.

Three statements from three posters all building the same information for me! Many thanks.

The take-away:
1) " "Slope range" still matters today, but mostly at longer distances (usually beyond 300m). "

This is the higher-velocity issue. Today's bullets are faster, so the impact is only at longer distances.

2) " Takes a little trigonometry (or a LRF that measures the angle) to get the proper hold-over for the actual range. "

This is the newer tech issue. First, if you have the range correct (LRF) you have eliminated the error by the ranging factor, even if not by the slope factor. Then if you have the angle correct, and the trig correct, you can eliminate error from the slope effect as well.

As much as the trig may put us off, in truth it's a ridiculously easy calculation for any microprocessor or even controller in that LRF to handle. So have current LRFs added a digital angle meter of any sort, and do they perform the slope effect calculations? I don't know, but it sure seems to be a reasonably simple and useful feature to build in.

-Mark
(aka: Mk 1)

The slope range modifier is no more complex than the sloped armor modifier. You're just dividing instead of multiplying. Say it's a 45deg slope up, very steep to that Pathan up on the hilltop. Divide LRF range by 1.4 (or multiply by .71, but that requires memorizing the 1/cosine table instead of just the cosine table).

@Mark1: A good LRF does have an angle meter, the cheap ones don't. Also, the longer-ranged LRFs will have one, since they're the ones that really need it.

Well no doubt about it … math of any type not withstanding. The performance of the ACW Springfield is very different than the modern M16/M4. That is my version of easy math …

All of the above. I think Old Glory summarized it best:

Trying to figure every factor into a set of rules will quickly turn into a quagmire. Weather, supply, daily morale, fatigue, mechanical repair, etc, etc, etc will never end.
Just make rules.

The best solution, as far as I am concerned, is either requiring all spotting to be done by check, rather than automatically, or have an activation rule so that each unit activates on a card draw or whatever – I Ain't Been Shot, Mum, being one example. Units that fail to activate in a particular turn simply did not spot the target. IABSM, as I recall, has a rule that units within some distance of the enemy – 9" if I recall – get to fire at the end of the turn if their card didn't come up.

My only other suggestion like Gerard is to styalise a bit. We do so with our assumptions on dead ground proably key at least from the Napolionic period on.

Spotting can be helped from a height if the target is not well cammoflarged.

One thinng not mentioned is skylining, we have not covered this in our rules simply the assumption with our low hills is that a unit is never skylined. We avoided it as it would be a lot of rules for not much gain most of the time as it is rarely unavoidable.

Spotting can be helped from a height if the target is not well cammoflarged.

Spotting from anywhere can be improved if the target is Not well camo'd, covered and/or concealed. Basic fieldcraft … along with noise & light discipline, etc. "If you can be seen you can be hit … If you can be hit you can be killed."
"Don't be a target."

One thinng not mentioned is skylining, we have not covered this in our rules simply the assumption with our low hills is that a unit is never skylined. We avoided it as it would be a lot of rules for not much gain most of the time as it is rarely unavoidable.

Yes, that would be too much unneeded detail. Most militaries or even insurgents would not skyline or even expose themselves unnecessarily. Or not very often … at least knowingly/on purpose …

When in doubt based on many considerations, when it comes to spotting, LOS/FOF, etc. Roll off … highest die chooses. Like I said so many things come into play with LOS, etc., if it is not 100% clear … roll off. And if target/unit is spotted, it should get a cover bonus. That concept or similar was used in other games systems, as well. Like AH's Tobruk …

Wolfhag:

Just for a fun comparison to the Army manual for target recognition ranges, here is Hanoverian/Prussian General Scharnhorst's Officer's Field Pocket book 1800-1811 distance recognition: (paces = about 28 inches)

2) To ascertain the Distance of the Enemy with the naked Eye.

At the distance of 2000 paces nothing can be discerned of infantry but the glittering of their arms; thus, if the colours, uniforms, files &c. are not distinguished, it may be considered to be at that distance. The files of cavalry will be seen at the above distance, but without being able clearly to perceive whether they are men on horseback.

The files of infantry cannot be distinguished at a greater distance than 1500 paces, and at the same distance, the horses of the cavalry cannot be distinctly seen, but it may be ascertained that the men are on horseback.

At 1000 paces the head may now and then be distinguished from the body, but it cannot be perfectly seen beyond 600 paces.

The faces of the men and the lace and facings of their uniforms may be seen clearly at 3 or 400 paces,

and at 70 or 100 paces the eyes of some of the men will appear like dots".

McLaddie,
I guess that's why they wore bright uniforms and funny hats so they could be recognized by friendlies.

Wolfhag

Both of you have good points !