fire value for mortars

[wololoh]

Hi,

I was playing around with PzB Normandy, and found that the mortar units were particularly ineffective, so looked a little further into it.
Example: American mortar of 4 guns with morale C (soft attack 7) fires at infantry in clear hex (defense 16). I expect the fire value to be 17 in this case.

Actual results are (from fire dialog):

- versus hex with 33 infantry: fire value 2 (basically nothing!)
- versus hex with 99 infantry: fire value 8
- versus hex with 198 infantry: fire value 17 (-> finally the expected value!)

So the expected fire value is only reached when firing at a fully stacked hex. Most importantly, the fire value literally goes to zero against "small" (actually quite common size) units.
In the manual I see the following: 

Stack Fire – a modifier applies to Direct fire and Indirect fire from half
the stacking limit (1.0) up to maximum stacking limit (2.0). This
represents the higher casualties due to the increased density in a hex.

However, what actually seems to happen here is that all fire gets a negative modifier (ranging from 0 to 1), unless firing at fully stacked hex. For this mortar fire, the fire value literally dwindles to nothing based on stacking value of the target hex. Is this intentional / is this the case for all ranged fire?

[Green]

The manual for Panzer Battles says that "Indirect fire is always alt resolved". So this means (as described in the pzc.pdf) that "...such Indirect Fire is applied against all units in the target hex, proportional to their strength, instead of being applied against a single target unit". Not easy to find but I think that is the explanation.

[Green]

It is also covered in the 'Getting Started' guide;

"Artillery in Panzer Battles uses the ‘Alternate Indirect Fire Resolution rule’ as standard. In simple terms, you can only fire once, but that fire is doubled in strength and will impact all defending units in hex proportional to their strengths. Mortars and direct fire artillery (infantry guns) do not use this rule and can fire several times in a turn. "

[Mowgli]

Just to rule out some of the potential causes:

Is the fire occuring in your turn or is it opportunity fire (*0.5 effectiveness!, manual p. 47)
Is the spotting unit detached (i.e. outside its HQ's nominal command range; *0.5 effectiveness!, manual p. 41)?
The fatigue of the firing mortar unit is good, I suppose?

@ alternate fire resolution (mentioned by Green, manual p. 106)
Note that the quote above says that the "alternate fire resolution" does NOT apply to mortars. Also, one would expect that (against single targets), the alternate fire rule would INCREASE firepower, not lower it (if there is only one target, the full *2 firepower would hit that target, not be spread out over many targets according to their strength). This also helps explain why only mortars seem to be so weak (they do not get their fire values doubled like other indirect assets...). But of course it cannot explain the actual fire values observed in the game, which really seem to be unexpectedly low...

@ stack fire/density modifier (mentioned by wololoh, manual p. 46, 106)
The rules seem to indicate that this factor can only increase, not decrease firepower. It doesn't say that firepower gets decreased if firing at a hex that is below half its stacking limit. I suppose that this is needed because of the alternate fire resolution: If there was no bonus for firing at "full" hexes, then the fire of indirect assets would get spread out too thinly over too many units. So you need to give arty a boost.

But maybe the manual is indeed misleading and it's the other way round (a malus for firing at "empty" hexes, rather than a bonus for firing at "full" hexes, which naturally hurts mortars who do not benefit from the "alt res"). Indeed that's the only explanation I can think of.

I also found this obscure note in the manual (p. 106):
"Total indirect fire on any one hex per turn limited to 1.5 max stacking value."

[Green]

Note that the quote above says that the "alternate fire resolution" does NOT apply to mortars. Also, one would expect that (against single targets), the alternate fire rule would INCREASE firepower, not lower it (if there is only one target, the full *2 firepower would hit that target, not be spread out over many targets according to their strength). This also helps explain why only mortars seem to be so weak (they do not get their fire values doubled like other indirect assets...). But of course it cannot explain the actual fire values observed in the game, which really seem to be unexpectedly low...

My apologies. As you say, mortars are indeed excluded from the Alternate Indirect Fire rule. Somehow by the time I got around to replying I had forgotten that the entire question related to mortars!

But I believe their attack value is still proportional to the total size of units in the hex. I assume the calculation uses the same basic proportional method as used by the Alternate Indirect Fire rule but only the target unit is affected. Of course the firepower is not doubled as they fire twice but otherwise the calculation should be much the same. So the attack value will increase as the target size increases. And target size would include the size of any non-target units in the hex, even though the non-targets would not be affected by the attack. 

Makes sense to me since more targets would mean each target would be more compact and therefore suffer more damage if attacked.

[wololoh]

Hi,

Thanks for your input. I'm still not seeing a rule which explains that the fire value linearly goes  to zero against hexes which are not fully stacked (edit: but I think Green is right in his last post, that the mortar fire is sort of treated the same way, although not exactly the same and not documented as far as I see. See also edit below)

"Artillery in Panzer Battles uses the ‘Alternate Indirect Fire Resolution rule’ as standard. In simple terms, you can only fire once, but that fire is doubled in strength and will impact all defending units in hex proportional to their strengths. Mortars and direct fire artillery (infantry guns) do not use this rule and can fire several times in a turn. "

I read this differently: namely that the impact of the fire is divided across the units proportional to their strenghts (i.e. when a large unit and small unit are stacked together, the losses are divided so that the large unit gets more losses than the smaller). Not that the fire value itself is impacted. (besides from the fact that mortars are excluded in the rule wording )

edit: did some testing with artillery. In the case of firing with artillery, the expected attack value seems doubled, and then each unit is attacked proportional to their strength (so indeed also for small units, the fire value goes to zero). For example firing at one infantry unit of 33 men has fire value 16, firing at a hex with three infantry units of 33 men has fire value 16 also, but applied to each unit separately.
(this example is for an attack which would have raw fire value 48, which is then multiplied by 2*33/200 per infantry unit of 33 men).

Is the fire occuring in your turn or is it opportunity fire (*0.5 effectiveness!, manual p. 47)

Note that for BzB Normandy, opportunity fire for the allies is actually 2* effectiveness ! (200% modifier in PDT, which is working as described by the way, I checked ). The rest of modifiers noted here are not applicable in the experiment.

[Green]

Thanks for your input. I'm still not seeing a rule which explains that the fire value linearly goes  to zero against hexes which are not fully stacked (edit: but I think Green is right in his last post, that the mortar fire is sort of treated the same way, although not exactly the same and not documented as far as I see. See also edit below)

I agree that this does not seem to be documented but if it works along the lines that I suggested then it appears logical. Not everything is documented and this may have been deliberately omitted to reduce the complexity of what is already an extremely detailed manual. Or perhaps it was overlooked. Either way, to me, it appears to be a feature rather than a bug.

[Mowgli]

"Artillery in Panzer Battles uses the ‘Alternate Indirect Fire Resolution rule’ as standard. In simple terms, you can only fire once, but that fire is doubled in strength and will impact all defending units in hex proportional to their strengths. Mortars and direct fire artillery (infantry guns) do not use this rule and can fire several times in a turn. "

I read this differently: namely that the impact of the fire is divided across the units proportional to their strenghts (i.e. when a large unit and small unit are stacked together, the losses are divided so that the large unit gets more losses than the smaller). Not that the fire value itself is impacted. (besides from the fact that mortars are excluded in the rule wording )

edit: did some testing with artillery. In the case of firing with artillery, the expected attack value seems doubled, and then each unit is attacked proportional to their strength (so indeed also for small units, the fire value goes to zero). For example firing at one infantry unit of 33 men has fire value 16, firing at a hex with three infantry units of 33 men has fire value 16 also, but applied to each unit separately.
(this example is for an attack which would have raw fire value 48, which is then multiplied by 2*33/200 per infantry unit of 33 men).

Yeah, I just started a PBEM for PzCampagins France '40 that also has both alt. fire resolution rules switched on. 
Indeed the wording is not entirely clear. 

"Alternative Indirect Fire Resolution – when this rule is selected, Indirect Fire of non-mortar, non-heavy weapon units is conducted under different rules. First, each such Indirect Fire is doubled in fire value, but the cost of firing is doubled. Second, such Indirect Fire is applied against all units in the target hex, proportional to their strength, instead of being applied against a single target unit."

Just like you, my first thought was that the total artillery fire value would be "split up/spread out" over all the units, with the larger units getting more of the fire than the small ones. But this doesn't make a lot of sense (all units have individual defense values!). Indeed your explanation (and testing) seems much more plausible. So "proportional" does not refer to the size of the unit in relation to that of other units in the hex, but rather just to the overall size of the unit (compared to some pre-determined levels/thresholds). 

I guess it works in a similar way as the "density factor" in Squad Battles: In Squad Battles, fire is always directed at a hex, not at a unit. All units in the hex are affected individually by the same base "fire value" of the firing unit. So each unit in the targeted hex individually applies its factors to that base fire value (cover, protection value, being unspotted, etc), including what's called the "density modifier": The smaller the unit, the greater the reduction of the base fire value. In the case of Squad Battles, the factor is (number of men in the unit /10) --> So when the fire affects a unit with just 1 man, the fire value is reduced to *0.1. If another unit with 9 men is in the same hex, it will also be affected, and more heavily so: by *0.9 of the fire. Just like it seems to be the case in Panzer Battles (which does feature a stacking bonus though!), the "density factor" can never be "positive" (greater than 1). Your numbers suggest that the density threshold in PzBattles is 200. Good to know! :)

But still the question why this affects mortars remains unanswered. Do you have the overall impression that "density" is also applied to all direct fire? (In Squad Battles, it is!) Does it take more direct firepower to achieve casualties against small units than against large ones?

[wololoh]

But still the question why this affects mortars remains unanswered. Do you have the overall impression that "density" is also applied to all direct fire? (In Squad Battles, it is!) Does it take more direct firepower to achieve casualties against small units than against large ones?

I tested infantry as well, their fire values are not affected by the unit density in the target hex (i.e. they work as you would expect based on rules).

I agree that this does not seem to be documented but if it works along the lines that I suggested then it appears logical. Not everything is documented and this may have been deliberately omitted to reduce the complexity of what is already an extremely detailed manual. Or perhaps it was overlooked. Either way, to me, it appears to be a feature rather than a bug.

Well, I personally find this questionable. The mortar fire just becomes so ineffective, even against a full strength German platoon on open ground the fire value becomes almost negligible (namely 2 for my example, which is by the way with a 60mm mortar unit from 327th glider inf).
This linear dependency on the target hex stacking just makes them seem very weak, to the point where they seem to become almost useless in many practical situations.


I would personally prefer something like the rule below (from the manual), which would also make the unit density have an impact, but without becoming extremely ineffective in many normal situations. 

Stack Fire – a modifier applies to Direct fire and Indirect fire from half
the stacking limit (1.0) up to maximum stacking limit (2.0). This
represents the higher casualties due to the increased density in a hex.

But at least by finding out how everything actually works, we can all plan accordingly .

[Mowgli]

I really wonder if this is an oversight? If so, it's a pretty big one. I agree that mortars seem pretty useless.

I also noticed inconsistency regarding the "Hedge Row" hexside obstacles in Pz Battles Normandy. The hexside obstacle which the alternate hex info labels as "Hdg Rows" actually uses the parameters of the "Hedges" entry (NOT those of the "Hdg Row" entry), i.e. the movement costs are lower and it does NOT provide any cover at all against enemy fire. It does render vehicles vulnerable though.