Blowing Up Vehicles

[Atgxtg]

I'm working on setting up a campaign for a specific sci-fi setting. One where characters in vehicles sometimes shoot at other vehicles and vice versa. In the setting various vehicles can often damage or destroy each other with one shot. 

My problem is in adapting the BRP rules.

For example, lets say we have two modern BRP tanks (Armor: 24, Hit Points: 140) shooting at each other with tank guns (15D6). Doing the math, we can see that on average, it will take five hits for one tank to take out the other. Factor in for an impale and it might happen in three. Still too many for the setting.

I've been thinking of ways to achieve the desired results, and am posting them below for other people's opinions and (hopefully) a better alternative.

Option 1: All of Nothing

If an attack gets past the armor the vehicle is destroyed. This is closer to my goal and to how it tends to work out in real life. But it makes hit points worthless, and would break down with bigger vehicles (tank gun takes out battleship).

 

Option 2: Hit Point Save

This is the same as option #1 exact that the vehicle gets a "saving throw" against it's remaining hit points to survive the hit. A roll of 96-00 is always a failure, and a 00 is probably a catastrophic one. It will probably still take several hits to take out a vehicle but at least there is always a chance of a kill.

 

Option 3: BRP Mecha and Resistance Table

The idea here would be to covert every to BRP Mecha scale (1/10) and then compare the incoming damage to the remaining hit points on the resistance table to see if a "kill" is scored. 

 

Anyone got any other ways to handle this in BRP? 

 

 

 

[Joerg]

Vehicles exploding might do so due to a construction flaw (which might be present for cinematic effects) that could be rolled.

Otherwise, the vehicle might have hit locations that catch fire or cause immediate (possibly partial) loss of energy/propulsion and a countdown to explosive malfunction if enough damage is inflicted. Or loss of steering, like popped tyres or a hit to the rear fluke or rotor.

When you write "destroyed", how much recognizable wreckage do you accept? Could a destroyed vehicle still have (badly wounded) survivors?

[Atgxtg]

3 minutes ago, Joerg said:

Vehicles exploding might do so due to a construction flaw (which might be present for cinematic effects) that could be rolled.

They might but it's usually due to an autocannon, rocket, energy beam, nuke, etc. striking the vehicle. 

3 minutes ago, Joerg said:

Otherwise, the vehicle might have hit locations that catch fire or cause immediate (possibly partial) loss of energy/propulsion and a countdown to explosive malfunction if enough damage is inflicted. Or loss of steering, like popped tyres or a hit to the rear fluke or rotor.

Yeah that could work, but it would mean coming up with hit locations, and even then I'm not sure if the attack could do enough to take out a system and knock out the vehicle. For instance, using my tank example, a typical hit is going to get about 28-29 points through the armor, which is less that 25% of 140 hit points.  But it's still an idea. I don't relish having to do up hit location tables for every vehicle, but it might be worth the effort. 

3 minutes ago, Joerg said:

When you write "destroyed", how much recognizable wreckage do you accept? Could a destroyed vehicle still have (badly wounded) survivors?

It varies. In most cases in the primary source they just go boom is a nice fireball,  but sometimes they just are intact but inoperable and one or more survivors get out. Some vehicles have ejection systems. I was thinking of allowing a LUCK roll to escape a destroyed vehicle. Maybe adjust the difficulty based upon how "destroyed" said vehicle is. A vehicle that get's "killed" twice over might be a hard LUCK roll to escape.    

[Gundamentalist]

I don't think your issue is about the rules but about how people seek advantage in combat. Your example is a brute-force example assault on an unknown vehicle. The combatants will slug it out until something happens.

However in combat against a known vehicle, the assailants will be aiming for publicised weak spots, for example, this link details WW2 Soviet knowledge of German Panther weak spots that are suitable for various types of weapons (including your examples of autocannon and rockets). The weak spots will have been identified by prior combat engagements and captured examples and circulated amongst troops facing the known vehicles. The assailants will attempt to place themselves advantageously so they can attack a weak spot. The engaged vehicle will try and minimise the attack vectors against the weak spots.

If you don't know about the weak spots you will have to be lucky instead. Maybe something based on the quality of the attack skill check and a Luck roll. And player-characters and NPCs operating a vehicle with weak spots should operate it in a way to minimise weaknesses as you live longer that way.

So to answer your quandry, I propose that your vehicle stats should include weaknesses. These weaknesses may or may not be known to their enemies. I guess that's down to how you want to run Field Intelligence. Older models' weaknesses will be well known, but new models may enjoy a period of invincibility before any losses or captures.

A hit on a weakness could bypass armour, or automatically kill the engine, or activate another damage subsystem, or some other way of immobilising the vehicle. An immobilised vehicle is a dead vehicle.

On a more abstract level, some sort of tactical advantage rule that adds an advantage to an attack roll which in turn improves the chances of impales may work instead, and could be simpler.

 

[Atgxtg]

1 minute ago, Gundamentalist said:

I don't think your issue is about the rules but about how people seek advantage in combat. Your example is a brute-force example assault on an unknown vehicle. The combatants will slug it out until something happens.

Iit is about the rules because: 

1.  I'm trying to emulate the results of the source setting, which do not match the results of the BPR rule.I'm going to need vehicles to be able to kill each other fairly often with one attack. TO do that I need to alter some rules. 
2. This isn't about how the player see advantages and weaknesses but how weapons actually work against vehicles. In real life (and most fictional setting at least try to factor in a bit of reality) heavy weapons can take out armored vehicles, but that isn't really the case with the BRP stats. In BRP even a critical hit from a LAW rocket (8D6 AP) doing max damage (96 points) through armor, won't kill a modern tank (140 hit points). The weapon just can't do 140 points of damage, and by RAW nothing less can stop or otherwise impair the tank. Any method of altering that means altering the rules. 
3.  BRP game mechanics do not factor in for weak spots, known or otherwise, other than by impales and criticals. To add in a way to exploit such weaknesses would require changing the rules. So yes, my issue is about rules. 
4.  

That said, I like your idea of adding weaknesses. Thanks,  I don't think it addresses my problem but it does make things more interesting, and would help with a specfic vehicle in the setting which pretty much has to be taken down by targeting a particular weakspot. So the idea helps

 

Now if all fairness to BRP, it's based around personal combat, and  was never really designed to handle vehicle combat, beyond the occasional chase. What we got was stuff that was added in piecemeal and the actual values didn't really matter much, since 20 points and 50 points usually mean about the same thing to a character. Dead by 5 points of 500 points doesn't matter.

 

I just looked at some test paper on battlefield statistics and the researcher broke down the "kills" in an interesting way, and one which might mesh with your idea of adding weaknesses. What the paper did was break down kills into catastrophic kills (vehicle go boom), mobility kills (vehicle immobilized), and firepower kills (vehicle weapons disabled).

 

I was thinking that:

A vehicle has to roll against it's current hit points when damaged.

• A roll under hit points means the vehicle is damaged but functioning normally.
  • Maybe the difficulty of this roll could be adjusted based on the hit point state of the vehicle? 
• A roll over hit points means a "kill" of some type.
  • Odd failure means a mobility kill (vehicle stops moving, but is otherwise intact)
  • Even failure means a firepower kill (weapons out but vehicle otherwise okay)
  • A roll that fails by more than 20% is a catastrophic kill (vehicle destroyed, character make a LUCK roll)
• Weaknesses could be factored in by targeting a spot/system and having it apply a modifier to the survival roll for the targeted weakness. For instance targeting mobility or firepower would ensure that they are what get's taken out on a kill, and targeting something for a catastrophic kill could could the kill margin to more than 10%.

 

 

 

 

[SDLeary]

5 hours ago, Atgxtg said:

Yeah that could work, but it would mean coming up with hit locations, and even then I'm not sure if the attack could do enough to take out a system and knock out the vehicle. For instance, using my tank example, a typical hit is going to get about 28-29 points through the armor, which is less that 25% of 140 hit points.  But it's still an idea. I don't relish having to do up hit location tables for every vehicle, but it might be worth the effort. 

How many do you need? Weapon System, Crew Compartment, Power Plant, Motive system, perhaps Nav System. And it would only be needed if armor was penetrated. It's not as if you are going to model vehicle facings, right?

SDLeary

 

[SDLeary]

There is also the option of adding things that have been tried out in other BRP type games, and home brews. Armor Piecing. Perhaps an AP round does fewer dice, and halves armor. 

Also, levels of success... Special gets a mobility kill, critical things go boom. You could even bring in Cthulhu style specials (1/2 chance or less).

SDLeary

[Atgxtg]

8 hours ago, SDLeary said:

How many do you need? Weapon System, Crew Compartment, Power Plant, Motive system, perhaps Nav System.

I don't know. 

8 hours ago, SDLeary said:

And it would only be needed if armor was penetrated.

Barring lights and antennae. I'm not sure 't know if having detail that's not needed is a plus.

8 hours ago, SDLeary said:

It's not as if you are going to model vehicle facings, right?

Well, I'd kinda like to for armor penetration purposes, but probably in an abstract way. Something like a tank loses 4 armor from it's sides, 8 from it rear, 12 from the top. Just to give players a reason to move around behind a tank, or to let aircraft be effective against armor.

 

 

[Atgxtg]

8 hours ago, SDLeary said:

There is also the option of adding things that have been tried out in other BRP type games,

Which isn't much, since few BRP games even have vehicles. So far the most helpful option was the KILL% from one of the Chtlhu variants. Do you know of any others? 

8 hours ago, SDLeary said:

and home brews.

I'm not familiar with any, although I hope someone else is.

8 hours ago, SDLeary said:

 

Armor Piecing. Perhaps an AP round does fewer dice, and halves armor. 

. Keep in mind here that armor isn't the big issue. For example, let's say we took two BRP "modern tanks" and cut the armor off the front of one, then shot at it with the other. 15D6 isn't going to take out (or by RAW, even impair) a 140 hp tank, without either a critical hit (180 points) or a impale that is 4 standard deviations higher than the norm (less likely than the critical).So AP options that reduce the damage just make the problem worse. What I need is a way to either reduce the hit points or maybe divide them against certain weapons. 

The thing is with how BRP works, even if you get 10 or 20 points through the armor, the tank is not impaired. In real life such a hit would trash some of the insides of the tank (and likely some or all of it's crew), heck in real life even a 2 point hit through the armor would do that, but in BRP the tank just loses a few hit point. It's like someone with 14 hit points taking 1 or 2 points of damage with generic hit points. 

That's what I'm trying to find a work around for.

Basically what I need is a way to model the same sort of lethargy that the game has for characters, where one shot can kill. Instead vehicles get hit point attrition. Even with general hit points, a character can take a major wound. But not vehicles. Even someone with 18 hit points can be dropped by 1D6 with a lucky impale or critical, but a vehiclee with 180 hit points cannot be stopped by 10D6, even with a critical. 

 

 

8 hours ago, SDLeary said:

Also, levels of success... Special gets a mobility kill, critical things go boom. You could even bring in Cthulhu style specials (1/2 chance or less).

SDLeary

Specials are already modeled with the impale rule (by RAW only AP weapons can impale vehicles, or at least armored ones). I can add in something for HEAT rounds and such, but the core issue, the high hit points, remains. By RAW a LAW rocket won't make a modern tank go boom even with a critical. It's not likely to make a vintage one go boom either. A lAW rocket, even the original M72 LAW should open up a "Vintage" tank like a tin can. And again, it's not so much the armor that is the issue in BRP, it's the hit points. 

 

[SDLeary]

So, as the issue is a kill, as opposed to complete obliteration of the vehicle, “damage” is applied to what is IN the compartment that is penetrated. So a round entering the engine compartment is applied to the engine. A round entering the crew compartment is applied to the crew, and so on. 

All those hulks littering the battlefield still have armor and hp.

This also provides some side opportunities; perhaps PC’s come across a battlefield and can get a “killed” vehicle going.

A bit more abstract than normal for BRP, but unless your going simulation, a playable option that shouldn’t bog thing down too much.

SDLeary

Edited December 31, 2023 by SDLeary

[Atgxtg]

1 hour ago, SDLeary said:

So, as the issue is a kill, as opposed to complete obliteration of the vehicle,

Somewhat. A lot of the time a kill is a catastrophic kill- that is vehicle and crew are dead. But depending on what shoots what and where, sometimes only the tracks get killed or some such.

1 hour ago, SDLeary said:

“damage” is applied to what is IN the compartment that is penetrated.

Okay but just what does that damage mean? And how much od the damage do we apply. What's left or what was rolled.

1 hour ago, SDLeary said:

So a round entering the engine compartment is applied to the engine.

Okay, let's say our 140 hp tank has an engine that has 25% of total hp, like a hit location. That's 35 hit points, and far more killable with the weapons in game. 

 

Now lets say a tank gun hits the tank and the engine takes 26 points of damage. Now what does that mean? Is it like with characters, that is no effect until the location reaches 0 hp? Or does the tank loose some speed?

1 hour ago, SDLeary said:

A round entering the crew compartment is applied to the crew, and so on. 

Exactly how? Using the example above if the crew compartment takes 26 points of damage does everyone in the compartment take 26 points? What if only 1 point gets through. Realsitically, even if 5% of a the energy of the round gets into the crew compartment it's bad for the crew. We're talking a couple of hundred thousand joules here.

1 hour ago, SDLeary said:

All those hulks littering the battlefield still have armor and hp.

That not really how damage works in BRP though, not even for characters. Even with hit locations a character is still alive until total hit points reaches zero. The only exception is when head, chest or abdomen takes twice it hit points in damage. With 35 point engines that's going to be hard to pull off. Especially with bell curves. Someone rolling 1D6 is going to see a 6 far more often than someone rolling 15D6 is going to see a 90.

That's  actually one of the reasons why Mecha scale appeals to me as an option. Give that tank Armor: 2 Hit Points: 14 in Mecha Scale, give that engine 4 hit points, and let that  15D6 tank gun do 1D10 damage, and suddenly an engine kill becomes a real possibility, as does a 2x engine kill explosion. Even the character works out better as 1 point through is 10 points in character scale, and bad news.  Yeah, that could solve a lot.  It even allows for a total hit point kill with a slightly above average special. 

 

1 hour ago, SDLeary said:

This also provides some side opportunities; perhaps PC’s come across a battlefield and can get a “killed” vehicle going.

Yup. And it's fairly realistic too.  Lots of cases where the crew get fragged but the tank seems fine except for this fist sized hole. Just look at Ukraine.

1 hour ago, SDLeary said:

A bit more abstract than normal for BRP, but unless your going simulation, a playable option that shouldn’t bog thing down too much.

Exactly. That's why I'm trying to find something that is quick, simple, and playable, but can still give acceptable results for the setting. It's not so easy.

BTW, in the source setting most hits are kills, some cause damage/impairment of some kind.  But also, most of the attacks are with weapons designed to shoot at what they are shooting at. 

 

Edited December 31, 2023 by Atgxtg

[sladethesniper]

Hmmm, how close do you want to keep it to regular BRP?

What I have found as a good workaround is to use Probability of Kill (or pK).

Step 1. Roll damage X, subtract armor Y from it = penetrating damage.

Step 2. Pentrating damage/current hit points of thing you are shooting in a percentage AKA the Percentage of instantly kill it.

Step 3. Roll % dice and if the % rolled is less than or equal to, the target is destroyed.

Step 4. If the target is NOT destroyed, subtract the damage from the HP of the object per normal. This reduces the current HP of target making it easier to kill it.

What this does is allow for insta-kills, and if something is "insta-killed" the thing is destroyed BUT still has that much HP able to salvaged off the wreck.

Be aware that a "kill" renders the thing non functional, all the way from damaging the engine so that it can't doesn't work anymore to causing an ammo explosion and it going up in flames.

That is how I do it.

-STS

 

[Atgxtg]

3 minutes ago, sladethesniper said:

Hmmm, how close do you want to keep it to regular BRP?

Good question. I don't want to depart too much, but I have toyed with a KILL% idea so I'm not far off from your model.

3 minutes ago, sladethesniper said:

That is how I do it.

It's pretty much how BTRC's Timelords does it too. Damage is read as a percentage of the total hit points. 

How do you handle the damage/hit point calculation? Do you do it on the fly for each hit? I'd probably want to simply that somehow. Say break hit point total up into 10% chunks. So a 140 hp tank would have a 10% kill chance per 14 points taken. 

 

Thanks.

 

 

 

[g33k]

18 hours ago, Atgxtg said:

I'm working on setting up a campaign for a specific sci-fi setting...

Option 1: All of Nothing

If an attack gets past the armor the vehicle is destroyed. This is closer to my goal and to how it tends to work out in real life. But it makes hit points worthless, and would break down with bigger vehicles (tank gun takes out battleship).

...

12 hours ago, Atgxtg said:

... Now if all fairness to BRP, it's based around personal combat, and  was never really designed to handle vehicle combat, beyond the occasional chase. What we got was stuff that was added in piecemeal and the actual values didn't really matter much, since 20 points and 50 points usually mean about the same thing to a character. Dead by 5 points of 500 points doesn't matter ...

So, your goal is evidently emulating a specific media property (which property is likely (dunno which one) a better match for tank-v-tank combat than BRP is).
I'd prioritize faithfulness to the setting over faithfulness to the BRP ruleset (or any other consideration, really... other than fun / playable rules).

 

But then ...

13 hours ago, Atgxtg said:

... I just looked at some test paper on battlefield statistics and the researcher broke down the "kills" in an interesting way, and one which might mesh with your idea of adding weaknesses. What the paper did was break down kills into catastrophic kills (vehicle go boom), mobility kills (vehicle immobilized), and firepower kills (vehicle weapons disabled) ...

 

8 minutes ago, Atgxtg said:

... Lots of cases where the crew get fragged but the tank seems fine except for this fist sized hole. Just look at Ukraine ...

So it seems like real-world "accuracy" (realism vs. modern battlefields) is also a priority (maybe your media of choice features this?).
I think it's worth clarifying this issue, both for us (so we can give better discussion); and for you (so your own project is closer to your wants & needs)!

Honestly, I'm inclined to largely abandon BRP's model of "combat" here, with HP's and AP's and such.
These "points" aren't the same thing; they aren't on the same scale.  In traditional BRP combat, the same HP's that damage your foe are used to penetrate armor.  But tank armor is so overpowered that hurting the people inside the tank is just automatic, if you've blown through the armor and reached the squishy. 

Anything that gets through modern tank armor destroys the system it hits... engine, main gun, crew-cabin, etc.  If what it hits is the ammo-chamber, then an internal explosion destroys EVERYTHING inside the tank (some of the more-damaging anti-tank rounds are themselves damaging-enough to also have that "destroys everything" effect).  This looks to me like a modification of your "all or nothing" result, above.

I'd focus your system on this feature.

Honestly, modern armored-warfare a lot more about having the better gear, and less about the "skill" of the "combatants..."  the skill-centric BRP game-engine isn't your best mechanical approach.  Just look at WWII & the German Panther & Tiger results vs. America's best, the Sherman.

[sladethesniper]

20 minutes ago, Atgxtg said:

Good question. I don't want to depart too much, but I have toyed with a KILL% idea so I'm not far off from your model.

It's pretty much how BTRC's Timelords does it too. Damage is read as a percentage of the total hit points. 

How do you handle the damage/hit point calculation? Do you do it on the fly for each hit? I'd probably want to simply that somehow. Say break hit point total up into 10% chunks. So a 140 hp tank would have a 10% kill chance per 14 points taken. 

 

Thanks.

 

 

 

Going by hit point chunks works, but since I am a wargamer, I have a calculator handy so I go down to the 1%.

-STS

[Atgxtg]

3 minutes ago, g33k said:

So, your goal is evidently emulating a specific media property (which property is likely (dunno which one) a better match for tank-v-tank combat than BRP is).
I'd prioritize faithfulness to the setting over faithfulness to the BRP ruleset (or any other consideration, really... other than fun / playable rules).

Yup.

3 minutes ago, g33k said:

But then ...

 

So it seems like real-world "accuracy" (realism vs. modern battlefields) is also a priority (maybe your media of choice features this?).
I think it's worth clarifying this issue, both for us (so we can give better discussion); and for you (so your own project is closer to your wants & needs)!

Ah. In the setting, vehicle can get damaged as well as destroyed. So it's a win win.

3 minutes ago, g33k said:

Honestly, I'm inclined to largely abandon BRP's model of "combat" here, with HP's and AP's and such.
These "points" aren't the same thing; they aren't on the same scale.  In traditional BRP combat, the same HP's that damage your foe are used to penetrate armor.  But tank armor is so overpowered that hurting the people inside the tank is just automatic, if you've blown through the armor and reached the squishy. 

I know the feeling, but if I abandon the BRP model here, why use BRP for the rest? I mean other than being a BRP fan. These days thre are alternatives that can handle vehicles better and still have a good skill based game for the PCs.  

3 minutes ago, g33k said:

Anything that gets through modern tank armor destroys the system it hits... engine, main gun, crew-cabin, etc.  If what it hits is the ammo-chamber, then an internal explosion destroys EVERYTHING inside the tank (some of the more-damaging anti-tank rounds are themselves damaging-enough to also have that "destroys everything" effect).  This looks to me like a modification of your "all or nothing" result, above.

Pretty much. THe idea of some sort of save is there both to keep hit points relavant, and to give PCs some chance of surival. SOmething that happens in both real life and in the setting. Heck in real life one on the resons why things are arranged the way the are in a tank is to give the crew added protection. A round that hits the engine probably wont be killing the crew too.

3 minutes ago, g33k said:

I'd focus your system on this feature.

It's in the lead right now. That or Mecha scale with hit locations. The latter being more BRP ish.

3 minutes ago, g33k said:

Honestly, modern armored-warfare a lot more about having the better gear, and less about the "skill" of the "combatants..."  the skill-centric BRP game-engine isn't your best mechanical approach. 

Oh skill is important, but a big tech advantage helps.  It's just that the leaps in technology are more pronounced. 

3 minutes ago, g33k said:

Just look at WWII & the German Panther & Tiger results vs. America's best, the Sherman.

Probably a bad example. WWII really showed that manufacturing and logistics are key. It doesn't really matter if the enemy has a bigger badder gun and twice the armor if you can out produce him ten to one, plus supply all your allies. 

[Atgxtg]

16 minutes ago, sladethesniper said:

Going by hit point chunks works, but since I am a wargamer, I have a calculator handy so I go down to the 1%.

-STS

LOL. I used to program my Tandy PC4 to calculate Skill Category Modifiers, Total Hit Points, and Hit Points per location. 😁

[SDLeary]

10 hours ago, Atgxtg said:

Okay but just what does that damage mean? And how much od the damage do we apply. What's left or what was rolled.

I would say that it's armor, so treat it as Armor! Deduct armor value, rest is passed to the items inside, rather than vehicle HP.

HP is deducted when the vehicle is abused... for example all those videos put out by their producers that show them jumping, as if at an old style Evil Kineval show.

10 hours ago, Atgxtg said:

Now lets say a tank gun hits the tank and the engine takes 26 points of damage. Now what does that mean? Is it like with characters, that is no effect until the location reaches 0 hp? Or does the tank loose some speed?

Reduced performance of some type. Speed, yes perhaps. Perhaps the cooling system was hit and the vehicle is now beginning to overheat (time limit).

10 hours ago, Atgxtg said:

Exactly how? Using the example above if the crew compartment takes 26 points of damage does everyone in the compartment take 26 points? What if only 1 point gets through. Realsitically, even if 5% of a the energy of the round gets into the crew compartment it's bad for the crew. We're talking a couple of hundred thousand joules here.

You mentioned HEAT rounds before. Assuming that, I would apply it to all (fire damage). Remember though that crews normally wear something along the lines of NOMEX. A kinetic round I'd say a Luck roll to see if your hit by shrapnel, using rules similar to grenades. In both cases a CON roll to see if they are knocked out (fumble?) or concussed.

 

10 hours ago, Atgxtg said:

That not really how damage works in BRP though, not even for characters. Even with hit locations a character is still alive until total hit points reaches zero. The only exception is when head, chest or abdomen takes twice it hit points in damage. With 35 point engines that's going to be hard to pull off. Especially with bell curves. Someone rolling 1D6 is going to see a 6 far more often than someone rolling 15D6 is going to see a 90.

That's  actually one of the reasons why Mecha scale appeals to me as an option. Give that tank Armor: 2 Hit Points: 14 in Mecha Scale, give that engine 4 hit points, and let that  15D6 tank gun do 1D10 damage, and suddenly an engine kill becomes a real possibility, as does a 2x engine kill explosion. Even the character works out better as 1 point through is 10 points in character scale, and bad news.  Yeah, that could solve a lot.  It even allows for a total hit point kill with a slightly above average special. 

In the case of vehicles like this, I'm seeing the "damage" as simply a way through the armor. Once through the armor, it's often secondary effects that cause the kill. The launching of turrets into orbit is the result of a critical hit (and I would argue this chance should be doubled on many Russian/Soviet designs).

I'm not familiar enough with the Mecha scale stuff to comment.

SDLeary

[Atgxtg]

1 hour ago, SDLeary said:

I would say that it's armor, so treat it as Armor! Deduct armor value, rest is passed to the items inside, rather than vehicle HP.

I'd figure it would be like with people, that is damage comes off of location/system and total hit point. THe idea being that like with a person, you might have a vehicle so banged up that it stops working even though no system is disabled. 

 

 

1 hour ago, SDLeary said:

You mentioned HEAT rounds before. Assuming that, I would apply it to all (fire damage). Remember though that crews normally wear something along the lines of NOMEX. A kinetic round I'd say a Luck roll to see if your hit by shrapnel, using rules similar to grenades. In both cases a CON roll to see if they are knocked out (fumble?) or concussed.

OKay, We're on similar ground here. 

1 hour ago, SDLeary said:

 

In the case of vehicles like this, I'm seeing the "damage" as simply a way through the armor. Once through the armor, it's often secondary effects that cause the kill. The launching of turrets into orbit is the result of a critical hit (and I would argue this chance should be doubled on many Russian/Soviet designs).

Yes,it's just figuring out how. I'm going to have to bend a few BRP rules but it should work.

 

1 hour ago, SDLeary said:

I'm not familiar enough with the Mecha scale stuff to comment.

Okay, let me give you the quick version.

IN BRP Mocha, large machines (mecha) are given thier own scale. Each point on the mecha scale is 10 points of normal damage. Weapons, armor and hit points are all scaled. Thus a tank with Armor: 20, Hit Points: 140 would have Armor: 2 Hit Points: 14 in mecha scale. Since weapons are scaled a weapon that would do 10D6 normally would do one-tenth that, or 1D6 in Mecha Scale.

One of the game effects of this is that you get a lore more variance in the damage rolls. While it's hard to get 50 points or more  on 10D6 (0.29%), it's a lot easier to get 5 or more on 1D6 (33.33%).  That's good for vehicle combat, since it gets us out of the bell curve of lots of dice, and the 68-95-97.5 rule.. Mechanically it would be the same as rolling 1D6x10. Now Mecha has hit locations (for giant robots anyway) too, although it might work with a major damage (major wound) rule for hits of half total HP , and a major damage table. 

 

But hit locations let people target specific areas.

[sladethesniper]

If you are ok with scaling... just play Palladium or import in the mega-damage system. I have found that even though the numbers are 'big" they are much more internally consistent as they are linear and map fairly well to real world joules/foot pounds/penetration tests, as opposed to some shady logrithm that is never explained in a role playing book.

Weird to think that anything Palladium does is "realistic"... it was probably by accident, but I have run the numbers several times over the decades.

-STS

[SDLeary]

13 hours ago, Atgxtg said:

I'd figure it would be like with people, that is damage comes off of location/system and total hit point. THe idea being that like with a person, you might have a vehicle so banged up that it stops working even though no system is disabled. 

 

Yes, but I would say that would be determined by "where" it hits. If it hits the Crew Compartment, then the crew itself is directly affected. If you hit the Engine Compartment, you could have it come off of vehicle HP, or have some mechanism to affect the engine directly. Same with Nav System, Fire Control, Motive Systems, and so on.

You could go further with hit locations and actually give them individual location points, but it seems cumbersome to create though not necessarily during play if you are using Locations for characters. This would allow you to have differing location HP values to ablate before things actually do bad things to said compartment and its contents.

Mythas Imperative (ORC)  uses Hull (armor) and Structure (HP). If you want to retain HP, and still have systems affected, they have an interesting method:

Quote

Whenever a vehicle suffers harm, the incoming damage is reduced by its Hull value. Any remaining damage is subtracted from the vehicle’s Structure points and has a percentage chance (equal to the penetrating damage) of affecting a System. If the vehicle is ever reduced to zero Structure it is either utterly destroyed, or so badly wrecked it must be scrapped.

Note also though that in Mythras, vehicles do have slightly different values... for example Battle Tank is listed as 15/100 (Hull/Structure)

SDLeary

[Atgxtg]

47 minutes ago, SDLeary said:

Yes, but I would say that would be determined by "where" it hits. If it hits the Crew Compartment, then the crew itself is directly affected.

Yeah but it's not like the crew gets shredded, leaving the rest of the compartment in pristine shape. SO if the vhicle took 10 points to the crew compartment, crew make LUCK rolls and the vehicle take 10 hit points worth of general damage.

BTW, I was thinking that for the LUCK roll, the difficulty would be based on the damage compared to the character's hit points. 

Damage <1/2 HP:Easy

Damage>HP: Hard

Failure means the character takes frag damage (4D6); success means only 2D6, special 1D6, and a critical means the character walks away without a scratch.

 

47 minutes ago, SDLeary said:

If you hit the Engine Compartment, you could have it come off of vehicle HP, or have some mechanism to affect the engine directly. Same with Nav System, Fire Control, Motive Systems, and so on.

I was thiking of treating it like with characters. THe damage comes off the location/system and from general hit points. 

47 minutes ago, SDLeary said:

You could go further with hit locations and actually give them individual location points, but it seems cumbersome to create though not necessarily during play if you are using Locations for characters. This would allow you to have differing location HP values to ablate before things actually do bad things to said compartment and its contents.

Yeah. It's a trade off between characters being able to target specific parts (tracks, main gun, engine, fuel tank,etc.) and the simplicity of just using a major wound mechanic, along with a a "major damage table" that could allow for a lot more results (taking out some lights, the antenna, night vision optics, the radio). 

Perhaps it I did up the table in increasing severity? That way someone could still target a specific system. 

47 minutes ago, SDLeary said:

Mythas Imperative (ORC)  uses Hull (armor) and Structure (HP). If you want to retain HP, and still have systems affected, they have an interesting method:

And it's free, too. I'll give it a look.

47 minutes ago, SDLeary said:

Note also though that in Mythras, vehicles do have slightly different values... for example Battle Tank is listed as 15/100 (Hull/Structure)

Not a problem since their weapons also do different damage.

Oh, and I do have a formula for working out armor value by thickness that I was planning on using. 

 

It kinda comes down to how close I want to keep this to the stats presented in the BRP core book, and CoC supplements. If I didn't use the BRP stats I could just base the armor and weapon values off of real world thicnkness and penetration data(RHAe). I'm trying to keep the values mostly compatible though. 

 

47 minutes ago, SDLeary said:

SDLeary

Thanks. 

[SDLeary]

36 minutes ago, Atgxtg said:

Yeah but it's not like the crew gets shredded, leaving the rest of the compartment in pristine shape. SO if the vhicle took 10 points to the crew compartment, crew make LUCK rolls and the vehicle take 10 hit points worth of general damage.

BTW, I was thinking that for the LUCK roll, the difficulty would be based on the damage compared to the character's hit points. 

Damage <1/2 HP:Easy

Damage>HP: Hard

Failure means the character takes frag damage (4D6); success means only 2D6, special 1D6, and a critical means the character walks away without a scratch.

 

That sounds like it would work well!

SDLeary

[Atgxtg]

5 hours ago, SDLeary said:

That sounds like it would work well!

SDLeary

That's good, because I changed it! 😁

In retrospect I don't see why a character with more hit points would be less likely to catch some shrapnel. So I changed it to the damage that the compartment takes. I think it makes more sense that a character get's injured if the compartment he is in get's blown to bits around him.  Like so: 

 

 

[Atgxtg]

Just a thought, but what if damage to locations came off the vehicles stats?

For instance, if using Mecha scale (10 to 1) then a point of damage to the engine or propulsion system (wheels, tracks) could come off the vehicles Rated Speed. So an APC with a Rated Speed of 7 that too 2 points of damage to it's tracks would lose 2 points of Rated Speed  and move at Speed 5. When Speed hits 0 the vehicle can n longer move.

 Damage to steering could apply a -5% to handling per point; damage to a weapon could affect's it's targeting ability (-5% to hit per point) with the weapon becoming inoperable at zero hit points, and and so on down the line.