GURPS Heavy Gear

[Mark Skarr]

I sat down to try, once again, to convert Heavy Gear to GURPS. I am aware that, hopefully, in the near future we’ll hear something about the new edition of SILCore. But, me, I’m anxious.

I discovered, and I don’t know why I never saw this before, that Heavy Gear’s armor rating is based off of a measurable number: Base Armor Value = Square Root (mm of Armor Grade Steel). Heyyyyyyy, we have a value for that in GURPS. Checking their weapons, they also list the weapons Maximum Effective Range (sounds like our ½D range) and a penetration value (how many mm of armor grade steel they can regularly penetrate).

So, a Gear’s frontal armor rating would be DR (((AV²)/25.4)×70). So, an HACS-01MG-MP Hunter’s frontal armor value of 15 would be a DR of 620.

Alright, the Hunter also masses 6,627 kg, so that would give it a ST/HP of 98. I'd wind up calling it 100, but that's just me.

Weapons become a bit more problematic:

The M222 Autocannon Rifle (LAC) that the Hunter carries as its primary weapon has an armor penetration of 65mm. That means that an average hit will only penetrate 179 points of DR (it’s roughly a 5dx10 pi++ weapon). That’s not nearly as problematic in Heavy Gear as it is in GURPS, since damage in Heavy Gear is a multiplier that is based on your Margin of Success.

The LAC in Heavy Gear has a Damage of x8. So, a hit by 1 means you plink off the Hunter’s armor, but a hit by 2 does a light damage roll to it. But, no matter how much damage you roll, you’ll never hurt a Hunter with its own gun in GURPS.

If you consider the RP-109 Pepperbox (LRP/24) the Hunter primary weapon, things get slightly better. It has a penetration of 140mm which allows it to penetrate DR 386 on an average hit (fundamentally, it’s a 5dx22 cr ex weapon). That’s better, but it would still require a phenomenal hit to do much more than scratch the paint on a Hunter.

Also, in Heavy Gear, you can buy Armor Piercing ammo for a weapon. This trait halves the armor value of the target (much like a GURPS Armor Divisor of (2)). However, it prevents the ability to overkill a vehicle, the best you can do is get a heavy damage, as the attack will over-penetrate.

So, my problem becomes: do I tack a (2) to each weapon, even though this would cause heavier weapons to obliterate the Hunter (like the Junglemower-10 which has a Damage Value of x15 [230mm armor pen], and does 6dx30 pi++)? Or does anyone else have any suggestions?

The reason I chose an HACS-01MG-MP Hunter, is that it is the ubiquitous Gear.

[Tema69]

Well, I don't know much about Heavy Gear rules, but wouldn't it be possible to compare "succeeding by 2" with "critical hit"? Assuming the gunner has a good skill, he'd get that fairly often?

Just my 2cents. :)

[lexington]

Perhaps the Hunter had Hardened Armor to protect itself from the armor piercing weapons?

[Mark Skarr]

Originally Posted by Tema69

Well, I don't know much about Heavy Gear rules, but wouldn't it be possible to compare "succeeding by 2" with "critical hit"? Assuming the gunner has a good skill, he'd get that fairly often?

I appreciate the input, any suggestions might help.

Succeeding by 2, while challenging for regulars or greens, is dirt simple for veterans and/or deulists. It would be like succeeding by 4 for a person will a skill of 12 and a person with a skill of 16.

Also, in Heavy Gear while you make a to-hit roll, your opponents make an active dodge roll. And the Damage is multiplied by that margin. So, if you're lucky and your opponent is not, you can get some decent margins.

Originally Posted by lexington

Perhaps the Hunter had Hardened Armor to protect itself from the armor piercing weapons?

In theory, all Gears would have some level of hardening. However, this is not normally the case. Specifically, the Hunter is no more special than a stock HMMWV (other than having a special place in the hearts of Terra Novans). That's why I chose it.

Also, this would defeat the purpose of putting an armor divisor on all weapons since we're back at square one.

[mlangsdorf]

Having thought about this in the past, I'd recommend calculating armor penetration base on an MoS 2 hit. That would give the LAC an armor penetration of 256mm, sufficient to penetrate a Hunter/Jaeger's armor but not good enough to reliably damage the bits inside. The LRP would have an armor penetration of 676mm, more than sufficient to blow through a Hunter's armor and damage stuff inside.

The other thing to consider is that a Junglemower VHAC can and should obliterate a Hunter. Even the most minimal hit has something like a 10% chance of blowing up something critical (Fire Control or Structure Hit that kills the gear); a solid (MoS2+) hit will either kill the pilot or destroy the gear outright.

[Mark Skarr]

Originally Posted by mlangsdorf

Having thought about this in the past, I'd recommend calculating armor penetration base on an MoS 2 hit. That would give the LAC an armor penetration of 256mm, sufficient to penetrate a Hunter/Jaeger's armor but not good enough to reliably damage the bits inside. The LRP would have an armor penetration of 676mm, more than sufficient to blow through a Hunter's armor and damage stuff inside.

That’s a very good idea, I wish I'd thought of it. However, we do run into the problem that, in GURPS a Gear would have Hit Points. A Hunter only has 100 HP. That LRP hit would do an average of 1,863 points of damage (based on its armor penetration). That would smoke through the Hunter’s DR of 620 and reduce the vehicle to -10xHP from a single rocket.

Go directly to bits. Do not pass go. Do not collect two-hundred marks.

Originally Posted by mlangsdorf

The other thing to consider is that a Junglemower VHAC can and should obliterate a Hunter. Even the most minimal hit has something like a 10% chance of blowing up something critical (Fire Control or Structure Hit that kills the gear); a solid (MoS2+) hit will either kill the pilot or destroy the gear outright.

Mmmmm. Junglemower-10. Sorry, that weapon just moves me.

Actually, a MoS2 would potentially cripple a Hunter (damage of x30), but according to the GURPS math, that hit would grey-mist a Hunter.

It’s a one-in-thirty-six chance, a light damage results in a pilot being killed (they have to roll a 2, then a 6). It’s not possible to “destroy” a gear on one light damage hit. And, while there is actually a chance of blowing the vehicle up with a heavy damage, there is also a chance that the crew survives that.

[Mark Skarr]

Okay, the problem with GURPS Heavy Gear keeps coming to me as Hammer+Eggshell. A weapon that, in Heavy Gear, can average some light damage on a Hunter is simply not going to be able to get through its DR. A weapon that can average some heavy damage is going to smoke the Hunter outright.

I think, this is an artifact of DP9 stating (and providing numbers that “prove”) the armor/damage values are exponential, while the game rules make them linear. A x19 weapon is not, fundamentally, scarier than a x15 weapon to someone in a Hunter (though a x23 weapon is). However, according to the math they give us, a x16 weapon should make someone with an Armor Value of 15 tremble: a x15 weapon/AV 15 would average 620 points of damage/DR, and a x16 weapon would average 706; that Hunter has 14 hit points left. Gentle Prophet forbid that x16 weapon rolls slightly above average damage.

In Heavy Gear a LAC, MAC and HAC won’t hurt a Hunter on an MoS of 1, will do light damage on an MoS of 2, and heavy damage on an MoS of 3 (4 for a LAC). A MoS 4 will destroy a Hunter from a HAC, a MoS 5 for a MAC, and a MoS 6 for a LAC.

In GURPS a LAC does ~51d of damage (x8 in HG), a MAC does ~79d of damage (x10 in HG), and a HAC does ~114d of damage (x12 in HG).

So . . . in my finite wisdom, how does this sound:

DR =2x(AV²)

Taking mlangsdorf's suggestion:
Damage = 2x average damage to penetrate equal AV's DR (3)

This means that a Hunter would have a DR of 450 and it’s LAC would do 6dx5 (3) pi++. A spectacular hit would get some damage through the Hunter’s DR. A MAC would do 5x9 (3) pi++, just barely enough on an average hit to get a little bit through. A HAC would do 6dx11 (3) pi++, which would seriously damage a Hunter.

I'll deal with shaped charge/special weapons a bit later.

Questions, comments, suggestions . . . anvils to the codpiece.

[lexington]

Just tossing an idea out:

Why not treat all attacks as triplex rounds? That way the damage can be very high against weak targets but still bounce off large ones.

3d vs DR5 = 5 damage
3d vs DR0 = 10 damage
1d+1d+1d vs DR5 = 0 damage
1d+1d+1d vs DR0 = 10 damage

You can even adjust recoil as needed to get the MoS effect you want.

Of course I don't know much about Heavy Gear and my math skills aren't up to snuff with most people around here so this might cause a serious problem somewhere else.

[Mark Skarr]

lexington,

I appreciate the input. However, our problem is, actually, the opposite of your suggestion: We need a weapon that can damage heavily armored targets, but not obliterate lesser armored targets (a common GURPS conundrum) in the same hit.

Exacerbating the problem is how few Hit Points the Hunter has, in comparison to its DR. And, honestly, I'd rather not just increase its Hit Points.

Your suggestion actually gives me an idea of how to make small pulse lasers work better in my GURPS BattleTech conversion. I’ll have to check that out when I get home.

[lexington]

Originally Posted by Mark Skarr

lexington,

I appreciate the input. However, our problem is, actually, the opposite of your suggestion: We need a weapon that can damage heavily armored targets, but not obliterate lesser armored targets (a common GURPS conundrum) in the same hit.

Well now I feel silly.

Originally Posted by Mark Skarr

Exacerbating the problem is how few Hit Points the Hunter has, in comparison to its DR. And, honestly, I'd rather not just increase its Hit Points.

No offense but, why not? If you want to maintain the feel of the game you should slide around DR and HP values until they're close to what you want. It seems to me that Heavy Gear and GURPS make a few key assumptions differently and that is preventing a direct conversion from working. I guess this is why I got confused, if some things need to be more durable just make them more durable.

I have to say I'm curious where you got this equation for DR: (((AV²)/25.4)×70)