Quote:
Originally Posted by electrum
3. Rigid armor
I have a judgment call to ask about for rigid armor. The blunt trauma mechanic only applies to flexible armor, and only if all the damage is absorbed. Because almost all other weapons are cutting/impaling, this puts crushing weapons at a pretty clear disadvantage.
Historically, maces/warhammers were used explicitly to deal with plate armor, but GURPS doesn't seem to reconcile this.
My friend suggests that maces are designed to deal with higher DR, rigid armor with their straight bonus damage. However, a steel breastplate is DR 5. Which means that my guy, with a weapon explicitly designed to counter rigid armor, with his 1d+3 damage, can only do a maximum of 4 damage to a knight's chest. This just seems incongruous to me, considering that in allknight situations, typical weaponry was pretty much entirely maces or warpicks.

I fail to see your problem with blunt trauma. First, blunt trauma only applies to flexible armor and in the Basic Set those flexible armors are specifically called out by being marked with an asterisk. Flexible armor applies to most damage types, it doesn't matter if it's crushing, cutting, impaling or any of the various piercing attacks, they're all affected by the blunt trauma rule. As per Basic Set (p379) blunt trauma requires a
full 5 points of damage to be absorbed by the armor in order to inflict 1 point of blunt trauma injury for a crushing weapon but a
full 10 points of damage to be absorbed by the armor in order to inflict 1 point of blunt trauma injury for any of the other mentioned types of damage. It also specifies that no blunt injury damage occurs if any damage actually gets through the flexible armor's DR.
So, let's pick a couple of weapons (thrusting broadsword, mace and flintlock pistol) and see how they do against rigid and nonrigid armor. For our purposes everybody is ST 10 for basic damage and skill doesn't matter since we're assuming a successful hit. This gives us 1d+1 cut or 1d imp for our thrusting broadsword depending on whether we slash or thrust with it, 1d+3 cr with our mace and 2d1 with a .51 flintlock pistol.
A double mail hauberk is flexible armor with DR5/3.
If we slash with our broadsword, we will only penetrate the armor on a roll of 5 or 6, which will allow either 1 or 2 points of damage to get through and it is multiplied by 1.5, so we do either 2 or 3 points of injury.
If we roll a 4, then we do 5 points of damage which is fully absorbed by the armor and, as it is not 10 full points of damage, no blunt trauma injury occurs.
Since nothing in the blunt trauma rules implies that the damage accumulates from round to round, we can never give blunt trauma from a ST 10 character wielding this weapon in that manner.
The average injury done by our thrusting broadsword when it slashes against a double mail hauberk is ([0 + 0 + 0 + 0 + 2 + 3] = 5/6 points of injury.
If we thrust with our broadsword, we only penetrate the armor on a roll of 6, which will allow 1 point of damage to get through and it is multiplied by 2, so we do 2 points of damage.
If we roll a 5, that damage is fully absorbed by the armor and again, as it isn’t 10 full points of damage, there is no blunt trauma injury.
The average injury done by our thrusting broadsword when it is thrust against a double mail hauberk is [0 + 0 + 0 + 0 + 0 + 2] = 2/6 points of injury.
The .51 flintlock pistol penetrates the armor on a roll of 7, 8, 9, 10, 11 or 12, which allows 1, 2, 3, 4, 5 or 6 points of damage to penetrate and it is multiplied by 1.5 for 2, 3, 5, 6, 8 or 9 points of injury.
A roll of 6 will be fully absorbed and again, it is less than 10 full points of damage, so no blunt trauma occurs.
The average injury done by our pistol when fired against a double mail hauberk is
[0 + 0x2 + 0x3 + 0x4 + 0x5 + 2x6 + 3x5 + 5x4 + 6x3 + 8x2 + 9x1] = [12 + 15 + 20 + 18 + 16 + 9] =
90/36 = 2 3/6 points of injury.
Because our mace is a crushing weapon, the double mail hauberk only gets DR 3.
The mace penetrates on a roll of 1, 2, 3, 4, 5 or 6 doing 1, 2, 3, 4, 5 or 6 points of damage which is multiplied by 1 for the same number of points of injury.
Since the mace always penetrates, the blunt trauma rules never come into play.
The average damage done by our mace when it strikes against a double mail hauberk is
[1 + 2 + 3 + 4 + 5 + 6] = 21/6 = 3 3/6 points of injury.
A heavy steel corselet is rigid armor with DR 7. Since it is rigid armor, blunt trauma doesn’t apply. I.E., if no damage actually penetrates the armor, no damage is taken.
If we slash with the thrusting broadsword and roll a 6, we do 7 points of damage which is completely absorbed by the DR of the armor, so no damage gets through.
The average damage done by our thrusting broadsword when slashing a heavy steel corselet is 0 points of injury.
If we thrust with our thrusting broadsword and roll a 6, we do 6 points of damage which is completely absorbed by the DR of the armor, so no damage is done.
The average damage done by our thrusting broadsword when thrusting is 0 points of injury.
If we fire our .51 flintlock pistol, we penetrate the armor on a roll of 9, 10, 11 or 12, doing 1, 2, 3 or 4 points of damage which is multiplied by 1.5 for 2, 3, 5 or 6 points of damage.
The average damage done by our pistol when fired into a heavy steel corselet is
[0x1 + 0x2 + 0x3 + 0x4 + 0x5 + 0x6 + 0x5 + 1x4 + 2x3 + 3x2 + 4x1] = [4 + 6 + 6 + 4] =
20/36 points of injury.
Our mace penetrates the armor on a roll of 5 or 6 for 1 or 2 points of damage multiplied by 1 for the same points of injury.
The average damage done by our mace when it strikes a heavy steel corselet is
[0 + 0 + 0 + 0 + 1 + 2] =3/6 points of injury.
Since none of our worked examples caused any blunt trauma injury, let’s do an example that does invoke those rules.
The armor is a TL 9 Tactical Suit which is flexible armor with DR 20/10 and we’ll use two weapons, a maul wielded by a ST 13 warrior and a 5.56 mm TL7 Assault Rifle.
The maul does 2d+3 damage and the assault rifle does 5d.
The armor is DR 10 to the maul which then penetrates it on a roll of 8, 9, 10, 11 or 12, doing 1, 2, 3, 4, or 5 points of damage which is multiplied by 1 for the same number of points of injury.
On a roll of 7, 10 full points of damage are done but fully absorbed by the armor thereby doing 2 points of blunt trauma injury (1 for each full 5 points of absorbed damage).
A roll of 2, 3, 4, 5 or 6 does 5, 6, 7, 8 or 9 points of damage which is fully absorbed by the armor and as all of these amount to a full 5 points of damage each inflicts 1 point of blunt trauma injury.
The average damage done by the maul is
[1x5 + 2x4 + 3x3 + 4x2 + 5x1] = [5 + 8 + 9 + 8 + 5] = 35/36 points of damage from penetration and
[1x1 + 1x2 + 1x3 + 1x4 + 1x5 + 2x6] = [1 + 2 + 3 + 4 + 5 + 12] =
27/36 points from blunt injury trauma where the weapon didn’t penetrate the armor
for a grand total of 1 26/36 points of injury.
The armor is DR 20 to the assault rifle which then penetrates it on a roll of 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 doing 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 points of damage multiplied by 1 for the same number of points of injury.
On a roll of 20, 20 points of damage are done but fully absorbed by the armor doing 2 points of blunt trauma injury (1 for each full 10 points of injury).
A roll of 10, 11, 12, 13, 14, 15, 16, 17, 18 or 19 is also fully absorbed by the armor and as all of these amount to 10 full points of damage each inflicts 1 point of blunt trauma injury.
The average damage done by the assault rifle is:
[1x540 + 2x420 + 3x305 + 4x205 + 5x126 + 6x70 + 7x35 + 8x15 + 9x5 + 10x1] = [540 + 840 + 915 + 820 + 630 + 420 + 245 + 120 + 45 + 10] =
4585/7776 points of injury from penetration and
[1x126 + 1x205 + 1x305 + 1x420 + 1x540 + 1x651 + 1x735 + 1x780 + 1x780 + 1x735 + 2x651] = [126 + 205 + 305 + 420 + 540 + 651 + 735 + 780 + 780 + 735 + 1302] =
6579/7776 points of blunt trauma injury where the bullet did not penetrate the armor
for a grand total of 1 3388/7776 points of injury.
From these examples we can see a few things:
First, the mace was a better choice than either the thrusting broadsword or the flintlock pistol against the double mail hauberk, doing 140% times as much damage on average compared with the pistol and either 420% or 1050% as much damage on average compared with the thrusting sword, depending on how it was employed.
Second, the mace was an infinitely better choice against the heavy steel corselet compared to the thrusting broadsword which couldn’t penetrate it at all and marginally worse than the pistol at 90% of the pistol’s average damage.
Third, blunt trauma injuries increased the average damage from the maul by, very roughly, 50% and more than doubled the average damage caused by the assault rifle. Put the other way around, flexible armor let anywhere from 150% to more than 200% damage through as to compared to rigid armor with the same DR, solely as a result of rigid armor providing complete protection against blunt trauma injuries.