[LT] Leather (& Textile) weight issues and Scaling to size.

[Trachmyr]

I've been trying to put together a comprehensive set of leather (& Textile) clothing/armor creation rules, but I am having serious trouble reconciling them with Low-Tech.

Standard Armor-Weight leather is 13/15 oz, this is per square foot. Lighter Leather would be 7/8 oz for DR1 versions (recently often called LARP weight), 3/4 oz for heavy garment/moccasin weight (DR0* +1 vs. Cutting), and 1.5/2.5 oz for Garment weight (no DR, treat as Ordinary Clothing).

Low-Tech seems to base armor on using 13/15 oz armor-grade leather weight at over DOUBLE the the surface area of a male.

For example, if I were to make in actualtity, a real, but simple leather curiass, from armor-grade Leather (13/15oz per square foot), I would need a 28in x 44 in project piece. This would leave the arms bare at the shoulder down, and would cover the chest and abdomen, but not groin. Total material weight would be 7.5 pounds without removing material for fitting... which with my skill level (Dabbler w/ Decent IQ & Taking extra time), would be a wash with the straps and buckles I would need to add. By Low-Tech, a fitted curiass covering those regions would weigh 11.4 pounds, maybe a bit less if I consider that it doesn't offer full protection to the abdomen, at 3in6 coverage (which is definately less than what my example is) this still would be 10.2 pounds, more than a third heavier!

Here's a simple one, a pair of vambraces, I would start out with two rectangular pieces of 13x10 inches, and 13/15oz weight. Weight would be about 1.6 pounds after removing trimmed material towards the wrist, but adding cords and eyelets. By Low-Tech, the weight would be 2.4 pounds! I'm constantly finding Low-Tech to be about 50% heavier than simple, barely-fitted, amateur efforts in the real world.

...and that's not taking into effect that I'd be a ST-12, 225-pound guy by GURPS rules... trying to outfit a 130 pound woman gives you extremely HARSH numbers.
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If there are any folks who were part of the playtest for LT (or Dan Howard, if you're reading this), I'd really love to know what assumptions you made to get the numbers you have for Leather.

As for fixes, I dunno, I could simply use lighter weights, but this would skew all the other armor types, making Leather & Textiles superior to many other versions... even after Dan Howards' suggested correction for Scale and Segmented plate.

One thing would be to scale weight based on HP (then assume the Table uses base weights for characters larger than 10HP). Scaling has been discussed before, and generally arrives at overly-harsh effects for high HP. However, if we were to assume that RACIAL weight is found by using the Cube-Law, but individual Weight is found by a Square, taking into account for increase in mass and efficiency (which also jives much better with the Height & Weight chart), then we could extrapolate a linear sizing increase amongst individuals of a race. 10 HP gives 1.0x armor weight, 13 HP gives 1.3x armor weight, HP 8 gives 0.8x Armor weight. Lowered weights would have the same cost*, and increased weights would have a a similar increase in cost but -30%* (no less than 100%). In this case, if most armor on the table assumes a ST/HP 12 man, we could reduce weights across the board by 1/6th to find new bases.

I would then reccomend using HP rather than ST in calculations involving mass, such as damage threshold for knockback. [I]* And I would use the smae effect on cost as weight if the value of the armor or clothing is primarily due to material (i.e., Bronze or Silk).

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Edited to Add: Ofcourse, I must give "room" in any base weights to allow for tailoring's reduction of weight, but given the large CF for tailoring, I can't assume that "Typical" fitted armor would include it.

This is the number I worked out:

Assuming a base of about 20.5 square feet for the average human (actually, the avergae man, women are about 17.4, but this can be chalked up to a lower average Mass/HP), and the Toso having about 36% of that surface area (Burn Victim claculations), this gives 7.4 square feet for the torso. Let's assume that a Expertly fitted armor will require about 5% more material than skin surface area, bring this to 7.8 SF, then divide by .7 to account for Expert Tailoring, we get 11.2 square feet. Multiply this by 14 ounces per square foot, and we arrive at 9.8 pounds. Let increase this to 10 pounds to accomodate fastners, laces, etc. IF we rule that the table in Low-Tech assumes HP12, then we would be right on target.

So it appears that reducing Weights in the table to 5/6ths listed, and scale linearly with increase or decrease in HP, we would have numbers which match the real world. However, Tailoring then becomes an issue, it's simply too costly, and should be avialble earlier on. Additionally, a cheap version of armor that increase weight by about 20% should be available (-0.2cf). I'd reccomend Tailoring to use the following, and allowing it for TL0:

Tailoring TL0
Flexible Leather/Textiles: Cost is +0.05CF per % of weight reduction up to 20%, plus +0.1CF per additional % of reduction up to 30%.
Ridgid Leather/Textiles & Flexible Others: Cost is +0.1CF per % of weight reduction up to 20%, plus +0.2CF per additional % of reduction up to 30%.
Ridgid Others: Cost is +0.15CF per % of weight reduction up to 20%, plus +0.3CF per additional % of reduction up to 30%.
Expert Tailoring TL1: Min. Weight reduction is 15%, and double the CF. Gives -1 to Targeting Chinks in armor, bonus to holdout, etc.
Masterful Tailoring TL1: Min. Weight reduction is 25%, and CF is 5x normal. Gives -2 to Targeting Chinks in armor, bonus to holdout, etc.

[DanHoward]

The base line was DR 2 hardened leather that was made from 16-18 oz leather. Everything else was extrapolated from that and then tweaked to fit the rest of the list. The main objective was to get leather to fit into a more realistic place in the comparative protection list. Assuming all are of equal weight the order of protection should be something like

Leather
Rawhide/Hardened leather
Padded cloth/Felt
Layered leather
Layered cloth
Scale
Lamellar
Mail
Brigandine
Segmented plate
Solid plate

It probably means that LT leather armour is a little too heavy compared to realistic values.

[Flyndaran]

That's if you are only counting the higher DR from mail. If counting its abysmally low DR agains crushing, it really sucks as armor.

[DanHoward]

The above list is resistance against points, which is all that really mattered historically. The most common threat in any battle by a long margin was from spears and arrows.

[Flyndaran]

Originally Posted by DanHoward

The above list is resistance against points, which is all that really mattered historically. The most common threat in any battle by a long margin was from spears and arrows.

PCs would still be pretty dumb to not keep at least one blunt weapon for all those mail wearers. The handicap is too severe for it not to have been commonly known.

[Anthony]

The problem with scaling weight to HP (or ST) is that it significantly (and unrealistically) encourages small characters. If you want, though, a standard estimate of human surface area is sqrt (weight * height / 3600 ), where weight is in kg, height is in cm, and area is in m^2 (yeah, that's some horrible unit confusion there). That works out to 2/3 * sqrt(W*H) if we want square feet, pounds, and feet. Thus, for a 6'/180 lb man (183cm/81kg) we get or 21.9 sf or 2.03m^2.

Other than that, I'd probably give a limitation on ST, or a flat disadvantage, for unusually heavy gear. One option is fractional SM; each .1 SM increases the weight of armor by 10%, but has none of the other effects of SM, and provides a 1% limitation on ST.

[Polydamas]

I wouldn't tie surface area rigidly to ST, because ST can easily vary 30% from that predicted by bodyweight. Keep in mind that GURPS DR is very coarse ... 13-15 oz leather might provide DR 1.5 but the rules have to reflect the empirical reality that layered or quilted linen provides more protection per kilo than most leathers.

Originally Posted by Flyndaran

PCs would still be pretty dumb to not keep at least one blunt weapon for all those mail wearers. The handicap is too severe for it not to have been commonly known.

The trouble is that in many cases, a spear or bow was still a better weapon. Most opponents will have plenty of targets with no armour, you have to get very close to hit someone with a mace held in your hand, and you have to want to kill or maim them. Sidearms like swords, axes, and maces were normally backup weapons.

Dan's comments about the most common threat aren't a bad approximation for societies with iron. Lots of societies without iron relied heavily on clubs and slings.

[Trachmyr]

Originally Posted by DanHoward

The base line was DR 2 hardened leather that was made from 16-18 oz leather. Everything else was extrapolated from that and then tweaked to fit the rest of the list. The main objective was to get leather to fit into a more realistic place in the comparative protection list. Assuming all are of equal weight the order of protection should be something like

Leather
Rawhide/Hardened leather
Padded cloth/Felt
Layered leather
Layered cloth
Scale
Lamellar
Mail
Brigandine
Segmented plate
Solid plate

It probably means that LT leather armour is a little too heavy compared to realistic values.

Ahhh... Thank you so much for the feedback!
16/18 is a really thick piece of leather, heavier the Sole rounds! And there's the extra 20% weight. A piece of leather that thick, I'd Give DR2* +1 vs, Cut (-1vs. Impale), and it's on the border of Flexible/Ridgid (Flexible normally, Treat as Ridgid is Layered with anything offering even partial DR).

Have have two questions then:
1) First is how the CF of Expert Tailoring was derived.
2) What was the Basline SIZE of armor, as in who was it fitted for... mass-wise or square-foot wise?

I ask, because I'm considering these changes/optional rules:

Option: Armor Sizing: The armor presented in Low-Tech uses a warrior for basline weights with a GURPS equivalent ST/HP of 12. Optionally, you may choose to size armors based on individual HP. To do so, find the final weight of armor, divide by 1.2, then multiply by HP/10. To find the cost of larger armor, simply increase the final cost by 10% per HP greater than 12. There is no cost reduction for lighter armor. This rule only applies to individual members of the same race and SM, use normal scaling rules otherwise.

Tailoring TL0
Flexible Leather/Textiles: Cost is +0.05CF per % of weight reduction up to 20%, plus +0.1CF per additional % of reduction up to 30%.
Ridgid Leather/Textiles & Flexible Others: Cost is +0.1CF per % of weight reduction up to 20%, plus +0.2CF per additional % of reduction up to 30%.
Ridgid Others: Cost is +0.15CF per % of weight reduction up to 20%, plus +0.3CF per additional % of reduction up to 30%.
Expert Tailoring TL1: Min. Weight reduction is 15%, and double the CF. Gives -1 to Targeting Chinks in armor, bonus to holdout, etc.
Masterful Tailoring TL1: Min. Weight reduction is 25%, and CF is 5x normal. Gives -2 to Targeting Chinks in armor, bonus to holdout, etc.
Cheap Tailoring: Little attention is paid to fit, and is often loose in areas or uses many straps and buckles to ensure a proper fit. Increase Weight by 20%. -0.2CF.

[DanHoward]

Originally Posted by Trachmyr

Have have two questions then:
1) First is how the CF of Expert Tailoring was derived.
2) What was the Basline SIZE of armor, as in who was it fitted for... mass-wise or square-foot wise?

1. There is no useful real-world data so I chose to keep it consistent with Dungeon Fantasy.

2. There wasn't one. Figures came from all sorts of sources. If there were inconsistencies then the above list took precedence.