Grate / Portcullis (or jail bars) and sawing through gaps instead of swinging

[Plane]

LT119 talks about Grates, and how this can include a portcullis.

Pretty much any image I can find of a portcullis seems to be in GURPS terms a "cross-hatched gate", while non-crosshatched grates are probably stuff like the vertical bars you see for jail doors or windows.

Although you can in theory swing a weapon at a flat grate, unless it's a curved sword, it seems like this would inevitably lead to the tip making contact before the body and I don't know if a weapon could stand up to that kind of abuse...

Possibly an axe could take it more since it's designed to stand up to a lot of cutting force at it's end as opposed to the body...

What I'm curious though is how GURPS would treat attacks with jagged/sawing edges for cutting through bars. It doesn't exactly seem like "swing" since there's no room for a windup, even though it's an attack with the side of a weapon like a swing would be.

Stuff like that (ie sawing bars, wood) seems designed for draw-cuts and to amplify pulling forces when you can't use momentum for force like a swing weapon does.

There must be some advantage to stuff built that way, ie why hacksaws have "teeth" instead of just a sharp edge (like a sword) though I can't really put into words why that is...

Does LT somewhere have special rules for drawcuts with weapons like these?

A floppy saw wouldn't be too good to "swing" in battle to cut someone (probably bounce off) yet if you have time to 'brace' (especially with those 2-person saws) and put pulling forward in, they could shine for doing stuff like dismembering slow enemy zombies.

[Rolando]

That type of action, sawing, is thrust or a base damage per turn and it takes time and fatigue, more St may help in getting the job done faster but not necessarily by much.

That type of serrated edge (and also grinding surfaces or tool) work by doing a steady damage that is not reduced by armor but instead reduce/degrade armor as they work, similar to corrosion attacks, but the reduced armor is only in the affected area (in the cut).

A cutting torch will work similarly, reducing armor and then reducing hit points steadily.

[DanHoward]

Regarding "zombie saws", I've talked to a tissue processing technician and he told me the following:
1. serrated knives and swords can't saw through bone.
2. Woodcutting axes and heavy blades such as cleavers don't "cut" through bone - they "break" through it.
3. A metal hack-saw takes 4-5 times longer to saw through bone than a proper bone-saw. Carpenter cross-cut saws are better than hack-saws.
4. Even a specialized bone saw takes a minute or two to cut through a decent bone (tibia, femur, humerus, etc.)
5. No saw is much use unless the target is immobilized on a rigid surface.

Conclusion: there is no point using a saw on a zombie unless it was on the ground and immobilized.

[Fred Brackin]

Originally Posted by Plane

L
Although you can in theory swing a weapon at a flat grate, unless it's a curved sword, .

Don't swing swords at iron bars (unless magic and enchanted with Penetrating Blade). Watch the History Channel series Forged in Fire the next time it comes around. They make knives and swortds on the show and that's one of the abuse tests they use. It's the sort of thing that breaks blades frequntly.

Axes won't cut iron bars either though they might stand up to the abuse longer. Heavy/sturdy axes are better for the wooden components of any gate or portcullis that has such things.

With a heavy sledge hammer you might bend iron bars or break the welds that hold them together---- eventually.

[Rupert]

Originally Posted by Fred Brackin

With a heavy sledge hammer you might bend iron bars or break the welds that hold them together---- eventually.

Pre-modern constructions like this are probably going to be riveted rather than welded. This will make them a bit easier to break up with a massive hammer, but compared to the proper tools (hacksaw, cold chisel and hammer, etc.) it'll still take a lot more time and energy.

[Fred Brackin]

Originally Posted by Rupert

Pre-modern constructions like this are probably going to be riveted rather than welded.

I think they might also be a grade of relatively soft wrought iron not commonly seen these days.

[malloyd]

Originally Posted by Plane

There must be some advantage to stuff built that way, ie why hacksaws have "teeth" instead of just a sharp edge (like a sword) though I can't really put into words why that is...

Saws don't cut in the same sense sharp edges do, they tear bits out instead, that's why you get a kerf. For serrated blades, which do still cut, the advantage appears to be that you can stress the material enough to split it by pulling it perpendicular to the direction you want the cut to expand, which is at least partly into the free space you are moving the blade in, instead of entirely into the rest of the uncut material.

Does LT somewhere have special rules for drawcuts with weapons like these?

On the timescale of a draw cut, there's probably no effect. Maybe even a reduction in effect - compare one stroke of a saw to one stroke of a machete and I bet the machete leaves a deeper mark on most materials. For something sitting still enough you can get multiple saw strokes in on it, it's a kind of corrosion damage I guess. It's not related to the damage you'd inflict by swinging the blade, since you aren't adding energy from the swing, and as most of the energy ends up moving the blade and not in the target material, it's probably not similar to the thrust damage either. It needs a new corrosion damage stat, which I suspect is entirely independent of the size of the weapon (reality check: a good wire or cable saw can indeed cut as fast or faster than a large handsaw in at least some cases), probably more a function of the tooth size and count.

[Polydamas]

Low tech p. 29 has damage rules for saws, but I would not recommend using the combat rules and times. It just takes too many seconds and its boring.

I would rather look up times to saw through 2 cm or 1" of hard wood, softwood, soft metal (brass? mild steel?) etc.

[DanHoward]

Originally Posted by Fred Brackin

I think they might also be a grade of relatively soft wrought iron not commonly seen these days.

Once it had been fashioned into a grate the metal would have been heavily work-hardened. In any case, wrought iron has similar mechanical properties to modern mild steel except that it is a little more ductile.

[Plane]

Originally Posted by DanHoward

Regarding "zombie saws", I've talked to a tissue processing technician and he told me the following:
1. serrated knives and swords can't saw through bone.

I was figuring you'd aim at the ligaments connecting the joints as opposed to the bone.

Originally Posted by DanHoward

5. No saw is much use unless the target is immobilized on a rigid surface. Conclusion: there is no point using a saw on a zombie unless it was on the ground and immobilized.

I don't know if they'd need to be completely immobilized, though obivously the more they can move the more they can disperse the force.

Zombie on it's back would be easiest to saw, but it's also possible to emulate, like say for example your ally puts a zombie into an "arm bar" it might not be completely immobile (and your ally isn't completely rigid) but it's probably enough to keep the muscles/ligaments taught enough for the teeth to bite into.

Originally Posted by malloyd

compare one stroke of a saw to one stroke of a machete and I bet the machete leaves a deeper mark on most materials

Doesn't one tend to 'chop' with a machete rather than do a draw-cut motion?

I'm just picturing your standard "hacksaw" and it seems like if I were cutting through a log, a hacksaw would work better than a machete.

Originally Posted by malloyd

It needs a new corrosion damage stat, which I suspect is entirely independent of the size of the weapon (reality check: a good wire or cable saw can indeed cut as fast or faster than a large handsaw in at least some cases), probably more a function of the tooth size and count.

I guess we'd also need to figure out how sawing blunts that corrosive effect over time as it dulls?