GURPS: Getting Run Over by a Tank

[naloth]

Originally Posted by Anthony

Treating it as a quick contest between the ST of the vehicle (~200 for an MBT) and the ST of the person being run over might work. Possibly something weight-based instead, as it really shouldn't be much different for living, unliving, or homogeneous.

The contest is probably best and should give similar results for humans (squish). With logST, the damage becomes cinemagically survivable for a few seconds (ST 10 vs logST ST36 replacing the ST200 for ~26 damage per turn).

[Kromm]

I'll point out that the rules I cited aren't directly about mass, pressure, etc. They are about the power of a motive system. In brief: You take damage because a motor strong enough to move tons of tank by dragging it along the ground – generally chewing up the ground nicely in the process – is now dragging a tank along you. Effectively, you're clamped against a big, blunt chainsaw.

If the mass of a tank just rocked onto you, it might be less deadly.

Might.

[Bruno]

Are we talking exclusively a "rolled over" interaction?

Often when people say "Alice was run over by a truck", they mean "Alice was hit by a truck and went under the vehicle" or even "Alice was hit by a truck and went in an unspecified direction". Generally these kinds of pedestrian-vehicle interactions start with a collision.

[Anthony]

Originally Posted by Kromm

I'll point out that the rules I cited aren't directly about mass, pressure, etc. They are about the power of a motive system. In brief: You take damage because a motor strong enough to move tons of tank by dragging it along the ground – generally chewing up the ground nicely in the process – is now dragging a tank along you. Effectively, you're clamped against a big, blunt chainsaw.

Yeah, that is pretty much a nonissue. A track (or wheel) that is working successfully is going to have the surface that is contacting the ground unmoving relative to the ground.

[malloyd]

Originally Posted by Anthony

Yeah, that is pretty much a nonissue. A track (or wheel) that is working successfully is going to have the surface that is contacting the ground unmoving relative to the ground.

But the ground isn't unmoving relative to the "ground". If it were the tread wouldn't leave an impression in it.

While I haven't closely watched a tracked vehicle run over anything, my expectation would be when the descending edge of the frontmost link contacts the ground, or anything else significantly deformable at these sorts of stresses, it shoves it down and back, and for something with some noticeable strength in tension like flesh presumably pinches and then rips off off the part of it now between the narrowing gap between the links. I suppose it's possible that isn't what happens, but I'd be pretty surprised if a tank could run over an animal and "just" flatten it without chewing it up some.

Wheels might have a better shot at that.

[evileeyore]

Originally Posted by naloth

That is a good point. It seems odd that you take crushing from an that you can lift and carry around. Perhaps you should subtract your ST/BL in some way before calculating crush damage?

Just because I can lift 200+ pounds, doesn't mean I want a 200+ pound metal tread vehicle to roll over my foot.



The one person I know who was driven over by a tank was in a camouflaged fox hole when the tank ran over it. He was uninjured... but he said it did take a bit to dig himself back out.

[naloth]

Originally Posted by evileeyore

Just because I can lift 200+ pounds, doesn't mean I want a 200+ pound metal tread vehicle to roll over my foot.

I didn't appreciate kids stepping on my feet, but that doesn't mean I got severely injured or instantly crushed either.

Would a 200 lb weight "just" rolling over your foot crush it? I'm not sure. Reality checking that seems like a bad idea. 200lbs jumping on my back suddenly wasn't that big of a deal (college days, juvenile friends). If I was proportionally strong enough to carry around a 200 ton tank, there's the implication that it would be encumbrance rather than "crush" weight.

Something driving over you isn't really an attack or a slam (where your mass is stopping for force rather than your ST). It's frame stress - pressure applied to your body due to weight. Treads would scrape a bit, but that's carpet burn compared to the pressure you have to endure to survive.

Remember that old Timex thing where they drove heavy stuff over watches to provide they could survive unharmed? I suspect that was pressure resistance rather than the ability to take a bullet.

[mr beer]

Once again it seems to me that we could do with a Mythbusters show that has the exclusive purpose of providing data to assist in modelling various scenarios in GURPS. There's plenty of mileage in an episode themed 'running into/over stuff with a tank'.

[Anthony]

Originally Posted by malloyd

But the ground isn't unmoving relative to the "ground". If it were the tread wouldn't leave an impression in it.

Treads aren't flat, so things they flatten get tread patterns on them.

[ColBosch]

I am a former US Army tanker, so I have some observations and anecdotes that might help here. I do not have the level of skill with GURPS that others have shown, so I won't be able to help much with actual game mechanics.

First, I've seen an accident involving one M1A1 Abrams slamming into another. Contact was between the moving tank's right-hand return wheel (the forward-most on the track) and the stationary tank's left-hand drive wheel (the rear-most, with the actual teeth to move the track). I'm not sure how fast the first tank was moving; it was a fairly short distance, but the Abrams accelerates very quickly. Both vehicles sustained considerable damage to their tracks, wheels, and skirt armor. There were several injuries: mostly bruises, but one crewman on the stationary tank suffered sprains bad enough to eventually lead to him getting a medical discharge. An unprotected human struck by that much force absolutely would've been killed.

Second, there is always some slippage between treads and the surface they're riding on. On hard surfaces the tracks slip because they can't get a good grip. On soft surfaces they slip because, well, the surface is pliable. As someone suggested earlier in this thread, a person wouldn't just have the vehicle pushing down on them. Kromm's metaphor of a "slow chainsaw" is perfect. While overall a modern tank has surprisingly low ground pressure, anything it runs over is going to experience different pressures in different places, as well as being ground up from the pulling forces.

Hopefully these help the discussion.