In Gurps, how powerful do you need to fight a tank?

[Anthony]

Originally Posted by Bathawk

(Incidentally, I was wondering about what the curve on survivability rates would be in say WWI or Vietnam, if the average solider had something like say DR: 5.

Quite substantial. Most shrapnel would be 1d to 2d damage.

[David Johnston2]

Originally Posted by Bathawk

What kind of artillery are we talking about? I assume shelling an area is anti-infantry, not anti vehicle, and not a ridiculous damage output?

Actually I suppose infantry carried anti-tank rifles and rockets are the best approach.

[Ulzgoroth]

Originally Posted by Anthony

Quite substantial. Most shrapnel would be 1d to 2d damage.

Of course, coverage is key. Shrapnel hitting limbs is maybe slightly less lethal but not any less disabling than shrapnel hitting torso, so just a vest has relatively limited impact.

[Rupert]

Originally Posted by David Johnston2

It's the only option you've got with a super who is impervious to small arms fire apart from another super.

No, use an anti-tank gun, or a tank, from a nice long distance and concealment - it's far more likely to hit even a fast super (basically, you're using it as a very large sniper). Or, if they're only just immune to small arms, anti-aircraft cannons would be a good choice - more powerful than small arms, very high rate of fire, and set up to engage fast moving targets.

If they're immune to that they'll also be immune to field artillery, so at that point you've got a whole new level of problem. Maybe they'll come within 10-15 miles of the coast and you can hit them with a battleship shell, assuming you have a battleship. Otherwise, it's a matter of massive bombs and missiles or nukes or (more likely) finding a vulnerability (poison gas, catnip, whatever) and using that. Or, as you say, another super.

[Rupert]

Originally Posted by Bathawk

What kind of artillery are we talking about? I assume shelling an area is anti-infantry, not anti vehicle, and not a ridiculous damage output?

(Incidentally, I was wondering about what the curve on survivability rates would be in say WWI or Vietnam, if the average solider had something like say DR: 5. It wouldn't save them from say, a mortar shell, reduce the threat of things like shrapnel, at least until a medic can arrive)

Shell fragments have quite poor penetration (they've a very poor ballistic shape, so they slow rapidly in air, armour, and flesh), but their jagged shapes make for nasty wounds. Even fairly poor flak jackets, like those used in WWII, Korea, and Vietnam protect against most fragments - for the areas they covered. DR5 all-over, with no weight, bulk, or heat cost would be amazing. It'd stop many fragments, so the effective reach of an explosive shell would be massively reduced, it would make a lot of pistol and submachinegun bullets almost ineffective (especially at long ranges), and it would remove a lot of minor (and not so minor) irritations from a grunt's life, like all those annoying cuts, scrapes, and burns you get in the field. Oh, and bayonet charges and melee in general becomes a lot less scary (and if both sides have this DR, almost pointless).

[Ulzgoroth]

Originally Posted by Rupert

No, use an anti-tank gun, or a tank, from a nice long distance and concealment - it's far more likely to hit even a fast super (basically, you're using it as a very large sniper). Or, if they're only just immune to small arms, anti-aircraft cannons would be a good choice - more powerful than small arms, very high rate of fire, and set up to engage fast moving targets.

If they're immune to that they'll also be immune to field artillery, so at that point you've got a whole new level of problem. Maybe they'll come within 10-15 miles of the coast and you can hit them with a battleship shell, assuming you have a battleship. Otherwise, it's a matter of massive bombs and missiles or nukes or (more likely) finding a vulnerability (poison gas, catnip, whatever) and using that. Or, as you say, another super.

Trying to hit a person, directly, with a battleship main gun is borderline impossible even if they have no more than normal human mobility. Certainly at 10 miles you're entirely wasting your time trying.

If they're somehow immune to AP shells but not to blast effects, dive-bombing might give you a slightly plausible shot.

[Anaraxes]

TL;DR Calculate half the weight lifted half the width of the tank to see if your ST can flip a tank without making it leave the ground. Flipping by throwing would be full weight of the tank for a minimum distance equal to the hull width.

Originally Posted by Varyon

... but that's a problem, because it makes flipping a tank this way easier than flipping one by actually lifting it up onto its side and pushing it over

Don't forget the mechanical advantage you from from the tank acting as a (second class) lever, with the fulcrum being the point still in contact with the ground on the opposite site / end of the tank.

I'd assume that the center of gravity of the tank is right in the middle. I don't know what they typically are in real life, unlike cars, but since the point of the treads is reducing ground pressure, having the weight significantly forward or rearward, or on one side, would only reduce the mobility of the vehicle. So, as in your previous post, you get a factor of two from the leverage; lift half the weight of the tank.

The tank pivots on the far-side tread as you lift, rotating the center of gravity over the fulcrum point. So, the height you need to lift is only until the CoG reaches that point -- half the width of the tank. The lift also gets continually easier, because as the super lifts, the weight vector changes angle relative to the tank, meaning the super only has to counter part of the weight, while the rest of it is helping to roll the tank. (This may be countered somewhat by the super needing to change their push point; see next para). Past the fulcrum, the tank will fall over onto its side on its own. (And might continue on its own, depending on inertia. But let's assume that doesn't happen, because moments of inertia in rotating non-deformable bodies are definitely outside my expertise.)

If you want it belly up, then you can repeat the process, except now the lever arm is the height of the hull, and you can push sideways to get the CoG over the top edge of the hull, lifting it only half the hull height, at which point the tank will roll the rest of the way over. Possibly more mechanical advantage in this step, because the load-fulcrum distance is a lot less than half the width/length of the tank. (An Abrams is 8 feet to the top of the turret, so around 5 feet to the top of the hull, which is to say the height of the side panels.) It depends on where the super can push -- tall enough to keep pushing the high track, getting the full width of the tank as their length from fulcrum to effort, or do they have to push further down the belly? (An M1 Abrams is 12 feet wide, so human-sized supers aren't going to be able to keep a grip on the edge of the track as it rolls onto its side. The Hulk would have it easier than Superman -- except of course Supes can just fly at an altitude of 12 feet while he's pushing.) The higher their push point, the more mechanical advantage they get.

Plus or minus pesky details like tanks not being perfect rectangular prisms (flipping it over from the back is probably easier, because the sloped front armor isn't going to stop it after that first step), or the treads having those angles on each end, which would make it a three-step process, or the treads coming off because they're not designed to hold the full weight of the tank in a sideways shear. But, we're supers flipping tanks! A reasonable ballpark is already beyond most four-color physics.

[Polydamas]

Originally Posted by Rupert

This doesn't reliably kill even unarmoured infantry. Unless you get lucky the best it'll do vs a non-shellproof super is pin them down. Someone then has to go into the area you're moonscaping, find the super, and deal with them.

Now I am imagining Batman pulling an entrenching tool out of his utility belt

[Varyon]

Originally Posted by Polydamas

Now I am imagining Batman pulling an entrenching tool out of his utility belt

"Luckily, I have my BatShovel right here!" Naturally, with a bat-shaped blade on it.

[Bathawk]

So as the thread is winding down, forget having to "one punch" a tank. Assuming enough defense to withstand a tank, what is the minimum you need to fight one? wether it's bending barrels, tearing off tracks or dislodging turrets? What's the minimum to be a threat?