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

Agreed and it might show why David Pulver gave the tracks DR 30 in the first place.

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

Do you know if there's anywhere in the tracks where you could just shove your arm in and get it stuck (and mangled if you're a normal human), akin to the spokes of a tire? If you've got enough DR to tank (heh) a cannon to the chest, the tracks would probably break before your arm would even be harmed (at least if it's general-purpose DR), and even if not the tank is just going to be stuck going around in circles with one set of tracks unable to move.


With that much general-purpose innate DR, one thing that might work for you would be to get enough levels of Super Jump to be able to Slam into tanks hard enough to break through their side armor. Combined with Walk on Air and a somewhat-lenient GM, you can even target the top armor, which will be a lot more vulnerable (basically, you jump up to a bit above the tank, plant your feet on solidified air - or however you justify Walk On Air working - while upside down, then before gravity takes hold you jump off again at full speed toward the top of the tank; you can't really rely on just falling really far unless you're also superdense, as a human-shaped and human-weight object in a dive has a terminal velocity of only around Move 100, which means dealing only 1d cr per HP). I'm not sure how the top armor compares to the armor on the treads, however - if a mobility kill is sufficient, you may want to go that route instead. Super Jump is actually a pretty cheap way to get high damage*; it normally has the drawback that you also take that damage, but if you've got enough DR to handle an anti-tank weapon, you've probably got enough DR to smash through a tank without injury.

*A standard human long-jump has a maximum distance of 7 yards, and every level of Super Jump doubles this - but you use the higher of Basic Speed and 1/5 your maximum long-jump distance to determine the speed. Wrecking a tank by going through it's front armor on an average damage roll calls for around 500d (actually more like 485d, but we'll round up; note I used Anthony's suggestion of dealing 200 HP Injury past 1500 DR for this). For a character with HP 10 to do this (assuming they have enough DR to survive), they'd need to be moving at around Move 5,000, around Mach 13.3. That calls for a long-jump distance of 25,000 yards, or Super Jump 12 [120] - a steal compared to the [2500] base for a 500d cr Innate Attack, but then you need even more points than that invested in "can survive Slamming into a tank at Mach 13.3," but if you've already got that going for you, might as well capitalize on it, right? Alternatively, you pay another [60] for Bouncing +50%, in which case a successful Jumping roll lets you simply bounce off the tank without taking any damage - although then you have a ~1.5% chance of pulping yourself in the attempt (thanks to a failed Jumping roll - I assume anyone who opts for this is going to have Jumping 16 or higher). As a bonus, because you retain IIRC 90% of your velocity on a bounce, you should be able to readily hit the side (or top with the Walk On Air option) of the tank - jump to land right beside it (or just above it), then bounce off the ground (or air) and slam into it. I'd personally assign a -2 to the relevant Jumping rolls for this (like a tic-tac), but that's cheap to overcome (of course, if you're really skilled, you could do a Rapid Strike to bounce between multiple tanks, wrecking all of them). And of course you don't need nearly as much damage if you're intending to go through the side or top armor.

EDIT: I'll note that I'm not a fan of how Bouncing works, as it feels rather broken, but I've confirmed with Kromm that the above is how it's meant to work. Personally, I think I'd rather interpret it as downgrading the slam to be one that is at however much speed you lost in the bounce (10% by default, but I think the wording of Bouncing says "up to 90%," so you could opt to adjust this for a given slam), but also give the option to make this a shove (deals no Injury, but deals double Knockback). So if you have HP 10 and slam into something at Move 5,000, then bounce off at Move 4,500 (losing 10% of your speed), that only results in a Move 500 slam. That's either 50d cr to each of you, or 50d cr dkb to just the target. Against a ~200 HP tank, that latter option will shove the tank back a couple yards (the former option probably won't damage it at all - unless you targeted the top armor perhaps, I forget how much DR that has - and knock it back about a yard... but unless you've got some serious DR of your own, you're probably pulped).

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

There's certainly places to get your arm caught. Here's a picture of some soldiers doing field maintenance on an Abrams.

(The long bar is, I believe, a socket wrench. When they said torque it down, they meant it. This pic gives you an idea of the sort of force that's considered routine maintenance, not damaging the equipment. This one gives you a good look at the inside of the track; looks like these soldiers are replacing a damaged link before wrapping the tread back around the wheels. Not an Abrams, but an M88 Hercules recovery vehicle. The track design is close enough, though.)

But, I meant to point out the row of "teeth" down the middle of the track on the inside that run through slots on the wheels. Suppose Indestructible Man lays his arm between those teeth and lets the track carry his arm between the track and a wheel. The road wheels can move a bit; they have a suspension system. Idler and drive, not so much. It seems to me that this action would stretch the track a bit as the arm goes around between the two tank parts. On the bright side, Indestructible Man doesn't have to exert any force. (He blew all his points on DR, and has only ST 10...) The tank engine is the thing stretching the track. On the down side, that force is going to be spread among many of the track shoes and their pins, so it will be more difficult (for the tank) compared to a focused effort targeting on one pin.

But given that tanks really do manage to break their own tracks, I'd say it's at least possible.

You might also break or bend those teeth on the inside of the track. If enough of those are damaged, the track will likely slide off the wheels as the tank maneuvers. Not quite as cinematic as tearing the turret off or wrapping the gun barrel into a spiral around your arm. But that attack might suit a more stealthy super that's content to sneak around the battlefield disabling enemy vehicles. (This sounds like a job for Mole Man!)

Do we even have rules for damage caused by a heavy weight? Not dropping it on someone, just sitting on them or slowing ramping up -- the goal being to calculate the DR needed for Indestructible Man. Pressure Support 3 makes you "immune to the effects of high pressure". But the pressure rules in Campaigns (B429, B435) are more concerned with breathing and atmospheric pressure than with mechanical damage. Maybe in Vehicles?

The inside teeth would be a very dull, slow chainsaw with a 1500 horsepower engine. Alas, I can't find the dimensions for the center guide tooth. It's a square cross section of about the same size as the track pins. You'd probably wind up bending both bars of a single tooth as the same time, so up to twice as hard as just bending one pin. (That's only +2 more ST with Super-Effort, though, equivalent to 3-6 tons BL. And since an Abrams can haul itself up a 60 degree gradient, the engine does have the ability to exert that much force via the tracks.)

(As long as I'm wandering off point with pictures, this mental image reminds me of the "VB 10000" ship salvage vessel, which was used on a 70,000-ton car carrier ship, the Golden Ray, which capsized off the Georgia coast a while back. It sawed the ship (and its contents) up into sections to be individually hauled away, using a "cutting chain" that wasn't as near as I could tell sharp in any way, but a fairly ordinary-looking chain. The chain was, however, driven by a 17,000+ horsepower engine.)

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

None that I'm aware of, and when it came up with respect to using Wall to create bridges (to determine the weight a bridge could support), RPK went with treating any bridge with enough DR to tank a 1-yard fall from the things moving over it would have no issues as a quick-ish hack. Personally, I'm fond of basing it on trampling damage (and I treat this as dealing full trampling damage - thr cr - if moving at faster than 1/5th your Move, half this - thr/2 cr - if moving faster than 1/15th your Move, and a quarter - thr/4 cr - if moving slower than that, which may include just staying stationary). But being caught in the gears seems like it would be more like having something bite down and worry away than simply having a heavy weight placed on you. I'd eyeball it as simply being thr cr - maybe with the damage based on 1.2xST since it's using the motive system (like how humans basically get +20% ST when grappling or striking with the legs). But, again, I'm assuming the character has enough DR to tank a hit by the main cannon, and if that's the case then unless the DR is limited such that it won't apply to being caught in a tank's gears (such as from having Ranged Only or similar) they're going to have enough DR to laugh at such. Although I wonder if their arm might be at risk of getting stuck - after all, if it takes a 1500 horsepower engine to shove your arm in there, ST 10 probably isn't going to be enough to get your arm back out...

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

Closest equivalent is the rules for grapple and squeeze, though what the effective ST of a given weight actually is isn't clear (if we assume BL for 1/10 its weight, that gives sqrt(weight/2) and a 120,000 lb tank has a crush ST of 245. However, that would be the entire weight of the tank, and tanks actually distribute their weight a lot better than that -- the M1 has a ground pressure of 13.9 psi and a track width of 25", so contact area likely in the vicinity of 600 square inches for a mere 8,300 lb and an effective ST of around 65.

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

Those are Marines

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

I do like the mental image conjured up by trampling. (Everything on the surface of the Earth is being constantly trampled by the entire 5.5 quadrillion tons of the atmosphere! It's even worse than being run over than an M1 tank!)

Hm. Invoke the pinning rules? ST 10 Indestructible Man isn't going to manage to break that pin, but a more typical brick might. The "weight" pinning the arm would be the track tension. But the pin rules are based on SM difference, assuming reasonably humanoid opponents. Which rapidly leads us to the infamous cube roots. But perhaps we can steal the principle (+6 equals a factor of 10), but use weight/pinning force instead of length. And then have the super use their ST, not their body weight to break free, which will mean BL (or the appropriate multiples for using more than one arm and using more time).

Or perhaps the other way around: figure a ST value for the pinning force, running the BL calculation backwards, and then make it a Contest of ST.

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

Maybe I'm just not getting it... but tanks seem both more and less common IRL than how Bathawk's statement reads. Well, that or my dubious understanding of GURPS is at work again, so I'm going to risk sharing my own take on this.

Unless we're in a setting where nearly all warfare is restricted to tanks, anything with "versus tanks" seems more niche than -40% indicates. I mean, even if you successfully keep it secret (Secret?) that your Damage Resistance only applies against attacks made by (or perhaps even from) tanks, you've got everything else on the battlefield to worry about. Or are tanks really that heavily present on the battlefield?

Okay, so what is the "more common" part? If we invert things, and your DR is against everything except tanks, once again you'll need to keep it secret (Secret?) because tanks aren't that far away in (for example) the United States of America. Well, in the American Midwest, anyway. We're not a war zone [insert sports joke here/], but there are a lot of military bases (outposts? Depots? Not sure what all to call them) here. I mean, most of them aren't the Army or Marines, but the Army Reserve or the National Guard... but that's enough for this to be a big issue. At least, once this gap in your defenses is known. Yeah, getting the tanks to where you (your tank-vulnerable character) are before you can flee is a nightmare, between getting authorization for the tanks and transporting them... but sooner or later, your character is probably getting shot by a tank. Barring an amazing dodge or other mitigating circumstances.

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

The rules for Accessibility limitations have a fundamental problem: they don't consider who is making the choices.

For an active ability, typically the PC is choosing the target. Thus, unless there are zero valid targets, it remains useful, and -20% for an ability that only works on half of all targets is fine.

For a defensive ability, typically the enemy is choosing what they use. This means an ability that only works against half of attacks is at best half as useful, and if the opposition recognizes the weakness, less than half as useful; overall, it should be around -60%. GURPS uses the same -20% for both.

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

Chuck boulders at it until the tank crew gives up.

Edit: Or use your super powers to relocate people before the tanks arrive at the destination.
What's the point of punching a tank? You think they'll call off the war efforts over that?

(This feels like some cartoony stuff to me and I'm not usually a fan of that, especially when it's for 'war' stuff.)