Chain Link Vs. Car

[Faolyn]

In my game last night, the players (action cops in a TL7 fantasy world) had to get into a ghost town that had been sealed off by chain link fence in order to stop the road pirates that had hijacked a shipment of hazardous material (refined ectoplasm) before the magical containment's duration ended and it got loose.

I couldn't find anything about the DR of a fence--plenty of info on steel bars and wooden planks and piles of cement, yeah. Nothing on chain link.

I rolled some dice and mumbled and took what I remembered from that episode of Mythbusters and they got through, no prob., because, of course, the PCs needed to get into the ghost town so I could start shooting at them. But has there been anything official on the strength of a fence like this? Or other type of fences?

[Bruno]

Unfortunately it's a heavy "It Depends". The fences the Mythbusters always end up driving into when a remote-controlled vehicle goes awol are temporary fences, not "real" ones. They're not fixed to the ground by fence posts, they're just standing on feet. These kinds of fences rely on their weight and symbolic value to stop people - you could totally knock these over with a car, although how drivable your car would be after I'm not sure. Depends on your collision speed I suspect.

It would be simpler and inflict less vehicle damage to just get out and haul out the wire snips, and a hacksaw for the crossbars.

These are typical not only around film shoots, but also around some construction sites (usually in more sub-urban areas, urban areas install permanent fences).

A "proper" fence should have heavy posts sunk into concrete blocks buried in the ground to a significant depth. Usually steel posts. This version is much sturdier.

It's much stronger, too, if it has the hollow steel crossbars at the top and bottom of the chain link. If it's just link strung between the two posts, it's much more vulnerable to abuse.

A chain link gate is different from a fence. It comes with a natural break point in it. This is what they tested on Mythbusters - it's not the chain link you break through, it's the lock or the chain holding the gate closed.

Note that they never actually bust through the portable fences when something goes AWOL...

[nanoboy]

Originally Posted by Bruno

Unfortunately it's a heavy "It Depends". The fences the Mythbusters always end up driving into when a remote-controlled vehicle goes awol are temporary fences, not "real" ones. They're not fixed to the ground by fence posts, they're just standing on feet. These kinds of fences rely on their weight and symbolic value to stop people - you could totally knock these over with a car, although how drivable your car would be after I'm not sure. Depends on your collision speed I suspect.

The time that the Mythbusters drove a car into a locked chain-link gate fixed to existing chain-linked fence resulted in the totaling of the car. Mind you, this was the weak point for a fence: the gate, and the car was undriveable after the collision.

[Bruno]

Originally Posted by nanoboy

The time that the Mythbusters drove a car into a locked chain-link gate fixed to existing chain-linked fence resulted in the totaling of the car. Mind you, this was the weak point for a fence: the gate, and the car was undriveable after the collision.

That wasn't a temporary fence - that was a fence with posts sunk properly.

[Faolyn]

Originally Posted by nanoboy

The time that the Mythbusters drove a car into a locked chain-link gate fixed to existing chain-linked fence resulted in the totaling of the car. Mind you, this was the weak point for a fence: the gate, and the car was undriveable after the collision.

Sorry; I should have been more specific: they did crash through the gate.

The PCs got the car a bit down the road before they had to abandon it.

But what the heck is the DR? I think we really need more examples of the DR and HP of ordinary things. All the guides that I can find--and I admit, I don't have a great memory--are for massive structures.

[nanoboy]

Originally Posted by Bruno

That wasn't a temporary fence - that was a fence with posts sunk properly.

Right, and I wasn't implying otherwise. It was the only episode I've seen where that was the test. In all other case, the fence was just there to catch errant autos.

Originally Posted by Faolyn

Sorry; I should have been more specific: they did crash through the gate.

The PCs got the car a bit down the road before they had to abandon it.

But what the heck is the DR? I think we really need more examples of the DR and HP of ordinary things. All the guides that I can find--and I admit, I don't have a great memory--are for massive structures.

They broke the gate, yes. Pretty much everything broke in that case. As far as the specific DR and, I have no idea. It probably varies a lot anyway. As a GM, I would just fudge the issue. (If I had players who wanted exact numbers and were sticklers for the rules, I would work it out, but if the players were more interested in continuing with the game, I would just narrate out something reasonable and move on.)

[Bruno]

I just rewatched the episode - the car was in fact drivable. The airbags deployed and the horn was stuck blowing, and the alignment was off, but it was still perfectly good for fleeing zombie hordes from in.

[Polydamas]

Originally Posted by Faolyn

Sorry; I should have been more specific: they did crash through the gate.

The PCs got the car a bit down the road before they had to abandon it.

But what the heck is the DR? I think we really need more examples of the DR and HP of ordinary things. All the guides that I can find--and I admit, I don't have a great memory--are for massive structures.

Because your players rammed the gate, p. B558 gives all you need to find the HP and DR of the "weakest link" (probably a Steel Bar or Steel Cable). I think some of the tech books have stats for chains and locks. Stats for the fence, with aluminum posts set in concrete, would be handy but they may be region specific (and to be honest, a chain-link fence is not what the collision rules were designed for anyways, so it may be best to wing it).

[Luke Bunyip]

A sheared off post stub could do a lot of damage to a vehicle. Take out suspension, tear a tire, crack an engine sump. I suppose my point is that a fence is not homogenous like a wall.

My 2c.

[jeff_wilson]

If the car hits the chainlink or hurricane fencing between the uprights, it can end up being more of a tug of war than a DR question as the wiring is drawn out and wraps around the car. You need a good head of speed to be sure of breaking free and even then it's risky that some will get under the vehicle and foul the wheels.