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General Climbing Discussion

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calculator for impact forces from a climbing fall


mousey

6-Nov-2004
11:50:16 PM

if your tie in is your weakest point you dont have much to worry about
the big killers beside the one you mentioned are pre-cut ropes, not having a belayer, and clipping bash in rust-pipes; these cannot be overlooked when determining the overall strength of your system. in order to avaoid the loss of strength mentioned, do not tie in but rather just put a prussick on the end of the rope and run it through a big pulley attatched to your harness -this will effectively reduce the angle the sections of rope must travel over and allow full strength. (please for the love of god dont take this seriously)
as far as im aware, the strength of the rope or the know has nothing to do with fall factor- just means if you have a shit system it will fail with a low loading
anyhow, bedtime


cheesehead

7-Nov-2004
12:01:42 AM

>a CORRECTLY PLACED AND NEW 15 kN rated bolt is not really more likely to
>fail than a 30 kN bolt. With a bit of corrosion and repeat impacts the
>15 kN bolt is likely to fail far sooner than the larger bolt because it
>is no longer capable of sustaining the original forces. Even when half
>a strong as new a 25 or 30 kn bolt will still sustain most conceivable

Not really convinced. in engineering, a factor of safety (factor of ignorance) is used for designing stuff to spec. Eg, if you design a beam to hold 2 tons, you rate it for a 1 ton operating load. This is because a) people will push their 'luck' b) you're not 100% sure what's going on inside those materials. Was that Russian titanium appropriated from the missile factory or the teapot factory?
That's rated operating strenght.

Climbing gear and some other stuff, for various reasons is given a predicted failure rating. Eg, a 15kN bolt is expected to fail at 15kN.
refer to - adski's I think - post about a load testing machine (and Mikl's gorgeous sling testing method). The force at which some of the gear breaks sounds scary.

HOWEVER, how much gear have people busted? Lets have some good honest reports about what gear's failed and when.
>>Gear doesn't fail unless you make it. Nuff said.
Good call, Claw. I think generally rock breaks or gear zippers first.
I also use gear I find, sometimes snip off busted threads from damaged wires, used knotted socks for pro... Ok, I only use new explorer socks, not cheap soviet ones, but you get the point.

NOTE - sorry, just realised I misread your post. My point still stands, and sounds like we're making the same one.
Ooh, isn't this fun! Nothing like a controversy over hypothetically how likely we all are to crater. Check out Dave Jones's pro in 'Hard Grit'. Love your work dreadbrother!

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