Forums: Climbing Information: General: Re: [patto] Quick and dirty test: What happens during shockloading? : Edit Log


Jan 4, 2013, 10:45 AM

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Registered: Aug 27, 2008
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Re: [patto] Quick and dirty test: What happens during shockloading?
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patto wrote:
redlude97 wrote:
You keep saying this but don't provide any evidence whatsover.
Evidence? I have settled on reason which has been discussed earlier.

The "evidence" used to argue the opposite has simply been people bragging about their whippers. Laugh

jt512 wrote:
You are never belaying me.
Who said I had offered? Besides you continue to confuse technical discussion with actual belay techniques. Crazy

The real world is quite varied. If you can't think and alter your behaviour to the present situation then you may end up in an unsafe situation.

As I found out earlier in the week, even something as simple as a fireman's belay can be difficult and ineffective if somebody simply relies on rote technique.
patto wrote:
Syd wrote:
The main peak load occurs over 85ms (that is, the width of the peak above the final base load). The most extreme part of the peak load happens in a shorter period. It is interesting to consider this in relation to active dynamic belaying. It is claimed that if the belayer jumps or steps or actively initiates a moves in some way, when a climber falls, he can reduce the peak loading on the climber. It takes an absolute minimum of 200ms for a person to react to some stimulus (such as hearing a yell "falling" or seeing a fall), and generally this time is much longer. Further time is then required for the belayer to flex in some way. To reduce the peak load on the climber, the belayer's jump would then have to be precisely synchronised with the 85ms peak load. To me, this seems almost impossible.

Any "dynamic" effect by the belayer is simply the belayer being lifted off the ground by the impact of the fall. It is virtually impossible for the belayer to actively contribute to any impact reduction.

Many people consider that dynamic belaying is an essential part of good belaying but actions other than allowing some rope slip through the belay device at the moment of impact and an indirect or semi direct belay, seem futile.

I completely agree with this.

And I believe there has been other good research to support this. Dynamic belaying was found produce only very minor reductions in peak load. If you are doing it to make you and you partner more comfortable on repeated sport climbing falls then I don't see a problem. In steep over hangs more slack or dynamic belays can avoid ankle damaging pendulums.

If you think it is an essential part of safety in TRAD climbing then you are misguided. The difference between a grigri and a ATC is far bigger. But unless you are frequently leading very tiny pieces then I don't believe dynamic belays are important. (Even when I've lead X rated climbes with RPs and ultra micro cams I've never felt the need for a dynamic belay. Personally I want a reliable catch and in the event of piece failure a reliable FF2 preventative measures.)

Certainly amongst MY local TRAD community dynamic belays are never emphasised.
Except your agreement is based on completely flawed theory by Syd. Your "reason" refers to some "evidence" that the reduction is minimal. Care to provide it? Evidence provide here through actual testing and theoretical calculations shows significant decrease in both peak loads and pendulum velocity. Yet you are going to keep sticking by your vague "reason" with "evidence" that isn't to be seen? Are you being deliberately obtuse in your old age?

(This post was edited by redlude97 on Jan 4, 2013, 10:46 AM)

Edit Log:
Post edited by redlude97 () on Jan 4, 2013, 10:46 AM

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