Forums: Climbing Information: The Lab: Re: [hafilax] Check my force calculator Excel spreadsheet: Edit Log




notapplicable


Mar 6, 2011, 5:03 PM

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Registered: Aug 31, 2006
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Re: [hafilax] Check my force calculator Excel spreadsheet
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hafilax wrote:
My question at that time was, does the rope recover at all between a piece pulling and it catching again on the next? If it doesn't recover at all then there is no benefit to placing gear that pulls. If it does recover then some energy is removed from the fall when a piece pulls.

The reading I have done makes it sound like the rope does recover a significant amount of it's elasticity almost instantly. I think Jay has commented on that more than once. Which is nice, at least when you are talking about a series of marginal placements where the second may have a better chance of holding after the first piece "slows you down" before pulling. That said, I feel there are some rather severe trade offs to the practice of placing a "ripper piece" when it is the first and only piece. Even if the reductions in peak impact forces are large.

The most important being that you will begin to catch the fall locked off in the completely wrong direction relative to the eventual direction of pull and you will likely be lifted towards that first piece for the fraction of a second that it holds. At which point you will be slammed down on to an essentially static anchor, whipped around as the direction of pull changes and you will be both braking in the wrong direction and your hand will be in the wrong orientation to provide the greatest mechanical advantage for locking off at your chest, instead of behind the hip. I think the belayer stands a much better chance of being able to control the rope, even with the increased impact, if you just take it straight on to the harness/anchor and have prepared for that from the beginning.

In that interest, I typically will belay palms up until a second piece has been placed off of the anchor, that way if the first piece blows I will have that small advantage when I reverse braking directions.


(This post was edited by notapplicable on Mar 6, 2011, 6:28 PM)



Edit Log:
Post edited by notapplicable () on Mar 6, 2011, 6:28 PM


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