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#27851 - 03/26/07 03:46 PM cordelette-attention RG
chip Offline
Carpal Tunnel

Registered: 10/06/01
Posts: 2679
Loc: Sittin' Pretty in Fat City
The new climbing anchors book by John Long does present a lot of changes in recommended rigging, most notably negative aspects of a cordelette and that using a daisy or other static tie in has been implicated as major factors in some recent fatalities. Our own RG is quoted at length and seems to be the mastermind behind the cordelette analysis. I'm ready to change but thought to ask a couple questions. First, does switching to a dynamic cordelette reduce the problems appreciably?
I've been aware of the unegual loading problem awhile after catching some falls by a second and noting that the load rarely gets shared as much as possible. When in a vertical crack or set of anchors (rare at the gunks), I've started tying the cordelette knot so that I purposely have more tension on the longer arms in order to reduce increased stretch weighting these less. Has any research been done as to whether this provides any improvement? Thanks in advance.

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#27856 - 03/26/07 08:01 PM Re: cordelette-attention RG [Re: chip]
GOclimb Offline
Pooh-Bah

Registered: 03/26/01
Posts: 2362
Loc: Boston
Personally, I'd just switch to another method - one which integrates some level of dynamic equalization. These are the only methods that I think, in the long run, will be successful in keeping the forces reasonably well distributed among pieces.

There are several reasonable choices out there, two of which are even in JL's book - Sliding-X with limiter knots, and what I think he called the duoglide. Other excellent options are the Mooselette, RG's own Nerdalette (damn, I think I'm getting the name wrong) and one popularized by CharlesJMM on RC.com. Sadly, none of these was recorded in JL's book, nor have they been tested aside from by a few users in the field. But they can be found online if you are willing to search.

GO

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#27857 - 03/26/07 08:52 PM Re: cordelette-attention RG [Re: GOclimb]
dalguard Offline
veteran

Registered: 03/22/00
Posts: 1515
Loc: CT
In which fatalities was a static tie-in implicated?

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#27858 - 03/26/07 08:53 PM Re: cordelette-attention RG [Re: GOclimb]
chip Offline
Carpal Tunnel

Registered: 10/06/01
Posts: 2679
Loc: Sittin' Pretty in Fat City
Thanks GO. If anyone runs across some links to these, please post.

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#27860 - 03/26/07 09:50 PM Re: cordelette-attention RG [Re: chip]
rg@ofmc Offline
Pooh-Bah

Registered: 12/25/99
Posts: 2472
Loc: Poughkeepsie, NY
Chip, I'm hardly the mastermind, but I did point out a while ago, at a time when people were chanting the SRENE mantra, that true equalization was unattainable, not just in a practical sense, but in theory. When John Long started on his latest anchor book, he had Jim Ewing of Sterling Ropes test some of my predictions, which were found to be of quite practical significance in spite of their idealized formulation.

Things have headed in a funny direction since then. I think most people, once they understood that cordelette anchors distribute the load rather than equalizing it, were reasonably comfortable with that, even if what it really meant was that the pieces were loaded sequentially. But as we started thinking about (the very small number of) catastrophic anchor failures, it became reasonable to wonder whether you can up your chances of survival if you can really equalize the load.

The trouble is that you can't equalize without introducing the possibility of extension, thereby violating another of the mantra's precepts. Other tests by Ewing suggested that extension had far less effect on the ultimate peak load than people thought. GO originally pointed out that these tests may be flawed, however, and I think he is right, although I still think that small anchor extensions (relative to the length of the belayer's tie-in) are not a serious threat, or perhaps I should say that the advantages of equalization outweigh the risks of small extensions.

One of the results of that discussion was the enormous Sliding X thread on rockclimbing.com, in which various people proposed and discussed different equalizing rigging systems. Personally, I can't see myself using any of them, but others feel differently and believe that some useful solutions are presented there.

Meanwhile, I, a climber who never uses cordelettes and just ties in with the rope, became interested enough in the equalization debate to try to design something that I thought might work and also which met my standards for general utility. The initial result is the Geekqualizer (yes, GO got the name wrong), and Mal Daly of Trango was intrigued enough to sew two up for me to experiment with. I originally posted some pictures of this gadget on Supetopo; they have now been reposted by someone on rockclimbing.com as well. Neither of those threads is active at the moment; searching for "geekqualizer" or a lot of scrolling will be required to find them.

As for the pictures themselves, here are some of them:

The whole unit:



The equalizing portion is a (small) Trango Alpine Equalizer:



Set-up with unequal arms:



Close-up of clove hitch and back-up connection:



All wrapped up:



I should add that the question of relatively dynamic materials vs. newer high-strength stuff is not about improving equalization, it is about reducing the peak load to the anchors. It is fairly clear that connecting a belayer to the anchor with dyneema is not a good idea; the rope should always be the thing that transmits belayer load to the anchor. Personally, I don't think it matters that much what the anchor rigging materials are as long as the belayer is connected to them with the climbing rope.

Dawn, I don't know about fatalities, but there is one set of tests done by a canyoneering group and another set by a rescue group that indicates that falls onto dyneema (such as one might take while tethered to a rappel anchor) produce forces in excess of the UIAA maximum limit and in some cases are enough to break the dyneema sling. I'll see if I can find the references.

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#27861 - 03/26/07 10:12 PM Re: cordelette-attention RG [Re: rg@ofmc]
chip Offline
Carpal Tunnel

Registered: 10/06/01
Posts: 2679
Loc: Sittin' Pretty in Fat City
Looks like a good solution, RG. Not available, eh? Maybe Trango will sew up some if called... Good folk there. Thanks for the reply.

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#27866 - 03/27/07 02:57 AM Re: cordelette-attention RG [Re: rg@ofmc]
dalguard Offline
veteran

Registered: 03/22/00
Posts: 1515
Loc: CT
 Quote:
Dawn, I don't know about fatalities, but there is one set of tests done by a canyoneering group and another set by a rescue group that indicates that falls onto dyneema (such as one might take while tethered to a rappel anchor) produce forces in excess of the UIAA maximum limit and in some cases are enough to break the dyneema sling.

I have no problem believing that but that's a very different subject.

I was following, to some extent, the discussions on rockclimbing.com and am one of those people not too concerned about the pieces being loaded sequentially rather than simultaneously, especially at the Gunks. I thought from the tone of the original post that some kind of real world accident had ensued which might cause me to re-evaluate my position. As long as it's still just geeks arguing equations, I'm OK with what I'm doing.

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#27869 - 03/27/07 04:34 AM Re: cordelette-attention RG [Re: dalguard]
MarcC Offline
Carpal Tunnel

Registered: 07/10/00
Posts: 3532
 Originally Posted By: dalguard
I was following, to some extent, the discussions on rockclimbing.com and am one of those people not too concerned about the pieces being loaded sequentially rather than simultaneously, especially at the Gunks.

'Cause the Gunks is different?

 Quote:
I thought from the tone of the original post that some kind of real world accident had ensued which might cause me to re-evaluate my position. As long as it's still just geeks arguing equations, I'm OK with what I'm doing.

IIRC, the fatal fall on Tahquitz a couple of years ago was likely due to the sequential loading and subsequent failure of 3 cam placements. I do not remember if a cordelette was involved.
_________________________
- Marc

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#27873 - 03/27/07 01:43 PM Re: cordelette-attention RG [Re: MarcC]
dalguard Offline
veteran

Registered: 03/22/00
Posts: 1515
Loc: CT
They never figured out what happened at Tahquitz. I believe there was a cordelette attached to someone but they aren't sure whether the gear was even in the rock at the time of the fall. The final report, I believe, suggested that they fell from somewhere between their supposed route and the rap off but friends of the guy who had the gear still attached to him said he wouldn't have walked around without cleaning it up.

Yes, the Gunks are different in some ways. I'd trust any single well-placed piece at the Gunks. The other two pieces are in case I've made a mistake in either technique or judgement. Based on current thinking, if I were somewhere building an anchor I really didn't trust, I'd put more thought into how I was equalizing it.

Mainly, I feel that if cordelette technique were dangerous it would be supremely obvious by now from the accidents that would have occurred. That's how I feel about the EDK too. You can run as many tests as you want but real life is telling us that both techniques work fine and since they're convenient and familiar, I'm going to keep using them.

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#27882 - 03/27/07 04:25 PM Re: cordelette-attention RG [Re: dalguard]
chip Offline
Carpal Tunnel

Registered: 10/06/01
Posts: 2679
Loc: Sittin' Pretty in Fat City
The gunks can also be different in that the anchor placements are often in a horizontal relationship (I know what you're thinkin' Smike), which tends to keep the arms of the cordelette more equal in length than in a vertical alignment. As such, there is less relative difference in stretch and consequent loading between the different elements of the rigging in a straight up or down pull. Obviously not true for every situation but more often the case than on some crack jam-fest.
This can work against you as well, as the side pull effect is then more pronounced on a horizontal alignment as the cordelette is essentially fixed in position against any wandering and will then load the anchor point farthest away from the pull much more than any other.

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