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dallas27
May 22, 2009, 4:23 AM
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My climbing partner showed me a sliding-X, but with 3 pieces instead of the usual 2 in a normal X. Is this legitimate? He said he read it in a book somewhere. I didn't get a chance to test it, and I'm not 100% sure how he crossed over the pieces, so I can't reproduce it.
Has anyone seen this? Know anything about it?
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irregularpanda
May 22, 2009, 4:35 AM
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dallas27 wrote: Has anyone seen this? Know anything about it?
Yes, I use it all the time. You do it the same way, sometimes you have to extend a sling on a piece or two. I'm sure other people will chime in with details, criticisms, compliments, whines, and other shtuff.
Assuming that all your placements are intelligent and bomber here's how I see it. Angles are the important thing. You'd rather have small angles between the strands. Also, when you use a "magic X" on a pitch that traverses or wanders, and the anchor is weighted, this anchor will be weighted with significant variation between the pieces.
For example. Two pieces on the left, one pice on the right. Follower is approaching the anchor from the right, and falls. The piece on the right will hold a significant portion of the fall, much more so than the right.
I digress: here's how to clip it..... 3 pieces and 3 biners.
Take your long sling, clip it to all 3 biners. Grab the part closest to you. Hold on to that. With the other hand, grab the sling between each piece (one at a time) and bring it to your first hand. When it gets there, give the newcomer a half twist. Repeat the process with the other sling between the remaining pieces. This is your master point.
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rocknice2
May 22, 2009, 10:41 AM
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Or just twist the 1st loop
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meanandugly
May 22, 2009, 10:52 AM
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Its legit, use it often.
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boymeetsrock
May 22, 2009, 1:06 PM
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irregularpanda's response is very good. Keep in mind that bomber gear is necessary as a piece blowing would mean LOTS of extension.
I use it when the situation is acceptable and feel comfortable with it.
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altelis
May 22, 2009, 2:04 PM
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boymeetsrock wrote: irregularpanda's response is very good. Keep in mind that bomber gear is necessary as a piece blowing would mean LOTS of extension. I use it when the situation is acceptable and feel comfortable with it.
i certainly use it, however b/c of just this possibility of lots of extension, i try and extend the pieces to get them as close together as possible and throw in a limiter knot or two....
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brawa
May 22, 2009, 2:32 PM
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I use it as well.
Only two downfalls I've noticed:
1) Potential for extension/shock loading. Tie limiter knots if you're worried (I don't)
2) If using nylon slings, 3 loops through a biner (6 loops if using 2 slings) gets pretty chunky. Make sure whatever you're clipping in with is big enough to swallow the loops, or use fancier skinny slings.
Edited to add: I first saw it used in Craig Luebben's anchors book, which is very very good.
(This post was edited by brawa on May 22, 2009, 3:44 PM)
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knudenoggin
May 23, 2009, 6:16 AM
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brawa wrote: Edited to add: I first saw it used in Craig Luebben's anchors book, which is very very good.
On p. 155 of this book he presents a FOUR-anchor "Slding-X"; he claims that In reply to: "If one piece fails, the slack disperses among the other three loops, so extension is minimal" and "if the loading direction changes, the slings will shift in the clipping carabiner to maintain equalization. Using a large carabiner and thin Spectra (Dyneema) webbing makes it easy for the slings to shift."
the testing done for John Long's Anchors book, which shows even a single
Sliding-X to bind, I'll wager that this monstrosity will be nowhere near
equalizing; and if one piece fails, the slack will only slightly extend to
adjacent piece and leave farther-removed piece(s) bearing the brunt of
the load--a sort of unequal distribution of slackness.
Moreover, he shows it with DOUBLE slings, "for redundancy", and although
urging the use of a large 'biner, he crams all of this tape into the small
(non-clipping) end of the chosen 'biner. --which breadth of tape will
weaken the 'biner.
DO NOT PASS GO.
*kN*
(This post was edited by knudenoggin on May 25, 2009, 5:54 AM)
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landongw
Jun 7, 2009, 9:10 PM
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The concept of "shock loading" being an existential threat has been essential debunked in bd labs, info on this is in John Long's newest anchor book.
A more real threat of extension is that you're chilling, giving a belay, distracted for a moment finding a bar to chew on. Suddenly the rope comes taut, that crappy tricam pops and, without warning, you sail off you perch, rope in one hand, candy bar in the other, for a hard, fast, four foot ride. While your anchor does not "shockload" your belayer might.
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bill413
Jun 7, 2009, 11:54 PM
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landongw wrote: The concept of "shock loading" being an existential threat has been essential debunked in bd labs, info on this is in John Long's newest anchor book. A more real threat of extension is that you're chilling, giving a belay, distracted for a moment finding a bar to chew on. Suddenly the rope comes taut, that crappy tricam pops and, without warning, you sail off you perch, rope in one hand, candy bar in the other, for a hard, fast, four foot ride. While your anchor does not "shockload" your belayer might. 
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patto
Jun 8, 2009, 12:38 AM
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landongw wrote: The concept of "shock loading" being an existential threat has been essential debunked in bd labs, info on this is in John Long's newest anchor book.
No the concept of shockloading HAS MOST DEFINATELY NOT been debunked.
In the case of a anchor extension with low mass, shock loading is insignificant. However in the case you describe with a belay in the system there is now a 80kg mass in the system. THIS WILL MOST DEFINATELY SHOCK LOAD THE ANCHOR.
(This post was edited by patto on Jun 8, 2009, 12:40 AM)
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rocknice2
Jun 8, 2009, 1:05 AM
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bill413 wrote: landongw wrote: The concept of "shock loading" being an existential threat has been essential debunked in bd labs, info on this is in John Long's newest anchor book. A more real threat of extension is that you're chilling, giving a belay, distracted for a moment finding a bar to chew on. Suddenly the rope comes taut, that crappy tricam pops and, without warning, you sail off you perch, rope in one hand, candy bar in the other, for a hard, fast, four foot ride. While your anchor does not "shockload" your belayer might. And, as a consequence, drop the candy bar!
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tomcecil
Jun 9, 2009, 3:39 PM
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AS Jim Ewing and JL discovered thru testing...
It is not recommended to dynamically equalize three pieces with one sling because of an effect called "ploughing" (the webbing bunches up) which results in inconsistent equaliztion on the three pieces. Using dyneema runners (they're slicker) and anodized biner(s) (also slicker) you can mitigate the down side somewhat--
Extension is an issue not because of potential increases in force but because while the belayer is 'extending' he or she is more likely to lose control of the belay-
There are to many variables in Trad climbing to have absolutes.
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dingus
Jun 9, 2009, 4:05 PM
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dallas27 wrote: My climbing partner showed me a sliding-X, but with 3 pieces instead of the usual 2 in a normal X. Is this legitimate? He said he read it in a book somewhere. I didn't get a chance to test it, and I'm not 100% sure how he crossed over the pieces, so I can't reproduce it. Has anyone seen this? Know anything about it?
Its too much for me. I use sliding Xs in some belays but would only equalize two pieces with one sling. If I needed to equalize a 3rd piece (so rare as to be exceptional) I would use a 2nd sling.
Most often I use a power knots on the first two pieces, whether they are equalized or not.
The 3rd piece most often I tie in directly.
Personally I don't fester over shock load - at all. I don't fester much over equalization either, for that matter.
DMT
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westbend
Jun 9, 2009, 4:08 PM
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In reply to: THIS WILL MOST DEFINATELY SHOCK LOAD THE ANCHOR.
Do you count any sudden ramp up of the load on the anchor? Or are you restricting this to loads that exceed the load that a reasonable anchor can manage? Or do you have some other definition?
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