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piquaclimber
Trad climber
Durango
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Topic Author's Original Post - Jun 30, 2008 - 11:57am PT
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I use the sliding x sometimes and most of my partners use it as well. Once in a while I will tie off one strand to prevent excessive extension.
Yesterday at the Ophir Wall my partner said that he felt it was unsafe. He had read something online that said as much. I found the article he was referring to an wondered what the folks here thought?
Thanks,
Brad
http://www.camp4.com/rock/index.php?newsid=451
PS. I cross-posted this to MP.com.
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Norwegian
Trad climber
Placerville, California
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Jun 30, 2008 - 12:30pm PT
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my understanding (i did'nt read your link) is that if one of the equalized pieces fails, then the x slides to a new equilibrium position, thus shock loading the remaining pieces with a static sling. this is the danger as i understand it. i use it all the time though.
lately though, i've been attaching the lead rope directly to the anchor pieces with clove hitches. this doesn't equalize 100% but no shock load occurs if a piece fails.
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maldaly
Trad climber
Boulder, CO
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Jun 30, 2008 - 12:36pm PT
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The Sliding X is not safe at all.
I use it all the time.
I also follow the three rules of setting up belay anchors:
1) Everything must be bomber.
2) Everything must be bomber.
3) Everything must be bomber.
4) Multi-directional with 2 down and equalized with a sliding x and one up tensioned against the X.
If you are worried about extension refer to rule #1.
If you are worried about redundancy, refer to rule #2.
If you are worried about equalization, refer to rule #3.
If you worry about not building a SeRENE anchor like your AMGA anchor course taught you, see rule #4.
Refer to the threads on rc.com about equalized anchors. When Jim (at Sterling) and John Long actually tested anchors with load cells they found two alarming things about the SeRENE anchors he (JL) had been preaching for a long time:
1) The "equalized" anchors are not really equalized. The master knot makes it worse.
2) In a climbing system the amount of additional shock load delivered from a blown anchor leg extending was so low that they were unable to measure it.
BTW, a sliding X does little to equalize either, unless the legs are the same length (It's the dynamic qualities of the material in the EQ rig that cause them to miss out on equalization. The amount of load that a dynamic EQ rig distributes to each leg is inversely proportional to the length of the leg. i.e. a longer leg gets less load.) If you use static material (Dyneema) for your EQ the distribution of the load will be more equitable but nowhere near perfect. I use the sliding X because it's simple and cool.
Fun Fact: The 2 death-by-anchor-failures that have happened in recent history, the Sandias and Taquhiz, both occurred in a SeRENE-cordallette-equalized-master-knotted anchor setup. Both happened because they failed to follow rules #1-4.
Climb safe, be smart, be careful about following rules.
Mal
Edited to add: If you can't meet rules #1-3, go find a different place to belay.
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couchmaster
climber
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Jun 30, 2008 - 12:37pm PT
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Rarely for me.
However, I also only follow Malcolm's rule #3
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maldaly
Trad climber
Boulder, CO
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Jun 30, 2008 - 12:48pm PT
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Mike, thx for the props. I'm just trying to head off one of those lame EQ threads that plague the climbing forums. If anyone out there is considering posting up about how you've devised a super-equalizing equalette, please refrain from posting it up here. RC.com is a better place for that.
As if it hasn't already been posted to death.
Mal
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the Fet
Knackered climber
A bivy sack in the secret campground
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Jun 30, 2008 - 12:58pm PT
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SeRENE, is a great goal to aspire to, too bad it doesn't exist. An anchor either extends or equalizes, the trick is to get the best compromise.
A tied cordelette is not a "SeRENE" anchor.
sliding X does little to equalize either a sliding X does a great job of equalizing, unless the powerpoint binds.
Use a sliding X with limiter knots. Or use a tied cordelette if the placements are bomber. Or use the rope.
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Mighty Hiker
Social climber
Vancouver, B.C.
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Jun 30, 2008 - 01:21pm PT
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Mal has hit it on the head - I particularly like his rules #1, #2, and #4. (Still thinking about #3.)
Must be my mountaineering background, where time is usually quite important. As long as the anchors are 100% solid, redundant, multi-directional, and you're tied to them, the rest is details.
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rgold
Trad climber
Poughkeepsie, NY
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Jun 30, 2008 - 02:01pm PT
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I almost never use a sliding-X. I think that, in most cases with most gear, a distributed anchor is good enough---forget about equalization, which was always a myth. If there was an effective way to equalize three-piece anchors, I'd adopt it immediately, because I think the failures we know about are very likely cascade failures brought about by failures in equalization, but so far I haven't seen anything (including something I designed and Mal made up for me) that is in fact effective in the field.
I do think Mal's post needs some further comment. I am afraid that what I have to say belongs to the genre of posts he was trying to head off. Sorry, Mal.
Mal wrote: (2) In a climbing system the amount of additional shock load delivered from a blown anchor leg extending was so low that they were unable to measure it.
I keep posting cautions about this conclusion without much effect, perhaps because I'm inclined both personally and professionally to be circumspect in my phrasing. So let me violate those principles with a bold statement:
The way in which the test was performed reveals nothing about the anchor loads that would be experienced in practice during extension. (I am very sorry to say that John showed me a prepublication version of his text and asked for comments, and I failed to read the details of the test in question and so did not raise this important objection when I should have.)
The reason is that the extension in the tests was a small fraction of the amount of rope involved, and so even on theoretical grounds there would be no reason to expect much of a load increase. But in real life the fall energy produced by extension will have to be absorbed by the belayer's tie-in, which could be quite short, making the extension significant relative to the amount of rope available for energy absorbtion. This could result in high anchor loads and must be properly tested before one can say with even a small level of certainty that extension doesn't matter. (I might add, althougth this is part of another discussion, that the anchor load could easily become critical if the belayer attaches to an extending system with a sling or daisy rather than the climbing rope.)
Mal wrote: BTW, a sliding X does little to equalize either, unless the legs are the same length (It's the dynamic qualities of the material in the EQ rig that cause them to miss out on equalization. The amount of load that a dynamic EQ rig distributes to each leg is inversely proportional to the length of the leg. i.e. a longer leg gets less load.)
It is true that the dynamic qualities of the material are what cause a knotted cordelette to fail to equalize when the legs are significantly different in length, but this is not true in principle for sliding systems, which, because of the pulley effect, should equalize tension throughout the anchor material. The reason for the italicized caveats is that friction over the carabiners in the system is significant and will impede and perhaps entirely defeat the theoretical equalizing effect of the sliding-X, making Mal's observation true for somewhat different reasons than he states. There have, in fact, been static tests in which the knotted cordelette equalized better than the sliding-X, although the sliding-X has fared better in drop tests. (This discrepancy may be due to the difference between static and sliding friction).
Although of questionable utility in equalization, the sliding-X does still have the advantage of being able to adjust, at least partially, to different directions of pull. A knotted anchor will load a single piece if the load comes from an unanticipated direction.
The RC.com "olette" discussions have called forth a host of Rube Goldberg contraptions of little or no practical utility. Perhaps lost this junkyard of creative concoctions is the fact that the original Long equalette is truly a better mousetrap for equalizing two anchors, because it is simple and eliminates much of the friction present in the sliding-X. If I was going to using a sliding system on two anchors, the equalette would be my choice.
Perhaps also lost in the discussion is that no one has found a practical and effective equalizing system for three-point anchors, and in particular, systems using a sliding-X or equivalent on two of the three anchor points do no better than a knotted cordelette.
In my opinion, a knotted cordelette (or for me, just the climbing rope) remains the method of choice for three-point anchors, with the following additional procedure: in constructing the anchor, low-stretch sling material on one or more anchor points should be used in order to keep the cordelette (or rope) arms approximately the same length. This is especially true for anchor points arrayed in a vertical line, a configuration which provides the worst-case scenario for ordinary equalization.
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tolman_paul
Trad climber
Anchorage, AK
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Jun 30, 2008 - 02:26pm PT
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Yes I still use it, was taught at Yos. mountaineering school 20+ years ago and like any piece of safety equipment and technique, you need to know when and how to apply it, and it's limitations.
I think some folks get so hungup on the triplicate quadlacate equalized duplicated anchors that its amazing they can get up anything. Also there seems to be a segment in the climbing community that anal-izes everything to death, but has little to know real world use of those setups. I'd prefer not to get caught in the dark or a storm due to all the time involved building and tearing down quadlicate redundant anchors at every belay, but that's just me. Perhaps I'm comfortable enough at my ability to evaluate my placements and build the anchor accordingly.
There is something to be said for a simple anchor when it suffices.
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Karl Baba
Trad climber
Yosemite, Ca
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Jun 30, 2008 - 02:45pm PT
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Macolm's rule's are total BS, except for #2 which is on the money.
But the OP talked about using the x for PROTECTION.
Much better to use a screamer on necessary but dicey pro in my mind.
Peace
karl
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Prod
Social climber
Charlevoix, MI
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Jun 30, 2008 - 03:04pm PT
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Use it, as well as a tied off cordalette, and have used the equelette, and have tied in with rope to gear, and one of my favorites is to wedge my feet against a tree on a hip belay (bringing up lighter climbers on easy stuff).
Basically I agree with TP.
MAL,
Your system seems complicated. I try to keep it to your rule #1 as a rule, and your rule #4 as a principal applied where necessary.
On a completely other note, at the same time I am writing this I am writing a note to my girlfriend. I nearly signed this Love Guy.
Love,
Prod.
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Moof
Big Wall climber
A cube at my soul sucking job in Oregon
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Jun 30, 2008 - 03:06pm PT
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Yes I use it, but yes it has limitations. Usually I end up using it in part of a larger setup, when I have 4 good pieces for downward (cuz sometimes I just can't help myself when placements are begging for gear!). I'll sliding X together a couple pieces to creat 3 points for the cordalette, and try to get another piece for upward pull. Usually the rock dictates the anchor more than rc.com, or Largo's most recent rant.
I objected to the sliding X being used by my partner only once, none have objected to my use of it so far (not to my face anyway). The anchor was 2 bolts, which he equalized with a 2' runner on a sliding X using lockers all around. My only gripe was that there was no redundancy if the sling failed. I know the sling isn't going to fail, but I really want redundancy against any single point failure. From then on he used 2 slings together, problem solved. In the same situration I usually using either two slings, one per bolt, or a 4' sling with a figure 8 knot at the bottom. With bomber bolts, redundancy is more important than equalization.
Strictly speaking SRENE is an oxymoron. You can't Equalize AND have No Extension for a multi-directional anchor. The best you can do is SRELE (surreal), where you aim for "Little Extension".
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bluering
Trad climber
Santa Clara, Ca.
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Jun 30, 2008 - 03:09pm PT
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Yep, I use it fairly often at anchors. Sometimes a cordalette, sometimes a SX, sometimes a funky combo of a SX and another piece slung to the x.
It's all situational. Just refer to Mal's rule#2 and quite overanalizing. Well, you're buddy was the one complaing, not you, so tell him to STFU and read largo's book.
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piquaclimber
Trad climber
Durango
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Topic Author's Reply - Jun 30, 2008 - 03:59pm PT
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Karl is right, I was asking about using the x for protection on a pitch, not for anchor purposes. Sorry for my poor communication.
I agree about the screamer Karl... if it's that sketch and if I have the gear available, I use the X with a screamer at the clip in point.
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Largo
Sport climber
Venice, Ca
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Jun 30, 2008 - 04:05pm PT
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One of the things that gets overlooked in all these discussions is something we confirmed during testing - namely, that all systems with a sliding powerpoint are prone to binding (as in the sling binding when weighted, negating the sliding motion) in what is known as the clutch effect. Using an anodized, pear-shaped biner all but eliminates the binding, so go with that.
JL
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piquaclimber
Trad climber
Durango
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Topic Author's Reply - Jun 30, 2008 - 04:11pm PT
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John,
Do you think the clutch effect can be partially mitigated by placing the bartracks of a swen sling in a specific place in the setup? Is the bartrack involved at all in the binding that you saw?
Or do you think the clutch effect is multiplied or reduced depending on the type of sling you are using? (Nylon vs Spectra)
Cheers,
Brad
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Largo
Sport climber
Venice, Ca
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Jun 30, 2008 - 05:05pm PT
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John,
Do you think the clutch effect can be partially mitigated by placing the bartracks of a swen sling in a specific place in the setup? Is the bartrack involved at all in the binding that you saw?
Or do you think the clutch effect is multiplied or reduced depending on the type of sling you are using? (Nylon vs Spectra)
Cheers,
Brad
BRAD:
I THINK IT IS SIMPLY A CASE OF FRICTION COEFFICIENT, MEANING THAT WHATEVER SLING MATERIAL YOU USE, IT TENDS TO BIND ON REGULAR ALUM., WHILE IT SLIPS ON THE POLISHED ARTICLE. SLING MATERIALS VARRY IN SMOOTHNESS (AND PRODUCE LESS FRICTION/BINDING) AND THIS MIGHT BE WORTH LOOKING INTO.
JL
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maldaly
Trad climber
Boulder, CO
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Jun 30, 2008 - 05:10pm PT
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rgold, you're forgiven for the geek nature of your posting. As usual your comments are accurate and insightful. Thanks for chipping in but don't ever do that again.
To all the other posters, I agree: Rule #2 is the best.
Mal
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Matt
Trad climber
primordial soup
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Jun 30, 2008 - 05:23pm PT
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lately though, i've been attaching the lead rope directly to the anchor pieces with clove hitches. this doesn't equalize 100% but no shock load occurs if a piece fails.
how many people do this?
i think this type of anchor was the culprit when those CO guys ripped off the DNB a few years back.
i know there is a fondness for the craft involved, one which goes to the famous photo of that bridwell anchor, but i have always felt like that type of anchor was basically cutting corners, and best to be used only when nothing else would work.
honestly, i don't understand the argument in favor (i.e. "this doesn't equalize 100% but no shock load occurs if a piece fails").
if you haven't really equalized anything (and you haven't), then you basically are loking at sequential shock-loading of as many pieces as it takes before one holds individually, or they all pop.
am i missing something?
(and yes, i am familiar with the ins and outs of a clove hitch)
EDIT
i agree entirely w/ the post below, by TP
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tolman_paul
Trad climber
Anchorage, AK
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Jun 30, 2008 - 05:33pm PT
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I've used the clove hitches in situations where, I was setting up a quick anchor, each point was bomber, and I was situated to where I was belaying from my harness and a fall wouldn't have loaded the anchor.
There are many different situations one finds themself in and anchors are built and equalized accordingly. I've used anchors that I wouldn't even trust to rappel on, and others I could use to winch a truck up, and most fall somewhere in between.
I guess my typical anchor would be a long loop of 1/2" supertape, equalized between 3 anchors, and tied with an overhand at the master point. The three point sliding X really suffers from friction, and when the webbing is long enough to allow the overhand knot it cleans it up a bit.
But it all depends. Best is knowing many different anchors, pros and cons, and using them as needed on a case by case, belay by belay situation.
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