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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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maldaly
Trad climber
Boulder, CO
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Jun 30, 2008 - 05:39pm PT
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tolman_paul,
The last sentence in your post is now my rule #5.
Mal
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bluering
Trad climber
Santa Clara, Ca.
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Jun 30, 2008 - 05:47pm PT
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Since piqua was talking about using the sx to equalize two pieces of LEAD PROTECTION for redundancy, clove hitching the two pieces would work also instead of a sx. I've done it, seems to work fine. Of course you gotta get the hitches just right for it to work effectively.
Of course, the hitches are probably better when setting two OPPOSING pieces.
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rgold
Trad climber
Poughkeepsie, NY
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Jun 30, 2008 - 09:38pm PT
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Mal (and Paul), I've enrolled in Over Anal - yzers Anonymous and have been through their 12-step program and...still...can't...help...geekish...posting...eeeaaaahhhhHHHH!
In my opinion, Jim's testing does show that extension in a sliding system used to equalize pro is of little concern, because in the case of pro the extension will almost always be tiny compared to the amount of rope absorbing energy. So the pro situation is very different from the anchoring situation, and this makes the sliding X or, better, an equalette, a good choice for two questionable pieces. The equalette will, in many cases, be too tricky to tie while leading, while the sliding X, although more subject to binding, is easily installed with one hand.
An issue I've never seen discussed with the sliding X is what happens to the power-point biner if one of the anchors fails. A turn of webbing holding the failed anchor is going to tighten around the power point biner, with significant potential for opening the gate or cross-loading the biner. Because of this, I'd say that the power point in a sliding X set-up on pro should always consist of two biners with the gates opposed.
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Jaybro
Social climber
wuz real!
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Jun 30, 2008 - 09:45pm PT
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of course not... trick question?
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Lost Arrow
Trad climber
The North Ridge of the San Fernando
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Jun 30, 2008 - 10:10pm PT
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I no longer use a sliding x. I tie in to a bomber with the rope and than back that piece up with more pieces and webbing to a single locker.
JDF
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Ed Hartouni
Trad climber
Livermore, CA
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Jun 30, 2008 - 10:13pm PT
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Answer the question:
I use the sliding-x sometimes, usually in a 3 piece anchor where it equalizes two pieces and the the rope goes to the third piece by a clove-hitch.
Sometimes I use the cordelette in the same manner, depends on the distance of the pieces.
Sometimes I use the cordelette with three pieces, especially if the legs are pretty much equal in length.
I always try to to follow Mal's first three rules...
The accident on the DNB will never be definitively analyzed. However it is possible that a flake blew and that all the pieces were behind the same flake. Note that that arrangement violates Mal's rules 1 through 3, and those people were experienced.
Read the accident report...
http://www.supertopo.com/climbing/thread.html?topic_id=554557&msg=557937#msg557937
I did try to measure the coefficient of friction in the "sliding x" configuration, the "clutching" can be significant, but it depends on how the sling sits, on top of each other or next to each other... so not a reliable setup, but less of a force differential than the cordelette in a very "asymmetric" configuration (one leg much longer than another).
As for "shock loading" analysis would say that it has to be a factor... so it would be interesting to push the analysis difference of the tests and the calculations... there is some good wisdom hiding in there that a concerted effort at understanding would reveal.
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k-man
Gym climber
SCruz
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Jun 30, 2008 - 11:26pm PT
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... OT from the OP ...
Using the lead rope to anchor, a friend showed me how to "equalize" with a bowline-on-a-bite.
FOLLOW RULE #3!
I now use this at all two-bolt belays.
A single biner on each bolt. Fast, and the least amount of gear
you can possibly use. You can adjust the bowline, if needed, to
assimilate a degree of "equalization."
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tom woods
Gym climber
Bishop, CA
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The thing with anchors is that we build them fro two purposes. For the follower and for the leader. For the folllower, barring an extreme swing, you could body belay the person from a good ledge.
For the leader, (that's what got the DNB folks a couple of years back) you're building a an upward or mulit directional anchor, but you have body weight on your side.
Things get interesting until you get back to the old schoolers and the leader must not fall mentality. I don't like falling either so problem solved, QED.
Tom
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Gobie
Trad climber
Northern, Ca.
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Did anyone read the OP??
Karl is obviously the only one that did.
It doesnt say anything about belays. Do rules 1-4 apply to protection as well? I wish all my pro was bomber, sometimes I settle for what I get. Hopefully it will slow me down before I get to rules 1-3 and its strong enough to apply force to rule 4.
Answer to question. I would prefer to extend my (dubious) pro to be as close to equal to each other as possible even if this results in a little bit longer of a fall. I did this once with a small brass hb and a loweball. I thought it was cute at the time and then I got higher and realized that it was my pro. I fell and pulled the hb and the loweball held. I cant be convinced this would of happened if they were on an X. I didnt have a calculator, or time to think about it, my brain just works that way.
"Have you ever been experienced...well I have."
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Ed Hartouni
Trad climber
Livermore, CA
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well, the link follows, and it does refer to anchors... I assumed these could be belay anchors...
and I do use the sliding x occasionally to equalize two marginal placements, judging that the distributed force would be held by the combination where both, one at a time, would not. I can't tell if this is one of the exceptions or not...
Sliding X (aka Death X)
by Editor
March 18, 2003
Republished with permission of the American Safe Climbing Association.
Many climbers use a "sliding X" to equalize two pieces - ususally beginner climbers with bolt anchors. You should NEVER use this except in two specialized cases (see below). While the sliding X does equalize the pieces, it assumes that neither could break, since if one does break, there is severe extension in the system - enough that it would likely cause the carabiners to break. Since it assumes neither piece would break, it's a stupid system - if neither would break, there's no need for equalization. If one might break, then there is WAY too much extension. This is why many call it the "death X." Instead, use one sling off of each bolt or piece. You can tie one shorter to approximately equalize the pieces if needed.
The two cases where the sliding X is used:
-Equalizing tenuous pieces in a larger anchor - for instance, two poor nuts in a large natural pro anchor. The nuts are equalized, then the sliding X is equalized with other pieces through a cordelette, webolette, or other non-extending method.
-Equalizing two very tenuous pieces in extreme aid - for instance, a hook and a bashie on A4 terrain.
Camp4 Editors Note- If you do have to use this system, make sure you make the twist in the sling before clipping the caribiner (see image above). If you don't and one of the anchors fail, the WHOLE SYSTEM WILL FAIL.
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k-man
Gym climber
SCruz
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I don't know Ed, I think I'll go with the updated info from JL.
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Ed Hartouni
Trad climber
Livermore, CA
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the dynamic behavior of the "clutch effect" has not been explored, as the physics of friction are somewhat complex, and the engineering (which is what the tests are all about) probably do not fully explore the issue.
There are two frictions, as it were, static and dynamic friction, and each has a coefficient associated with them, the dynamic coefficient usually being smaller than the static coefficient.
In our case, the power-point 'biner (which acts as a pulley) slides freely until the normal forces of the webbing produce enough frictional force to prevent the slings from sliding. Whatever the configuration of the webbing is at that time, it acts like a two-legged cordelette, that is, the the forces on the pieces connected to the webbing are inversely proportional to the length of the legs.
As long as the force on the sling is less than the generated static frictional force, the sling will remain static in the possibly unequal force configuration.
However, if the forces are larger than the frictional force, the sling will begin to slide again and equalize. The sliding will be "sticky" because of the dynamic coeff. but it is possible that the equalization will be complete.
One way to reduce the friction is to use a 'biner with a larger diameter aluminum shaft, effectively reducing the "wrapping angle" and thus greatly reducing the frictional forces. I think this is demonstrated empirically in John's recollection of the tests, reducing the coefficient of friction has the same effect, and doing both would greatly reduce the tendency of this system "to clutch".
I'll get back to my dissertation on the calculational details soon... but you can look here (look at several posts in this general area and hey dirtineye, check this for me! please... and cleo too).
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Elcapinyoazz
Social climber
Joshua Tree
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obvious implication is that you would want to use spectra slings with little nylon in them for a decreased friction coefficient?
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the Fet
Knackered climber
A bivy sack in the secret campground
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I'd say with about 99% certainty that the "clutch effect" on a sliding X is not due to friction of a sling on the biner, but is due to having two wraps of webbing going around the biner (one with a twist in it) and the two wraps of webbing binding on themselves and the biner. Try it with a sliding X; pull down on the powerpoint biner and move it side to side, if the X binds you can feel the clutch effect. Then try a biner on a single strand of webbing, the friction is negligible.
Using a large diameter biner mitigates this effect substantially. Or you can pretty much eliminate the clutch effect if you have a sliding X with limiter knots and you make the strand with the twist in it a little loose. I keep saying this but no one is getting it, so maybe it's too complex for general use.
As for the original question I have used a 12" sling to make a sliding X to equalize 2 pieces, but really it's only needed on hard aid. If I put 2 pieces in because it's a long way down to the next piece, or I'm pulling a hard move and I can't have that piece fail I'll just put them in series.
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Ed Hartouni
Trad climber
Livermore, CA
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a sliding-x with limiter knots is not a sliding-x...
also, the coef-of-frict for nylon on nylon is not that dissimilar to that of nylon on aluminum...
Elcap... I think spectra is interesting not so much for the reduced coef, but because the slings tend to be square, rather than ribbons, and the squares sit next to each other rather than over/under... this reduces the normal force considerably as one sling does not trap the other against the 'biner. You cannot guarantee this configuration in an engineering sense with the 'biners that are available, but you could see how you might design a special 'biner.
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ontheedgeandscaredtodeath
Trad climber
San Francisco, Ca
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This not really a "real world" question, but if one piece blows, would some dynamic or static friction not be beneficial in that it would prevent a shockload to the second piece?
I don't see the point of the sliding-X cept on aid, beyond saving a runner and a biner.
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maldaly
Trad climber
Boulder, CO
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GEEK ALERT!!!!
You guys might want to think about moving this conversation over to rc.com. It's getting pretty thick...
;-)
Mal
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Scrunch
Trad climber
Provo, Ut
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Tools in a toolbox, like anything else in climbing.
Climbing in Big Cottonwood, Your only pro a #2 microstopper in a seam? Throw in two, equalize with a SX, and throw screamer on it. BOMBER!
In Little Cottonwood at a two-bolt anchor? Two clove hitches and your done. 3/8" by 3" bolt in granite arn't going anywhere.
Keep in mind that a modern dynamic rope, by UIAA standard, can't produce more than 12kn of force on any part of the system. In a factor 1.77 fall situation. With 180kg of weight on it. Most ropes now boast a sub-10kn rating (though one of my favorites, MAXIM, has a few 10.5's)
If you climb on crap gear, you roll the dice. But if thats all you got, you might as well stack the deck in your favor. At least the stuff will slow you down.
The point is that Almost every tool has it's place, especially a tool as light to carry as knowledge.
(I prefer my metaphors shaken, not stirred)
Adam
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Matt
Trad climber
primordial soup
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from the tread that ed linked to:
Their anchor -- which appears to have pulled in its entirety during the accident -- consisted of the following. One 3/8-inch Alien and one #4 Black Diamond Stopper were clove-hitched together to one of the lead ropes approximately three feet from Eldridge's tie-in point. Two double-stem Camelots, .5 and .75 were each independently clove-hitched about a foot and a half apart on the other lead rope with 15 inches separating the lower piece form Eldridge's tie-in point. There was no evidence that bolts or other fixed protection were involved in the anchor.
All of the anchor pieces were severely damaged, though it is impossible to know whether the damage occurred when they were pulled out or during the fall and final impact. Nevertheless, the two Camelots were each bent in a similar way suggestive of a severe downward force after being placed in a vertical crack.
A loose quick-draw and a few carabiners were also found at the base. Their original purpose could not be determined, and they may have simply unclipped from the falling climbers -- a common occurence.
Analysis
Both Dunwiddie and Eldridge were skilled climbers, and in the days prior to their deaths they had completed a number of challenging free and aid routes in the Valley. Based on the location of the bodies, and on the topo of the Direct North Buttress found in their possession, they were probably on the DNB at the time of their accident. Rated at 5.10c and known for both its length and route finding difficulty, the DNB includes several sections of "run out" climbing and loose rock.
What can we learn? This accident hits close to home for most climbers because the party involved was very experienced with difficult climbing and familiar with Valley rock -- as have been at least a third of Yosemite fatalities, historically. Other factors, such as rock fall from above, may have been involved, but the prime suspects are basic anchor and leading concepts that all of us are often tempted to ignore: avoiding anchors in suspect rock, sharing the load to an adequate degree, and stuffing in that first (and second) lead piece right off the belay. If you can't meet these criteria, continue on with the realization that your survival may depend only on your climbing skill and on the quality of the next handhold. At least five other cases of complete anchor failure (protection pulling out -- not breaking) have occurred in the Park in the last 30 years. (Source: Lincoln Else, Climbing Ranger, Yosemite National Park)"
just for clarification-
my point above was that (in the absence of a pair of 3/8" bolts in granite) i would prefer some sort of imperfect equalization that would at lest distribute the load to a degree, to a system where one can expect multiple pieces to be loaded sequentially.
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k-man
Gym climber
SCruz
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Scrunch,
In Little Cottonwood at a two-bolt anchor? Two clove hitches and your done.
Two binners and a bowline-on-a-bite! Mo bettah ...
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