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raymond phule
climber
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Do anyone have a picture of the quad?
Why 2 looking biners on the equalette? Wouldn't 1 on one of the strands actually work better?
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Tomcat
Trad climber
Chatham N.H.
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Meanwhile,while this is being resolved.Make your anchor,equalize as you see fit,clip through,move up,place bomber piece on next pitch,hang rope through it,step back to belay,tie/clip in,bring up second TRing them through that higher piece.They are set to go.If it's your lead,pull the rope back through.
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Largo
Sport climber
Venice, Ca
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JL said: The fun (to me) of this particular challenge is to try and drum up a solution with just the one long piece of cord and no gizmos, do-dads and/or horsefeathers.
It's been done several times already, and months ago, though perhaps you missed it at the time - no doubt you were quite busy as your book was close to going to press.
The Mooselette, the CharlesJMM anchor, and the Gordolette all accomplish this admirably.
GO
All have too many do-dads and extras. Moreover, they don't equalize three anchor points--that's the real challenge. Four anchors is easy to get load distribution. Three is perhaps impossible to achieve with one sling.
JL
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Paul Raphaelson
Ice climber
Brooklyn, NY
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I question a couple of the basic premises of the anchor uproar. I'm not the first to ask this, but how vital, really, is equalization? I understand that it's desireable from an engineering standpoint, but we've already established that it's not so easy to get everything we desire ... some compromise are probably in order. If your pieces are sound, then there is a high probability that any one of them could take the full force of a factor 2 fall*. Which leaves the other two pieces available for redundancy. An unloaded backup piece (or two) might in fact be a good thing.
Lack of extension still seems desireable, for a few of the reasons stated (Iike not ripping the belayer off the ledge and adding to the forces/soiled knickers).
A cordelette seems like a reasonable compromise in many situations. What it always brings to the party are speed, simplicity, lack of dependence on gadgetry, and (relative) ease of evaluating.
I look at some of the proposed alternatives, and immediately think No Way. I see serious real world danger in any system whose complexity makes it difficult to evaluate at a glance.
It seems like the cordelette is most out of its element when direction of force can't be predicted at all (traversing pitches, etc.). In these cases something that can dynamically equalize, like the humble X and its derivatives, seems like a better compromise.
I suspect a great danger is that people get so obsessed with rigging that they forget about the idividual protection pieces. We labor over how well the rigging can compensate for changes of load direction without asking how omnidirectional the placements themselves are. I see this all the time. Some pieces are likely to pop when tugged sideways, period ... it makes no difference how sophisticated their connection to the rope is.
Finally, do we have reliable data on actual fall forces generated in factor 2 falls held with a belay device? Not counting Gri Gris and other autolocking/autoblocking monsters, I wonder how much force anyone can really generate at the belay end. These devices work as force multipliers, not as rigid clamps. I remember reading on a rescue site that most people were unable to lower a 400 pound rescue load at all without losing control, using ANY standard belay device. That's less than 2 KN! How exactly are we able to generate 10 KN on a belay anchor, even with the questionable practice of redirecting the rope through the anchor? According to the movie playing in my head right now, belay gloves might be a better idea than a custom piece of hardware for equalized rigging.
*If you have individual pieces that are marginal, like micronuts, or anything in suspect rock, this might be an invitation to equalize that piece with another, using an X, and to use that equalized pair as a single arm of the larger anchor. A traditional practice, and still pretty smart, IMHO
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GOclimb
Trad climber
Boston, MA
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JL said: All have too many do-dads and extras.
None use anything besides overhand knots, clove hitches and biners. In many cases, fewer knots/hitches and biners than the equalette.
Moreover, they don't equalize three anchor points--that's the real challenge.
Yes, actually. They do. The CharlesJMM does not do so as well as the other two, but it does do so over a small range - larger than the range of the equalette, in my limited testing.
Four anchors is easy to get load distribution. Three is perhaps impossible to achieve with one sling.
Not impossible. As I said, it's been done, and those three do it admirably well.
I can post additional pics if you like, but can't do so now, I'm at work.
If you'd prefer to pick this up offline and go to email, I believe the email listed under my supertopo login is correct. Just click on my username in the upper left-hand corner of my post.
GO
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rgold
Trad climber
Poughkeepsie, NY
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"I question a couple of the basic premises of the anchor uproar. I'm not the first to ask this, but how vital, really, is equalization? I understand that it's desireable from an engineering standpoint, but we've already established that it's not so easy to get everything we desire ... some compromise are probably in order. If your pieces are sound, then there is a high probability that any one of them could take the full force of a factor 2 fall*. Which leaves the other two pieces available for redundancy. An unloaded backup piece (or two) might in fact be a good thing."
I think "desirable" is the right term. If you can achieve better equalization than we get now without massive extra complications, then that seems to me to be an unmitigated good thing. But the "if" is a pretty big one.
"A cordelette seems like a reasonable compromise in many situations. What it always brings to the party are speed, simplicity, lack of dependence on gadgetry, and (relative) ease of evaluating."
All true. In fact, tying in directly with the rope is even better. But fixed arm rigging is inferior in the equalization department. The question is whether there is a better alternative.
"I look at some of the proposed alternatives, and immediately think No Way.
Me too.
"It seems like the cordelette is most out of its element when direction of force can't be predicted at all (traversing pitches, etc.). In these cases something that can dynamically equalize, like the humble X and its derivatives, seems like a better compromise.
There seems to be a growing number of tests that suggest that the cordelette is almost never very good, even when the arms are of equal length, so it is never really "in" its element. As for falls directly onto the anchor, they will almost never be directly in line with the power point and so the cordelette will in, this sense, almost always be out of its element.
"I suspect a great danger is that people get so obsessed with rigging that they forget about the idividual protection pieces.
I have much more faith in people's intelligence.
Finally, do we have reliable data on actual fall forces generated in factor 2 falls held with a belay device? No counting Gri Gris and other autolocking/autoblocking monsters, I wonder how much force anyone can really generate at the belay end. These devices work as force multipliers, not as rigid clamps. I remember reading on a rescue site that most people were unable to lower a 400 pound rescue load at all without losing control, using ANY standard belay device. That's less than 2 KN! How exactly are we able to generate 10 KN on a belay anchor, even with the questionable practice of redirecting the rope through the anchor?
Well, we know that belay anchors built by experienced climbers have failed catastrophically in the field. (I think I have heard of five such incidents in the past ten years.) In no cases were the anchors made up of pieces we would think of as marginal before they're placed. So either the forces can in some cases be higher than we expect (perhaps a kink jams or a turn of rope around something adds extra friction), or even very experienced climbers sometimes seriously misjudge the holding power of their anchors. From an engineering perspective, equalization is the best strategy for guarding against such outcomes.
"According to the movie playing in my head right now, belay gloves might be a better idea than a custom piece of hardware for equalized rigging.
I don't know about a better idea, but I think they're a damn good one.
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Largo
Sport climber
Venice, Ca
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"Not impossible. As I said, it's been done, and those three do it admirably well."
When I see more than one loop or one strand going to a primary placement, and instead see a bunch of biners cipped in at weird angles or funky knots and multiple strands running to and fro the power point, I don't even study the thing because I know such a rig will never catch on. But I should probably look at these systems a little closer and get some ideas about how to simplify things.
The rig I'm looking for has a single, sliding power point, single strands going to the three placements connected to the primary placements by ONE biner and one knot. No cross strands up high between placements, and only one limiter knot per strand. Such a rig can be easily arranged and will yield very good equaliization but since the whole things slips and slides and dynamically adjusts, once you place limiter knots this is no longer the case and without the knots the extension problem is grave.
So I'm still looking, but if the cat has been licked according to the above criteria, I'm all ears and eyes.
JL
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Frog Man Junior
Social climber
CA
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I say three peices, 3 slings, and screamers are great! Until they won't stop screaming and the kids are waking up!
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GOclimb
Trad climber
Boston, MA
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When I see more than one loop or one strand going to a primary placement...
All three anchor methods I mentioned have one loop per primary placement.
and instead see a bunch of biners cipped in at weird angles...
The only one of the three I mentioned that could qualify for the above would be the Gordolette. In fact, the CharlesJMM in its standard format has fewer biners than the equalette!
or funky knots...
As I said - only overhand knots and cloves.
and multiple strands running to and fro the power point...
Uh, each of the three has one loop coming out of the powerpoint per protection piece - just like the cordelette.
I don't even study the thing because I know such a rig will never catch on. But I should probably look at these systems a little closer and get some ideas about how to simplify things.
Your choice, of course, but if you don't look at them, you really shouldn't mischaracterize them.
Cheers!
GO
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raymond phule
climber
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"There seems to be a growing number of tests that suggest that the cordelette is almost never very good"
I have only heard of the Long et al tests. Are there any more?
"Finally, do we have reliable data on actual fall forces generated in factor 2 falls held with a belay device?"
My link above has some information.
"Well, we know that belay anchors built by experienced climbers have failed catastrophically in the field. (I think I have heard of five such incidents in the past ten years.) In no cases were the anchors made up of pieces we would think of as marginal before they're placed."
Do you have any information of these cases? I have heard of an accident on the DNB but have zero info.
"So either the forces can in some cases be higher than we expect (perhaps a kink jams or a turn of rope around something adds extra friction),"
The worst possibly case might be if the climber fall onto the belayer. My quess is that a 5 m fall onto the belayer would put a huge force on the anchor and would rip out a perfect 3 piece anchor.
"or even very experienced climbers sometimes seriously misjudge the holding power of their anchors."
People do misstakes.
"From an engineering perspective, equalization is the best strategy for guarding against such outcomes."
I disagree, knoweledge about the problems that could occur might be a better guarding.
Do you really have enough information about the accidents so that you can draw your conclusions? After reading your post I get the impression that 5 good anchors, 3 good pieces in good rock that backup each other with no huge extension, for example using a cordellete, completely failed. Do we really know this?
The reason for failure could be many things. Bad pro, pro that anly could take a force in one direction, an anchor with a large extension. The climber might have taken a 10 m fall onto the belayer. Not enough pieces.
Edit: Here is some info about the DNB accident
http://www.supertopo.com/climbing/thread.html?topic_id=20228&msg=20402#msg20402
Seems like a long class 2 fall onto the belay and that the rock might have been suspect. Extension could also have been an issue. An equalised anchor would probably have been good there.
edit: here is another one
http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?do=post_view_flat;post=509416;page=1;mh=-1;guest=5506676;sb=post_latest_reply;so=ASC
Seems like the second made a traversing fall on a cordellete and the belay ript. The belayer might have been connected to the belay with a static sling (special knot, prussik) and the pieces might have been less than perfect. Sounds definitely like a strange acident and might have shown a failure of a cordallete in practice where an equalized anchor might have hold. Edit: Seems to be more uncertainties about the accident than I first thought.
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Largo
Sport climber
Venice, Ca
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Go said: The CharlesJMM is the shite.
Kindly show us how this thing works. I don't have time to search the web for photos.
Thanks, Go.
JL
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the Fet
Knackered climber
A bivy sack in the secret campground
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Why are we fixated with the idea of three pieces for an anchor? Why not two and why not four?
Good question. IMHO 2 pieces of bomber pro equalized seems sufficient. 3 gives you a backup (one of those pieces might not be so bomber after all). Four seems a little overkill, but with any marginal placements 4+ may be the way to go.
Do we really need to make every anchor so it can take the worst possibly scenario... I just see an unecessary scenario with even longer lines on nutcracker because everybody is trying to perfectly equalize many pieces of good pro on all belays.
I prefer all my anchors to be totally reliable. e.g. If a leader fall turns into a self-rescue with two people rapping off the anchor, I want absolute confidence in the anchor. I don't think you always need to perfectly equalize, but equalizing 2 pieces can give you up to twice the strength in about the same amount of time.
Why 2 looking biners on the equalette? Wouldn't 1 on one of the strands actually work better?
Then there'd be no redundancy. One strand of webbing/cord should never break... but neither should a rope or belay loop, and that's happened in the past year.
All (added: Mooselette, CharlesJMM, Gordolette) have too many do-dads and extras. Moreover, they don't equalize three anchor points--that's the real challenge. Four anchors is easy to get load distribution. Three is perhaps impossible to achieve with one sling.
That's true, they share the load, but don't equalize it. The Astroglide will equalize 33/33/33, neglecting friction, but like the Mooselette, CharlesJMM, and Gordolette it is too complex to catch on, and easily visualy inspect (in the dark when you are knackered).
If your pieces are sound, then there is a high probability that any one of them could take the full force of a factor 2 fall*.
No, a small cam could break in a factor 2. Or 10+ year old cam slings could snap, flakes break off, etc.
I see serious real world danger in any system whose complexity makes it difficult to evaluate at a glance.
I agree, and think a sliding W backed up with the rope or slings is probably the way to go if you need to equalize 3 pieces.
If you can achieve better equalization than we get now without massive extra complications, then that seems to me to be an unmitigated good thing. But the "if" is a pretty big one.
rgold hits the piton on the anvil with that statement. By using a sliding X with limiter knots or an equalette (which is almost the same thing) you have acheived pretty good equalization on two pieces, probably coming close to doubling your strength and safety factor, with almost no extra complications (compared to a cordelette).
Equalizing 3 pieces adds a layer of complexity to the problem, that is even more challenging than equalizing 4 pieces. Due to friction, the simple sliding W will probably beat out all other designs at effectively equalizing 3 pieces. There's been a lot of effort (in the rc.com sliding X thread, etc.) to come up with something that will replace the cordelette and; simply, equalize 3 pieces, limit extension, with only one cord. But so far no simple solution.
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raymond phule
climber
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I have thought about this and now I belive that 2 equalised pieces and 1 or maybe 2 pieces as a backup would be a very good anchor. It should be stronger than any non equalised anchor (that have worked good for many years), like using a cordellete, slings or the rope in many cases and it is not that dificult to set up with an equalette or sliding x.
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GOclimb
Trad climber
Boston, MA
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JL, I wouldn't necessarily call the CharlesJMM the best of the rigs, but since you asked.
To do a CharlesJMM rig:
1 - Pull the three loops down into a powerpoint, just like you would for a cordelette.
2 - Put a twist in the line going from the two outside pieces, and clip a biner into the three loops that make up the powerpoint.
3 - Loosely tie overhand knots in the two outside strands.
4 - Pull down on the powerpoint biner to equalize the strands and tighten the knots.
I'll post pics as I have time, very busy at work right now.
Here's an old pic I took of the finished product. Note that I've put extra slack in the strand with the twist so you can see it. Normally it would be taut with the other strands.
GO
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GOclimb
Trad climber
Boston, MA
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I'm not a graphic artist, and due to the limited(!) interest, I'm not going to put a ton of time into this. Anyway, please pardon the fact that these look like crap.
Cheers!
GO
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rgold
Trad climber
Poughkeepsie, NY
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Equalization was embraced as an essential ingredient in anchor construction until it turned out that our methods for achieving it don't even come close in many cases, and since then the discussion of better alternatives is burdened with the question about whether equalization is worth seeking at all. It was necessary when we though we had it, but it became unimportant when it turned out we didn't have it. Hmm.
""There seems to be a growing number of tests that suggest that the cordelette is almost never very good"
I have only heard of the Long et al tests. Are there any more?"
There was a series done by Attaway and reported in a Mountain Rescue conference. The results are not available online, but Attaway's conclusion that the cordelette did not meet their standards for equalization were reported in an online forum. Sorry, I don't have references.
"Finally, do we have reliable data on actual fall forces generated in factor 2 falls held with a belay device? My link above has some information."
A great link, thanks for it. But no useful data on factor-2 falls reported there, unfortunately
""Well, we know that belay anchors built by experienced climbers have failed catastrophically in the field. (I think I have heard of five such incidents in the past ten years.) In no cases were the anchors made up of pieces we would think of as marginal before they're placed."
Do you have any information of these cases? I have heard of an accident on the DNB but have zero info."
Sorry, I'm going on memory. There is the DNB case, the Tahquitz case, a case I read in the AAC accident reports a few years ago, a case Attaway mentions as the motivation for his report on fall impacts, and the case Werner referred to earlier in the thread. The random way this information comes to us suggests the likelihood of other cases we haven't heard about.
In general, there is very little information about what actually happened. In the Tahquitz case, the official conclusion excluded anchor failure as the cause.
""From an engineering perspective, equalization is the best strategy for guarding against such outcomes."
I disagree, knoweledge about the problems that could occur might be a better guarding."
Here I think you are wrong. As you say, peopel make misstakes, even in the presence of knowledge of the problems. They are sometimes wrong about which piece is good. The best strategies are those that minimize potential load to all pieces, are tolerant of off-axis loading, and redistribute the load to remaining pieces if one fails. These are the only available means of coping with the uncertainties that are part of real life.
"Do you really have enough information about the accidents so that you can draw your conclusions? After reading your post I get the impression that 5 good anchors, 3 good pieces in good rock that backup each other with no huge extension, for example using a cordellete, completely failed. Do we really know this?"
No. We know very little about these accidents.
But it is also the case that very few experienced climbers have ever had their anchor judgements subjected to a real test, much less a statistically significant sequence of tests. This means that most climbers really have no basis in reality for judging the strength of their anchors. The tragedy described by Werner earlier in this thread indicates that these claims are not simply hypothetical.
Once again, in the face of this really quite massive uncertainty, equalization is the best strategy, if it can be achieved.
"The reason for failure could be many things. Bad pro, pro that anly could take a force in one direction, an anchor with a large extension. The climber might have taken a 10 m fall onto the belayer. Not enough pieces.
But the effect of all of these things would be mitigated by having an equalized anchor that can adapt to off-axis loads and does not suffer from the possibility of large extensions. Your own analysis of the cases you linked to concludes an equalized anchor might have helped.
In any case, I don't know if there is exactly an "uproar" about all this. It seems to me that a relatively small group of climbers is interested in the intellectual challenge involved, and most others feel that the distributive (rather than equalizing) methods that we have are plenty good enough. It may be that those who are interested will eventually come up with a solution the mainstream will adopt, or it may turn out that the complexities of fabricating equalizing anchors and especially the associated problems of friction will ultimately doom the enterprise to a generally disregarded cult status.
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murcy
climber
San Fran Cisco
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Thanks for posting that, GO!
I'm puzzled, though. The two limiter knots freeze the sum of the lengths of the two outside legs; if they're taut, the powerpoint travels along an ellipse. But then the center strand's length, when taut) is constant, too, and so describes a circle. So it seems to me that apart from the one or two directions at which the circle and ellipse intersect, all the weight will be taken at the powerpoint either by the strand that connects the two knots directly (in which case the center piece is unweighted), or by the two other strands (in which case the center piece gets twice the load of the others, as seems to be the case in your photo). Or am I mistaken?
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rgold
Trad climber
Poughkeepsie, NY
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For those who are interested in such things (perhaps the empty set), I'd like to propose a reappraisal of the effects of a small extension in an anchor.
Conventional wisdom has been that extension is bad because of the "shock load" it would cause. As has been pointed out many times by now, the term "shock load" has never had a proper definition, but forgetting about the shock aspect, certainly the understanding is that the resulting load would be large in the context of possible anchor loads.
I'd like to suggest that maybe conventional wisdom has things exactly backwards; that in fact it is the fixed-arm cordelette that will impose a relatively large load on the remaining pieces, and that by constrast, an anchor that with a small extension will actually produce smaller loads on the remaining pieces than the cordelette would have.
Now "small extension" is ultimately going to need a definition too; my suggestion is that the ratio of extension to the length of belayer tie-in (assuming the belayer uses the rope to tie in)---in other words an H/L ratio for the fall caused by the extension and absorbed by the tie-in---is an appropriate measure of smallness.
Consider what happens if one piece of a cordelette anchor fails. With no extension, the load is immediately transferred the remaining pieces (actually, probably to just one other piece). The rope has no ability to recover during this transfer, precisely because the absence of any extension provides no moment when the tension in the rope is reduced. The net effect is that the remaining piece or pieces get the full maximum impact of the fall, the same impact that would have been delivered to the anchor had it remained intact, but now shared by fewer pieces. Put another way, no benefit is obtained from the energy needed to extract the first piece.
There is an instant in which a shared load is suddenly shared by fewer pieces; this is certainly a candidate for a "shock load" imposed by the cordelette.
Next, consider what happens when a piece fails and there is a small extension. During the instant of extension, rope tension drops to zero. When the load comes on the remaining pieces, they only have to arrest the remaining part of the fall, which clearly involves less energy absorbtion and so a lower peak load. In this setting, the energy involved in stretching the rope up to the point of extraction is removed from the total energy that must be absorbed by the remaining anchor.
This reduction effect is mitigated by the fact that the rope will have been "stiffened" by the first stretching and so will develop higher peak loads, and of course by the added effect of a (low fall factor) belayer fall. Perhaps the load on the anchor will be higher or the same, but it is also entirely possible that a lower anchor load will be observed, precisely as a result of the fact that a small extension allows the extracted piece to function as an energy absorber.
The fact that Wootle's tests essentially showed no "shock load" would be explained by the combination of a very low extension ratio and the energy-absorbing opportunity the moment of extension provided. This analysis would predict that the remaining piece in Wootles tests would have experienced higher loadings when the cordelette was employed. I believe, but am not sure, that some of his data does fit this pattern.
If testing were to bear this out, then small extensions would be viewed as possibly beneficial rather than always harmful, and yet another "benefit" of fixed arm rigging would become questionable.
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rgold
Trad climber
Poughkeepsie, NY
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Very nice insight Murcy. I agree that the CJMM rig never equalizes, in the sense that the probability you hit the two equalizing points is zero.
I don't have the time now to check, but one does wonder whether limiting knots in some of the other three-anchor rigs may also impose geometric constraints on equalization.
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murcy
climber
San Fran Cisco
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rgold writes:
"Consider what happens if one piece of a cordelette anchor fails. With no extension, the load is immediately transferred the remaining pieces (actually, probably to just one other piece). The rope has no ability to recover during this transfer, precisely because the absence of any extension provides no moment when the tension in the rope is reduced. The net effect is that the remaining piece or pieces get the full maximum impact of the fall, the same impact that would have been delivered to the anchor had it remained intact, but now shared by fewer pieces. Put another way, no benefit is obtained from the energy needed to extract the first piece."
I don't get it. If it took energy to yank the piece out, that energy is not going to create force on the remaining pieces. Imagine that it took nearly all the energy of the fall to yank the first piece; the falling climber would be slowed to nearly a stop, and the remaining pieces would have very little to hold. Of course, the rope might not be able to absorb too much more energy, but hey, it was going to have to absorb it all anyway.
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