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JimTitt
Jul 29, 2012, 5:48 PM
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Well it was worse than I hoped for!
With the anchor points at equal height so the middle leg the shortest (about 1/3rd shorter) it was 11%/79%/and 10%.
I added draws into the outer legs to make them 1/3rd of the centre leg length and got 17%/62%/21%.
I tried playing with the centre knot to bias toward the outer legs but under load this seemed to just slide through until the centre strands locked the knot up.
The problem as always is that the difference between good equalisation and none at all is so small, 5mm in the leg lengths makes all the difference and there doesnīt seem anyway of either tying knots that accurately or controlling what happens in the centre knot well enough.
(When Iīm setting-up for a lot of these tests Iīm actually watching the read-outs to start out equalised and it is a question of mm adjustment until in the end the rope weave is the limitation, then I tighten the cloves and watch it all go haywire!).
On the other hand the Bearbreeder method does join all the pieces together in a simple, redundant and no-extension method which makes it as good as it gets realistically.
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bearbreeder
Jul 29, 2012, 5:55 PM
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so am i gunna die? 
what i would be interested in is seeing the load where the longest arm is the double strand in all uneven arm lengths ... similar to a vertical crack ...
thanks for the test ... ill keep on using it which will no doubt provoke comments here 
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rgold
Jul 29, 2012, 7:48 PM
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With the middle leg doubled and 2/3 of the outer legs, the Hooke's Law analysis predicts that the middle anchor would get three times the load of each of the outer anchors. Instead, it looks more like four times the load, probably because the clove hitches give a bit more than the central knot and so bleed even more tension out of their anchor arms.
By the way, had Jim doubled the connection to an outer leg, the prediction would be a 22% : 33% : 44% distribution, which still (of course) has one anchor load double one of the other anchor loads.
There isn't much more I can say about all this. Jim's tests, as far as they go, support the simple hypothetical calculations which, so far, have proven to be on target for every situation that has been tested. My guess is that the misnamed Metolius Equalizer will still do poorly, but not as badly as the results Jim got, because of the absence of the clove hitches.
At this point it seems fairly certain that double strands to just one of the anchor points will result in highly skewed loading, unless the arm leading to that anchor is much longer (e.g. twice as long as one of the other arms). The question about whether one should deliberately choose such loading when much more equitable distributions are attainable---with no real increase in complexity---is both personal and situational.
Hopefully, our anchors will always be individually good enough, and never tested to the extreme anyway, so that none of this matters.
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JimTitt
Jul 30, 2012, 9:07 AM
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A vertical setup is easier to test because it removes one of the practical difficulties I have doing the horizontal orientation (McKently doesnīt say what they did about this when they tested the cordalette). The strain guages have considerable weight (the smaller ones I used on the outer pieces are over 5lbs each) and to pull them into the line one thinks the force is going to take when tying the centre knot equalised a real pain and the accuracy suffers. Beverly tested horizontally so his guages lay on a board which solves the problem.
I adjusted the leg lengths as near as possible in thirds. From top down with the doubled strand on the top piece I got 48%/19%/33%. Changing to the doubled strand on the bottom piece 8%/9%/83% so at least the theory is correct about the double strands being stiffer but the results are somewhat erratic at best.
I also tried the Metolious concept with Dyneema and no clove hitches but as usual the tying the master point makes this a lottery of what force goes where, with all three legs the same length 17% on one single strand, 56% on the other single and 27% on the double strand not being what we should get.
Itīs pretty clear that the dominant effect in load distribution is tying the master point and it is hard to see how out on the cliff one could ever realistically expect a reasonable amount of equalisation which is also what Beverly implies.
Whie I had a vertical setup I tried the `clove hitch the pieces in series methodī with what I thought was a reasonable attempt to account for the differing lengths and stretch. Clearly 2%/5% and 93% shows room for improvement!
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rgold
Jul 30, 2012, 12:19 PM
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Thanks so much for these tests Jim!
Whether or not Hooke's Law applies in principle, it seems that stretchiness does matter. My guess is that in "stretchy" rope, the amount of rope elongation is enough to mitigate the variation introduced by the power point knot, whereas with low-stretch materials, small differences in arm length caused by power point knot irregularities can have effects large enough to bury the Hooke's Law distribution.
If this is true, then either the climbing rope or a rope cordelette looks like a more reliable load distributor than low-strength slings like the "Equalizer."
The series rigging with clove hitches comes out as one would expect. When I do it with, say, three vertical pieces, I rig the bottom two with the rope snug between them and then, when cloving the top piece, pull things up so the bottom two carabiners are horizontal, the theory being that a load will stretch things down and there will at least be some distribution to the upper pieces. Whether this actually works or not I have no idea.
Thanks again for introducing a cool dose of reality to what is otherwise a lot of hot air.
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acorneau
Jul 30, 2012, 12:52 PM
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JimTitt wrote: ... as usual the tying the master point makes this a lottery of what force goes where... Itīs pretty clear that the dominant effect in load distribution is tying the master point ...
This makes me wonder if these results gives even more validity to the concept of the mini-sliding-x as implemented in the Equalette/Quad.
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bearbreeder
Jul 30, 2012, 2:45 PM
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thats really good to know thanks for the test ...
my opinion is that no system is "ideal" ... and that in general i strive for simplicity, redundancy and minimal extension
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JimTitt
Jul 30, 2012, 3:04 PM
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At least with a rope system there is miles of stretchy rope and an enormous knot to take a lot of the impact out of the system, I tied the rope (a 9mm) into a cordalette to try something and needed 8m to be able to tie the master point even with a very compact 3-point system. The fig.8 tied in 6 strands looks to be an impressive shock absorber as it pulls tight!
Probably a good avenue to explore in fact since the alternative to sharing the force between several pieces (which is proving difficult) is to reduce the force altogether.
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tomcecil
Aug 2, 2012, 12:05 PM
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"what a waste of paying a guide or an instructors when they do not even cover the basic such as building an anchor with rope" majid
"I suspect that he's not alone. My guess is that it's just too much trouble for many guides to fully cover, and give all the necessary context around, rope-only anchors. It's certainly easier for them, and quicker for the client, to show how to build an anchor with a cordelette."Crack
A real waste of time is listening to anyone with such ridiculous generalizations--
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cracklover
Aug 2, 2012, 2:24 PM
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tomcecil wrote: "what a waste of paying a guide or an instructors when they do not even cover the basic such as building an anchor with rope" majid "I suspect that he's not alone. My guess is that it's just too much trouble for many guides to fully cover, and give all the necessary context around, rope-only anchors. It's certainly easier for them, and quicker for the client, to show how to build an anchor with a cordelette."Crack A real waste of time is listening to anyone with such ridiculous generalizations--
If reading my post is such a waste of time, why waste even more time bothering to respond? Particularly with a post that offers absolutely nothing of substance? If you have something to add that's not a "ridiculous generalization" - please do.
GO
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jacques
Aug 2, 2012, 2:27 PM
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majid_sabet wrote: I wonder how many pages of scientific papers you write every time you climb
I just read this thread rapidly and don't believed it. I used to ask to my partner to built an anchor with the rope at the end of an aid pitch without any sling. This is not commun use, but it is good to understand that whatever the situation, there is always a solution.
I look at some picture on that thread and wonder if some people ever climb in remote area. You need to use your rope in few situations. When there is three cam placement very far a part ( in british where coming at canon, I made three weak anchor and I tied them togheter more to slow down my heart beat than for safety.) or when you use all your sling under to avoid a rope drag. There is also an other situation when you went that your protection pop up in a sequence from the weaker to the more solid to maximize your chances...but it is rare.
Actually, I red a lot of scientific paper on what happen in a fall...not on what to do or not because every thing is possible. I just learn to adapt my equipment to as many situation as I can |
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tomcecil
Aug 2, 2012, 4:52 PM
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no need to--
just read Rgold and you may learn something------
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majid_sabet
Aug 2, 2012, 7:08 PM
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tomcecil wrote: "what a waste of paying a guide or an instructors when they do not even cover the basic such as building an anchor with rope" majid "I suspect that he's not alone. My guess is that it's just too much trouble for many guides to fully cover, and give all the necessary context around, rope-only anchors. It's certainly easier for them, and quicker for the client, to show how to build an anchor with a cordelette."Crack A real waste of time is listening to anyone with such ridiculous generalizations--
I honestly don't think is too much of a trouble to teach essential skills to climbers rather, today's guides are just don't care to teach and students are too lazy to ask for extra knowledge.
I train 100s of climbers a year to build anchors and sure we could drop a couple sling and ask them to build a sliding x....or whatever but no, if they can't build an anchor with ropes, cords, slings, webbing etc, they are not passing the course.
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JimTitt
Aug 2, 2012, 7:22 PM
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I know something bad is going to happen to me soon, Iīm agreeing with both Jacques and Majid!
Tying ones self to something immovable with the rope is surely the first and most basic principle in building belays.
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crasic
Aug 3, 2012, 5:16 AM
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acorneau wrote: So let's discuss these systems if there is a large 10' ledge where the anchoring options are 10' back from the edge and the belayer wants to be seated at the edge. (A common scenario at one of my regular spots: Upper Mt. Scott, Wichitas, OK.) What I usually do is pull up enough slack so I can clove to the first piece and have enough slack to sit on the edge. Then I use the BOAB to go to pieces 2 and 3, and will clove that back to myself when seated at the edge. I'll then use that cloved biner as the belay biner for my belay device. This puts the weight mostly on the BOAB/#2/#3 pieces with piece #1 (cloved) sharing the load or nearly loaded. It takes two full-length runs of the rope between the edge and the pro 10 feet back, plus the rope for the knots. The Bazillion anchor would take 4 full 10' runs between the butterfly/master point and the pro and would be a PITA to get all three strands at the right length without a lot of futzing around. Cracklover's Fig-8+X system would only take two, the one "loaded" strand going to the belayer and one that isn't loaded at all. Thoughts on this type of scenario?
Why not just build a nice tight anchor up near the pieces with a power point there using whatever system you like, set up a direct belay then clove hitch yourself to the anchor with 10ft of rope to walk back to ledge and just pull slack while your ATCGuide/Reverso/alpine clutch is 10ft away by the anchor?
It will only use 10ft more rope to anchor yourself in.
If you want to shorten your tie in without walking back to the belay I take a little extra slack, (say 11 ft for the 10ft ledge), tie a bight and clip a biner through it about 4 feet away from my end, clove hitch the strand from your harness to the biner and then lengthen shorten the loop to get the exact length you need. Or you can clip a biner to your harness and then just clove hitch to shorten the tie (I do the former because I find it easier to adjust a weighted clove hitch at eye level then one on my harness, but the later is cleaner)
(This post was edited by crasic on Aug 3, 2012, 5:20 AM)
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wivanoff
Aug 3, 2012, 11:33 AM
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"crasic wrote: Why not just build a nice tight anchor up near the pieces with a power point there using whatever system you like, set up a direct belay then clove hitch yourself to the anchor with 10ft of rope to walk back to ledge and just pull slack while your ATCGuide/Reverso/alpine clutch is 10ft away by the anchor?
I think it's a bad idea. It sux to try to operate the ATCGuide/Reverso/alpine clutch from 10ft away. (You belay with an alpine clutch? Surely you mean Munter Hitch?) Sometimes you have to feed the live end into the belay device while pulling the brake end. Not to mention the issue of lowering or dropping a loop to assist your second.
If you're going to do something like that, I'd recommend creating a powerpoint with an alpine butterfly or in-line Fig 8 in the 10ft of rope and closer to where you're standing.
YMMV, but I'd hate to operate the belay device from 10 ft away.
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jacques
Aug 3, 2012, 12:49 PM
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majid_sabet wrote: I honestly don't think is too much of a trouble to teach essential skills to climbers rather, today's guides are just don't care to teach and students are too lazy to ask for extra knowledge.
One think that i find hard to teach is to use essential skill in a real situation. Are you better to know less and know it better than to know a lot of technique and not be able to remember it as you need it.
After one or two years, I ordinarly remember what I learned as I think that I was in danger and make a knot or anchor under supervision. Learned at the bottom of the cliff, I don't even remember them few hours later. Every body know that some people panic under stress and that state of mind influence there way of thinking. When we saw fatal mistake on basic technique, should we critic the stupidity of the climber who didn't adapt is technique to the situation or should we look at how he learned his technique to be able to use it under stress?
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bearbreeder
Aug 3, 2012, 3:43 PM
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RCers can get into theoretical arguments on the intrawebs all they want about what to "teach" ...
the reality which im seeing every single day up here in squamish is that there are plenty of climbers who come up here with skills that are minimally practiced and jump on the many moderate multis we have up here ...
now these may be "new" climbers, or in other cases they many be "experienced" climbers who go out a few times a year and are quite rusty ... regardless they can barely make basic gear anchors, they are slow as hell at setting up belays, and take double the time they should to get up multis ... and cause traffic jams
go ahead and teach em fancy rope anchors, most of them wont remember em or will be very slow with them for lack of proper practice ... now you can say that its their fault for not practicing it, but when yr stuck behind several parties that have the same issue, the point is moot ...
if you want to teach these skills to weekend, or worse holiday, warriors ... you need to keep em absolutely and utterly simple ... since theyll use them at most a few times in the summer, and will be too busy with kids/work/life to practice em (thats just how it is when i ask em why they arent quick and efficient) ...
ive seen many people struggle to tie even the most basic cloves, munters, anchors on the 12th+ pitch of a moderate at the end of the day ... they can tie em perfectly on the ground when well rested and watered after being shown ...
again this is not some theorectical intrawebs thing ... i see this every day ... its the nature of the moderate multis, the rusty weekend warriors, and the newish climbers ...
the worse are the holidays ... for both the may and huly long we were invaded by americans, who to be perfectly blunt, many had absolutely no business being on 5.7/5.8 multis if they wanted to get up in a reasonable time ... it was quite obvious that they rarely climbed multis, especially crack ones, and much of their knowledge was theoretical ...
KISS
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moose_droppings
Aug 3, 2012, 4:17 PM
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bearbreeder wrote: RCers can get into theoretical arguments on the intrawebs all they want about what to "teach" ... the reality which im seeing every single day up here in squamish is that there are plenty of climbers who come up here with skills that are minimally practiced and jump on the many moderate multis we have up here ... now these may be "new" climbers, or in other cases they many be "experienced" climbers who go out a few times a year and are quite rusty ... regardless they can barely make basic gear anchors, they are slow as hell at setting up belays, and take double the time they should to get up multis ... and cause traffic jams go ahead and teach em fancy rope anchors, most of them wont remember em or will be very slow with them for lack of proper practice ... now you can say that its their fault for not practicing it, but when yr stuck behind several parties that have the same issue, the point is moot ... if you want to teach these skills to weekend, or worse holiday, warriors ... you need to keep em absolutely and utterly simple ... since theyll use them at most a few times in the summer, and will be too busy with kids/work/life to practice em (thats just how it is when i ask em why they arent quick and efficient) ... ive seen many people struggle to tie even the most basic cloves, munters, anchors on the 12th+ pitch of a moderate at the end of the day ... they can tie em perfectly on the ground when well rested and watered after being shown ... again this is not some theorectical intrawebs thing ... i see this every day ... its the nature of the moderate multis, the rusty weekend warriors, and the newish climbers ... the worse are the holidays ... for both the may and huly long we were invaded by americans, who to be perfectly blunt, many had absolutely no business being on 5.7/5.8 multis if they wanted to get up in a reasonable time ... it was quite obvious that they rarely climbed multis, especially crack ones, and much of their knowledge was theoretical ... KISS
Sounds like it's a bitch to be as good as you and climb moderate, multi-pitch routes.
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bearbreeder
Aug 3, 2012, 4:28 PM
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you do realize that many people up here do a quick run up 6+ pitches of a moderate for a warm up or cool down at the start/end of the day ... or use it to access more climbs on the upper part of the chief dontcha ya
it is what it is ... sadly i can never remember em yankee holidays to stay away from the jams
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crasic
Aug 3, 2012, 4:52 PM
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wivanoff wrote: I think it's a bad idea. It sux to try to operate the ATCGuide/Reverso/alpine clutch from 10ft away. (You belay with an alpine clutch? Surely you mean Munter Hitch?) Sometimes you have to feed the live end into the belay device while pulling the brake end. Not to mention the issue of lowering or dropping a loop to assist your second. If you're going to do something like that, I'd recommend creating a powerpoint with an alpine butterfly or in-line Fig 8 in the 10ft of rope and closer to where you're standing. YMMV, but I'd hate to operate the belay device from 10 ft away.
Personally I haven't used an alpine clutch, but I've seen it used in a pinch if they needed self locking belay for whatever reason. A munter will work as well.
I haven't had any issue pulling in slack on a guide from 10-20ft away, usually do it on topouts, leave the guide by the tree and then back off like 20 feet to the edge so I can see my partner climb, never really had any issues. If you need to lower for whatever reason then you need to walk up to the anchor anyway. In fact, I'd think that lowering on an "extended" powerpoint (e.g. with the power point on an alpine butterfly down by you) would be harder in an emergency situation because you still need to pass a sling through a redirect higher up (or do the "rotate the biner trick" do inch them down). Which if the power point is loaded and your ten feet away from the nearest hard-point/redirect would be difficult, not to mention if the power point is on your tie in (as one of the schemes above has the alpine butterfly) you have even more problems. Ideally I would have the anchor extended next to me on the cliff edge, but on most topouts there simply isn't enough rope to do that.
I also avoid mixing my *personal* belay/tie-in and the belay as a hard rule so making the power point on my tie-in strand is a big personal no-no. Extending the anchor down to you is viable but requires more material which was what my comment was trying to address.
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acorneau
Aug 3, 2012, 5:21 PM
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crasic wrote: I haven't had any issue pulling in slack on a guide from 10-20ft away, usually do it on topouts, leave the guide by the tree and then back off like 20 feet to the edge so I can see my partner climb, never really had any issues. If you need to lower for whatever reason then you need to walk up to the anchor anyway. In fact, I'd think that lowering on an "extended" powerpoint (e.g. with the power point on an alpine butterfly down by you) would be harder in an emergency situation because you still need to pass a sling through a redirect higher up (or do the "rotate the biner trick" do inch them down).
Use a Munter hitch and you won't have to deal with any of that. Using a Munter would also negate any issue with how close or far it was to the belayer; you operate it the same way no matter how close you are.
In reply to: Ideally I would have the anchor extended next to me on the cliff edge, but on most topouts there simply isn't enough rope to do that. I also avoid mixing my *personal* belay/tie-in and the belay as a hard rule so making the power point on my tie-in strand is a big personal no-no. Extending the anchor down to you is viable but requires more material which was what my comment was trying to address.
If you've lead the pitch and created your anchor with a master point, just tie your rope off with the slack you need to get to the edge (clove, fig-8, etc) and use the line going down to your climber to create your new master point, no extra materials or rigging required.
(This post was edited by acorneau on Aug 3, 2012, 5:23 PM)
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jacques
Aug 4, 2012, 4:39 AM
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bearbreeder wrote: the reality which im seeing every single day up here in squamish is that there are plenty of climbers who come up here with skills that are minimally practiced and jump on the many moderate multis we have up here ... [..] especially crack ones, and much of their knowledge was theoretical ... KISS
wish that those people who climb with too much responsability to practice there skill will understand that sport climbing is also a great sport. The goal are different and the time invest to climb at the same level is shorter in trad, but it is a smart choice to do sport if you don't have time to practice. Just don't bother those who have time to praqctice.
in the 60 - 70, they said that 60% of the time on the cliff is used to practice there skill. A 5.10 climber need fifteen hours of training to keep is level. In trad, it is still true, but if you don't have too much time, sport is a very good alternative to a lack of time to train.
(This post was edited by jacques on Aug 9, 2012, 2:23 AM)
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majid_sabet
Aug 4, 2012, 5:16 AM
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let's just end this thread and use whats on the wall
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wivanoff
Aug 4, 2012, 1:11 PM
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crasic wrote: Personally I haven't used an alpine clutch, but I've seen it used in a pinch if they needed self locking belay for whatever reason.
crasic wrote: A munter will work as well.
crasic wrote: I haven't had any issue pulling in slack on a guide from 10-20ft away, usually do it on topouts, leave the guide by the tree and then back off like 20 feet to the edge
crasic wrote: In fact, I'd think that lowering on an "extended" powerpoint (e.g. with the power point on an alpine butterfly down by you) would be harder in an emergency situation because you still need to pass a sling through a redirect higher up (or do the "rotate the biner trick" do inch them down).
I used my nut tool to rotate the ATC-Guide in the VERY few times I had to lower someone. No redirect necessary. A quick Munter off my harness makes a nice backup.
crasic wrote: Which if the power point is loaded and your ten feet away from the nearest hard-point/redirect would be difficult, not to mention if the power point is on your tie in (as one of the schemes above has the alpine butterfly) you have even more problems.
This thread has a lot of good information. Unfortunately, it's starting to drift.
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