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jensen
Sep 20, 2012, 9:32 AM
Post #27 of 47
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In reply to: Your anchor has two independent arms, not three.
In reply to: If you think dynamic equalisation will occur then you are loading the pieces unequally. Since dynamic equalisation wonīt occur anyway you are better off just clipping the lot and tying an overhand,
In reply to: Better still is to use a simple, faster, versatile system ... this is called the rope. |
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JimTitt
Sep 20, 2012, 10:37 AM
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You will get some equalisation but not as much as you probably hoped for! But the general concept nowadays is that avoiding extension is preferable to the partial equalisation you achieve in most cases.
Many of us have built belays using the rope for the last 40 years or more, tried all the fancy systems and generally stick with the rope except in very specific circumstances. There are plenty of threads on this subject!
Dynamic equalising systems arenīt taught or used by most organisations for good reason.
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edge
Sep 20, 2012, 1:11 PM
Post #30 of 47
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jensen wrote: In reply to:  Have you used this 3-armed Quad before? It looks like it wouldn't be that simple to adjust the 2 arms on the left using clove hitches because those 2 arms are fixed in length and because all 3 arms are about the same length, plus it doesn't help that the arms of a Quad are short from the cordelette being doubled before being tied. I suspect you'd probably end up using more gear to extend placements before being able to adjust the arms with clove hitches. If your experience is otherwise, please let me know.
You can clip the left and center pieces with each end of a folded-in-half cordelette. Now tie an overhand just left of center, and another just right of center (or adjust for the situation). Clip the resultant strand of quadrupled cordelette to the right hand piece. Pretty friggen simple.
If I was one of those who bought into the whole "elette" fad, then I would use this method often, but I'm not so I don't.
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LostinMaine
Sep 20, 2012, 4:46 PM
Post #31 of 47
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jensen wrote: It is interesting that all you rope anchor builders are satisfied with just using the rope...
I find it more interesting that so many people are not satisfied with just using the rope for the majority of cases.
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jensen
Sep 22, 2012, 8:11 AM
Post #32 of 47
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Thanks for the explanation! It was really helpful. And you're right, that rigging is pretty darn simple. And because you cilp two of the pieces before you tie the knots, that solves the all-strands-are-fixed-and-the same-length problem that I was concerned about.
I have encountered one minor issue though when experimenting with it in my living room. That is that the resultant strand of quadrupled cordelette seems to end up fairly short in length. But I think the answer to that problem would be to just use a somewhat longer cordelette.
I'll have to play around with it some more but, so far, I like it a lot more than my solution.
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patto
Sep 22, 2012, 8:19 AM
Post #33 of 47
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LostinMaine wrote: jensen wrote: It is interesting that all you rope anchor builders are satisfied with just using the rope... I find it more interesting that so many people are not satisfied with just using the rope for the majority of cases. 
As somebody who almost exclusively builds anchors out of rope I have yet to see many good arguments in favour of cordalettes.
Since I am very efficient with the rope, cordalettes are not faster, easier or more flexible.
The only real advantage to me is if I plan on leading two pitches in a row. But even then it only saves about 60seconds for the belay for the sake of carrying TWO cordalettes.
Simply put I don't carry a cordalette when multipitching.
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jensen
Sep 22, 2012, 8:25 AM
Post #34 of 47
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In reply to: You will get some equalisation but not as much as you probably hoped for! But the general concept nowadays is that avoiding extension is preferable to the partial equalisation you achieve in most cases.
I guess if you get negligible or very little dynamic equalization then it does makes sense to make no-extension the priority over equalization. But I wonder exactly how much partial dynamic equalization you get from systems like the Quad or Equalette. If you know of any studies which measure the dynamic equalization of using the Quad or Equalette versus the standard cordelette, please let me know where I can find them. Thanks.
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JimTitt
Sep 22, 2012, 10:41 AM
Post #35 of 47
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Itīs complicated to put it mildly!
With the system you show youīll be gettinga load split of ca.62%/38% on the two sliding legs and probably 0%/100% on the left fixed leg.
The dynamic systems equalise to a certain extent but the static (fixed) systems are also difficult to equalise satisfactorily and with more than two pieces in the anchor itīs virtually impossible to get the loads equal. A system like yours is the worst of two worlds because you have probably no equalisation at all on the left side as itīs fixed and tying the overhand destroyed whatever equalisation you might have achieved, plus the invitable extension if the right side fails.
With a setup as you have shown the load has to be at least 15° offset to one side before the karabiners start moving as the friction is considerable and up to this angle there is no difference in the load distribution for either a dynamic or a static system (providing they started out with the same equalisation).
The situation also changes depending on whether the pieces are arranged horizontally as you usually see in the diegrams or arranged vertically. In a vertical orientation the limiter knots can be very close together and extension restricted to a few inches. With a fixed system in the vertical orientation the unequal length of the arms makes equalisation impossible anyway and so a dynamically equalising system is the better choice.
Horizontally orientated the position is reversed and a static system is preferable.
However life being what it is the pieces are usually all over the place and it will be impossible to decide which is the better so the default is not to use a dynamically equalising system.
You shouldnīt be belaying on pieces which MUST be equalised to hold the load since if one does fail the rest will inevitably fail. It is very rare in a cimbing career (unless you are an alpinist) that you must belay on crap since one can find something better somewhere else or just abandon the route and abseil off.
You should be belaying on a number of pieces each of which WILL hold the load and if one does fail (since we canīt normally judge the strength that well) then another will hold. This is the redundancy or back-up principle and what is generally taught these days and eliminating extension is essential to give the next piece the best chance of survival.
Simplicity is even more important to aim for since anchor failures from whatever system (dynamic or static) is used are unheard of, disasters due to elementary screw-ups like clipping into the wrong part or even forgetting to clip in altogether are however more common!
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louBlissab
Sep 22, 2012, 12:36 PM
Post #36 of 47
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In reply to: Even though I currently still use the standard cordelette system, I'm not happy with it or any of the others for various reasons.
Jensen,
What reasons do you have for not being happy with the standard three-point equalized cordelette system that most climbers use?
It's fast, safe, works 100 percent of the time and the rope is independent of the anchor system. It would be difficult to find another climbing partner with the same complex anchoring thought process to swing leads with.
I am not sure how long this system takes to rig, but I would not want to be on some crappy belay ledge freezing in the rain and wanting to get down in a hurry, trying to figure this rig out.
Just one person's opinion.
AB
(This post was edited by louBlissab on Sep 22, 2012, 12:49 PM)
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jensen
Sep 24, 2012, 7:44 AM
Post #37 of 47
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In reply to: With a setup as you have shown the load has to be at least 15° offset to one side before the karabiners start moving as the friction is considerable...
Is that number, 15°, from tests you've personally performed or is it from studies published somewhere?
That is not what I expected at all. If that's the case then what I'm calling the 3-Armed Quad (that is, the system that the Edge described in his posting) won't cut it as well. And I was so hopeful for that one...
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jensen
Sep 24, 2012, 7:52 AM
Post #38 of 47
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In reply to: What reasons do you have for not being happy with the standard three-point equalized cordelette system that most climbers use?
I was pretty happy with it until I read John Long's latest Climbing Anchors book where he talks about the equalization issues with it and introduces the Equalette as a better solution.
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JimTitt
Sep 24, 2012, 10:51 AM
Post #39 of 47
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jensen wrote: In reply to: With a setup as you have shown the load has to be at least 15° offset to one side before the karabiners start moving as the friction is considerable... Is that number, 15°, from tests you've personally performed or is it from studies published somewhere? That is not what I expected at all. If that's the case then what I'm calling the 3-Armed Quad (that is, the system that the Edge described in his posting) won't cut it as well. And I was so hopeful for that one...
The 15° is a rough figure which depends on the materials you use but a near-enough ballpark for normal purposes. It is from both tests Iīve done (and Iīve done hundreds) and from tests done elsewhere. Itīs also easy to work out from the coefficient of friction which for aluminium on nylon rope is between 0.2 and 0.3 depending on the velocity which gives an angle of repose of 12° to 17°. Testing shows it is in the 13°-15° range depending on the type of cord and a few other variables.
Itīs the same no matter how you tie the system!
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LostinMaine
Sep 24, 2012, 4:49 PM
Post #40 of 47
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jensen wrote: In reply to: What reasons do you have for not being happy with the standard three-point equalized cordelette system that most climbers use? I was pretty happy with it until I read John Long's latest Climbing Anchors book where he talks about the equalization issues with it and introduces the Equalette as a better solution.
So as not to rehash all that has been said and demonstrated by Jim Titt (and some others), I recommend reading through this thread:
http://www.rockclimbing.com/..._reply;so=ASC;mh=25;
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ClimbSoHigh
Oct 12, 2012, 4:54 PM
Post #41 of 47
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I like how you are doing a good job analyzing the short comings and compromises of conventional anchor techniques, and are getting you brain churning in the safety of your living room rather than in the field. IMO it is very important to try and figure out "why can't I do something this way" on the ground, and then seek out a reason why experienced climbers do not do it that way and why. A key is to check your pride at the door, and be able to realize something really is a bad idea after you spend hours by yourself thinking about how great it is. I have spent many hours dicking around with possible alternates, and then asking why experienced climbers do or don't do it. Having been there, I feel the following points might be helpful...
1 - Always start with bomber pro. ALWAYS!! This is WAY more important than improving/perfecting equalization or no extension.
2 - The rope is the strongest and most durable soft good you have when climbing. If you are swapping leads, or climbing single pitch, I cannot think of a single good reason not to anchor with your climbing rope.
3 - Cordalettes really only make sense for guides, parties of more than 2, or people that will be leading several pitches in a row. This requires 2 cordalettes for the party.
4 - Keep things simple.
5 - Check and double check everything. Keeping it simple not only helps with efficiency, but also makes it easier to inspect.
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surfstar
Oct 30, 2012, 6:47 PM
Post #42 of 47
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ROPE STRETCHING PITCHES
The other thing that makes a cord anchor useful.
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patto
Oct 30, 2012, 8:02 PM
Post #43 of 47
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jensen wrote: I was pretty happy with it until I read John Long's latest Climbing Anchors book where he talks about the equalization issues with it and introduces the Equalette as a better solution.
John Long should be burned at the stake for the number of beginners he has confused and mislead with this edition of his book.
J. Long's conclusions regarding extension were totally false and the excessive focus on equalisation unsubstantiated.
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avalon420
Oct 30, 2012, 8:35 PM
Post #44 of 47
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surfstar wrote: ROPE STRETCHING PITCHES The other thing that makes a cord anchor useful.  ) there is typically more than enough gear between belayer & climber to simul-climb the rest.
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shimanilami
Oct 30, 2012, 8:54 PM
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avalon420 wrote: But by that point in time (rope stretch ) there is typically more than enough gear between belayer & climber to simul-climb the rest.
Classic!
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surfstar
Oct 30, 2012, 10:19 PM
Post #46 of 47
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shimanilami wrote: avalon420 wrote: But by that point in time (rope stretch ) there is typically more than enough gear between belayer & climber to simul-climb the rest. Classic!
I usually just untie and use the cordelette to gain another 20' of rope
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avalon420
Oct 30, 2012, 10:44 PM
Post #47 of 47
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surfstar wrote: shimanilami wrote: avalon420 wrote: But by that point in time (rope stretch ) there is typically more than enough gear between belayer & climber to simul-climb the rest. Classic! I usually just untie and use the cordelette to gain another 20' of rope
(This post was edited by avalon420 on Oct 30, 2012, 10:56 PM)
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