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phile
Trad climber
SF, CA
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Sep 23, 2014 - 12:12pm PT
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I am forever mystified at why it takes people today so f*#king long to set up belay anchors on multi pitch climbs...
HA! It would slow you down too if you had to figure out how to hang a quadolette and 3 lockers off your single #3 Camelot.
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oldnutz
Trad climber
OAKLAND
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Sep 23, 2014 - 12:41pm PT
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Normally with appropriate knots the point of failure is at the karabiner so discussing the relative knot strength is a bit of a waste of time. Where it is relevant is if you tie into pieces with a clove hitch where things get marginal quickly.
uh oh...I'm sorry but I have to ask Jim T...define "marginal" within the context of this sentence?
I had been led to believe, in regard to a multi-pitch anchor (not TR anchor), that clove hitches could help reduce max forces.
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Tvash
climber
Seattle
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Sep 23, 2014 - 12:59pm PT
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Clove hitches are fine for anchoring a belayer with a climbing rope. I haven't seen anyone use them with cordelets.
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dubhouse
Trad climber
Los Angeles, CA
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Sep 23, 2014 - 01:01pm PT
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The most important finding from John Longs experiments for the recent anchors book is the value of using dynamic cord for over static cord. What he found was that using a more dynamic cord in anchors will always reduce forces significantly even to the point where a weaker, more dynamic cord(eg. nylon) will not fail and a stronger, static cord(eg. dyneema) will fail.
So, even with mild extension, as long as you are using somewhat dynamic material, shock loading forces will be reduced dramatically and are not likely to cause any issues.
-tavis
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Largo
Sport climber
The Big Wide Open Face
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Sep 23, 2014 - 01:07pm PT
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Most of the elaborate rigging systems are on little use on the vast majority of anchor arrays. They only come into play when the primary anchors are sh#t, and you need to spread the load or risk anchor failure fi the leader pings straight onto the anchor. This happens so infrequently on the routes most people climb that a cordellette will usualy suffice. But when the primary placements are piss poor, knowing a few tricks can be a life saver.
No-extension is a better objective than equalization since the later is rarely achieved save for the "quad" clipped to side by side bolts and rigged with anodized krabs.
JL
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Tvash
climber
Seattle
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Sep 23, 2014 - 01:14pm PT
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What effect does anodizing have? It wears off a biner almost immediately. It's just for color coding, I think, no?
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Largo
Sport climber
The Big Wide Open Face
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Sep 23, 2014 - 02:00pm PT
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We did a lot of testing with Sterling and found that binding was a bigger factor than first suspected, especially with sliding X, where a sling is basically hitched around the biner, less so on somethng like a quad, where anchor point biners are clipped though a comparatively wide loop. In both cases, the rope ran apreciably better and bound far less when wide-mouth anodized biners were used. Basically, the cord sticks on non-polished aluminium when an attached sling is cinched or sitting fairly snug around the shank of the biner. In short, the combination of the wide mouth and the anodize polish reduced the binding and when an anchor had to self adjust, the results were worth the trouble of using the special gear - but only in those situations when the primary anchors were crap.
JL
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Tvash
climber
Seattle
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Sep 23, 2014 - 02:11pm PT
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A used biner's rope surfaces get polished pretty quickly - I assume that's as good as anodizing at reducing friction (a good thing - given that anodizing doesn't last long on such a surface).
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Largo
Sport climber
The Big Wide Open Face
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Sep 23, 2014 - 02:35pm PT
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It's the combo of the the wide mouth and the anodizing that inhibits the binding. Any polished surface will probably achieve the same results given the wide mouth. Fact is, the times you really need this are almost nill. We did the testing mostly to find if true equalization was EVER possible. Turns out it is, but only with the quad - wide mouth - anodized medly. And with two side-by-side bolts in good shape, it hardly matters how you tie them off. They so rarely fail in good rock.
JL
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Tvash
climber
Seattle
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Sep 23, 2014 - 02:36pm PT
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You might consider using a more conventional cordelet anchor setup.
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Tvash
climber
Seattle
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Sep 23, 2014 - 02:46pm PT
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I use a quad with a fatty nylon/dyneema sewn runner and a wide mouthed anodized locker. The teen program I'm involved it standardizes on a tied power point cordelet - but some of them are as thin as 5 mm, so I'm going to inject a little alternative anchor love into the program with some specific breaking strength numbers (these kids ask about everything).
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Tvash
climber
Seattle
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Sep 23, 2014 - 03:38pm PT
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The knots reduce the strength of your single 7 mm considerably because you're not using a double fishermanned loop and you're using clove hitches.
I put in a lot of trad anchors, so I like a system that's optimized for whatever comes along. For a 3 point anchor the system (3 Nanos, a locker, and the runner) weighs 147 g or thereabouts.
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Tvash
climber
Seattle
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Sep 23, 2014 - 03:54pm PT
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I always go for the free safety for that 1/1000 chain of events that might lead up to a factor 2 fall directly onto the anchor - even if I can't think up a scenario when that might happen beforehand. As has been said, with two bolt anchors - lots of stuff works fine.
Just my philosophy. I know that speed (weight) is safety. My stuff's all pretty light. If I can prevent one of my students from biting in during their climbing life with a little bit of extra robustness here and there, it's worth it to me to be a bit of a nerd in some areas.
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Tvash
climber
Seattle
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Sep 23, 2014 - 04:06pm PT
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You just gotta know when to say "Yer off belay" and when to say "Sorry about this" (nodding to the anchor)
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oldnutz
Trad climber
OAKLAND
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Sep 24, 2014 - 09:17am PT
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I believe in the JL/BG climbing anchors book it was recommended to use clove hitches with the equalette (in some scenarios), in order to both easily adjust the arm length and also provide a reduction in max forces on each piece, since the clove hitch will gradually slip well below the breaking strength of the rest of the anchor components.
Not sure if JimT's "marginal" statement refers to this aspect of the clove hitch, which could be a good thing by lessening force on marginal placements.
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JimT
climber
Munich
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Sep 24, 2014 - 10:58am PT
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uh oh...I'm sorry but I have to ask Jim T...define "marginal" within the context of this sentence?
I had been led to believe, in regard to a multi-pitch anchor (not TR anchor), that clove hitches could help reduce max forces.
Like in the picture below from prrdylady. The tests done for the DAV show that with dynamic loads on thinner cord clove hitches fail at lower levels than previously thought. The DAV have a criteria of requiring (or expecting) a single point on a belay to hold 6kN (in case it is taking the full load) and with most cord and tape the clove fails below this. From memory 8mm was the only one that held from the ones they tested.
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JimT
climber
Munich
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Sep 24, 2014 - 11:07am PT
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A used biner's rope surfaces get polished pretty quickly - I assume that's as good as anodizing at reducing friction (a good thing - given that anodizing doesn't last long on such a surface).
We´ve done an enormous amount of testing of friction of nylon rope, cord and various tapes over the years and never detected any difference in anodised, worn anodised, non-anodised aluminium or ground or polished stainless at normal climbing loads. We even had some karabiners specially treated with various types of low-friction anodising to test and there is no noticaeble benefit. The variation of the friction between various makes of tape and cord is vastly greater.
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BG
Trad climber
JTree & Idyllwild
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Sep 24, 2014 - 11:09am PT
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which could be a good thing by lessening force on marginal placements.
In nylon, knots can have a shock absorbing and force lessoning impact. With Dyneema, a knot may be an achilles' heel.
As a stunt coordinator, I've rigged falls with a series of loosely tied knots as shock absorbers back in the day when we used wire cable attached to nylon rope.
If you analyze the DMM factor 1 and 2 dynamic drop tests with nylon vs. Dyneema slings, the impact force with a nylon sling (that did not break) actually decreased slightly when tied with an overhand knot.
The Dyneema sling broke (both knotted and unknotted) in nearly every fall factor 1 and 2 test with 120 cm and 60 cm length slings at impact force of roughly 10 to 11 kN when knotted with an overhand and 22 to 25 kN when unknotted.
In every FF1 and FF2 test where the unknotted sling did not break, the impact force was less with the nylon sling vs. Dyneema sling.
Because of Dyneema's low melting point, high lubricity (slipperiness), and lack of elasticity, knots create a weak point in Dyneema. Maybe not the best material when used with knots for multi-pitch anchors?
I'd like to see more testing with Dyneema slings and clove hitches, often used when rigging 2 pieces in opposition vs. the same rigging with nylon slings.
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Largo
Sport climber
The Big Wide Open Face
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Sep 24, 2014 - 12:18pm PT
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In all the testing we've seen/done over the years, it seems that problems arise in proportion to the elasticity of a given piece in the roped safety system. The more stretch, the less the poroblems. Tech webbing and cordage is "stronger than steel," but it gives so little that this often compromises a system built to produce "soft" falls by way of the inherent stretch of the components.
Long story short, the old nylon is heavier and bulkier but in many regards is still the go-to stuff in rock climbing.
JL
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SammO
Social climber
Ohio
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Sep 24, 2014 - 12:53pm PT
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Props to Largo, BG, and JimT for up-to-date info that appears to meld bench data and real-world data. My humble summary offering:
Multiple anchor systems vary; OP scenario appears as a typical fixed one, where each piece appears trustworthy, as opposed to a marginal rap system where one or more is suspect. Equalization is paramount in the latter, as no single piece may hold. This is not true in fixed cases, I would hope! There, the redundancy principle is for backup, should any portion of a system fail, including a carabiner, bolt/piece, single sling unit, and so on. Locking biners reduce risk of something rotating, which has resulted in slings or ropes unclipping themselves.
Most of the reputable solutions here seem fine, and the basic cordelette which isolates each leg after initially equalizing the directionality is the fastest, simplest compromise. Directional forces might apply the load mostly to one or the other bolt during use, but that's minor loading; if that bolt OR that half of the sling failed, the load would suddenly swing onto the other bolt, but that is more like a pendulum swing, compared to a one or two foot drop, statically, onto it if an X system were used.
Keep in mind, also, that while the basic systems here all may serve adequately for the stated purpose, funny things happen in the real world, ie climber reaches anchors, clips directly into system to do something, then slips off stance - shock load, where choice of sling materials etc. suddenly matter.
I'm pretty sure far more have died from failed anchors, than from failed protection pieces. These are not "arguments" but valuable discussions where newbies et al may read how/what those with 50 years experience have settled on, and why.
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