Like this one at Tahquitz?

I'm amazed that it took you this long to figure out that the cordelette isn't perfect.

But I eagerly await further developments and testing that could produce a simple, lightweight and h#lla strong anchor that will never fail, and can also be used for rap slings, ascending a rope, extending to the ground from a too-short rap rope, looped around a 6' diameter pine or easily tied into improvised multi-step etriers.

I have used cordalette, but only other pplz - and only a few times.. I got turned to the good ol webolette a long time ago and have never turned back. It's 16 feet with extra large loops at both ends (great for accomodating 2 biners for a TR setup), it's quick and light, and easier to equalize 4 strands instead of 6!

I also have a couple smaller 12' ones, but those have the more annoying smaller loops on the ends (which only really accomodate a single biner - my 16' I believe was custom made for a climbing shop near me).. They are rated at 22kn when doubled for an anchor, or 14kn single strand. Lightweight and strong, easy to untie any knots put in it. Only downside (after reading the sliding x thread), is that you can't do certain fancy equalization techniques that you can with the cordalette (speaking only in the aspect of creating a 3 point anchor - I'm sure there are ways with other anchors and techniques, not to be covered here).

So in short, I have no plans of using a cordalette in day to day climbing, but do see it's purposes - it just doesn't have a purpose on MY rack.

rgold posted a way to use a webolette in an equalizing system. You clove it off, then rig a 3way sliding x below all of it.

I musta missed it - and I've been looking for a way.. I've toyed with it, but couldn't get anything right that seemed solid that I would use.. Anyone got a link - I browsed through some of his posts, but couldn't (quickly) find it... I'll look more later if no one wants to make it easy on me :)

http://www.rockclimbing.com/...p.cgi?Detailed=69926

Hi, all:

I only just received the initial data crunching and work ups from the statisticians, both nationally recognized PhD data wizards and experienced climbers. The drop tests themselves were conducted by the guy widely considerd the leading drop tester in the US, who has all the fancy UIAA drop towers and computer assist gear at his disposal. It took the poor guy weeks and hundreds of drop tests to finish the study.

I can't post the actual graphs and box charts, nor yet the long lists of numbers. But I can quote an abridged version of a few paragraphs from the study that give a clear indication of how the cordelette performed under dynamic loading (factor one fall). These paragraphs concern the initial testing, done with the cordelette (in both equal and unequal arm length configurations) connecting only two primary anchor points.

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A. Cordelette, equal length: Tests simulating a factor 1 fall demonstrate that on average, a cordelette, equal length configuration generated an absolute difference in load that was a little less than 1 kN. Repeated measurements of the difference in the forces generated varied somewhat across multiple tests. Contrary to conventional wisdom and popular usage, the cordelette, with equal length arms is not a very effective system to achieve equalization.

D. Cordelette, unequal length: This clearly-the-worst-configuration tested produces an absolute average difference in force between the anchor arms of almost 3.5 kN. Aside from generating the largest difference in force of the riggings measured, the cordelette, unequal length rigging was the most inconsistent when repeated measures of this difference was taken. In some cases, the difference in load measured was greater than 5 kN! To put it bluntly, the cordelette, unequal length configuration is the poorest performing anchor considered in all the testing conducted. Not only is equalization very poor, the degree of equalization varies wildly from fall to fall. This configuration is very unpredictable, except in that the difference in the forces generated from a fall will be high. The cordelette unequal length is simply to be avoided.

Summary: While the equal armed cordelette distributes a dynamic load to an (barely) acceptable degree, and will no doubt remain a viable option in that configuration, a cordelette rigged with unequal arms is an inferior–and likely hazardous--choice when contrasted with the far more efficient load distribution of the sliding x and the equalette.

John, nowhere do you describe what the angles are between the individual pieces. This greatly affects the load distribution. If the angle between each piece is relatively small, the direction from which the load comes can vary more and still distribute the load. The wider the angle the more critical it become to anticipate the direction of the load.

The next factor that you did not mention is what type of cord was used. A 7 mm nylon cord will stretch more than a 5.5 mm Spectra cord. I would predict that the elastic cord will demonstrate the "unequal arm effect" to a much greater degree than the static cord.

So it would be possible to get a wide variety of test results depending on all these varying factors.

"relative deformation of the shorter arm will be higher than that of the longer arm.

Therefore, the tension of the shorter arm will be greater.

False. Both arms must deform to the same degree. They must. The shorter one deforms more relative to its length.

Now what happens when you have a cordellette made out of a static material like Spectra? Not everyone knows this but Spectra is as low stretch as Kevlar. It has an elongation of 1% at 30% of its tensile strength. Perlon has, if I remember correctly, about 3-5% elongation. If you compare the RELATIVE stretch of different lengths of Spectra and Perlon it is obvious that there will be a larger amount of stretch. The Spectra will distribute the load more evenly between the two anchor points than the Perlon given the same angle between pieces but different arm lengths.

You are just plain WRONG. An elastic cord can be thought of as a spring. Assume that the spring obeys Hook's Law that is xk=F where x is the displacement and k is a force constant, and F is the force exerted by the spring. The force constant for a cord is inversely proportional to the length of cord. If you have twice the cord, you have half the force constant. [Of course Hook's law assumes a linear response, which isn't actually true].

...

The Spectra will distribute the load more evenly between the two anchor points than the Perlon given the same angle between pieces but different arm lengths.

And your answer is....BUZZZ! Wrong. Tech cord leads to a higher difference in force felt between the two legs of the anchor than nylon does...ie: worse equalization with a cordelette setup.

John has stated this before in other threads, and it will be published in John's book.

Let me say this again...without trying to use textbook physics to make my point. Cordelettes with master point knots, fixing the length of each arm...do not equalize well with unequal arm lengths (vertical crack setups). Nylon cord will distribute the force between the legs of the anchor better than tech cord will.
The reason for this have been stated before, and will be stated again in John's book, I'm sure. I'm not gonna try and argue why myself, I'll f* it up trying to explain it.

If you don't wanna belive me, don't. But take a look at Johns new book, once it hits the shelves.

Cheers,
Jim

You owe at least a link to something backing up your argument.

so what am I missing here?

Given what has been learned, what would you do differently in the way you set up the anchor? Let's call this an interim solution pending the release of John's new book.

Let us suppose that some of us would like to continue to use the cordelette in the tied-off mode, that is, with static equalization, the "traditional" configuration. Given what has been learned, what would you do differently in the way you set up the anchor? Let's call this an interim solution pending the release of John's new book.