* 4-placement designs are rarely used in practice, so experimenting with them may be amusing and educational but not really of practical value unless the design readily adapts to a 3-placement version. 3-placement anchor designs continue to be posted, even recently, that do not actually balance forces (equalize). The most daunting design challenge appears to be an effective, KISS, 3-placement anchor design that easily adapts to a 4-placement version.

....... so I thought I'd spend some time in my garage looking into one of the underlying issues of this thread: sliding friction at the master point of anchors........

........I would like to open the debate: is uneven load distribution for 3 pieces anchor (as provided by b---- mode) acceptable ?

or should we go for 3 ways sliding X ??

In other words, is the added complexity of the 2 parts cordelette worth it ??.........

Here´s an illustration of how to tie the Double Figure 8. From this configuration, to create uneven loops you simple take in some of the cord of one loop which will feed the other one.

You could also obtain a similar result with a Bowline on a bight.

........I would like to open the debate: is uneven load distribution for 3 pieces anchor (as provided by b---- mode) acceptable ?

or should we go for 3 ways sliding X ??

In other words, is the added complexity of the 2 parts cordelette worth it ??.........

...... Thanks. The 2-loop figure 8 is clear and simple to recall. Wonder if it is practical to arm-chair-eval which 2-loop knot holds up better under pro failure and/or cut cord.......

Bill L.

4-placement designs are rarely used in practice, so experimenting with them may be amusing and educational but not really of practical value unless the design readily adapts to a 3-placement version. 3-placement anchor designs continue to be posted, even recently, that do not actually balance forces (equalize). The most daunting design challenge appears to be an effective, KISS, 3-placement anchor design that easily adapts to a 4-placement version.

In light of John's research that tells us the standard cordelette set up has had us all hanging off basically ONE piece for years- I don't think I have a problem with a 25%-50%-25% rig like Mike's. (Running the odd arm to the best piece of course).

KISS is still important and the biggest problem with creating the perfect rig is always the added complexity.

So what is the advantage of a "troublette" over a sliding-X? I'm missing it.

Normalizing to the sliding friction of the sliding-X, I measured the sliding friction of the equalette to be about half that. The sliding friction of the troublette measured about half that of the equalette (1/4 that of the sliding-X), which is what you'd expect just by looking at their designs.

lower sliding friction is better, because that will allow better balancing of forces during the instant of peak fall force, thus better achieving the design objectives of the anchor

many of the designs can cover both well enough

So far, the proposed anchor designs using 4 placements to achieve uniform load distribution are relying on unbalanced load distribution subsets to handle failure scenarios (RGold’s Chopolette being the only exception)

What about friction at the anchor biners where the cord makes a U turn? For anchor designs relying on this U turn to achieve load redistribution, wouldn´t the use of bigger radius anodized biners reduce friction significantly thus improving the overall load redistribution capabilities?

There's never been a problem that could be solved with a slingshot for which someone won't propose a nuclear solution.

healyje asked what I meant when I referred to "the obvious 4-placement solution made with three 2-anchor equalelettes." In the spirit of good clean fun and didactic utility I thought I'd post an illustration of an "obvious" 4-placement solution, with a few comments.

Edited to clarify explanation.


So far, the proposed anchor designs using 4 placements to achieve uniform load distribution are relying on unbalanced load distribution subsets to handle failure scenarios (RGold’s Chopolette being the only exception), ie, when a 4 pieces Mhabicht or Equalette suffers a placement collapse, the resulting configuration will only provide uneven load distribution. So in the end, if you adopt these designs you are implicitly settling for a 25% - 50% - 25% distribution.
.

Edited to clarify explanation.


So far, the proposed anchor designs using 4 placements to achieve uniform load distribution are relying on unbalanced load distribution subsets to handle failure scenarios (RGold’s Chopolette being the only exception), ie, when a 4 pieces Mhabicht or Equalette suffers a placement collapse, the resulting configuration will only provide uneven load distribution. So in the end, if you adopt these designs you are implicitly settling for a 25% - 50% - 25% distribution..

Normalizing to the sliding friction of the sliding-X, I measured the sliding friction of the equalette to be about half that. The sliding friction of the troublette measured about half that of the equalette (1/4 that of the sliding-X), which is what you'd expect just by looking at their designs.

I thought we were spending all this time trying to do better. What objective metric would you propose to gauge "well enough"? Or would your metric be subjective?

But seriously, we're looking at anchor solutions ranging from those with no self-equalization, such as the 1-knot cordelette, to perhaps those made with pulleys. We do seem to sense that reducing friction in an anchor's equalizing components is good, mainly because John Long seems to say that the equalette is better at equalizing than the sliding-X (which he says gets within 10%). Is it worth going to the troublette (and why not, since it's simpler and reduces sliding friction)? Is there a compelling reason to adopt the equalette? Is the sliding-X totally out of the question? Absent tests that simulate actual fall forces, we just don't know.

Jake, that was mine and it's just a non-commercial version of Trango's AE and subject to all the same comments as it is...

I just happen to prefer the equalette and mhabicht's designs to yours, papounet's, and knudenoggin's. Remember, we're not after perfect equalization, no friction, and no extension - we're after designs the represent acceptable compromises in exchange for for options that provide versatile and best-under-the-circumstance anchors.