Trango Alpine Equalizer

I recently started using the Trango Alpine Equalizer on occasion and find it simple, quick versatile, and effective to use.

When using a cordelette or an equalette, if one strand fails the anchor will not fail. However with the Alpine Equalizer, if the Ultratape (spectra/nylon sling) fails, the whole anchor fails.

A clove hitch at each piece could head off this situation, but then it seems that other benefits of the equalizer are lost.

I'm curious as to why this lack of redundancy is okay in this situation. Are sling failures rare? I don't question the gear or the extensive testing Cormier Mountaineering did on this gear, but I am looking to understand how this potential failure mode was analyzed in determining whether this is an acceptable anchor system.

Any insight would be appreciated.

Thanks,
Glenn

The strength of the webbing in the Alpine Equalizer is 25kN. Other non-redundant components: rope, harness (16kN), belay carabiner (25kN), belay device.

Inspect your Alpine Equalizer before using it to make sure the webbing isn't damaged, and then use it without worrying about lack of redundancy. It's as strong (or stronger) than other non-redundant components in your belay system.

How about tying overhand knots in each "leg" above the rings? This would add redundancy and still allow equalization unless the angle of pull came from some where way off the intended direction of pull.

Ron Olsen wrote:The strength of the webbing in the Alpine Equalizer is 25kN. Other non-redundant components: rope, harness (16kN), belay carabiner (25kN), belay device. Inspect your Alpine Equalizer before using it to make sure the webbing isn't damaged, and then use it without worrying about lack of redundancy. It's as strong (or stronger) than other non-redundant components in your belay system.

Ron,

Thanks, for the reply and the perspective adjustment. I guess after all that has been drummed into my head about redundancy in anchor construction, it is easy to overlook the lack of redundancy elsewhere in the system as a whole. :)

-Glenn

Robert 560 wrote:How about tying overhand knots in each "leg" above the rings? This would add redundancy and still allow equalization unless the angle of pull came from some where way off the intended direction of pull.

Wouldn't that take longer to set up and kill the hole reason for wasting your money on such a gimmicky anchor?

demo here:

youtube.com/watch?v=ocp1EYm…

Its fast and simple. If you have bomber gear and take care of your sling these concerns are minimal. To avoid extending tie an over hand in the center strand.

One of the main time savers for me is that I dont have to deal with tying a knot for the master point to equalize. which if loaded takes time to untie as well. I use the AE for big walls all the time for the above reason. Fixing a line on it is fast and simple.

freerangequark wrote:I'm curious as to why this lack of redundancy is okay in this situation. Are sling failures rare?

The rig is designed for ease of load distribution given a marginal anchor. A marginal anchor would be defined as an anchor where any single bomber placement is not adequate on its own to handle all the expected loads it could encounter, & maybe, plus a given safety factor.

If you limit the ability of the rig by attempting redundancy, you forgo some degrees of directional loading that can also maintain that distribution. You also have material concerns with knotting/hitching that breaks down the fibers & also a strength reduction which is more as a percentage comparison to nylon, but probably still strong enough.

Load distribution with marginal anchors is a complex situation. As climbers don't regularly factor 2 the anchor, this issue doesn't really come to light very often. But you can get a good idea reading Luebben's & Long's respective anchor books.

Into this 2 factor can be the duration/size of impact, relative location of a climber fall to the anchor, and lack of material resiliency within dyneema/spectra -- this rig needs the dynamic rope, which is a no brainer for lead climbing. If this distribution can't maintain, the marginal anchor can have a problem regardless of the higher safety factor perceived. Meaning that thinking only in terms of redundancy and rig strength is pointless, or maybe better to say, not as important as adequate distribution off of solid protection placements and with good angles if you actually plan on bombing the anchor. (even with proven drop test result, this is still can be a volatile point of debate between even professionals; most of the ill-perceived argument of redundancy & grossly overstated safety factor being based on dogmatic principal to make whomever look important from whatever experience is claimed; but that's another topic for my venting tangent)

I like the trango product for efficient rock anchor static loading that could end up being directional as the clutching effect is reduced. But, for recreational alpine climbing & potential rockfall routes, not so much; I'd rather rely on nylon accessory cord and/or climbing rope, they have more potential beneficial usefulness to me. More than any rigging concept, though, I'd just rather not fall on the anchor to begin with.

I know the AE works well for people, but I don't really see the benefit because I am concerned about my anchors being serene. In the demo, clove hitching the pro is just as time consuming as an equalette or cordallette. I only see the AE being more efficient if you forgo limiting extenion.

Yes, the AE works really well for equalizing. However, I do feel that No extension/limited extension is important even with bomber gear. IMHO, "limiting extension is not a concern if you have bomber gear" is along the same thinking as "redundancy is not important if you have bomber gear." Both rely on robustness of individual pieces as an excuse to shave off a layer of security. I would take exception to a 1 point anchor on the premise that the piece is "bomber," so I personally feel limiting extension is also important.

In the end, its a matter of your comfort with the setup. Obviously, 99.9% of the time, a AE without clovehitches would be just fine. Likewise, 99.9% of the time 1 good piece of pro would hold you for a belay. That said, I am not comfortable about not limiting extension, so AE doesn't gain me anything.

IMHO, the best anchor rig is a triple/quadruple length sewn runner or a good old cordalette.

Cheers
Evan

Ricardo wrote: Assume we are talking about a 3 anchor system. If one of your anchors is Bomb Proof then it will not matter which system you use i.e.. equalizing or tied off. But the concern arises with a system that has 3 hairy anchors. Which should I use?

I disagree with the foundation here. The purpose in anchor building is adequate load distribution over the duration of the hit. If all we needed were one good placement, then why do anything with rigging? You need load distribution with rock anchors because one good placement, no matter how good it is, can't handle the load. That's really what making an adequate anchor from a marginal situation is; not whether or not the placements are marginal.

To explain this point, if we have three crappy placements that can't handle any distribution, then we don't have an anchor no matter how we decide to rig it. If we have crappy placements, we should do something else; if there's no other choice, then we can't hit the anchor.

I would much rather look at distributing 15-16kN over 2-3 good placements. Then look at what your pro is rated; 3 good placements that can only handle 2kN each probably aren't adequate, except maybe a bail anchor; but an anchor with 2-3 good placements at 8-12kN each is certainly a better bet to take a full hit. Then, rig good angles and use a system that has resiliency which the dynamic rope & belay offer.

The numbers were arbitrary and excessively low for simplicity. It was the concept that was the point. Multiple placements that do not distribute loading vs. those that do. When limiting knots are used it is almost certain that the load will not be distributed, some angles will stress one anchor and not the others in actual use. My point is that there is no perfect system for multiple anchors but that different situations will favor one over the other. I totally agree that crappy anchors should not be relied on. But what do you do in a worst case scenario?

Maybe this example will be clearer.

7 kN, 7 kN, 7 kN equalized will hold about 21 kN force.

14 kN, 14 kN, 14 kN limited (knotted) will not hold above 14 kN if the duration of force is long enough (and off axis) to zipper the anchors.

Each method has it's risks. That is all I'm saying. Limiting knots will protect you from a catastrophic collapse but they negate the mechanical advantage of equalization. (if off axis)

You can prevent slippage in a pulley system by welding the axel to the wheel but then what was the point of using a pulley?

The best way to determine if my ideas were correct was to test them through experimentation. After all, seeing is believing.

I set up a system in which I had three anchors of equal strength. I then determined the maximum load for a single anchor. I set up an equalizing system based on the diagram in "The Complete Climber's Handbook" on page 154 fig. 10-8.

As expected the force was distributed and easily held. I then tied an overhand knot and converted the system to a pseudo-equalized one. I was surprised that the forces remained equalized and indistinguishable from the equalized system. 1 point for the tied off system.

Things changed when the force moved off axis. First the self-equalizing system. I began to move the force off axis to the left and the right. By swinging the weight I introduced additional force due to centrifugal force and you could see that the load increased but the equalized system held even when the swing was more vigorously applied.

I then tied off the system and attempted a gentle swing to one side, the result was a dramatic collapse with the first anchor visibly bending and failing the second anchor failed much more quickly and the third failed so fast I heard it more than saw it.

Conclusions: If the line of force can be predicted and does not move more than a few degrees off axis tying off does provide additional security. However if the line of force moves off axis sufficient to unload the additional anchors the system is compromised. Q.E.D.

To see the why this is so take a length of rope (doesn't need to be long) tie the two ends to 2 different points clip a carabiner into it and pull until you have tension. Pluck either leg of the rope and you will see that both are loaded. Slide the carabiner to either side while maintaining tension, same thing. Now tie a knot with a loop in it and clip into the loop. Apply tension, all is fine. Then move to one side you will see that one leg remains taut but the other becomes limp. The load is now entirely held by one anchor.

Mark Nelson wrote
I disagree with the foundation here. The purpose in anchor building is adequate load distribution over the duration of the hit. If all we needed were one good placement, then why do anything with rigging? You need load distribution with rock anchors because one good placement, no matter how good it is, can't handle the load. That's really what making an adequate anchor from a marginal situation is; not whether or not the placements are marginal.

Theoretically a single bombproof placement which can held about 12kN is enough. The standard rope test requires that a fall with 1.7 fall factor doesn't exceed 12kN (with 80 kg): for example a Sterling Evolution Kosmos reach 8.8kN. My point is that it is actually pretty hard to generate forces bigger than 10 kN
Any C4 bigger than .5 is rated at least 12kN.

However, there is absolutely no way to tell whether or not a placement is bombproof: ALWAYS USE A MINIMUM OF 2 OR 3 GOOD PROTECTIONS

Considering these forces, distributing force between bombproof placements wont make much difference in most case. What you want is to avoid successive shock loading which might increase the chance of popping protections : no extension and equalized. The EA doesn't meet this requirement.

(note that equalized doesn't necessarily means force distribution)

In practice, it is impossible to distribute forces between several protections without extension: self-equalizing systems require extension. You can limit the extension with an equalet or by adding an overhang knot on the longest arm of a magic x system. (BTW magic X doesn't equalized that well due to the friction in the X)

If you know the direction of the pull, the best way to get an equalized, no extension system with some force distribution is the cordalette with a 7 mm Perlon. Slings or any tech cords have no elasticity and thus will be really sensitive to how well you rig the system and how well you estimate the direction of pull. Any change in the direction of pull is likely to load a single protection.

However, one concern with the Perlon cord is the elasticity : protections on shorter arm will take more load and protections on longer arm will take less load. Thus, if you want to distribute the load, you need to have arms with more or less the same length. One way is to extend the protection which is further with a sling, and, then, rig everything with a perlon cord.

Another solution is a mixed system. If you have 2 hairy protections (micro nuts or small cams like 00 TCU)and 2 good protections, you can rig the 2 hairy with a magic x. The x is considered as one multi-directional protection combining force of both hairy protection. Then you rig the magic X and the 2 good protection with a cordalette. This system is more likely to hold if the good protections pop than a system with all protections rig with a cordalette because when the good protection pop, the pull direction will change and the magic x will self-equalize.

Is making an "Alpine Equalizer" with a cordelette safe and secure? If so, what mm? Thanks.

Steven Thaw wrote:Is making an "Alpine Equalizer" with a cordelette safe and secure? If so, what mm? Thanks.

yes it safe. if you are comfortable using spectra or technora cord for a cordelette given its disadvantages it would slide and distribute force better because it has a lower coefficient of friction (slicker) than perlon. otherwise use 7mm perlon.