By Glenn Gordon
From Buffalo Grove, Illinois
Aug 26, 2009
| 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 | 
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By Ron Olsen
From Boulder, CO
Aug 26, 2009
| 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. |
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By Robert 560
From The Land of the Lost
Aug 26, 2009
| 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. |
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By Glenn Gordon
From Buffalo Grove, Illinois
Aug 26, 2009
| 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 |
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By Rschap
Aug 26, 2009
| 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? |
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By SAL
From broomdigiddy
Aug 27, 2009
| 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. |
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By Buff Johnson
From Coniferous, CO
Aug 27, 2009
| 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. |
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By Evan1984
Aug 27, 2009
| 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 |
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