Self-equalizing vs. static anchor
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John Long wrote:Quad -JLwhats a Quad? my 2 sense: Use bomber gear for belay anchors. If there is not bomber gear options, belay somewhere else. I also like to use the rope to anchor off. |
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Darren Mabe wrote: whats a Quad? my 2 sense: Use bomber gear for belay anchors. If there is not bomber gear options, belay somewhere else. I also like to use the rope to anchor off.Quad = Google Books Link |
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srene sar-har nerds kiss srele quad acr slidingx. or was that p90x? |
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mattm wrote: I'd also be interested in reading about these tests. In my experience, Rescue anchors are only vaguely similar to climbing ones. In SAR-HAR, EVERYTHING is MUCH MUCH stronger, over engineered and redundant. If these tests were with RESCUE anchor systems I'm not at all surprised they held. What you want tested are the FUNKY anchors climbers run into and are forced to use since it's the only option. Weird Rock, small nuts, placements in non-ideal directions etc etc.This is actually not entirely true. The two things I see different are the need to use less elastic mainlines and larger mass. While the difference in mainlines between what climbers use to soft-catch and what you need to manage an evac is important to take note of, it still gives you a worsened case than what a dynamic rope would do at the anchor. The rocks, ice, mountains, trees, physics, gravity, etc. They are all still the same and trad gear is still trad gear. Although, arguing a crappy set of dogshit placements is worthy of testing as a viable anchor doesn't really tell us anything other than we have a crappy anchor which we already know going into the test. Increases in the safety factor by doubling up materials and trying to build in added redundancy does not necessarily make the situation more safe nor more operationally effective. It is only perceived that everything needs more, because more is better, right? To some extent, speed is still safety in a varied environment. Rich, off the top of my head look at JoshSAR at the ITRS online, though you still would want a larger sample set and you won't see the videos on how they setup anchors which was all pretty much straight forward using climber's mentality of rocks' natural features and keeping things quite simple. They even tried placing bad pro with the good pro. |
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I have been lurking on mp for a while and I finally decided that I would post. I may be a little late for posting to this thread, but maybe it will add to the discussion. |
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Kyle Heise wrote:I have been lurking on mp for a while and I finally decided that I would post. I may be a little late for posting to this thread, but maybe it will add to the discussion.This discussion will continue for decades more... Out of all those thing you listed you neglected listing the strongest, minimalist, and most versatile approach. Using your climbing rope for an equalised anchor. |
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1 use the rope if swinging leads |
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All this is moot if all your anchors are bomber and it is multi-directional. |
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I just clicked on this an laughed when I realized I was the one who opened up this can of worms 4 years ago! |
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Funny you should ask. Folks seem to only talk about a piece blowing. Well I was involved in an accident earlier this year that resulted in one leg of our pre-equalized, two bolt anchor being chopped. If I had Magic-X'd I would be dead, no question. Doesn't happen often but it happened at least once. |
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The one down side of equalizing with your rope is if you have to self rescue you have to escape the system first. I personally like an ovbious power point for my second to clip into. |
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I'll bite..escaping the anchor is the stupidist god damn thing ever..what will you do / downclimb..rappel with no rope ?? WHAT |
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john strand wrote:I'll bite..escaping the anchor is the stupidist god damn thing ever..what will you do / downclimb..rappel with no rope ?? WHAT You never ,, ever can really equalize an anchor..not really. Build your anchor the best you can, use your ROPE to tie in end of story.No, but you can ascend/descend the rope, anchor your injured partner, and take the rope to rap off; or rap down with your injured partner. Both of these options require you to escape the belay. Of course, this can be done even with a rope anchor, it just has to be done differently than with an independent anchor. How I anchor in, either with the rope or with a cord, is not decided by the extremely remote possibility that I may have to escape the belay. |
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patto wrote: Out of all those thing you listed you neglected listing the strongest, minimalist, and most versatile approach. Using your climbing rope for an equalised anchor.Thank you patto! I spend most of my time on tr, mainly because I lead trips for grade school-aged kids. Also, being a Wisconsin based climber I have not had the opportunity to multipitch. I have read about that anchor at one point, but it slipped my mind. I would say that it is a great option, being minimalist and versatile; however, I my gut tells me to contend with "strongest". Before I can do that though I'll have to try it and read up on it a bit. Does anyone have any thoughts about the addendum part, with the opposing anchor to maintain the direction of pull centered? Is it even worth it really? ps- I was a bit surprised that anyone would comment after me. So this is great! |
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JBennett wrote:http://blackdiamondequipment.com/en/experience-story?cid=qc-lab-sling-strength-in-3-different-anchor-configurationsI think to some extent this is a fair point. However, Clyde Soles makes the point, "Lab tests don't tell the full story of how well a rope works in the field. Some ropes are designed to do little more than look good on tests. They are safe when used properly but may handle poorly and wear out quickly" (The Outdoor Knots Book, 35). Consider the difference between Perlon, Spectra, Spectra-A, and Black Diamond's Gemini. Strength Comparison of Prospective Cordelette Materials* 1. Tensile Strength (Single Strand) 12 kN-7 mm Perlon (Sterling) 17 kN-5.5 mm Spectra (Blue Water Titan) 18 kN-5.5 mm Spectra A (Maxim) 22 kN-5 mm Gemini (Black Diamond)aka: Tech Cord(Maxim) 2.Loss in Strength When Knotted with a Figure Eight 8%-7 mm Perlon 47%-5.5 mm Spectra 39%-5.5 mm Spectra A 60%-5 mm Gemini 3.Cordelette Strength (One Anchor) 22 kN-7 mm Perlon 17 kN-5.5 mm Spectra 23 kN-5.5 mm Spectra A 18 kN-5 mm Gemini 4. Loss in Strength After 200 Flexing/Bending Cycles 0%-7 mm Perlon 6%-5.5 mm Spectra 40%-5.5 mm Spectra A 45%-5 mm Gemini 5. Cordelette Strength after 200 Flexing/Bending Cycles 22 kN-7 mm Perlon 16 kN-5.5 mm Spectra 14 kN-5.5 mm Spectra A 10 kN-5 mm Gemini
The 48" runner they used, was likely made of HMPE (i.e., Spectra to Americans or Dyneema to Europeans). This material looses strength when knotted, when Perlon (which is basicaly nylon for all intents and purposes) does not. They claim, "[K]nots reduce the ultimate strength by anywhere from 40-60% and the failure mode is always at the knot". If your point was to say, go with the sliding-x, I think the lab test evidence says yes and no at the same time. It is true that knots weaken ropes/cords/webbing because it "pinches" the the material. The knot type is also important. The overhand knot reduces strength to 58-68%. Whereas the figure-9 is at 68-84%. My point is this: Strength is never the real issue. The Black Diamond link preformed a test only comparing the measurements of strength using all of the same material and had everything controlled. That is how you conduct a test. However, there are other variables to consider. The link states, " I'm not going to get into the merits or negatives of each situation (e.g., shock loading if one anchor placement blows, how "equalized" they actually are, etc)". Their test means very little. I do not thing that the strength of gear even comes into question (unless you do not inspect it and then it fails). The larger concern is pro placement and how it is affected by the system you use. If a system is not equalized well, you run the potential risk of loading an anchor point too much. If you placed pro poorly and it is loaded more than the others the probability of failure is greater. |
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Malcolm Daly wrote:All this is moot if all your anchors are bomber and it is multi-directional.As much as i hate to disagree with someone with much more experience than myself, i think that making such a broad statement is dangerous. i would guess that most climbers, other than the most experienced ones, cannot determine exactly how strong their pieces are as they are very rarely significantly tested. i think most of us can tell a shitty placement from a good one but in many cases the line between good and totally bomber is quite blurry. additionally, i remember reading a statement from metolius that said, basically, 1 in 20 seemingly "bomber" cam placements (considering the placements were judged by doug phillips, i trust that they were actually bomber) failed. on the other hand, given that a high factor fall is quite rare and that dynamic ropes limit the impact force, speed and efficiency is more important that amazing load distribution. you shouldn't spend more than 3 min building a 3 or 4 piece anchor (not including the time to get good placements). since i am much less experienced than most of y'all, here's a quote from rgold on the taco. rgold wrote:He may have consciously or unconsciously settled on 1/20, as it is the threshold probability for deciding on statistical significance. No matter what, I think the message is that our ability to judge well-placed cams is nowhere near perfect, and that failures, although surely unwelcome, are also intrinsic to the very complicated processes that make a cam hold. Small differences in the friction properties of the crack interior, small differences in the solidity of the crack interior, small differences in the "impurities" of the crack interior (water, grass, mud), and small differences in the configuration of the crack interior can all potentially have a large effect on cam performance. The fact that a cam may move, sometimes considerably during a fall, means that the original placement may not be the one that is operative. Really the only response to most of these uncertainties is to make sure the cam lobes are compressed enough that they will be able to tolerate an unexpected change in crack dimensions. There's nothing to be done about unanticipted frictional anomalies. |
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J Mac..... |
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And as for all these citations of single strand 6mm strengths...... |
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You guys realize you're posting to a 4 year old thread? Some thinking about what is and what is not acceptable may have changed since the first post. |