Quad made from 2 dyneema slings?
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Shane1234 wrote: Isn't the quad strength 22kn? There's 2 slings/4 strands so 22 + 22 = 44kn then the 50% strength loss which brings it back to 22kn?Not sure if I have ever seen a strength test for more than 1 knot in the same webbing. I would assume it wouldn't make a difference since they are isolated and unlikely to affect each other so yea like any other normal balanced anchor with a knot 22kn. rockandice.com/lates-news/c… I don't really see this adding anything just use 1 sling with a knot. I guess if you really wanted something stronger having 2 slings setup both with sliding X so you have a backup without a knot would give you 2 sets equal to 35kN+ of strength (yea you still would be limited so if a rock fell on one of the bolts it would likely cut both so still not as safe from that regard)? |
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divnamite wrote: Unless my eyes are crooked, the picture by OP clearly show uneven bolts and therefore, QD ... are out of the question.Disagree. For an anchor with two modern bolts, equalization is unneccesary. Full stop. Has anyone ever died because they used two draws instead of a quad, thereby failing to properly equalize their two bolt anchor? I'll bet that accident has nevery happened. I will repeat: equalization, while lovely in theory, isn't worth the time you soend thinking about it. Spend that energy on something important that will actually contribute to your longevity, like flossing your teeth or something. |
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JCM wrote: Disagree. For an anchor with two modern bolts, equalization is unneccesary. Full stop. Has anyone ever died because they used two draws instead of a quad, thereby failing to properly equalize their two bolt anchor? I'll bet that accident has nevery happened. I will repeat: equalization, while lovely in theory, isn't worth the time you soend thinking about it. Spend that energy on something important that will actually contribute to your longevity, like flossing your teeth or something.Agreed, but with vertical anchors, it's nice to have the biners at least close to level. TRing on a super uneven set up could lead to unclipping of one of them if the ropes angle too much. |
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Pete Spri wrote: ... TRing on a super uneven set up could lead to unclipping of one of them if the ropes angle too much.What would you classify as super uneven? On one route we put up two draws but it's so offset that the top draw bears all the weight and the lower draws sits about 2ft lower and 1ft across just hanging there like you've just placed it lead climbing up. |
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Couldn't say, depends on what the rock looks like too. |
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JCM wrote: Disagree. For an anchor with two modern bolts, equalization is unneccesary. Full stop. Has anyone ever died because they used two draws instead of a quad, thereby failing to properly equalize their two bolt anchor? I'll bet that accident has nevery happened. I will repeat: equalization, while lovely in theory, isn't worth the time you soend thinking about it. Spend that energy on something important that will actually contribute to your longevity, like flossing your teeth or something.I'm not sure what you are saying. If the bolts are uneven, then using two quickdraws means top draw will take all of the forces. As far as time spent, spending extra 30 seconds tying a MP on two bolt anchor is a fairly easy decision, just like flossing. |
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John Wilder wrote:It's fine./thread. It's toproping on bolts, people. |
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Shane1234 wrote: Isn't the quad strength 22kn? There's 2 slings/4 strands so 22 + 22 = 44kn then the 50% strength loss which brings it back to 22kn?It is impossible in real life usage to equalize the load evenly. Simple arithmetic doesn't work here. If you want more strength it is better to use double length sling folded. |
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Pavel Burov wrote: It is impossible in real life usage to equalize the load evenly. Simple arithmetic doesn't work here. If you want more strength it is better to use double length sling folded.No, don't need more strength, just curious. |
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divnamite wrote: I'm not sure what you are saying. If the bolts are uneven, then using two quickdraws means top draw will take all of the forces. As far as time spent, spending extra 30 seconds tying a MP on two bolt anchor is a fairly easy decision, just like flossing.He is saying you don't need to balance force on 2 bolts of an anchor. 1 bolt is well more than the amount of strength needed to hold a fall. The only reason you have 2 bolts is so if 1 bolt was to break you have a backup. In this case even if they are uneven the 2nd bolt will still be perfectly fine to hold a fall with a little extra drop. (how many of you have taken 20ft fall on a single bolt and had it hold, your worried about a 3ft fall?) Now if you have 2 rusty bolts that are clearly not full strength than maybe you want to make sure they are balanced, or maybe just not use them as anchors because they are in question. This also means if everyone is doing this that 1 bolt is likely to take more wear than the other but that isn't much different than bolts during a lead so I don't think it is a huge deal. |
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I did not read thru the entire thread here: but I would NOT suggest asking the "general public" technical questions. that's a good way to get hurt. ask a professional, go to the sling manufacturers website, read up in Freedom of the Hills, or ask an industry professional. some dyneema materials are NOT recommended for knotting, they cinch, burn, and fail at less than spec'ed values, under dramatic loading. |
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David Gibbs wrote: YBut why bother with something that complex? Brian L. wrote: Out if curiosity, what exactly about this do you find complicated? In order of complexity, I'd actually rank the obvious options like this: Draws < Quad < Tying a Master Point Reason being the draws and quad are ready to go (unless the bolts are vertically aligned, but not the situation here). Just clip when you get to the top. The Master Point need's to be tied each time. Draws are simpler because you don't have to tie them to begin with. This isn't the first time I've heard this argument, so not trying to dig on you. It seems to me a lot of people over-emphasize the "complexity" of a quad anchor.If you're going to compare pre-tied to pre-tied, go with a pre-tied master-point as well. When I'm single-pitch climbing and setting up TR anchors on several climbs in a row the same day, I'll generally tie my master-point for the first climb, and just re-use, as tied, for the later climbs. So why is it more complex? A quad generally uses twice as much material as a master-point. Twice as many knots. More decisions as to where to put those knots. When clipping the rope biners to a quad, you need to clip each biner to different strands in the quad, while in the master-point, you just clip both biners to both strands in the master-point. Another disadvantage of the quad, is that it is essentially a single-application tool. TRing on a two-bolt anchor. It doesn't extend well to multi-pitch sport, and it definitely doesn't extend well to trad anchors where you will often have more than two points. A master-point anchor extends to both of these as well. Why learn something that is so situation-specific, yet with no effective advantages, and some disadvantages? |
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ViperScale wrote: Now if you have 2 rusty bolts that are clearly not full strength ... or maybe just not use them as anchors because they are in question.This sums up my thoughts on equalization, and why it is unneccesary. If your bolts/pieces are solid, you don't ned load sharing since any one piece is more than enough to hold the full load, and the second or third piece is simply as emergency backup. If your pieces are not solid, find another anchor to use. It is good to understand equalization for the rare scenario where you really do have to rely on mediocre anchor pieces, but this really doesn't happen as often as people think. It is almost always better to belay 10 feet higher or lower at better gear. My main opposition to the modern equalization schemes (quads, equalettes, etc) is that they are a mental band-aid that make people feel better about trusting sub-optimal anchor gear. This is why you see beginner climbers building perfect science-project equalized anchors with poor gear, or with all the gear behind one flake. The emphasis is on the wrong part of the "SRENE" acronym. Solid and Redundant (note: redundant includes not putting all your gear in the same crack) are the parts that really matter, and we'd probably see better anchors if this were the emphasis. And I don't think that saying "just do all of the above" is the right answer either. In theory, perfect SRENE anchors are great. In the real world, climbers will always settle for "good enough", given limited time, attention, gear, anchor location opprotunities, etc. In this case, it is important to make sure the right aspects (Solid, Redundant...in that order of importance) are the ones that are good enough. So, throw out your quad and equalette. Stop worrying about equalization. It is a waste of brain space. |
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ViperScale wrote: He is saying you don't need to balance force on 2 bolts of an anchor. 1 bolt is well more than the amount of strength needed to hold a fall. The only reason you have 2 bolts is so if 1 bolt was to break you have a backup. In this case even if they are uneven the 2nd bolt will still be perfectly fine to hold a fall with a little extra drop. (how many of you have taken 20ft fall on a single bolt and had it hold, your worried about a 3ft fall?) Now if you have 2 rusty bolts that are clearly not full strength than maybe you want to make sure they are balanced, or maybe just not use them as anchors because they are in question. This also means if everyone is doing this that 1 bolt is likely to take more wear than the other but that isn't much different than bolts during a lead so I don't think it is a huge deal.Do you ever use one piece for anchor? I get that JCM doesn't like equalization, which is fine in my opinion because perfect equalization doesn't happen real life. The idea is about back up as you said. So what method do you use to do two bolts anchor? Well, if the two bolts aren't anywhere even, then using a simple master point system does a really good job of that. |
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the problem with uneven bolts and draws is not "equalization" ... |
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John Wilder wrote: I dont even carry a cordlette when sport climbing. If the bolts are that far out of alignment, I usually have at least one extra draw with me and I'll use that to make the second draw longer, so the draws are *roughly* the same length.You know you can tie a long sewn sling into a masterpoint, correct? Like the one OP has. |
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Jesus, people worrying about knots on dyneema slings which are 22kN - half brings it to 11kN - if you are generating even half of what needs to break it while TOP ROPING, you are doing something wrong. |
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John Wilder wrote: I dont even carry a cordlette when sport climbing. If the bolts are that far out of alignment, I usually have at least one extra draw with me and I'll use that to make the second draw longer, so the draws are *roughly* the same length.Tripled/extendable/alpine type draws are nice for this also. They give you various length to choose from, so you can usually get both rope-end biners to sit in about the right place. If I'm planning on toproping from a two bolt anchor, be it on a sport climb or otherwise, I usually make sure to have a couple of these handy. Also, if concerned about draws unclipping, odd loading scenarios, etc, a locker draw is a quick and easy way to have for a big of extra security and peace of mind. For toproping on 2-bolt anchors, the nicest setup I've seen was a guy I climbed with in Indian Creek a few years back (where pretty much every popular route involves a 2-bolt anchor). He had two designated anchor draws, with locking DMM revolver biners on the rope side. The revolvers made pulling the rope through on toprope oh-so-smooth. |
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JCM wrote: He had two designated anchor draws, with locking DMM revolver biners on the rope side. The revolvers made pulling the rope through on toprope oh-so-smooth.He probably didn't climb with any petite partners! I tried that once and it was pretty easy to pull the belayer off the ground. Sometimes I just clip two draws in, sometimes I'll use a sling. If I'm planning to work something out on TR for a while I also have used a quad. Not because I'm worried about equalizing between two bolts, it just puts the two biners the rope is running through at exactly the same height. That makes for a really large bend radius and a nice easy rope pull. The knots are already tied, just clip it in and go. Whatever the tied off configuration I do like using cord just because it seems to hold up to abrasion better and it's cheap. |
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JCM wrote: For toproping on 2-bolt anchors, the nicest setup I've seen was a guy I climbed with in Indian Creek a few years back (where pretty much every popular route involves a 2-bolt anchor). He had two designated anchor draws, with locking DMM revolver biners on the rope side. The revolvers made pulling the rope through on toprope oh-so-smooth.That's a very expensive setup - I've had my aluminum biners on anchor draws wear grooves in two weeks at the Creek. Started using steel biners for planned top ropes (but still bring regular alum. biner draws if it's only me and my partner - it's not much wear if there is not much top-rope dogging going on). My TR equipment for the Creek includes an ascender now - so much easier on the elbows. |