Scaffold Hitch
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The Scaffold hitch, otherwise known as a Poacher's knot, Barrel knot, or Strangle-Snare, is an end-termination knot used mostly in the tree-climbing industry. |
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The pull-test study I could find, and most of the hard figures mentioned, came from the following site by caver Collin O'Neill: |
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I don't have a ton of answers for you quickly, but I do run a tree business on the side, and climb relatively frequently. |
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We pulled a couple of these a few years ago and they outperformed the figure eight on a bight. It's an inherently tight knot so a back-up/second knot is not indicated. It was damn-near impossible to untie after a few loading cycles, as I recall. |
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ZANE wrote:am i forgetting something?The bunny ears. As to why not use the scaffolding hitch as a tie in, I can think of several reasons. 1. Pain in the ass to untie. 2. It would push your tie in points together, altering the fit of your harness depending on your pelvic length. Or you would have to tie in through the belay loop and that sucks too. 3. The one and only time I clip into the belay loop and climb is when TRing a route that is longer than a single rope. This allows the belayer to use one device and not pass the knot. A butterfly or 8 on a bite would work perfect here, a Scaffold Hitch would not work. 4. I do the above method up to once a year. For the frequency, if it aint broke, don't fix it. I can really only see using it to fix a dedicated rope for a birthday party if you're running a wall. Even then, I can't see the advantage. I do use this hitch to tie my own dog leash... |
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The knot was pretty thoroughly tested way back in 2006; here's a link to the results: british-caving.org.uk/rope/… |
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The OP's photo appears to be of a slip knot (on a barrel). I tied what appears in that photo and got a slip knot (on a barrel). I googled scaffold hitch and found a completely different knot from that pictured by the OP. Am I missing something? |
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Based off the picture and the description of tying it, the knot in the OP is just a simple noose with a double overhand knot instead of a single (there is a difference between a slipknot and a simple noose and it is based on which is the standing end and which is the working end). The knot in the OP should not be referred to as a "scaffold hitch" because it is not a hitch, it's a noose. A hitch must be tied around something in order to stay tied (like a clove hitch or girth hitch), but a noose has a loop that will tighten when the standing end is pulled (like the knot pictured in the OP or the hangman's noose). |
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Brady: Thanks for the explanation. I just tried pulling on the other strand coming out of what I called a slip knot (tied with a double overhand), and that other strand (the working end?) doesn't slip. But then I can still pull out the loop (from the standing end?), so that someone's neck can slip out. I'm still missing something. |
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I use the barrel knot all the time for terminating lanyards |
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George: In the picture of the OP the end of the rope that runs out of the picture (i.e. you don't actually see the end) is the standing end (the end "stands" and doesn't move) and the end that you see is the working end (the end you work to tie the knot). So if when you pull on the working end the loop is tightened and the knot ultimately undone, then you have a slipped knot. If the when you pull on the standing end (as pictured in the OP) the same thing happens, then you have a noose. So based on what you said you did tie a noose not a slip knot (most people don't know the difference, like with the band "Slipknot" really they are probably referring to a simple noose but that doesn't sound as intimidating). |
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Brady: Based on what you said, I did tie a noose. It seems to be the same as what is pictured by the OP. I therefore have a hard time understanding that the pictured noose can hold 14.5 kN. Even if we load the working end, will the tightened double-overhand "barrel" grasp the standing end's strand sufficiently to prevent the loop from pulling out if the carabiner is anchored? |
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Well the rope doesn't need to grasp itself, the standing end is what the force would be pulling against. So as it pulls the loop gets tighter, it won't be pulling the loop larger; that's what makes it a noose. But I have no idea what kind of rating the knot has, I would expect it to be fairly high since it is based off a double overhand. Again though, for most climbing purposes this isn't the best knot. |
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Doh! Call me a cow's tail (butt not a horse's ass) for not grasping that. |
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This: I am not arguing DON'T use it, it is used in industrial and arboreal setting frequently. I can see this in a lanyard, its' high efficiency might allow you to use smaller cordage, and the slippage that's reported gives you some cushion (but probably not worth relying on). In regards to a tie in point, it's an absolutely dreadful knot. Many reasons have already been stated. Any slippage that acts as a impact absorption is redundant past the use of a dynamic rope. Further, to maintain the purported 90% efficiency of a rope rated to 22 kn is just under 20 kn. There are many other sources of lower strengths in a climbing system. In trad your pro isn't going to hold to that degree, same is true of ice. In top rope...what are you doing to generate those forces!?!? Which leaves us with sport, at which point your belay devices are gonna fail before then anyway and your body is going to begin to have some serious boo-boos between 8 and 14 kn, depending on the source. |
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Cody's youtube video is a joke. Only a braindead person would think they're making any sort of useable knot (hitch, noose, whatever) as they show at :35. But Darwin being Darwin... |
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I use this knot all the time when bailing. It was originally shown to me by a rope access guy, and it's excellent for connecting a piece of cord to a nut or piton in a two piece rappel anchor. Never leave a 'biner connecting cord to a bail piece - it's a waste of good gear. Much easier to remember than the bowline at the end of a long day. |
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It's a slip knot. A double slip knot. If you err while tying and tie the working end (tail) as the slipping part of the knot, then loading the loop could cause the knot to fail catastrophically. Granted, it'd be hard to tie it that way, but once tied, visual inspection would unlikely distinguish it from a correctly tied knot. |
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Nathan Flaim wrote: It's pretty hard to screw up this knot when feeding cord through the eye of a pin or the end of a wire. And then you have to screw up tying it on BOTH rap pieces before you die, and your 3rd anchor backup piece will have to fail (if you have gone that far). Try it instead of the bowline or re-threaded eight... you will like it! |
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It is probably the most common way of making a lanyard in Europe. Great for keeping kids safe or short access sections based on cables if you don't have enough VF rigs, or are not carrying them because you are ski touring etc. |
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Gunkiemike wrote: And yet there have been accidents associated with it. So either A) there are brain dead people out there on rope, or B) a normal person, new or otherwise, could make this mistake. In either circumstance, I don't care, I just hate dead bodies at the crag...between the smell and the helicopters flying about, it really puts a damper on my day. Not splitter bruh! Let's all make a concerted push to not die. |