Scaffold Hitch

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.

Scaffold hitch
Typically it is tied to create a lanyard for personal tethers.

Its stated qualities are:

- very compact profile; supposedly the most compact of any secure end knot

- good impact absorption; the knot "stretches" significantly more than either the eight-on-a-bight or clove hitch, somewhat reducing shock-loading

- grabs firmly onto what it's tied to; a carabiner is held securely in place to maintain gate orientation and reduce risk of cross-loading. This behavior causes the knot to become somewhat difficult to untie after huge loads, but is always easily remedied by removing the biner from the knot and capsizing it.

My question: Is there any reason this knot isn't more well-known, or used at all? It is extremely simple to tie and inspect, and seems to have no clear disadvantages over any other knot in its proper application.

In rock climbing, on the somewhat rare occasion that we use carabiners in place of a tie-in, the standard practice is to use two opposite-and-opposed biners with a figure eight on a bight, resulting in the two connectors juggling and clattering furiously around. We double them in the hopes that at least one might be in the right orientation during a fall, thus reducing but not eliminating the odds of gate-loading.

Originally I thought it was due to strength; however apparently the Scaffold performs at a 95% retention of rated line strength, higher than both figure-eights and clove hitches. In the pull tests I could find, 8mm cord tied with this knot failed at an average of 14.5 kN

It seems like in this specific application this could be a simple and much safer alternative to the typical setup.

Thoughts?

The pull-test study I could find, and most of the hard figures mentioned, came from the following site by caver Collin O'Neill:

caves.org/section/vertical/…

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.

The anchor hitch is a similar one, and more commonly used. Check out this thread for termination knot discussion.

arboristsite.com/community/…

I dont know much about the scaffold hitch other than how it is tied, I don't use it. I think you would need a backup regardless... There are so many knots bends and hitches that *could* be used in climbing applications that just aren't standard practice. How many knots do you really use when climbing? Fig 8, cloves, fishermans and overhand are 90% of my knots (am i forgetting something?). I'm sure there are scenarios where something else would be easier, but it comes back to using what I am comfortable with and can tie properly without worry.

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.

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...

The knot was pretty thoroughly tested way back in 2006; here's a link to the results: british-caving.org.uk/rope/…

The tests were on what the Brits call cow's tails and we would call lanyards or maybe PAS's. They tested high fall factor falls and did static tests. It is clear that if you are actually going to fall on your lanyard it is best if it is made of rope and that the attachment points are knots rather than any kind of sewing. The best knot combination was the figure-eight to the harness and what the OP mistakenly called a "scaffold hitch" and the report calls the "barrel knot." Here's a summary table from the report.

Lanyard Load Comparisons

I wouldn't use the barrel knot as a tie-in knot (note the testers didn't even consider it) because it compresses the harness tie-in points (or forces you to tie in to the belay loop). If, like me, you are one of those folks who clip the belay device to the rope tie-in loop rather than the harness belay loop, then with the scaffold or barrel knot there is no loop to use in this way.

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?

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).

That being said. I can see how the pictured knot would be very strong, but there are other things to consider when selecting a knot other than strength. I would not trust the way this would pull on the hard points of a harness, and I'm not going to be tying in with a carabiner unless it's little kids switching frequently between top-ropes. (both things already stated above)

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.

I use the barrel knot all the time for terminating lanyards

Its great for that as it locks the biner in place unlike an 8 ... The barrel knot is a knot that tightens around the biner when loaded

However there is no reason for most climbers to know this knot ...

The basic figure 8 is something that all climbers know anyways and works well enough ...

Most climbers dont practice rarely used knots and cant tie em when the chips are down

Hell most climbers can even do a munter mule

KISS

;)

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).

The only time you would use a slipped knot in climbing is a slipped half hitch at the beginning of a mule knot, or for a very scetchy rappel that I would recommend no one ever try. Nooses could be useful in climbing, but generally you want a fixed loop (figure 8 or overand on a bight) rather than a noose. Or it just comes down to using what you know as bearbreeder pointed out, a climbing situation where someone's life is being trusted in the knot is not a time to experiment.

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?

Seems that a stiff rope would have a harder time grasping itself.

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.

Doh! Call me a cow's tail (butt not a horse's ass) for not grasping that.

This:

https://youtu.be/_Mv2apjIa5Q

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.

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...

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.

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. 

Nathan Flaim wrote:

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. 

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!

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.

Gunkiemike wrote:

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...

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.