Alpine butterfly bend to join 2 ropes

Disclaimer: I love and use the EDK and think that its wonderful and magical when done properly.

Does anyone have any good input on using an alpine butterfly bend for double rope raps? Seems as though it takes care of the potential capsizing issue of the EDK, as the knot is designed to take opposing loads. Also, it doesn't seem to take up any more bulk than the EDK, so wouldn't seem to increase snag potential.

I know this topic has been beaten to death in the climbing community, but I have never heard of this knot being brought into the mix.

-Alex

Seems like a complex solution to a simple problem.

Problem: The EDK can roll off the ends if the ends are too short.

Solution: Make the ends longer.

By eliminating the potential of capsize, it seems like a pretty good solution to me. Thanks for your input.

A properly dressed and tightened flat overhand with plenty of tail also takes care of the potential to capsize.

Em Cos wrote:A properly dressed and tightened flat overhand with plenty of tail also takes care of the potential to capsize.

Longer tails does not mitigate capsize potential. Properly dressing the knot helps mitigate but does not eliminate.

Perhaps my disclaimer is lost on blind eyes, I understand and use the EDK. I am wondering if others in the climbing community have experience using the alpine butterfly bend and what their experience was regarding rope snag. This knot is easy to tie, plays to the advantages of its intent (opposing loads), eliminates capsizing and is easy to untie after prolonged loading.

-Alex

Alex Jacques wrote:Disclaimer: I love and use the EDK and think that its wonderful and magical when done properly. Does anyone have any good input on using an alpine butterfly bend for double rope raps? Seems as though it takes care of the potential capsizing issue of the EDK, as the knot is designed to take opposing loads. Also, it doesn't seem to take up any more bulk than the EDK, so wouldn't seem to increase snag potential. -Alex

If I'm picturing the knot you're thinking of, it doesn't have a flat side like the EDK, so it WOULD be snag prone. Not as bad as a fat dbl fisherman's, but somewhat worse than the EDK.

Gunkiemike wrote: If I'm picturing the knot you're thinking of, it doesn't have a flat side like the EDK, so it WOULD be snag prone. Not as bad as a fat dbl fisherman's, but somewhat worse than the EDK.

That was my thought Mike, possibly more snag than EDK, but less than the alternatives. It's a pretty low profile knot... Curious if others have had success.

-Alex

The potential problem with a capsizing knot is if it rolls off the ends of the rope. Long tails mitigate this. The amount of force required to capsize a properly dressed and tightened flat overhand far exceeds what one would normally see in a rappel. If and when the knot does capsize, the resulting knot is tighter and requires even greater force to roll again. After a small number of rolls, (2 or 3? Can't recall exactly) the knot will hold until the force increases to the point of breaking the rope at the knot.

So long tails will not keep a knot from capsizing, but they will keep that capsizing from mattering. Tied properly (well-dressed and tightened), with sufficient tails, there is no danger from capsizing.

Em Cos wrote:The potential problem with a capsizing knot is if it rolls off the ends of the rope. Long tails mitigate this. The amount of force required to capsize a properly dressed and tightened flat overhand far exceeds what one would normally see in a rappel. If and when the knot does capsize, the resulting knot is tighter and requires even greater force to roll again. After a small number of rolls, (2 or 3? Can't recall exactly) the knot will hold until the force increases to the point of breaking the rope at the knot. So long tails will not keep a knot from capsizing, but they will keep that capsizing from mattering. Tied properly (well-dressed and tightened), with sufficient tails, there is no danger from capsizing.

I'm aware. Again, looking for input on parties that have done multiple rappers on an alpine butterfly bend, not looking to discuss the EDK as I am well versed in its application and safety profile.

-Alex

I apologize, you brought up the flat overhand as a point of comparison, and seemed to be wondering why the alpine butterfly is never mentioned as an alternative. I think the answer to that is that for many climbers including myself, no alternative is needed. You mentioned a weakness of the flat overhand being a danger of capsizing, I was trying to point out there are ways to completely eliminate that danger without changing knots. If you know all that already, and still prefer a different knot, have at it.

Alex,

Nothing wrong with looking for better ways to do things, but in a certain sense, you're trying to reinvent the wheel.

The flat overhand is a proven and safe-performing knot for rappeling.

I am proposing a knot that is easier to untie, and fits the design of oppositional loading, with similar profile for getting caught to the EDK. That is all. Thanks.

Alex Jacques wrote:I am proposing a knot that is easier to untie, and fits the design of oppositional loading, with similar profile for getting caught to the EDK. That is all. Thanks.

I'd like to see a photo of what you're proposing. You say "the knot is designed to take opposing loads". But isn't every knot?

Personally, I would have a harder time tying an alpine butterfly bend as my muscle-memory versions involve the rope being in one piece. While i love alpine butterfly knots, having to re-learn to tie one with loose ends is off-putting. Of course it can be done with a little bit of practice, but like the OP asks, is it worth it?

Well,

notableknotindex.webs.com/b…

says this:

"Both the Butterfly Bend and the jam-prone Ashley Bend* can be mistakenly tied to form something that looks like the intended knot, but has poor security properties and can roll apart under certain loads in certain conditions. What makes this more dangerous is that the negative properties of this evil impostor are not usually apparent when setting the bend.

This evil or malignant imposter bend is discussed by Ashley in his Book of Knots as entry #1409 and as its more stable shifted form under entry #1408. The only difference between the two is that the more stable form has its free ends rotated or twisted relative to one another in the opposite direction from the insecure version.

Although the danger of tying this imposter is greater in the attempted Ashley Bend, one can imagine the "b" shape rotated counterclockwise, revealing that this same path of error for the Butterfly Bend is at least possible. The general knot form of the half hitch loop is another possible evil impostor for the Butterfly Bend and the Butterfly Loop, especially with some alternative tying methods for the loop.

If you feel that you may make such a mistake for these bends, the Zeppelin Bend is an excellent alternative, which has no serious impostor risk when tied with the "b" and "q" method, and may be immune to evil impostors regardless of method. The issue does not seem to affect the two common means of tying the Butterfly Loop"

I've wondered the same thing, the alpine butterfly bend in many ways does seem like an ideal knot to join two rappel ropes. However it is more complicated to tie and few climbers are familiar with it. The EDK is simple to tie, everyone knows how to check it, and as long is it's well-dressed, with very long tails and a second EDK tied as a backup, its perfectly safe.

So I doubt the EDK is going to be superseded as the rappel knot of choice anytime soon.. I don't think I would even experiment myself, since despite knowing that the Butterfly should work perfectly on paper, I've never seen climbers use it, and I'm not about to be the first to try it when I know the EDK works fine..

animatedknots.com/alpineben…

I've also wondered the same thing about the Zeppelin bend, which is an amazing knot that's easy to tie, and really could be a perfect rappel knot. But it's also a more obscure knot, so for the same reasons I'm not going to be the one to experiment with this..

animatedknots.com/zeppelin/…

If you are after an alternate abseil knot that is:

1. based on a knot most climbers know
2. is a flat knot
3. is easy to tie
4. is easy to untie
5. is strong
6. is easy to check it is tied correctly

then look no further than the flat fish sandwich:

people.bath.ac.uk/dac33/hig…

How about this one?

de.m.wikipedia.org/wiki/Pak…

Alex Jacques wrote:I am proposing a knot that is easier to untie, and fits the design of oppositional loading, with similar profile for getting caught to the EDK. That is all. Thanks.

I have wondered the same thing myself, though have not tied it for a rappel. The butterfly is designed to take pull on either end of the rope. With the overhand, the way that it is being tied subjects it to pull the strands in an "untie" direction. And while not a concern that is very valid in rappelling, if the overhand was loaded like this in a more high load scenario, everyone would be telling you that it is a big no no BECAUSE it is being pulled into a capsizing position.

Still, I think with the butterfly you end up with a loop on either side that is wrapped around the direction of the rope's travel, and ultimately, this is still going to have as much hang up potential as a double fisherman's, hence why I gave up on this knot for this purpose. The low profile nature of the overhand is precisely why I use it. IF the butterfly had the same profile, it would be a big win because it would still be giving you about 65% strength of the rope whereas rapping on an overhand gives you about 500-700 pounds before starting to capsize.

I've had this thought before, mainly because the Alpine Butterfly is so strong and easy to untie after loading. While I haven't tested it in the field I have tried a few little experiments at home. The major anti-snag advantage of the EDK isn't so much its overall low bulk, but rather its complete lack of bulk on one side. The EDK'a underside is every bit as smooth as bare rope.

Try this out: take a two bits of accessory cord, tie them together, and run the knot over the edge of a table or desk while keeping tension on both ends. You'll find that the EDK rolls perfectly over the edge, while the Alpine Butterfly Bend will catch on the edge a bit.

That said, it still seems unlikely to snag very badly. I would absolutely use it for fixed ropes, since a non-jamming knot is a huge advantage there. Plus the extra stability doesn't hurt when being cyclically loaded like that. I've never used the Alpine Butterfly Bend for rappel ropes because it usually doesn't get too jammed anyways, but I would consider it for large parties and/or overhanging terrain.

Here's the knot in question.

Alpine butterfly