The EDK is officially known as an overhand bend or an overhand flat knot. It would be far better to refer to this knot by one of these names as they do not strike fear into those that use the knot.
The Overhand Bend (AKA Overhand Flat Knot/Euro Death Knot)
In this photo the tail is very short and there is no back-up to the Overhand Bend.
Photo from Wikepedia
Most people like the overhand bend for two reasons. First, because of the knot's asymmetrical profile, it tends to pull smoothly over edges and doesn't get caught as easily. And second, it is very easy to untie.
To tie the knot, lay both ends of the rope together. Make sure that they are pointed in the same direction and then make an overhand knot in both ropes at the same time. This is the overhand bend. Most guides tie a backup by adding a second overhand bend next to the first. This will keep the knot from rolling if there are unexpected high loads.
In the past, most climbers tied the overhand bend alone. If the knot is tied by itself without a backup, there must be a significant tail. It is not recommended to tie the overhand bend by itself.
Some people tie an overhand eight in lieu of an overhand bend. This is far more likely to roll than a unbacked-up overhand bend and is not recommended.
Most of our guides tend to tie not only their rappel ropes together with an overhand bend, but their cordelletes as well. Guides tie their cordelletes with this knot because it is easy to untie. A cordellete that may be opened has a great deal more flexibility. It can easily be opened up and used like a webolette. Some like the ability to open up a cordellete because an open cordellete without a welded double-fisherman's knot can be cut up more effectively for anchor material.
Following is a short video from the Canadian guide, Mike Barter, on how to tie a overhand bend.
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--Jason D. Martin
8 comments:
I heard a suggestion that to reduce the bulk of the knot but still prevent it from rolling, you could tie and overhand on one of the strands behind the overhand bend.
I believe the proper name of this knot is the 'flat overhand bend'.
I don't think the flat overhand is a good choice for a cordelette, even if you plan on untying it often. A figure-8 bend (aka flemish bend), is much stronger, more symmetrical, can be untied, and does not require very long tails or a backup knot.
The EDK is actually one of the worst possible bends by most objective measures- it's weak, prone to slip or roll, and requires a very long tail and/or backup knot to be safe. If used repeatedly, the knot must be frequently inspected. The only reason it makes sense for rappelling is that it's only used once before being untied, the long tails aren't an issue, and it has the benefit of not getting easily snagged.
Dan,
This knot is widely used amongst both US and international guides to join cordelletes together.
In tests, the knot tends to roll once or twice and then the rope breaks. This would indicate that it is just as strong as any other knot.
You can back the knot up with a second overhand in order to keep it from rolling.
The flemish bend is fine as well. The only problem with it is that if you use it to tie two ropes together for a rappel, it has a higher likelihood of getting stuck on the descent.
I'm just saying I think the flat overhand is a poor choice for a cordelette. I wasn't suggesting using a flemish bend for rappelling, though I think that would be acceptable.
Personally I use the EDK for rappelling, with a second overhand as a backup, and very long tails.
Since cordelettes are typically used repeatedly before untying, I think it's more important to use a secure, compact knot. And since the strength is much lower than a rope, I think it's also important to use a strong knot. I don't know the strength of the flat overhand bend compared to others, but the sharp angle it creates suggest it would be weaker than other bends, and Ashley book of knots describes it as "among the weakest of the bends".
For a cordelette that can be untied, I think the flemish bend is one the best knots, it's simple and reliable. The alpine butterfly bend is probably better, and certainly easy to untie, but most people are not familiar with it.
Dan,
The flat overhand bend is far simpler to tie than the flemish bend.
Also, please find me an example of anchor/cordelette failure due to the use of flat overhand bend - then I will consider finding it's supposed inferior strength to be an issue.
It is plenty strong for it's usage, and is in fact faster to tie and untie, making the cordelette more versatile in anchor building situations.
I always use a double fisherman's knot for my cordalette. Easy to untie, no harsh angles, no back up knots. It never ever rolls. Very superior knot for that use.
The lab testing I have seen shows the EDK to roll the worst of all the joining knots. The eight was bad also, but not as bad. The only time I would consider using an EDK is if that Rap has a history of hanging ropes... or if I am going to 'biner-block that side of the rope.
I know one very well known AMGA IFMGA guide who will remove from his Facebook posts any posts that call the Flat Overhand Bend the Euro Death Knot or EDK. The flat overhand bend is a great joining knot for cordelettes as well as tying two ropes together. It is amazing that some still find it controversial. This topic comes up every season like some mad, robotic comet, stuck in a vinyl record tracking groove.
The "inferior strength" of a flat overhand to a flemish bend has been consistent in every comparison test that I have been able to find. It is a knot with widely varying test results, sometimes it rolls over and over until it comes of the ends, sometimes it locks up and breaks after a couple of rolls. All the testing I have seen shows a final result in the range of 40-50% of the rope MBS. Flemish bends seem to produce results around 65% of MBS. The flemish bend consistently breaks at the knot where one of the strands enter it. The other knot used for cordalette is the double fisherman's, which shows results of around 75-80% of MBS consistently.
I think everyone agrees that when used to join rappel ropes, the strength of the EDK is far more than adequate. Used in a cordelette, weather using this weaker knot makes the overall anchor weaker is complex question. In the video I link below they conclude that in the quad anchor the weaker knot doesn't matter (they do test the knot itself to see how strong it is) Personally, I use an open cordalette and just incorporate the ends into one of the other knots in my anchor, which avoids the whole issue.
https://www.youtube.com/watch?v=Hfn21EzAHgU&t=572s&ab_channel=HowNOTtoHIGHLINE
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