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andykirkpatrick
Jun 26, 2006, 3:52 AM
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Hi
The whole issue of abseil knots (rope joining) seems to cause a lot of problems for people, so I wrote this piece to try and come up with a solution that was as good as the "Euro death knot" , but would be used by those who prefer something that looks like a proper knot. I'm sure it will cause some interest and debate! It's based both on stuff I've picked up from other climbers and from an artile writen by Steve Reid at Needle sports in the UK.
http://www.psychovertical.com/?abseilknot
cheers
Andy
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the_iceman
Jun 26, 2006, 10:06 AM
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Eeennteresting.
Now all we need is for someone to get on and argue with that using some bogus statistics.
'80% of the time, 100% of overhand knots will come untied at a 47% load. As compared to the Inverted Uberfly Fishermans knot, which holds 100% of half it's strength, when tested at a 60% load. Anybody who disagrees is just stupid and deserves to die. Because I have 2 years of indoor climbing experience, so I would know!'
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jercech
Jun 26, 2006, 4:18 PM
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dude, don't be dissin' my Inverted Uberfly Fishermans knot until you've tried it with a Yosemite finish.
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wings
Jun 26, 2006, 4:58 PM
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In reply to: but would be used by those who prefer something that looks like a proper knot
People shouldn't get too wrapped up on things that "look like a proper [insert]". Nuts are pretty small, but they seem to work okay.
However ... here are some interesting links:
http://www.xmission.com/...yer/testing/EDK.html
http://www.needlesports.com/advice/abseilknots.htm (the reference article, which is linked to in the page)
Hard data trumps "looks".
I seem to recall seeing more data on the double overhand, but I can't find it.
- Seyil
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wings
Jun 26, 2006, 5:10 PM
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In reply to: Why would the double overhand knot be superior to the *flat* double fisherman's knot that Edelrid tested
In my opinion, the double overhand is easier to tie (with gloves, in the dark, etc ...), and still effective enough with LOTS of margin for error (in terms of strength).
- Seyil
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kimgraves
Jun 26, 2006, 8:15 PM
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Hi Andy,
The failure mode of the EDK means that you’re dependent upon leaving enough tail so that it can roll – maybe multiple times – prior to it “catching.” But how much tail is enough – a foot, two feet, three feet? The double EDK certainly seems like an improvement over the single in that if the second knot was cinched up tight to the first it would help prevent the roll over. It’s certainly something to consider.
For me however, using a knot that has an indefinable failure variable (how long do you make the tails?) I’ve always seen as a risk – a risk with no redundancy. When I first started climbing in the 70’s we used the double fisherman’s knot (DFK) for this application. It’s true that it was hard to untie, but as far as I know, it has no failure mode other than breakage.
The argument that because the DFK is not flat it can get stuck when pulled, while true, represents a less catastrophic event than knot failure. If a knot fails during a rap, someone has a good chance of dieing. Ropes getting stuck are a challenge but not a catastrophe. The “flat double fisherman’s” (FDF), pictured above would, solve that problem of flatness. Does anyone know of any tests done on this knot?
Finally the argument that the DFK, and I assume the FDF, are hard to untie is also not a catastrophic event. You don’t usually have to untie the knots until you’re on the ground or at a point where you’re safe. You then have time to work on the knot and get it out – I’ve never been able to not get it out.
So that’s my 2¢, or 2p, on the matter. I guess I’ll continue using the DFK unless there is a serious chance of the rope getting caught and then consider the double overhand.
But let me end with a question: Does anyone have any data of tying two ropes together using a butterfly knot? You could back that knot up with an EDK or a FDF in the same way. It would be easy to untie, relatively flat, and as I understand it, not have a failure mode. It’s an even bigger knot than the DFK, more complicated and harder to inspect but would solve the problem of the fisherman’s knots being hard to untie. Just a thought…
Best, Kim
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rgold
Jun 26, 2006, 9:09 PM
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The Edelrid tests include two knots that roll less than the EDK and are stronger, one by 15% and one by 40%. Tom Moyer's link is no longer correct, but the results are still available here.
I agree with Beesty511 that it is hard to imagine why these knots are not a better alternative for those with EDK jitters.
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cintune
Jun 26, 2006, 9:31 PM
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Not to argue against the double overhand, because it is pretty bitchin' ultimate, but has anyone ever tested a rethreaded alpine butterfly?
- Not much bulkier than a DO, overall,
- Flips upright when going over edges, although the loops might catch a snag.
- The rope runs true out of the knot instead of pulling it apart, so no rolling to wonder and worry about,
- The double loop can be clipped to backup the prussik when passing the knot.
-Fairly easy untie, but won't untie itself.
- A very strong knot in terms of not weakening the rope.
Just a thought on another rainy day. I'm probably forgetting something crucial. I would run outside and try it, but it's pouring. Someone tell me why it sucks.
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kimgraves
Jun 26, 2006, 9:55 PM
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In reply to: The Edelrid tests include two knots that roll less than the EDK and are stronger, one by 15% and one by 40%. Tom Moyer's link is no longer correct, but the results are still available here.
Thanks Rich for the corrected link. I'm convinced! But maybe that's because I find a double fisherman's easy to tie and inspect.
DT-FK
TT-FK
I would imagine you could "fix" the deformation issue of the TT-FK by making knot "A" a double overhand (shown below) rather than the single as shown above. I'm wondering if you preserve the 40% gain or if the double weakens the knot.
http://www.rockclimbing.com/...p.cgi?Detailed=75163
But since the findings say the DT-FK is "absolutely safe" even with dissimilar diameter rope and easy to untie after being loaded, why bother?
In an alpine situation, where it's shitting on you and you're wearing belay mitts, it seems the TT-FK is the way to go since in pencils out at 40% greater strength than the EDK, is idiot proof, and looks easier to dress properly than the EDK. What do you think, Andy?
Best, Kim
(This post was edited by kimgraves on Aug 9, 2007, 2:31 AM)
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andykirkpatrick
Jun 27, 2006, 2:40 PM
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I know I’d get some good reactions from this!
First of why do I think this is the ultimate? Well the main reason for writing this was that as far as I’m concerned the plain overhand is actually the best knot, and has allowed me to rap about 5,000 metres+ of rock and ice safely and with not one hang up.
The problem is that many people just don’t like the look of the plain overhand, sometimes leading to them tying the ultra dangerous figure of 8 version.
What I wanted to do was come up with a knot that was 100% safe and more importantly very easy to tie, after all more accidents occur due to badly tied knots rather than the wrong knot being used. An abseil knot is generally tied at the end of the day, or during times of forced retreat, and there are a lot of factors that can cause a failure to tie the correct knot, and so simplicity is key.
The main reason for the piece was that there are lots of novice climbers out there who are confused about this topic, and would like a definitive answer. Knowing 20 different knots just isn’t helpful (yes some of the above knots are great, but they just muddy the water, and are best left to camp 4 car park banter). The double overhand therefore is my take on the ultimate rap knot because:-
it’s safe
It’s easy to tie
It’s easy to untie
It’s quick to tie
It’s less likely to hang up
Anyone can tie it (in the dark, one handed etc).
Cheers
Andy
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andykirkpatrick
Jun 27, 2006, 2:43 PM
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I know I’d get some good reactions from this!
First of why do I think this is the ultimate? Well the main reason for writing this was that as far as I’m concerned the plain overhand is actually the best knot, and has allowed me to rap about 5,000 metres+ of rock and ice safely and with not one hang up.
The problem is that many people just don’t like the look of the plain overhand, sometimes leading to them tying the ultra dangerous figure of 8 version.
What I wanted to do was come up with a knot that was 100% safe and more importantly very easy to tie, after all more accidents occur due to badly tied knots rather than the wrong knot being used. An abseil knot is generally tied at the end of the day, or during times of forced retreat, and there are a lot of factors that can cause a failure to tie the correct knot, and so simplicity is key.
The main reason for the piece was that there are lots of novice climbers out there who are confused about this topic, and would like a definitive answer. Knowing 20 different knots just isn’t helpful (yes some of the above knots are great, but they just muddy the water, and are best left to camp 4 car park banter). The double overhand therefore is my take on the ultimate rap knot because:-
it’s safe
It’s easy to tie
It’s easy to untie
It’s quick to tie
It’s less likely to hang up
Anyone can tie it (in the dark, one handed etc).
Cheers
Andy
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cintune
Jun 27, 2006, 2:56 PM
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Good points, no doubt. But the car park banter is good too. Never saw the TT-FK before; it's a beauty.
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jercech
Jun 27, 2006, 3:37 PM
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The problem with using new, unfamiliar knots isn't their theoretical advantages in one-handed tieing, in the dark, in a sleet storm. The problem is that when I pull a EDK out of the toolbox and tie it, my friends look at me like I'm trying to kill them, make me replace it with a conventional double fishermans knot, and then refuse to climb with me again until I renounce my errant ways.
Until the publishers of MFotH include the EDK it just isn't going to become widespread.
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kimgraves
Jun 27, 2006, 5:11 PM
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Hi Andy,
I appreciate your criteria of easy tying and wanting to warn people of the real danger of the figure 8.
My problem (and this is personal) is that I find the EDK easy to tie, but hard to dress and difficult to inspect for proper dressing because you’re looking at the relationship of two strands of rope in relationship to each other as well as to themselves. And if the two lines are similar in color the job becomes harder.
Laugh if you want, but at my gym the staff has to tie figure 8's in all the ropes on a daily basis so climber can clip in with biners - insurance doesn’t want people tying their own knots. You'd be surprised how often the knots are dressed improperly by staff who are experienced climbers. All the tests show that the EDK must be dressed properly to work.
AND the question about safe tail length is unanswered.
With the double fisherman's knot (DFK) the job of inspection and dressing I find much easier because you're inspecting one strand of rope for proper geometry. If you can tie a DFK than the DT-FK is no harder. It's 15% stronger than the EDK and has no failure mode other than brakeage. Tail length is modest - 10cm in the test, I think.
And the TT-FK is the simplest of all the knots to tie. I could easily tie (AND DRESS) it with my heavy mitts on. It deforms, but doesn't roll, so tail length can be modest as well. And it's 40% stronger than the EDK. I think tying and dressing a double EDK with my mitts on would be much harder.
When I came back to climbing several years ago, after a 20 year layoff, I was surprised to find that the doubled figure 8 and EDK were is such wide use. Both seem problematic for the reasons stated above. In days of yore we tied in with a one and one-half fisherman’s knot. (See below) It was small, easy to tie, easy to inspect, easy to dress, and you could get it really close to your harness (swami in those days). Anyone know why its use was discontinued?
http://www.rockclimbing.com/...p.cgi?Detailed=75218
Best, Kim
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cracklover
Jun 27, 2006, 6:45 PM
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Andy, I don't see anything in your treatise that shows any benefits of this knot aside from "I say so". I don't see anything wrong with your knot, though, aside from the fact that it's pretty bulky, which - as you pointed out - could make it more likely to get hung up in some cracks.
Personally, I use an EDK with an additional overhand tied in one of the strands behind the main knot. If one of the strands is thinner, I use that one. Like your knot, it's essentially a backed up EDK, but it has the added benefit of having almost the same profile as the EDK. It also passes the KISS test, and the "yup, looks safe" test - for those who care about that one.
Of all the knots without the rollover failure mode that I've played with, it has the smallest profile. I'm sure I'm not the only one to have come up with this knot, but it seems pretty much perfect to me. I'd love to see it tested to failure a few times by a competent crew, though.
GO
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el_jerko
Jun 28, 2006, 1:15 PM
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My $.02...
Overhand knots are the absolute worst for slabs for the very reason they are good on steep ground; they do not roll. This might keep you out of some cracks, but it will burn a hole through your sheath after pulling a pitch or two on a course slab.
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nnowinowski
Jun 28, 2006, 2:55 PM
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Seems like the ckt's (climbing knot theorists) on the site could use an hour or so at a hanging belay freezing their adze off while their knots are stuck. If my friends won't rap an edk, they're no friends of mine.
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j_ung
Jun 28, 2006, 3:03 PM
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j_ung moved this thread from General to The Lab: Online Climbing Safety Test Discussions.
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reg
Jun 28, 2006, 4:05 PM
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In reply to: My $.02... Overhand knots are the absolute worst for slabs for the very reason they are good on steep ground; they do not roll. This might keep you out of some cracks, but it will burn a hole through your sheath after pulling a pitch or two on a course slab.
hugh? i mean the only time an edk "stands up" is under tension like going over an edge or round a corner - otherwise it'll flop from side to side and even roll over when loosely pulled. also i would hope my rope can drag along a slab for more then 400' before it suffers a hole in the sheath. am i wrong?
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aikibujin
Jun 28, 2006, 4:14 PM
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In reply to: also i would hope my rope can drag along a slab for more then 400' before it suffers a hole in the sheath. am i wrong?
Yes, you're wrong. It only took one full length rappel (200 ft) on the granite of Stone Mountain to wear a hole in my rope's sheath.
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reg
Jun 28, 2006, 4:32 PM
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In reply to: In reply to: also i would hope my rope can drag along a slab for more then 400' before it suffers a hole in the sheath. am i wrong? Yes, you're wrong. It only took one full length rappel (200 ft) on the granite of Stone Mountain to wear a hole in my rope's sheath.
humm.......which rope got damaged - the rope you were pulling on or the one following? - i'm thinking somthing else was goin on like a restriction at the anchor maybe
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pastprime
Jun 28, 2006, 5:32 PM
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Kimgraves; I still tie in with the grapevine/fisherman's thing. I think it was also promoted in the first Chouinard Equipment catalog, but maybe my memory on that is faulty. It is a great knot. Compact, very fast to tie, easy to get right where you want it, easy to untie after use, but no tendency to untie itself. Once in a while someone gets nervous when they see me use it. It is funny how some people think the only one safe way to do something is the way they were taught.
My guess on why it disapeared is that the figure eight is somewhat easier to teach, and can be more easily checked for accuracy with a glance from a distance by the instructor. Those were the reasons I taught it, even though I used the grapevine myself when away from classes.
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schveety
Jun 28, 2006, 5:55 PM
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Call me crazy here, but over the hundreds of times I've pulled the rope after rappeling - using a DFK - I've never once had it get stuck - and that's been in many varied situations - different rock types, different slope, different environment - alpine, etc.
I've only ever had a problem with getting the very end of the last rope stuck as it's sailing down - damn fuzzy rope and ledges!!
Nor do I think the DFK is that hard to tie and inspect, but I'm kind of a safety, double-checking freak
Anyway, my 2 cents, long live the DFK!
With that said, I have rapped with the EDK and was a little nervous about it, but it seemed to work well, and I studied it's behavior as other people were on the end - so I'm not opposed to it, I just think the DFK is more fool-proof
Watch, I'll bet anyone $10 I get my rope stuck at the knot on my next rappel
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kimgraves
Jun 28, 2006, 5:57 PM
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In reply to: maybe my memory on that is faulty.
:lol: Maybe you should change your name to "inmyprime!" Here is the page from the Chouinard catalog you refer to. That's where I learned it too. Thanks to climbaz.com for the pic.
http://www.climbaz.com/.../graphics/page27.JPG
In reply to: My guess on why it disapeared is that the figure eight is somewhat easier to teach.
That's interesting. I guess back "in the day" we had to teach ourselves everything because there were no gyms, no classes, no mentors. Let's have a movement to bring back the 1-1/2 Fisherman's knot!
Best, Kim
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