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andykirkpatrick
Jul 19, 2006, 1:04 PM
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Hi
A couple of weeks ago I posted about an article on my website called 'The ultimate abseil knot' http://www.psychovertical.com/?abseilknot, both because I thought it a good idea to focus new climbers on one knot that was guaranteed to work, with few compromises and more importantly wouldn't scare the shit out of them. Of course this started a huge debate, with loads of great knots coming the light, and lots of for an against argument for both trad knots and new age knots. AT the end I stand by the knot described, even though personally I still use a plain overhand.
Following the post I received a LOT of e-mails from people too scared to post on here and get shot down, and many where as I expected from new climbers who just wanted to know ONE way that worked. Then yesterday I got an email from Miguel Grillo in Portugal (hey they may have beat us in the world cup but I'm man enough to respond) with an e-mail that was quite disturbing, so I've pasted it here for any one who's interested.
Cheers
Andy
First of all, sorry about my poor English.
I'm writing to you because your recent article about THE ULTIMATE ABSEIL KNOT.
During year I used the Simple Overhand Knot to rappel. But one day I almost saw my climbing partner falling because this simple knot. We were trying to open a new winter route in the East face of Cāntaro Magro, one of the huge and challenging winter walls of Serra da Estrela, our highest mountain (in Portugal). We climbed all night in bad snow and weather conditions and in the morning we were tired. We 80 meters below the summit we decide come down and trying this climb another day. We began rappelling. One after one, we were closer to the base. In the last rappel, my partner was the first to down. When he was in the middle of the 60 meters rappel I casually look to the knot. What I saw was the ropes sliding into the knot. Scared I put my hands, and try to stop the ropes sliding. Firmly, I put a Prussik Knot holding the two ropes and my partner arrive safely to the ground.
I don't know what happen, what was the reason. The Knott was well madding but the 8.5mm ropes were very wet.
For me this was very scared and after this, I and my friends never made this rappel knot again.
Last winter to Spanish Climbers died using this knot.
Maybe a will go try the Double Overhand Knot after reading your article.
Thanks to share your experience with all us.
Cheers
Miguel Grillohttp://
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j_ung
Jul 19, 2006, 1:31 PM
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Yikes! :shock:
Anybody have a pull tester to yank on a few wet EDKs? With various rope diameters? And different diameters?
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epoch
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Jul 19, 2006, 1:52 PM
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WOW!!
I would like to see the results of testing...
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j_ung
Jul 19, 2006, 2:01 PM
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I emailed sterlingjim to point this thread out. I'd love to hear what he has to say about this.
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justthemaid
Jul 19, 2006, 2:33 PM
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The results could be interesting.
Seems like there were some low temperatures involved too.
Should ask Miguel how new the ropes were. New ropes might slip-slide in a knot easier..
He states that they were cold and tired. It could be possible the knot was tied with an improper turn or the strands may not have been tightened down sufficiently.
Cudos to Miguel for his quick thinking, and I'm happy this turned out OK.
I've always been a fan of tying the second overhand for peace of mind anyhow.
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climbingnurse
Jul 19, 2006, 2:36 PM
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Testing has been done on wet EDKs. The data is available here:
http://www.xmission.com/~tmoyer/testing/EDK.html
Signed,
Someone who still believes the EDK is the best knot for rappelling
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reg
Jul 19, 2006, 2:45 PM
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In reply to: Miguel Grillo wrote: What I saw was the ropes sliding into the knot. and: Maybe a will go try the Double Overhand Knot after reading your article.
I know his use of the english is not perfect but he's not saying that the knot was rolling over itself - which is the prob with this knot - but that the ropes (pl) ie: tails - were sliding into the knot. there is something wrong with that where as the side of the knot with the rap lines being pulled away from each other at 180deg - the knot would roll before the tails would be sucked into the knot. maybe he ment that it was rolling. yikes is right!
for sure a backup overhand on top would have stopped this. given the tendency of this knot to roll and by it's very name (edk) I believe it should always be backed up. I was rapping off seneca once under the totaledge of a guide. when I wanted to back up the edk with another knot he said it was ok and not to touch it. I didn't - but I will never do that again.
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billl7
Jul 19, 2006, 2:56 PM
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Failure of the EDK by simple slippage seems odd.
This link (edit: same tmoyer link as posted by climbingnurse) indicates that a badly tied EDK has been seen to fail at 200 lbs. Don't know if badly tied means badly dressed, mis-tied, or just loose - nor whether any of these fail by other than rolling over.
Bill L
Edit: I see now. The badly tied overhand that failed at 200 pounds did so by rolling; the "badly tied" refers to "sloppy - crossing strands and loose" on 11 mm dynamic rope.
The data there also shows an 11mm dynamic and 8mm static joined with a well-tied overhand where the end pulled through the knot. Interestingly, the knot was soaked for ~5 minutes before testing; however, it failed at 1410 pounds in one test while many other like-tests resulted in a rolled failure at roughly similar forces.
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j_ung
Jul 19, 2006, 2:57 PM
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In reply to: Testing has been done on wet EDKs. The data is available here: http://www.xmission.com/~tmoyer/testing/EDK.html Signed, Someone who still believes the EDK is the best knot for rappelling
Well, there you go... might bode ill for Miguel's knot. Thanks, climbingnurse.
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billl7
Jul 19, 2006, 3:12 PM
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I'm only worried about the EDK if Miguel can say for sure that the knot was well-dressed with all 4 rope strands pulled tight.
I'll add that mistakes happen to all of us and so I'm considering a 2nd overhand as a back-up to the 1st; not committed to that yet though.
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justthemaid
Jul 19, 2006, 3:32 PM
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linked it for you
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philbox
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Jul 19, 2006, 10:09 PM
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In reply to: Following the post I received a LOT of e-mails from people too scared to post on here and get shot down, and many where as I expected from new climbers who just wanted to know ONE way that worked. Then yesterday I got an email from Miguel Grillo in Portugal (hey they may have beat us in the world cup but I'm man enough to respond) with an e-mail that was quite disturbing, so I've pasted it here for any one who's interested. Cheers Andy
Hi Andy,
Thanks for bringing this up. Great to get feedback on peoples attitudes towards posting on rc.com and in particular this forum.
I would like to point out to everyone that this forum is NOT to be used for flaming or trolling. Take that sort of behaviour to the community forum. This forum is for serious discussion only. If a beginner wishes to ask a serious question albeit a naive one then we owe it to that person to offer them a serious answer.
We should all use this forum from the point of view that the only stupid question is the unasked one. Sure it may be that the inevitable n00B!!111 comes in here and blunders around and may upset those who don't particularly like to repeatedly answer the same question over and over again. I certainly do not want this to turn into a beginners training forum.
We should certainly encourage a high level of intellectual thought put into both questions and answers. Any encouragement we give to the naive as to their seeming thoughtless question (or for that matter answer) should be well thought through before hitting the submit button.
Please be civil in your treatment of others in this forum.
Thank you all for the moment that you have taken to consider this request.
Phil...
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andykirkpatrick
Jul 19, 2006, 10:14 PM
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Well said!
It wasn't a criticism of this forum, I just think some people feel like a one to one approach makes them feel a little less exposed - even if in this case it ends up as the topic of discussion!
Thanks for taking the time for writing that though.
Andy
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philbox
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Jul 19, 2006, 10:27 PM
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Oh no, I didn't take it as criticism of this forum. I did however think it was worth ensuring that everyone was fairly clear as to the intent of the forum.
I definitely want to make sure that people such as yourself feel free to come here and speak you mind in an atmosphere that is at least civil. I'll be keeping watch over the forum from time to time to ensure a modicum of civility is maintained so that scholarly discourse may prevail.
This is about the encouragement of the free flowing of ideas and thought in a reasonably safe environment free from the normal internet wars, flamery and trollery. Certainly not wanting to offer any form of censorship here. Just wanting to keep the tards at bay.
Carry on all.
Phil...
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pindrvr75
Jul 20, 2006, 9:06 AM
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We might have missed something here. Is the EDK failing when exposed to the edge of a ledge, off a rap ring or when side loaded?
Given, an eight will fail if side loaded, but are we illustrating here that the EDK does the same or does it just roll over because of weight load regardless of circumstance even when both strands are sharing the load equally. It seems to me that a double overhand defeats the purpose of tying the overhand in the first place. One might as well use a 2x or 3x fishermans..same amount of bulk!
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heiko
Jul 20, 2006, 11:09 AM
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I am repeating a question that I asked already in similar threads:
When was the last time EVER, ANYWHERE, that climbers fell out of a rapell b/c their properly tied overhand failed :?:
I simply seem to get no answer.
(And don't get me started about unproperly tied knots. If you unproperly tie a not that represents the only protection against death, well...).
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csproul
Jul 20, 2006, 1:22 PM
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In reply to: (And don't get me started about unproperly tied knots. If you unproperly tie a not that represents the only protection against death, well...). |
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heiko
Jul 20, 2006, 1:42 PM
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tied, dressed... that's nitpicking. do it right and it will hold.
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dirtineye
Jul 20, 2006, 1:50 PM
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In reply to: tied, dressed... that's nitpicking. do it right and it will hold.
Yep.
And climbers never make mistakes either, so why worry about using a knot that is KNOWN to fail if you make a slight mistake?
You ought to know that most accidents require some bad luck and some mistakes, and it is downright STUPID to discount the possiblility of making mistakes while climbing.
Climbing hubris, complacency, poor logic-- thinking that because you have done something right 1000 times means that you will do it right on number 1001, when the REAL issue is, check nad recheck and be sure each time that you hvae done it right, THAT is how you keep from screwing up-- failing to pay attention to these things gets people killed.
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heiko
Jul 20, 2006, 2:00 PM
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Would anyone blame the figure eight after decking because he didn't tie in properly??? I don't get it guys.
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csproul
Jul 20, 2006, 2:10 PM
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In reply to: Would anyone blame the figure eight after decking because he didn't tie in properly??? I don't get it guys. |
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paulraphael
Jul 21, 2006, 11:26 PM
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The flat overhand knot isn't a perfect rap knot, because it's unusually sensitive to being tied wrong. Yes, it's our responsibility to do things right and to check ourselves, but a big part of safety is adopting procedures that discourage mistakes and minimize their consequences. The flat overhand requires more vigilance than just about any other knot we use in climbing.
That being said, I still think it's the BEST knot to use in most circumstances. It may be flawed, but I think its flaws are less harmful than the flaws of all the current alternatives. including the one proposed here.
It's up to you and your partners to have a routine--tie it, dress it, tighten it, check it, maybe double check it. It's a fast enough knot to tie that even with all the anal retentiveness you'll probably save time compared with a double fishermans or a backed-up figure 8.
The main reason the single overhand is so good is that it is so resistant to hanging up when you pull it. A hung rope can be a life threatening EMERGENCY on long routes, especially in an alpine setting. The main worries with this knot have to do with its performance with wet, icy, and radically different sized ropes--unfortunately, these are most likely to be issues on long route in alpine type settings. The same places you really don't want your rope to get stuck.
I have no idea why the original poster had that scary experience. I do know that the overhand knot has been tested to death in almost every type of combination of ropes, well tied, badly tied, wet, and icy. It seems to hold up.
If I was truly worried about the knot failing more than I was worried about the rope getting stuck, I'd probably use one of the proposed (and well tested) Edelrid knots, like the inline double fisherman's. Not as easy to tie, but bombproof. For what it's worth, I've never felt the need to do this.
When interpreting tests like the ones at http://www.xmission.com/~tmoyer/testing/EDK.html, keep in mind that the knotted strand is one of the two strands of rope, so the knot takes HALF of the load. Even in their worst case scenarios--with a loose, sloppy overhand knot, the knot didn't capsize until 200 pounds. It would take 400+ pounds of load on the pair of rope strands to generate this load on the knot. Even so, with the tails long enough, even the worst variations of the knot finally failed at over 2000 pounds. You'd need to hang over 4000 pounds on the pair of strands to generate this.
Again, if you use these knots, practice tying them. Leave 18" tails. People argue about how long they have to be ... just make sure they're long. And methodically tighten them on all 4 strands and check them. It's a drag, but it's actually fast, and it's a knot you can learn to tie in the dark with cold, tired hands pretty easily.
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paulraphael
Jul 22, 2006, 6:23 PM
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Don't bet your life on hombaked tests like mine. But you might want to repeat something like it yourself, just for some firsthand perspective.
I tied two ropes together with a traditional EDK, and hung them as a single strand from a ceiling anchor. The ropes were an old 10mm Beal rope that I no longer lead on, and a 6mm static accessory cord, of the type big-balled alpinists might use as a trail line. Both ropes were soaked in water (but not frozen). The EDK was tied with 18" tails, well dressed, and tightened on all four strands with a quick tug.
I then clipped my harness in below the knot and bounced my full bodyweight (about 180 lbs) several times.
I have no idea what the peak forces were, but I'm convinced I put much more load on the knot than I ever have during a rappel. All the load was on a single strand. And I've never had such a hard time untying the knots! even the butterfly knot I used to clip in with needed to be untied with pliers.
Anyway, I was happy, and a bit surprised, that the EDK did not budge. It didn't capsize or slip even once. It simply welded itself into a mass that I'd hate to have to untie with cold hands at a hanging belay. So it's a good thing that in real life I don't put loads anywhere near this on my rap knots.
What does a test like this prove? Nothing in absolute terms. But it's worth trying for peace of mind, especially if you try it with samples of the actual ropes you use in the mountains. See for yourself how the different ones work together ... and how they do when wet, frozen, loosely tied, etc.
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