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USnavy
Sep 12, 2011, 10:02 AM
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So lately I have been told by an increasingly large number of people that tying the Yosemite finish AKA sport knot can cause the figure eight to fail. Apparently if something catches through the tie off loop, the whole knot will fail. Does anyone know anything about this? One dude in Yosemite fliped out on me swearing I was putting myself in serious danger. I have been using that tieoff for years, 2000+ falls later it still holds, every time. Its just a complete B to untie if you take a whipper on it.
(This post was edited by USnavy on Sep 12, 2011, 10:04 AM)
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JimTitt
Sep 12, 2011, 10:57 AM
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If you load the across the loop the knot will flip, after one or two flips the rope end is free to slip through.
Since with a normal 8 this also occurs and both tie-in methods are used by countless people every day without incident this is perhaps merely a theoretical consideration, this "thing" that catches the loop probably having killed you anyway. A real death knot is to tie two ab ropes with an 8 and tuck both ends back!
Use a re-threaded bowline on the bight, you know it makes sense!
Jim
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notapplicable
Sep 12, 2011, 1:08 PM
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Someone was trying to tell me that a few months back but they could never really explain the mode of failure or demonstrate it. It was one of those, "I heard it from somebody who heard it from somebody" type of situations.
While I suppose a figure-8 knot could roll and untie, I doubt that one ever has or ever will.
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sungam
Sep 12, 2011, 1:31 PM
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I am seriously not seeing the method of failure here. You mean the loop that is made by the section of rope that would usually go between the 8 and the back-up knot, but is instead tucked back in?
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JimTitt
Sep 12, 2011, 1:59 PM
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Naw, that´s USNavy´s command of English! I assumed he means if you cross load the tie-in loop you formed through your harness points, possibly!
Jim
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sungam
Sep 12, 2011, 2:22 PM
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Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess.
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sungam
Sep 12, 2011, 6:50 PM
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So having rope tucked into that bend actually makes it roll at a lower force?
Edit: Just to note, I can't look at the file right now.
(This post was edited by sungam on Sep 12, 2011, 6:53 PM)
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carabiner96
Sep 12, 2011, 7:07 PM
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2,000 falls later????
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iknowfear
Sep 12, 2011, 7:10 PM
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sungam wrote: So having rope tucked into that bend actually makes it roll at a lower force? Edit: Just to note, I can't look at the file right now.
yep, thats what mammut research says...
file is in german anyway.
(This post was edited by iknowfear on Sep 12, 2011, 7:11 PM)
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tH1e-swiN1e
Sep 12, 2011, 7:49 PM
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A properly tied and tensioned figure eight, with any reasonable amount of tail, needs no back up. Only thing that an overhand or a finish knot on the tail of the rope does is take up the extra slack. Nice thing about a Yosemite finish is that if you're weighting the rope a bunch (ie falling), makes the figure eight easier to untie.
A figure eight on a bight just doesn't either come untied on its own, or fail under a load by the tail end of the rope pulling through. Which is why its the recommended knot for tying in.
I think there's been a ton of testing through the years on this knot. I seem to recall, that even if you didn't finish following through completely (miss the last pass through), the knot still functions (though at a further reduced strength).
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sungam
Sep 12, 2011, 7:59 PM
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We are talking about circle loading, such as when a flat fig 8 is used to connect to rap ropes or when you attach to the anchor with a carabiner clipped through your loop of rope instead of into your belay loop.
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Diphthong
Sep 12, 2011, 8:00 PM
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This diagram, particularly steps 2 to 3, reminds me of the internet meme:
1) Tie figure eight
2) ...
3) Profit!
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Capture.JPG
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Gmburns2000
Sep 12, 2011, 8:04 PM
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iknowfear wrote: sungam wrote: Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess. look here:  The gist: Fig 2: Knot opens at 20!!! kg. Fig 3: Ring-force only holds up to 160kg. So if you clip your PAS only into your rope ring you are considerably lowering the margin of safety! Source: http://www.bergundsteigen.at/...krautundruabn%29.pdf Edited to add: The swiss alpine club now strongly advises against backthreading the fig-8 in any circumstances.
So, there's a problem using it when tying two knots together (i.e. - instead of the EDK or triple fisherman's), but what about when tying in to the harness?
N/A - that was me who told you that a while ago when we met at the New. I had heard that the knot could untie if it wasn't finished properly. We tried to roll it so that it would untie and we were successful, but it was damn hard to get it to actually roll and untie (as in, we had to get pretty physical with the knot to make it slip through). I still use the knot as a backup over the more common double-fisherman.
However, I was climbing with a guy here in brasil last weekend and he showed me how he ties it: instead of following the end back through the whole of the knot at the bottom, he followed it through the split of the lower two loops.
Sorry if that's not a good visualization, maybe I can get a pic later on to show what I mean. Either way, using my faint ability in Portuguese, he said it was "mais seguro," which I interpreted as being "safer." The dude does mountain rescue here, so he's pretty knowledgeable, but I've always been curious if anyone could show, in a photo or video, a step-by-step action of how this could be tied incorrectly (on the harness), and the consequences (and a photo of the correct way to tie it, if one exists).
I've never been able to find anyone who can substantiate how this can fail (again, on the harness only). I've only ever found people who have said that it can, and that list includes myself.
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happiegrrrl
Sep 12, 2011, 8:34 PM
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i think this thread could use the Voice of Reason... RGold, you out there?
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iknowfear
Sep 12, 2011, 8:42 PM
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Gmburns2000 wrote: iknowfear wrote: sungam wrote: Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess. look here:  The gist: Fig 2: Knot opens at 20!!! kg. Fig 3: Ring-force only holds up to 160kg. So if you clip your PAS only into your rope ring you are considerably lowering the margin of safety! Source: http://www.bergundsteigen.at/...krautundruabn%29.pdf Edited to add: The swiss alpine club now strongly advises against backthreading the fig-8 in any circumstances. So, there's a problem using it when tying two knots together (i.e. - instead of the EDK or triple fisherman's), but what about when tying in to the harness?
[..]
I've never been able to find anyone who can substantiate how this can fail (again, on the harness only). I've only ever found people who have said that it can, and that list includes myself.
Look closely at figure 3! (actually the fourth image) According to tests done by mammut the ring holding power is reduced to 160 kg. Thats the failure mode, not "normal" operations (like falling).
(This post was edited by iknowfear on Sep 12, 2011, 8:43 PM)
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patto
Sep 12, 2011, 8:48 PM
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happiegrrrl wrote: i think this thread could use the Voice of Reason... RGold, you out there?
Reason?
A figure-8 is dangerously close to rolling failure if the two loaded strands come out of the knot at the same end.
This should be known. This is why using a figure-8 on a bight for joining rap ropes can and has lead to deaths.
Tuck away finishes increase the 'rollability' of the knot.
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Gmburns2000
Sep 12, 2011, 9:14 PM
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iknowfear wrote: Gmburns2000 wrote: iknowfear wrote: sungam wrote: Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess. look here: The gist: Fig 2: Knot opens at 20!!! kg. Fig 3: Ring-force only holds up to 160kg. So if you clip your PAS only into your rope ring you are considerably lowering the margin of safety! Source: http://www.bergundsteigen.at/...krautundruabn%29.pdf Edited to add: The swiss alpine club now strongly advises against backthreading the fig-8 in any circumstances. So, there's a problem using it when tying two knots together (i.e. - instead of the EDK or triple fisherman's), but what about when tying in to the harness?
[..]
I've never been able to find anyone who can substantiate how this can fail (again, on the harness only). I've only ever found people who have said that it can, and that list includes myself. Look closely at figure 3! (actually the fourth image) According to tests done by mammut the ring holding power is reduced to 160 kg. Thats the failure mode, not "normal" operations (like falling).
Yeah, ok, I see that, but honestly, I would hardly ever clip in to that end of the knot. If I did then I'd be clipping into the belay loop and, by chance or convenience, clipped that end of the knot at the same time.
What about clipping on the other end (the end going to the belayor)?
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timstich
Sep 12, 2011, 11:44 PM
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Sweet Jebus you damned Euros! Stop using a figure 8 to tie your two ropes together and go back to the EURO DEATH KNOTT aka overhand knot.
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rockforlife
Sep 13, 2011, 4:06 AM
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OK i have seen a video on this I will try and find it.
The knot that failed was NOT the Yosemite finish, it was just randomly tucking it back through.
If do the REAL Yosemite finish, from what i have seen and tried, it will not just fall apart like the other "finish".
Cant find the video, its on youtube somewhere, on the video they just tuck the end in, with out the wrap around the back of the knot. when they pull it flips kind of easily.
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jt512
Sep 13, 2011, 4:10 AM
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iknowfear wrote: sungam wrote: Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess. look here: [image]http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=5958; [/image] The gist: Fig 2: Knot opens at 20!!! kg. Fig 3: Ring-force only holds up to 160kg. So if you clip your PAS only into your rope ring you are considerably lowering the margin of safety! Source: http://www.bergundsteigen.at/...krautundruabn%29.pdf Edited to add: The swiss alpine club now strongly advises against backthreading the fig-8 in any circumstances.
The figure-8 version of the EDK is a death knot even without tucking back the tails. It has already been shown to be too weak for joining rappel ropes and has been reported to have caused at least one fatal rappel accident.
Jay
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blueeyedclimber
Sep 13, 2011, 2:01 PM
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JimTitt wrote: Naw, that´s USNavy´s command of English! I assumed he means if you cross load the tie-in loop you formed through your harness points, possibly! Jim
No, that's not what I believe he meant, because I have heard something like that as well. I am pretty sure he means the tail that is tucked in, if it catches on something, it could compromise the knot.
Like, someone else mentioned, whoever said it to me also could not duplicate it or remember exactly how it works. I believe I do the figure 9, not the Yosemite finish.
Josh
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damienclimber
Sep 13, 2011, 9:00 PM
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jt512 wrote: iknowfear wrote: sungam wrote: Oh, I see. So the knot rolling goes over the end faster since the tail is tucked through. Huh. Kinda makes sense, I guess. look here: [image]http://www.rockclimbing.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=5958; [/image] The gist: Fig 2: Knot opens at 20!!! kg. Fig 3: Ring-force only holds up to 160kg. So if you clip your PAS only into your rope ring you are considerably lowering the margin of safety! Source: http://www.bergundsteigen.at/...krautundruabn%29.pdf Edited to add: The swiss alpine club now strongly advises against backthreading the fig-8 in any circumstances. The figure-8 version of the EDK is a death knot even without tucking back the tails. It has already been shown to be too weak for joining rappel ropes and has been reported to have caused at least one fatal rappel accident. Jay
rappeling used to be so ez. 
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wonderwoman
Sep 13, 2011, 9:10 PM
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rockforlife wrote: If do the REAL Yosemite finish, from what i have seen and tried, it will not just fall apart like the other "finish".
Perhaps the other "finish" knot is really and UNfinished knot?
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