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a_scender
Feb 25, 2004, 8:10 PM
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what do you think the best rappel knot is for joining two ropes of the same size? I think the overhand has the least chance of becoming snagged, but should always be backed up. Maybe a figure eight instead?
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superdiamonddave
Feb 25, 2004, 8:15 PM
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I used to use the double fisherman's knot, but now I use the overhand knot because as you said, it has less of a chance of snagging. I always dress it well and make it real tight. I also leave at least 15 inches of tail in case it rolls, though it never has.
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davidji
Feb 25, 2004, 8:16 PM
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In reply to: what do you think the best rappel knot is for joining two ropes of the same size? I think the overhand has the least chance of becoming snagged, but should always be backed up. Maybe a figure eight instead?
T2.
My apologies if it was actually a serious question.
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wanlessrm
Feb 25, 2004, 9:06 PM
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Never a figure 8! = Death on Rappel
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oldsalt
Feb 25, 2004, 9:40 PM
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By an overhand knot, do you mean laying the two ends parallel to each other and tying a single overhand knot in the pair as if they were a single rope?
In Seamanship classes, I always taught to avoid the overhand. Of course, few dock lines experience 10 KN.
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superdiamonddave
Feb 25, 2004, 9:43 PM
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Oldsalt,
That is the exact way it is done. It seemed weird to me the first few times I used it, but it works great.
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vegastradguy
Feb 25, 2004, 9:46 PM
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oldsalt- yup. tie as one so the ends face the same way, with 10-12" of tail.
while not recommended for use in general climbing, this knot is acceptable for rappelling because it only needs to hold the weight of the climber (take into account bouncing on rappel and such)....but it doesnt need to hold high forces like a tie in point does. its primary advantages are: 1) doesnt snag and 2) is easy to untie. it is NOT recommended for joining ropes of different diameters.
this lovely little knot is referred to as the EDK (European Death Knot) because it looks dangerous, but strangely isnt.
i still use the fishermans. cant bring myself to rap on the thing. of course, with double lines, the fishermans is fairly small, so it doesnt snag like a single line will.
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skerry00
Feb 25, 2004, 9:48 PM
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I would agree that the overhand knot or "american death knot" is the best way to go, I didn't belive it until I used it in the Tetons on some rappels, it didn't snag a bit. Make sure you leave a good tail(I usually leave a foot and a half or so).
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skerry00
Feb 25, 2004, 9:50 PM
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Oh, I was told it was called the "american death knot", either way, it's a cool name
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oldsalt
Feb 25, 2004, 9:54 PM
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Dave,
Thanks, I've added it to my mental useful facts list.
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shakylegs
Feb 25, 2004, 10:12 PM
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oldsalt, you just need to get your rappel rope stuck once, and you'll easy be converted.
Oh, one thing no one has mentioned, and I had to learn the hard way: do not tie a back-up knot to the overhand. Chances are the back-up will catch on something.
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kman
Feb 25, 2004, 10:35 PM
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In reply to: In Seamanship classes, I always taught to avoid the overhand.
...Ayy but this is climbing, not sailing ya scurvey dog.
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northclimber
Feb 26, 2004, 5:13 AM
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The figure 8 also work well as long as you tie it so that the two end face opposite direction. back it up with a double fisherman on each side.
The good thing about this setup is that it is fine for rope of different diameter and it is easier to untie than the fisherman alone.
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mmckinney
Feb 26, 2004, 5:31 AM
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In reply to: I used to use the double fisherman's knot, but now I use the overhand knot because as you said, it has less of a chance of snagging. I always dress it well and make it real tight. I also leave at least 15 inches of tail in case it rolls, though it never has. |
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madmax
Feb 26, 2004, 11:44 PM
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Another vote for the overhand knot. For rapping its as strong as any other knot and way less likely to get stuck. Tying another knot to back it up just defeats the whole purpose of the overhand in the first place.
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sfclimber
Feb 27, 2004, 3:08 AM
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Great to see this topic come up.
The last time I was out climbing my partner (that I was climbing with for the first time) suggested rappelling off of this knot. Having never seen any information on this knot before, I refused and he graciously agreed to go with the more traditional grapevine knot.
After now seeing so many others comment on the knot I just did a quick google search on the knot too. Looking at the first few hits would seem to confirm the concensus on this thread that a well dressed overhand with long tail is a suitable rappel knot (though many of these articles recomend tying a second overhand as backup).
http://www.mountaineers.org/...nts/CN102_Knots.html
http://www.mountaineers.org/.../CN203_RapKnots.html
Accident using flat figure 8, concludes that overhand is superior.
http://www.rockandice.com/...s/accidents.127.html
Accident using overhand, inconclusive, many references to rangers, guides, etc. that use it for rappel
http://www.geocities.com/...es/stories/knot.html
Still don't know if I'll ever try it though. It just looks scarey!
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hammer_
Feb 27, 2004, 3:20 AM
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EDK no back up
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johnnord
Feb 27, 2004, 3:37 AM
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In reply to: Another vote for the overhand knot. For rapping its as strong as any other knot and way less likely to get stuck. Tying another knot to back it up just defeats the whole purpose of the overhand in the first place.
Let me also make a pitch (again, sorry for the pun) for dropping the word "safe" from our discussions. Climbing is risky, not safe. Our goal is to manage the risk. 100% is "safe." Unfortunately, 99.9999% is the best we can hope for.
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jonnyb
Feb 27, 2004, 6:03 PM
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Anyone ever used the 'figure 9' knot? I was shown it by a partner of mine. I won't try to explain how to tie it, but it sits up off the rock like the EDK, but won't roll over, and is the easiest thing to untie. I haven't been able to find any info on it online, though.
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sfclimber
Feb 27, 2004, 7:45 PM
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Here's an additional page of information including a set of 20 pull tests using a mixture of flat overhand, flat figure 8, and the standard grapevine.
http://www.xmission.com/...yer/testing/EDK.html
Results show that even when tied sloppy and using a soaking wet rope, the grapevine is by far the strongest.
However a well dressed, pretensioned (pulled separately on all 4 strands) overhand on a variety of rope brands and sizes didn't roll until 1400 lbs. or more for a rope that was not wet.
When the rope was wet the knot rolled at 950 lbs. in one test.
Dressing and pretensioning the rope is critical! A sloppy overhand, not well pretensioned, failed at as low as 200 lbs.
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johnnord
Feb 28, 2004, 12:20 AM
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Please correct me if I am mistaken (I'm sure on this forum someone will :wink: .) When we are talking about rollover on the overhand knot, it is not the same as failure. That's the reason for the long tails. The knot rollsover several times during testing, and each subsequent time at a higher weight. In other words, the knot becomes stronger with each rollover until the rope breaks at the knot at its normal breaking weight. So even the loose, undressed knot that rolls over at 200 lbs, will roll over the next time at a higher weight. Did I misread something?
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jt512
Feb 28, 2004, 12:28 AM
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In reply to: Here's an additional page of information including a set of 20 pull tests using a mixture of flat overhand, flat figure 8, and the standard grapevine. http://www.xmission.com/...yer/testing/EDK.html Results show that even when tied sloppy and using a soaking wet rope, the grapevine is by far the strongest. However a well dressed, pretensioned (pulled separately on all 4 strands) overhand on a variety of rope brands and sizes didn't roll until 1400 lbs. or more for a rope that was not wet. When the rope was wet the knot rolled at 950 lbs. in one test. Dressing and pretensioning the rope is critical! A sloppy overhand, not well pretensioned, failed at as low as 200 lbs.
No, the overhand not did not "fail" in any of the tests. When it was tied sloppily it rolled, but it tightens up as it rolls, and eventually the rope fails at the knot at an acceptably high load. In other words, what Johnnord said.
Of course you should still dress and pretension the knot.
-Jay
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vegastradguy
Feb 28, 2004, 12:31 AM
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the only time i've ever rapped off an EDK was the only time we had to jug the line to free the knot. so, while the fishermans is perhaps more likely, (although personally, i've never had it catch on me), the EDK is certainly not immune from catching.
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johnnord
Feb 28, 2004, 12:45 AM
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In reply to: the only time i've ever rapped off an EDK was the only time we had to jug the line to free the knot. so, while the fishermans is perhaps more likely, (although personally, i've never had it catch on me), the EDK is certainly not immune from catching. |
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