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mbg
Feb 28, 2004, 12:47 AM
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In reply to: Never a figure 8! = Death on Rappel
Really?? I'd say that's going a bit overboard. I've almost always used an 8 and have never heard of anyone having a problem until the R&I ref. Even sfclimber's reference to the knot's failure in Zion says that the knot is ok if dressed and tightened properly. Every climber knows how to tie a figure 8 (I hope!) so if one were to find themselves at the top of a doubble rap and not 100% sure of how to tie some of the other more obscure knots, I'd suggest going with what they know (properly dressed and tightened of course).
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johnnord
Feb 28, 2004, 1:51 AM
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As I read the data--
http://www.xmission.com/~tmoyer/testing/EDK.html
--there is nothing inherently wrong with the figure 8. It's strong enough. The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor.
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jt512
Mar 1, 2004, 6:10 PM
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In reply to: In reply to: Never a figure 8! = Death on Rappel Really?? I'd say that's going a bit overboard.
Yes, really. It's not going overboard.
In reply to: I've almost always used an 8 and have never heard of anyone having a problem until the R&I ref.
So what are you going to do, keep using a figure 8 until you do "have a problem"? What a brilliant idea.
In reply to: Even sfclimber's reference to the knot's failure in Zion says that the knot is ok if dressed and tightened properly. Every climber knows how to tie a figure 8 (I hope!) so if one were to find themselves at the top of a doubble rap and not 100% sure of how to tie some of the other more obscure knots, I'd suggest going with what they know (properly dressed and tightened of course).
The overhand knot is not obscure. And, in fact, it is easier to tie than a figure 8.
In reply to: As I read the data-- http://www.xmission.com/~tmoyer/testing/EDK.html --there is nothing inherently wrong with the figure 8. It's strong enough. The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor.
Speed? An overhand is quicker to tie than a figure 8. And when speed is important is exactly when a climber is most likely to make a mistake, and that is the problem with the flat figure 8. If you don't tie it perfectly it is a death knot. The overhand, on the other hand, allows for a greater margin of error.
Read the conclusions of the author of the pull tests:
"The flat-overhand is clearly better than the flat-figure-eight. The flat-eight is represented three-to-one in the accidents despite (to the best of my knowledge) many more climbers using the overhand. The flat-eight also starts flipping at a lower load (750 lbs vs 1400 lbs for well-tied, 110 lbs vs 200 lbs for badly tied) than the overhand, and it eats two to three times as much tail in each flip."
-Jay
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mustclimb69
Mar 1, 2004, 6:16 PM
Post #29 of 58
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Reef knot or square knot...then you can do the whole alpine butterfly thing for the safety loop...but usually just a reef knot and back it up with double overhands. if the route is slabby or has a high risk of getting cought then the overhand with super long tails.
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rrrADAM
Mar 1, 2004, 6:28 PM
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EDK (Euro Death Knot), also known as a simple overhand.
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dcclimb
Mar 1, 2004, 6:38 PM
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For ropes of the same diameter I use the EDK as well. As JT said it is quick, effective, easy, and safe.
For ropes of different diameters, the double fisherman.
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scotto
Mar 1, 2004, 6:42 PM
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out of curiosity - what would you use if you were joining say a 10.5 and a 10.2 - or a 10.5 and an 11.0???
would either of those be considered "the same size rope"
cause I have 3 ropes and none are the same size.
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sfclimber
Mar 1, 2004, 6:44 PM
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In reply to: In reply to: 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.
Actually, the knot will definatively fail at one of two points: rope failure, or knot rolls right off the ends of the tails (which may occur well below the breaking strength of the rope).
However, in the article quoted, the author states:
I do not think that there's an easy definition of the strength of the flat-knots. Most of the time, if the tails are long enough, the process of repeated flips stops at some point and the knot cinches tighter and then holds until the rope breaks. In my testing, this often happened just as the knot was about to run out of tail. Since this process is so uncertain, I regard the force at the first flip as the failure load for the knot. I have seen other test data published which simply lists the strength (force at rope-failure) of the flat-knots. I think this is extremely misleading.
So my usage of the term 'fail' within the context of the article was correct. Though, the reader should understand the author's definition of the term when considering the data.
Thanks to all for pointing out the ambiguity.
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madmax
Mar 1, 2004, 6:47 PM
Post #34 of 58
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[quote="scotto"]out of curiosity - what would you use if you were joining say a 10.5 and a 10.2 - or a 10.5 and an 11.0???
would either of those be considered "the same size rope"quote]
I think a 10.5 and a 10.2 a definitely safe to tie together using an overhand, and the 10.5 and 11 as well. The 10.2 is probably safe with the 11, but that's just a guess.
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mandrake
Mar 1, 2004, 7:13 PM
Post #35 of 58
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In reply to: For ropes of the same diameter I use the EDK as well. As JT said it is quick, effective, easy, and safe. For ropes of different diameters, the double fisherman.
I've seen this a couple of times in this thread, not to use the EDK with different diameter ropes. However, when looking at the Tom Moyer tests, the 8mm static and 11mm dynamic tied together with an overhand didn't roll until 950 (wet) to 1330 lbs. (dry). Why not use it for different diameter ropes?
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csoles
Mar 1, 2004, 7:28 PM
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In reply to: Why not use it for different diameter ropes?
Old myths die hard. The offset overhand bend (proper name) is fine with climbing ropes of different diameters.
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johnnord
Mar 3, 2004, 2:20 AM
Post #37 of 58
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In reply to: As I read the data-- http://www.xmission.com/~tmoyer/testing/EDK.html --there is nothing inherently wrong with the figure 8. It's strong enough. The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor.
Speed? An overhand is quicker to tie than a figure 8. And when speed is important is exactly when a climber is most likely to make a mistake, and that is the problem with the flat figure 8. If you don't tie it perfectly it is a death knot. The overhand, on the other hand, allows for a greater margin of error.
I am sorry that my meaning was not clear. I was arguing IN FAVOR OF THE OVERHAND (EDK) KNOT because of the speed factor. I thought the context was clear, but obviously not. jjt512 is exactly correct.
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johnnord
Mar 3, 2004, 2:21 AM
Post #38 of 58
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In reply to: As I read the data-- http://www.xmission.com/~tmoyer/testing/EDK.html --there is nothing inherently wrong with the figure 8. It's strong enough. The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor.
Speed? An overhand is quicker to tie than a figure 8. And when speed is important is exactly when a climber is most likely to make a mistake, and that is the problem with the flat figure 8. If you don't tie it perfectly it is a death knot. The overhand, on the other hand, allows for a greater margin of error.
I am sorry that my meaning was not clear. I was arguing IN FAVOR OF THE OVERHAND (EDK) KNOT because of the speed factor. I thought the context was clear, but obviously not. jjt512 is exactly correct.
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johnnord
Mar 3, 2004, 2:23 AM
Post #39 of 58
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In reply to: In reply to: As I read the data-- http://www.xmission.com/~tmoyer/testing/EDK.html --there is nothing inherently wrong with the figure 8. It's strong enough. The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor. Speed? An overhand is quicker to tie than a figure 8. And when speed is important is exactly when a climber is most likely to make a mistake, and that is the problem with the flat figure 8. If you don't tie it perfectly it is a death knot. The overhand, on the other hand, allows for a greater margin of error. I am sorry that my meaning was not clear. I was arguing IN FAVOR OF THE OVERHAND (EDK) KNOT because of the speed factor. I thought the context was clear, but obviously not. jjt512 is exactly correct.
This got all fouled up. The "Speed?" is jt512's. The apology is mine. Sorry twice. :oops:
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bullheadedmonkey
May 5, 2004, 4:16 AM
Post #40 of 58
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You do not want to use a overhand figure 8 where both tails are on one side. A friend of mind was likely killed because he used that knot 10 years ago. It was reported in the 1995 Accidents in NA moutaineering book. It was sad to read that more recent report about the death that was likely caused by the same mistake.
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iamn8seemewreck
May 5, 2004, 4:35 AM
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The double overhand knott is one that will work and is compatible with the standard. Quite possibly a barrell knot will work as well. A figure 8 is not one. If joining two ropes of different diameters then a sheith bend would be used.
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nonick
May 5, 2004, 5:34 AM
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This is from
http://www.thebmc.co.uk/safety/train/skill_4.htm
Joining two ropes
For a long abseil where it is necessary to join two ropes a reliable knot must be used. Probable the most reliable is the double fisherman’s knot, but this can become jammed after an abseil. An alternative is an overhand knot but make sure the ends of the knot are long (you only want it to undo easily after you have completed the abseil).
--------------
I read of a case where this guy used a fig 8 to tie two ropes. It wasn't a fig. 8 woven, he tied two ropes together like you would tie a fig. 8 (not woven in). Needless to say he died.
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cfnubbler
May 5, 2004, 1:26 PM
Post #43 of 58
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In reply to: The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor.
Less chance of the knot snagging, sure...
But an increase in speed and ease in untying??? This is a total non-issue. I don't know about you, but I tie and untie my rap knot once in a descent. The speed advantage of the EDK is in that sense so trivial as to be irrelevent.
-Nubbler
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brianinslc
May 5, 2004, 1:36 PM
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In reply to: In reply to: The issue is the potential for getting the knot caught when it is pulled...and speed and ease of untying. Sometimes, speed is an important risk management factor. Less chance of the knot snagging, sure... But an increase in speed and ease in untying??? This is a total non-issue. I don't know about you, but I tie and untie my rap knot once in a descent. The speed advantage of the EDK is in that sense so trivial as to be irrelevent.
I'd disagree. Anything that's KISS when you're tired, the weather is bad, its dark...
There's plenty of times when I rappel multiple times in a day when I untie and retie my rap lines. And, if you're bailin' off an alpine climb in a thunderstorm, sometimes even seconds count.
"Speed and ease" DO count for something.
Brian in SLC
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cfnubbler
May 5, 2004, 2:01 PM
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In reply to: Anything that's KISS when you're tired, the weather is bad, its dark...
Agreed, but I wasn't commenting on simplicity. IMHO, speed and ease of untying is not in and of itself a compelling reason to choose one rap knot over another.
Personally, I use the EDK, but certainly not for that reason...the reduced chance of a snag is where truly significant time might be saved.
-Nubbler
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keithlester
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May 7, 2004, 2:28 PM
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I use the double sheet-bend, I appear to be the only one.
I like it because it works with two ropes with different handling characteristics, lies neatly, will take a really heavy load without locking, and unties very easily
My regular climbing partners mostly use the overhand, but it is a little harder to untie after being weighted.
I'd be curious to know if anybody else uses the double sheet-bend, and what experiences they have had with it. :roll:
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keithlester
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May 7, 2004, 2:29 PM
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I use the double sheet-bend, I appear to be the only one.
I like it because it works with two ropes with different handling characteristics, lies neatly, will take a really heavy load without locking, and unties very easily
My regular climbing partners mostly use the overhand, but it is a little harder to untie after being weighted.
I'd be curious to know if anybody else uses the double sheet-bend, and what experiences they have had with it. :roll:
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oldsalt
May 7, 2004, 2:41 PM
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A slight twist to the discussion here:
Since learning that the Figure 8 Rappel Device (not the knot) is not as safe as an ATC, I have always used the ATC. I have only done single pitch raps, so the issue of joining ropes has not come up while outdoors.
What rappel device are people using with joined ropes?
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jt512
May 7, 2004, 3:33 PM
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In reply to: A slight twist to the discussion here: Since learning that the Figure 8 Rappel Device (not the knot) is not as safe as an ATC, I have always used the ATC. I have only done single pitch raps, so the issue of joining ropes has not come up while outdoors. What rappel device are people using with joined ropes?
The same device you'd use for a one-rope rappel.
-Jay
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