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styndall
Nov 13, 2005, 11:27 PM
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I've been playing around with a 10.5 dynamic rope and some 7 mm cord, and both an EDK and a double fisherman's seem solid when I tugged.
Which of these is most appropriate and strongest? Is there some better knot for joining?
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sypher2049
Nov 13, 2005, 11:39 PM
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I have been taught not to ever join two different size diameters of rope.
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veganboyjosh
Nov 13, 2005, 11:49 PM
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In reply to: I have been taught not to ever join two different size diameters of rope.
i dunno who taught you this, but people have been joining different size ropes for about as long as there has been rope.
in case you were joking, um...awesome...
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climbingnurse
Nov 13, 2005, 11:53 PM
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Well... I think it's safe to say that sypher is none too experienced. But seriously, I've been wondering the same thing. I always end up using the fisherman's when joining a rap line to my climbing line, but I'd be psyched if someone could tell me that I'd be perfectly safe using the EDK.
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sypher2049
Nov 13, 2005, 11:57 PM
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OK I feel like an idiot, but thats what I was taught. I didnt understand why, but I went with it and never done it.
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jv
Nov 14, 2005, 12:01 AM
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You could wade through the several threads below to learn that the EDK and Double Fisherman both work for joining your two ropes. But the DF is harder to untie after it has been weighted. Whichever you use, make sure you dress the knot well and inspect it at each rap.
One knot that has proven to be lethal is a bastardization of the EDK where you tie a figure 8 instead of an overhand. It rolls at very low loads.
JV
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handtraverse
Nov 14, 2005, 2:04 AM
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styndall....yup, those who said it so far are correct...using the fisherman's knot is THE knot for joining 2 ropes of differing diameters. I use it all the time for a variety of situations....just be careful to the extent your willing to push it's limits. Remember always...safety first!! :wink:
http://www.fauxandwood.com/lynnandtom2.JPG
Handtraverse
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"Mountains are not fair or unfair - they are just dangerous." - Reinhold Messner
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overlord
Nov 14, 2005, 6:55 AM
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id go with double fisherman. easy to tie and easy to inspect.
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jv
Nov 14, 2005, 5:59 PM
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I used to use the DF because that's the way I learned to join any two climbing lines. After rapping Chrimson Chrysalis with a 10 and a 7 joined by an EDK, I now go with the EDK all the time because it is so much easier to untie than a DF that's been weighted.
I don't know why people are so reluctant to adopt the EDK. Maybe it's the unfortunate acronym it has come to be known by. Maybe people think that such a simple knot can't possibly be safe.
JV
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qtm
Nov 14, 2005, 7:07 PM
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The EDK has two advantages; it's asymmetric, and thus does not lie flat and doesn't get caught up in things. Second it's much easier to untie. The DF is a much more secure knot, and really, you know how secure it is after you've rapped off one and then struggle to untie it.
Here's a site with some good info.
http://www.needlesports.com/advice/abseilknots.htm
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jv
Nov 14, 2005, 7:34 PM
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I forgot to mention the second advantage of the EDK, mentioned by a few above, that it is far less likely to become jammed than a DF. That's why we used it at Red Rocks. Found a quote from another thread that might give you some comfort:
"The overhand knot, used for joining two ropes for rappel, is reportedly in widespread use in Europe and has been for many years. It's certainly a commonly used knot in the states and has gained in popularity within the past decade. Rock and Ice magazine, George Bracksieck (7/11/97) states "The one-sided overhand knot (tails parallel and together) remains the best knot for rappelling, even with different diameter ropes. Be sure to leave plenty of tail and to set it snugly." Petzl catalogs show the overhand knot as suitable for joining two ropes for abseil. The American Mountain Guides Association (AMGA) Guides Manual , section 2.1 on Knots, diagrams the overhand as one used for tying two ends as a rappel knot."
JV
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pipsqueekspire
Nov 15, 2005, 5:56 AM
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In reply to: You know that you can join 2 ropes together in a water knot as you do slings? (yes, also known as a ringbend..this knot also provides a nice, smooth continuity). Then, on each side of the water knot I tie a triple fisherman's knot. An additional beauty of this knot system is that after it's been under load, it still unties easily.
Wow- This is a big knot! While this is a very safe knot it is very big and much more likely to get stuck in a crack. It is also very hard to tie and untie quickly when you need to take the ropes apart or put them back together. The EDK is the AMGA knot because it is fast, easy to untie, pulls easier and is good for diff. diameter ropes. EDK with long tails that the way to go.
-pip
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waynew
Nov 15, 2005, 4:46 PM
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qtm's reference is worth checking out - Thanks!
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jv
Nov 15, 2005, 6:45 PM
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In reply to: ...I don't know, it still sounds a little "shaky" to me...why else then recommend long tails.
The safety advantage of the EDK will become clear to you next time your DF jams when you are still several raps from the ground.
JV
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qulith
Nov 15, 2005, 7:33 PM
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In reply to: I learned this knot arrangement from a seasoned climber, except he started out with a square knot. But I don't like to use a square knot in this case because I feel that the rope is stressed by the stretching nature of the square knot as opposed to the "compacting" affect produce by the water knot.
It should be noted that in general a square knot should NOT be used in climbing. This knot is meant to be used in rigging sails. It is not secure and can easily become untied.
Try this:
1. Tie the square knot.
2. Tension the knot.
3. Now take one of the tails and pass it back over the knot.
4. Watch the knot slip.
In handtraverse's description this will not happen because the ends are tied and kept from crossing back over the knot, but when ever I see someone mention a square knot in a climbing situation I cringe.
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asandh
Nov 15, 2005, 7:47 PM
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:)
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sspssp
Nov 15, 2005, 8:26 PM
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I once got in a discussion of this with a certified guide (for whatever that's worth 8^)) . His suggestion which seemed reasonable, since you usually tie the EDK with long tails. After tieing the ropes with the EDK, he takes the long tail on the skinnier cord, and ties a double fisherman backup. The ropes are joined with the EDK, but the skinny cord has an extra knot, just like you are taught to tie a double fisherman to backup you figure 8 when tieing into your harness. The double fisherman isn't weighted and since you are only doing this for the skinny cord, the final knot still have a pretty low profile (as far as pulling and getting it stuck goes).
One comment on really long tailes on the EDK. When you go to rap, make sure you feed correct lines into your rap device. I know it sounds dumb, but with the extreme length of tails I see some people tie, it is probably only a matter of time before somebody(s) is going to bite it by feeding one of the tails into their rap device.
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justen
Nov 15, 2005, 10:08 PM
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One of the best knots in GENERAL to join differing diam. ropes is the sheet bend, which is really a version of the bowline. Especially if you tie it with 2-3 turns on the smaller rope (analogous to the two bends in the mountaineering bowline).
No comment on how well/poorly it performs concerning jamming when pulling ropes. I would say that it is more symmetrical than asymmetric.
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styndall
Nov 15, 2005, 10:36 PM
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In reply to: One of the best knots in GENERAL to join differing diam. ropes is the sheet bend, which is really a version of the bowline. Especially if you tie it with 2-3 turns on the smaller rope (analogous to the two bends in the mountaineering bowline). No comment on how well/poorly it performs concerning jamming when pulling ropes. I would say that it is more symmetrical than asymmetric.
It only takes me about 15 seconds worth of bouncing on a regular sheet bend for the knot to come entirely undone. The double seems a bit stronger, but still loosens and pulls readily with some jouncing. This is a knot I would NEVER rap on.
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handtraverse
Nov 16, 2005, 2:40 AM
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First, let's keep in mind that the original question posted here was regarding tying ropes of different diameters together. The EDK is only OK for ropes of EQUAL or NEAR EQUAL DIAMETERS!
qulith wrote: In reply to: It should be noted that in general a square knot should NOT be used in climbing. This knot is meant to be used in rigging sails. It is not secure and can easily become untied.
I agree with you and I was not suggesting the use of a square knot...just in case anyone in the audience took it that way.
I, too, was surprised to see the square knot being used in the arrangement I mentioned earlier. I actually happened to be on the trail next to the cliffs when I spotted 3 guys, one by one of course, in a 175' free rap...not noobies by any means.
pipsqueekspire wrote: In reply to: Wow- This is a big knot! While this is a very safe knot it is very big and much more likely to get stuck in a crack. It is also very hard to tie and untie quickly when you need to take the ropes apart or put them back together.
Like I said, the knot is not difficult to untie after normal load. Eventhough it may seem a bit bulky, the mental comfort it provides when you're free rapping a hundred feet over the ground makes it worth the effort. Besides, I'm not usually in a hurry to tie or untie except for emergencies.
As far as getting the knot stuck on multi pitch raps...I never had a problem because I make sure the rope path is clear just to avoid that very dilema. In reality, no matter what kind of knot you use, they're all equally capable of getting caught in a crack. For that matter even a minor twist in the rope can snag in a crack! We probably all experienced that at one time or another. (I find the "hardest" part of a double rope rappell is PULLING the rope back down! :wink:)
What IS a problem, no matter what kind of knot you tie is to pull the wrong rope when retrieving it, and create a jam at the biner...then you're screwed!
Handtraverse
__________________________________________
"Mountains are not fair or unfair - they are just dangerous." - Reinhold Messner
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climboard
Nov 16, 2005, 3:08 PM
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In reply to: First, let's keep in mind that the original question posted here was regarding tying ropes of different diameters together. The EDK is only OK for ropes of EQUAL or NEAR EQUAL DIAMETERS..
If you read the earlier posts you would see we were referring to ropes of different diameters. The EDK is fine for this application. There are some very helpful links in earlier posts that discuss this.
In reply to: As far as getting the knot stuck on multi pitch raps...I never had a problem because I make sure the rope path is clear just to avoid that very dilema. In reality, no matter what kind of knot you use, they're all equally capable of getting caught in a crack. For that matter even a minor twist in the rope can snag in a crack! We probably all experienced that at one time or another. (I find the "hardest" part of a double rope rappell is PULLING the rope back down! :wink:) What IS a problem, no matter what kind of knot you tie is to pull the wrong rope when retrieving it, and create a jam at the biner...then you're screwed! Handtraverse
All knots are not equal when it comes to getting hung up. It's chances are dependent on the size and shape of the knot. Many people have found through experience that the EDK is less likely to snag on something than most knots, especially the Double Fishermen's. This isn't a big deal on smaller routes but it can be a huge deal on longer routes.
__________________________________________
"Mountains are not fair or unfair - they are just dangerous." - Reinhold Messner
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knudenoggin
Nov 28, 2005, 7:21 PM
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In reply to: First, let's keep in mind that the original question posted here was regarding tying ropes of different diameters together. The EDK is only OK for ropes of EQUAL or NEAR EQUAL DIAMETERS!
(like the Sheet Bend), it might in fact be more appropriate for unequal ropes
(differing in dia. or flexibility, e.g.). And this implies that one should orient
unequal ropes to take advantage of the asymmetry: "The smaller or more
supple rope [should] on the bottom." [The Outdoor Knots Book, Clyde Soles]
With reference to the www.needlesports.com/advice/abseilknots.htm image
of what they call "Overhand knot" (and then, unfortunately, go on to give yet another
meaning to "Dbl.Oh.Knot" :roll: ), their yellow rope is in this "bottom" position.
And in setting the knot as shown, the left hand should hold it such that the index
finger lies between the yellow & blue ends, and then pull the yellow rope
towards oneself, the blue just off to the side (this sets the ends farthest against
the draw that the loaded parts will put on them).
For greater security against the knot rolling (which many tests & useage show
to not occur until force well in excess of what abseiling generates), one can
make a full turn/wrap with the "bottom" (here, yellow) rope before tucking
its end out through the knot body; this will make a much surer choke
of the loaded lines at the entry point. And, again, this is better done with the
more flexible or thin rope (which will be harder to roll up around the thicker
one, or will better tighten than a stiffer one).
In reply to: I, too, was surprised to see the square knot being used ...
There, it becomes asymmetric (unlike in rope), in the form regularly seen when
"girth hitching" (boo--bad term!) webbing slings/loops together. I've not seen
any test data for such a bend, but it does seem secure (to my surprise).
For ropes, others have used the Thief--Square but loaded on dia. opposite ends--
in this mid-knot position, so that the Dble.Overhands (Strangles) would slide
up and abutt the center knot to better lock (and the Thief is even easier
to untie than the Square/Reef). But these are large structures, as noted.
*knudeNoggin*
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jimfix
Nov 28, 2005, 8:05 PM
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In reply to: One of the best knots in GENERAL to join differing diam. ropes is the sheet bend, which is really a version of the bowline. Especially if you tie it with 2-3 turns on the smaller rope (analogous to the two bends in the mountaineering bowline). No comment on how well/poorly it performs concerning jamming when pulling ropes. I would say that it is more symmetrical than asymmetric.
At least someone knows what their talking about. A sheet bend (with backup hitchs) is the best method for different diameter ropes.
http://www.tollesburysc.co.uk/Knots/Sheet_bend.htm
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