rappel with butterfly knot??????

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whitemeat

Big Wall climber
San Luis Obispo, CA
Topic Author's Original Post - Dec 8, 2013 - 05:11pm PT
so it has crossed my mind that the butterfly knot transfers energy really well and for is low key and stays upright when rappeling much like the euro death knot. so for double rope reppels is it safe to use this knot to join 2 ropes??????

the butterfly knot used to tie 2 ends togeather
the butterfly knot used to tie 2 ends togeather
Credit: whitemeat

I know I am going to die but has anyone used this???
WyoRockMan

climber
Flank of the Big Horns
Dec 8, 2013 - 06:08pm PT
http://www.supertopo.com/climbing/thread.php?topic_id=1256717
Malemute

Ice climber
the ghost
Dec 8, 2013 - 06:35pm PT
the Double Overhand Bend, DOB
Credit: Malemute
faster than the butterfly
flat like the EDK
shorter tails than the EDK
safer than the EDK
ontheedgeandscaredtodeath

Social climber
SLO, Ca
Dec 8, 2013 - 07:08pm PT
Dunno, but I wouldn't do it cause I don't like having to remember how to tie too many different knots. Also, people have been rapping for 100+ years or whatever and no body really seems to ever have concluded the butterfly is the way to go.

If the pull is bad have the last guy move the knot beyond the catchy looking edge. I think it's an issue people worry more about than an actual problem. Every rap epic I've ever had involved a caught tail, not a knot.
Q- Ball

Mountain climber
where the wind always blows
Dec 8, 2013 - 08:52pm PT
I trust a Zeppelin Bend much more. Very easy to tie and untie but virtually unknown, even to Ashley (bible of knots dude)
-Q
pyro

Big Wall climber
Calabasas
Dec 9, 2013 - 01:35am PT
I rapped from el caps nose sickle with it seems scary...
rgold

Trad climber
Poughkeepsie, NY
Dec 9, 2013 - 08:31am PT
It is probably ok in terms of security; this is the knot usually recommended for tying off core shots. I would want longer tails than in the picture. But it will not roll over edges and obstructions the way the EDK and other "flat" variations do and so will be a somewhat inferior choice for featured rock.

There doesn't seem to me to be any good reason to use the butterfly, however. If you want a knot that unties easily but is more stable than the EDK, the good ol' once-popular square knot backed up with a double fisherman's is the way to go. If you want unquestioned stability and aren't concerned about difficulty of untying, the double fisherman's is best. And if you want reduced pull-down resistance and less liklihood of hanging on featured rock, then the EDK is the choice.

I think the EDK has pretty much won the contest, except possibly in rescue situations when high intermittent loads and/or wet ropes are involved.
Scole

Trad climber
Joshua Tree
Dec 9, 2013 - 09:51am PT
Why?
Morgan

Trad climber
East Coast
Dec 9, 2013 - 11:59am PT
More likely to catch on stuff and maybe easier to come undone. Those don't sound like pluses to me. The only situation where it seems like it would work well for rappelling is when you are using a small diameter rap pull down cord and don't want the main rope to slip through the ring. In that case you end up with a loop (for a locking carabiner back to the main rope) and a separate knot joining the main rope and the pull-down rope.
ionlyski

Trad climber
Kalispell, Montana
Dec 9, 2013 - 12:43pm PT
Rgold, do you have a statement about the double EDK shown above? Seems like another candidate for a winner.

Arne
j-tree

Big Wall climber
Classroom to crag to summer camp
Dec 9, 2013 - 11:25pm PT
If I'm worried about the pull, then I'll use an EDK... but otherwise,

I almost always use an alpine butterfly to isolate a double fisherman for my fixed lines and raps. The main reason is that the doublefisherman is a bombproof connection but the butterfly allows it to never get weighted, thus everything is bomber but super easy to untie.

(This is also my go to knot for connecting the lead line to the haul line when aid soloing in the "continuos loop" method.)

Here's what the knot looks like:
best way to connect two ropes for a fixed line.
best way to connect two ropes for a fixed line.
Credit: Climbing Tech Tips

When you're tying it, the easiest way is to use the "tie in your hand" method and place the double fisherman's knot inot the middle strand. (where the space between the two ropes is on the following picture:
Credit: http://www.southee.com/

Then you finish tying it like the following diagram shows:
http://www.southee.com/Knots/Knots_SingleLoops.htm
http://www.southee.com/Knots/Knots_SingleLoops.htm
Credit: http://www.southee.com/Knots/Knots_SingleLoops.htm
rgold

Trad climber
Poughkeepsie, NY
Dec 9, 2013 - 11:57pm PT
Rgold, do you have a statement about the double EDK shown above? Seems like another candidate for a winner.

There seem to be several options for people who don't trust the EDK (although there doesn't really seem to be any basis for this mistrust).

The Double EDK pictured is very bulky, and the weight of it will tend to make the knot flop sideways and so not perform as well sliding over edges. There is another version, apparently popular in the UK, in which one simply ties two overhand knots rather than one, which seems preferable to me although it has some of the same downsides as the knot pictured above.

Personally, I wouldn't go anywhere near the double EDK without having seen some good testing data. The reason is that, as we have seen with the catastrophic flat figure-eight, knots that seem intuitively stable can exhibit some potentially fatal rolling capability, and if a big knot does roll, it will eat up a lot of tail along the way.

If a backup is needed, for example for soaking wet ropes (in which the EDK rolls more easily) and for ropes of unequal diameter, I think a single overhand backup in one strand, pictured below for ropes of unequal diameter, is superior because the total knot is much more compact and the single backup still chokes off rolling. The catch is that you have to know which strand to tie off.

EDK in different diameter ropes---secured
EDK in different diameter ropes---secured
Credit: rgold

EDK in different diameter ropes---incorrect way
EDK in different diameter ropes---incorrect way
Credit: rgold

EDK in different diameter ropes---correct way
EDK in different diameter ropes---correct way
Credit: rgold

The butterfly-fisherman's combination is good for fixed lines but is a stuck-rope nightmare waiting to happen for rappels on featured rock. That loop is gonna lasso every flake and spike it encounters...
Reilly

Mountain climber
The Other Monrovia- CA
Dec 10, 2013 - 12:51am PT
Being originally of a nautical bent I always tied ropes of differing diameters with a sheet bend -
easy to undo and, obviously, safe. And I did so rather frequently.
Ed Hartouni

Trad climber
Livermore, CA
Dec 10, 2013 - 01:43am PT
good advice, I'll just add another consideration: familiarity... I have my partners check the knot before we rap on it, that assumes that the partner knows what the knot is supposed to look like when tied correctly, and can spot a knot that isn't...

using an unfamiliar knot makes the partner check pointless

I use the double fishermen's when I'm not worried about the pull, and I've started using the EDK in situations where the pull might be an issue

probably the only two knots I tie for rapping in the last 40 years.
but that's just me
rgold

Trad climber
Poughkeepsie, NY
Dec 10, 2013 - 07:54am PT
Being originally of a nautical bent I always tied ropes of differing diameters with a sheet bend -
easy to undo and, obviously, safe.

I've used a sheet bend too BITD, but I think it comes with cautions and so is not "obviously" safe. It is essentially a bowline and so, at least in the climbing context if not the nautical context, is subject to loosening under intermittent load, which can happen rappelling. I'd use a double sheet bend and make sure to back it up with a fisherman's knot, which makes the whole configuration analogous to the square knot backed up by the fisherman's, but better adapted to different diameters.
Curt

climber
Gold Canyon, AZ
Dec 10, 2013 - 09:23am PT
There seem to be several options for people who don't trust the EDK (although there doesn't really seem to be any basis for this mistrust).

Well, renaming the thing probably couldn't hurt...

Curt
Malemute

Ice climber
the ghost
Dec 10, 2013 - 09:31am PT
The Double EDK pictured is very bulky, and the weight of it will tend to make the knot flop sideways and so not perform as well sliding over edges.
This is false.

Personally, I wouldn't go anywhere near the double EDK without having seen some good testing data.
I'm still waiting for Kolin Powick to test it, but it isn't that onerous to try it out by rappeling with a belay.

I find it interesting that people use a variety of rappel knots, because of deficiencies.

These threads show up from time to time because the knots in current usage are lacking in some aspect.
EDK: needs long tails
figure 8 bend: will roll
figure 9 bend: slower to tie
double fisherman: not flat like the EDK
inline double figure 8: not flat like the EDK
EDK+EDK: slower to tie, 2nd knot could catch
square knot backed up with double fishermans: slow to tie, not flat like the EDK

Blakey

Trad climber
Sierra Vista
Dec 10, 2013 - 12:45pm PT
^^^^^^^^

Work has been done on this and isn't too hard to find.

http://www.needlesports.com/catalogue/content.aspx?con_id=75b7be92-45dd-474a-9229-9c9e00a60c7f
Malemute

Ice climber
the ghost
Dec 10, 2013 - 03:05pm PT
I was asked if there is any pull test data on the DOB.
There isn't.
But ... Tom Jones of Black Diamond tested the Fig 9 for me years ago.
The knots are different, but it shows the advantage of an extra wrap.
My Conclusions:
A. Figure 8 knot should be used with a backup knot.
B. Figure 9 knot is essentially a backed up figure 8.
C. Maybe I'll use a fig 9 next time.
Tom Jones
Black Diamond Equipment, Ltd.
http://www.fishproducts.com/tech/rope.html


Various rappel knots I have looked at:
Credit: Malemute
Credit: Malemute
Credit: Malemute
Obviously I have tied and untied them.
I've pull tested them in nylon string (for what it's worth).

The DOB is the best.
blahblah

Gym climber
Boulder
Dec 10, 2013 - 04:29pm PT
OK I tied Malamute's new knot and have to agree that it looks better than the traditional EDK, and is easy and quick to tie.
But until it's been pull tested with real climbing rope and vetted, I think I'll stick with EDK--there don't seem to be any real-world problems with a properly tied/dressed EDK, so if it ain't broke . . .
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