Author Topic: bend for connecting round cord to webbing  (Read 11353 times)

bcrowell

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bend for connecting round cord to webbing
« on: December 21, 2012, 11:26:22 PM »
An offset overhand bend is often used to join two climbing ropes for a long rappel. (It looks scary, but the advantage is supposed to be that, compared to other bends, the knot is less likely to get snagged when you pull the rope down.) When building climbing anchors with tubular webbing, you use a ring bend (water knot).

What would be a secure bend to use if you needed to join a piece of 14 mm webbing to a 9 mm climbing rope? Because the two pieces of rope are dissimilar, it worries me that a bend would fail. One option that occurs to me is to tie a rewoven figure-8 at the end of one rope, forming a loop, and then tie the other rope into this loop, also using a rewoven figure-8. This might be bulky, but at least each knot would be tied using a single material...?
« Last Edit: December 21, 2012, 11:27:07 PM by bcrowell »

SS369

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Re: bend for connecting round cord to webbing
« Reply #1 on: December 21, 2012, 11:41:30 PM »
Hi bcrowell.

Adopt a fishing line knot such as the Albright knot. Long, but not too bulky.
Using the Albright or any similar types I would tie a stopper in the end of the webbing, form a bight and wrap the rope around it tying it the way of the directions show.
There are many to pick from and try (experimentally at first of course).

What is the real (world) need here?

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bcrowell

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Re: bend for connecting round cord to webbing
« Reply #2 on: December 22, 2012, 12:10:46 AM »
the real (world) need here?

Thanks for the suggestions. The situation I'm envisioning is this. In the sport of canyoneering, you typically descend a canyon by rappelling, and once you do the first rappel, you can only go forward (down) not back up. One of the things that can go wrong is that you find your rope isn't long enough for a rappel, or you have a rope get stuck so that you can't pull it down after yourself. A possibility that can be used in such an emergency is that you can use webbing to replace some or all of your rope. (You're usually carrying webbing for building anchors.) To get enough length, it might be necessary to connect a piece of webbing to a piece of rope.

If I'm understanding correctly, the Albright is a sheet bend with a bunch of extra wraps of the thinner cord. This makes me a little uneasy, both because I've never heard of an Albright being used in climbing, and also because it seems like its use is to connect two round cords of unequal diameters, whereas I've got a round rope and a piece of webbing.
« Last Edit: December 22, 2012, 12:15:22 AM by bcrowell »

Sweeney

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Re: bend for connecting round cord to webbing
« Reply #3 on: December 22, 2012, 11:27:23 AM »
You might be able to tie a variation of the Beer knot by sliding the rope into the webbing if it will go - you would need to test this as I've never heard of it being used with rope. Otherwise a double (or triple) fisherman's should work (and be a real pig to undo!).

Barry

SS369

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Re: bend for connecting round cord to webbing
« Reply #4 on: December 22, 2012, 02:43:14 PM »
the real (world) need here?

Thanks for the suggestions. The situation I'm envisioning is this. In the sport of canyoneering, you typically descend a canyon by rappelling, and once you do the first rappel, you can only go forward (down) not back up. One of the things that can go wrong is that you find your rope isn't long enough for a rappel, or you have a rope get stuck so that you can't pull it down after yourself. A possibility that can be used in such an emergency is that you can use webbing to replace some or all of your rope. (You're usually carrying webbing for building anchors.) To get enough length, it might be necessary to connect a piece of webbing to a piece of rope.

If I'm understanding correctly, the Albright is a sheet bend with a bunch of extra wraps of the thinner cord. This makes me a little uneasy, both because I've never heard of an Albright being used in climbing, and also because it seems like its use is to connect two round cords of unequal diameters, whereas I've got a round rope and a piece of webbing.

Good day bcrowell.

For one thing, you can go back up your canyon line and that should be part of your repertoire!
Another thing is you should be taking adequate amounts rope.
Possibly use the Prusik rope that you undoubtedly have with you and that would allow for ascension to go the last few feet (?) of miscalculation.

The Albright knot would work with the stopper/backup overhand as I suggested (or many of the fishing knots for that matter), but if you are unsure, either test it at a comfortable altitude or forget about it.

Your original idea of a two loops bend is a good one and if you already feel comfortable with that, you should plan on it. I wouldn't worry about bulk as you should also know how to pass the knot and be carrying the material to do so. And if bulk is not an issue, then many rope bends can be considered.

How many feet of webbing do you normally carry on a descent?

I see no reason that you could not rappel down webbing though it will be slick as heck. There are many ways to increase the friction so it is manageable, but descending slow will be key.

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Luca

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Re: bend for connecting round cord to webbing
« Reply #5 on: December 22, 2012, 05:37:48 PM »
HI bcrowell,

I know very little about climbing(nothing,it can be said), I like the knots, so I know some mountaineering knot for what a  knot is in itself,without ever having depth regarding the relative use in the various real situations during the climber's activity.So I do not know if these suggestions can be useful for you:

http://www.youtube.com/watch?v=0eJjE6uR9Q0

http://www.youtube.com/watch?v=uRYCvhm2I2E

This seems a slipped Lapp(I would prefer the term"Sami")knot( http://davidmdelaney.com/Lapp-knot/Lapp-knot.html / http://igkt.net/sm/index.php?topic=1955.0  ) used as a Becket(note however what Dan Lehman writes about this use in the thread by me linked)hitch around a(doubled)loop made with a webbing.
Another:

http://www.youtube.com/watch?v=rG3iENZ0l-c

http://www.youtube.com/watch?v=9Dq0wRBxtGQ

A video(not so clear) about the steps for this Macroknot(fundamentally seems a Slipknot passed through the webbing's loops in a particular way,and then"re-slipped"):

http://www.youtube.com/watch?v=TS-tYLDtR1o

In the hope that these knots appear completely useless to your eyes, so that I no could the risk of bear a life on my conscience!

                                                                                                       Bye!

P.S.I do not know if this could be another suggestion:

http://igkt.net/sm/index.php?topic=4116.0



James Petersen

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Re: bend for connecting round cord to webbing
« Reply #6 on: December 22, 2012, 07:05:02 PM »
I have found that the 2x2-Round-Turns-Bend holds well tied in some very small tape and some 6mil. cordage that I have.  My testing has been very informal and incomplete, but you might want to experiment with it yourself. The knot is extremely easy to remember and has, in my preliminary investigations, holds well in shock/bungee cord, tape, and braided cordage. When tied in laid nylon cordage, the knot is reliable when the round turns are taken in the direction of the lay. When the turns are taken against the lay it runs without fail.  In tape, the
 second round turn (closest to the working end) should be placed inside the first. But be warned, after being heavily loaded, it is nearly impossible to untie
.

I have included one photo in this post, but there are some more on my original post about the knot: http://igkt.net/sm/index.php?topic=4150.1

X1

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Re: bend for connecting round cord to webbing
« Reply #7 on: December 22, 2012, 07:30:17 PM »
Because the two pieces of rope are dissimilar, it worries me that a bend would fail.

The Zeppelin bend tied on dissimilar ropes seems to be a very secure knot. 

http://igkt.net/sm/index.php?topic=2159.msg15248
« Last Edit: December 22, 2012, 07:30:57 PM by X1 »

SS369

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Re: bend for connecting round cord to webbing
« Reply #8 on: December 23, 2012, 12:45:54 AM »
Here is an Albright using web to rope.

This was loaded to approx. 300 lbs. and held with no discernible slippage. I personally would consider using it if it were an emergency.
I might add more wraps with a stopper on the rope and possibly make the webbing into an overhand loop. But this worked as is.

It would be worth your while to do some safe testing on your ropes/webbing before use.
And then carry sufficient rope to begin with!

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Dan_Lehman

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Re: bend for connecting round cord to webbing
« Reply #9 on: December 23, 2012, 05:59:35 AM »
Here is an Albright using web to rope.

Wrong on both counts --and I'm amazed at the main
mistake (what knot)!!?  (The 2nd count is admittedly
me interpreting the relation "x to y" as a hitching, per
ideas X1 & I have had.)  Really, how can this one assert
that this is an Albright knot ??!  --on what basis?

(What is shown is a triple sheet bend of rope to tape
--and of the less well regarded opposite-ends version.)


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Dan_Lehman

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Re: bend for connecting round cord to webbing
« Reply #10 on: December 23, 2012, 06:28:01 AM »
the real (world) need here?

Thanks for the suggestions. The situation I'm envisioning is this. In the sport of canyoneering, you typically descend a canyon by rappelling, and once you do the first rappel, you can only go forward (down) not back up. One of the things that can go wrong is that you find your rope isn't long enough for a rappel, or you have a rope get stuck so that you can't pull it down after yourself. A possibility that can be used in such an emergency is that you can use webbing to replace some or all of your rope. (You're usually carrying webbing for building anchors.) To get enough length, it might be necessary to connect a piece of webbing to a piece of rope.

"+1" to what was said previously about such a situation
being something to well avoid (who's to say that magically
one's tape will be adequate to make up some too-short
rope reach?), and also care about abseiling on tape.  (You
might want to try this before believing that it's a viable
resource!)

Quote
If I'm understanding correctly, the Albright is a sheet bend with a bunch of extra wraps of the thinner cord.

Although that was shown, above, you're not understanding
correctly (didn't see where that was suggested?).  Rather,
the Albright is more like one end tying a blood knot's wrapping
around the other end formed in a bight.  What is shown above
is a triple sheet bend, opp.-sided.

As rope tends to be more substantial than tape --and i.p. as
it stands in your stated circumstance (but, "14mm tape" ?!)--,
my inclination would be to *hitch* tape to the rope.  And my
first thought of how to to this is to tie what I call a "multiple
Lapp bend"
--which in the minimal (non-"multiple") version
is simply a reverse sheet bend (but the added wrapping, getting
a least one full turn, makes a big difference!).  To tie, bring the
tape across the rope bight so that the tape cross diagonally
to turn around the rope's tail and the comes around its
SPart, over itself down through the bight, AND THEN continue
to turn around the rope's & tape's SParts --NOT around the
tail further (if you want to untie it!).

Given the insubstantialness of the tape, I'd finish this
bight-hitch by bringing the tape's tail out through its initial
turn (so, yes, one can't tie it tightly from the start).  With
rope-2-rope of similar sizes, the bight should be able to nip
the wrapping tail adequately; but with tape, I'm less sure,
so go for the extra tucking, where its SPart turn will nip it.

Now, about that "if you want to UNtie it" : the point to wrap
the bight tail only initially is that it allows the loosening tact
of pulling bight legs apart to pry out some hitching SPart,
and then working the bight tail back through this loosened
turn, and so on.  (Were one to make more than the initial
wrap, pulling legs apart would be very difficult, at best.)

Quote
You might be able to tie a variation of the Beer knot by sliding the rope into the webbing if it will go - you would need to test this as I've never heard of it being used with rope.

That's thinking!  (Were one unable to access tails, then one
could try a butterfly or overhand among other mid-line
eyeknots.)  But I don't think that 14mm is adequate for 9mm core :
pi x 9mm > 2x14mm > interior space of tape tube; Do Not Pass Go.

Quote
... occurs to me is to tie a rewoven figure-8 at the end of one rope

Maybe it's just a problem of silly knot-naming, but why would
one go to the bother of "re-weaving" a fig.8 eyeknot when
tying it with a bight is available, in this case?!   ::)   ;)


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SS369

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Re: bend for connecting round cord to webbing
« Reply #11 on: December 23, 2012, 01:58:31 PM »
Here is an Albright using web to rope.

Really, how can this one assert
that this is an Albright knot ??!  --on what basis?

(What is shown is a triple sheet bend of rope to tape
--and of the less well regarded opposite-ends version.)


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Dan, you are correct. I tied this to show another option, gave it the wrong name and it went south from there. I should edit the "silly" name. Thank you for noticing.

Why do you feel that representation is the less regarded version, if you please?

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bcrowell

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Re: bend for connecting round cord to webbing
« Reply #12 on: December 23, 2012, 05:13:32 PM »
For one thing, you can go back up your canyon line and that should be part of your repertoire!
You can, and it is. However, once you ascend back up to the rappel anchor at the top of the cliff, you still need to find a way to re-rig so that you can get down. (Retreating all the way up the canyon isn't an option, since you don't have 12 ropes you can leave behind for a canyon requiring 12 rappels.)

Another thing is you should be taking adequate amounts rope.
Yes, of course, but there are things that can go wrong. I gave an example previously in this thread:
[...] you have a rope get stuck so that you can't pull it down after yourself.

I wouldn't worry about bulk as you should also know how to pass the knot and be carrying the material to do so.
Bulk is an issue. When you get down to the bottom of a rappel, you have to pull the rope down after you. If a bulky knot gets snagged, you can be stranded: you can't get the rope down, but you also can't ascend the rope to clear the snag (because clearing the snag would cause you to drop).

Anyway, thanks, all, for the suggestions! Since I haven't seen a suggestion that is likely to be significantly less bulky than a joined pair of figure-8 loops, I guess that's what I'd use in this situation. It involves only a knot that I'm 100% sure I'd be able to remember, and I'm convinced it would be 100% secure, since I'd only be knotting like to like.
« Last Edit: December 23, 2012, 05:16:25 PM by bcrowell »

Dan_Lehman

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Re: bend for connecting round cord to webbing
« Reply #13 on: December 24, 2012, 07:10:22 AM »
However, once you ascend back up to the rappel anchor at the top of the cliff,
you still need to find a way to re-rig so that you can get down.

It should be noted that the too-short-of-a-rappel situation
at hand is one done using a single strand of rope at its
full length
(which is set to be retrieved by some thin line
to a clever rigging of the anchor).  Because if one were doing
the preferred sort of abseil with twin lines (of either a long
rope or two tied together), there's be not tying on of tape
and then pulling the rope down --unless one's prepared to
join separate tapes to both ends ... !

Quote
Since I haven't seen a suggestion that is likely to be significantly less bulky than a joined pair of figure-8 loops, I guess that's what I'd use in this situation. It involves only a knot that I'm 100% sure I'd be able to remember, and I'm convinced it would be 100% secure, since I'd only be knotting like to like.

The Albright knot and what I described are both less bulky
--"significant" or not, well, YMMV.  Their bulk is in a bight of the
rope wrapped by thin tape, which is less than the rope knotted.

But in what I see (see above) as an extend-the-end-of-a-rope,
I do have to ask how one expects to retrieve the line : if the release
line undoes the anchor so that the rap rope drops, then the knot
of tape-2-rope is likely so close to the drop point that there should
be no real danger of its getting hung up.  OTOH, if the release line
is meant to pull down the rap line by pulling some stoppered tail
high up --rope running back through an anchor point (against which
the stopper had held fast for the rappel)--, then we must question
how the newly joined tape will get past the anchor!?
I'm not seeing it ... .


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Dan_Lehman

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Re: bend for connecting round cord to webbing
« Reply #14 on: December 24, 2012, 07:17:59 AM »
Why do you feel that representation is the less regarded version, if you please?

The sheet bend with tails (& SParts) on opposite sides
seems to do more slipping in tightening than leaves me
comfortable.  I recall that Rob Chisnall reported on some
testing that he'd done in various materials on these two
basic versions, and came to the conclusion that it seemed
a mixed bag depending upon material.  And I know that
Dave Richards found some sort --but I don't know WHICH--
of the knot to slip in some of his trio of materials.

I think that the opp-sided version gains if one tucks the
bight tail back up through its apex.  This opp-sided version
seems to draw more, um, *square* and looks the better
for it, perhaps; but that slow walking of material through
the knot unsettles me about it.


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