Author Topic: Brainstorming Session: Bends  (Read 5326 times)

DaveRoot

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Brainstorming Session: Bends
« on: November 03, 2005, 04:54:31 PM »
Here's an idea which might be interesting and productive.

The idea is to have a "brainstorming session" where we can record all of our thoughts about various knots in a particular category (bends in this case).  Then someone with the time and the appropriate skills/tools can simply go through this thread and make a list of all of the individual knots which were mentioned, and distill all of the comments for each knot.

The resulting documentation will be a useful resource for practical information about various knots (however raw it might be at first).  As we brainstorm other categories of knots, and as the presentation of the information is refined, we'll be getting closer to a practical, comprehensive, and useful IGKT resource for people to use for their knotting needs and enjoyment.

So, starting near the top of the English alphabet, what do we know or feel about the different Bends?  What are their strengths and weaknesses?  Under what conditions might you use each one?  Under what conditions would you not use them?  And so on...

To start us off, here are the names of some bends (add any others that you know of).  Pictures of these bends can be seen at http://www.Layhands.com/Knots/Knots_KnotsIndex.htm#Bends:

Alpine Butterfly Bend (similar to the Hunter's Bend, Ashley's Bend, and Zeppelin Bend)

Ashley's Bend (ABOK #1452)

Carrick Bend (ABOK #1439)

Double Dragon Bend

Double Fisherman's Knot (ABOK #1415)

Double Sheet Bend (ABOK #1434)

Figure-Eight Bend (ABOK #1411)

Fisherman's Knot (ABOK #1414)

Hunter's Bend (Rigger's Bend)

Overhand Bend (ABOK #1410)

Reef Knot (ABOK #1402) (included because some people erroneously use it as a bend)

Ring Knot (ABOK #1412)

Sheet Bend (ABOK #1431)

Zeppelin Bend (Rosendahl's Bend)


Dave

DaveRoot

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Re: Brainstorming Session: Bends
« Reply #1 on: November 03, 2005, 09:07:31 PM »
Here are some comments gathered from various sources about different bends (in rope or string).  Any clarifications, corrections, additions, etc., are welcome.

The Reef Knot (sometimes incorrectly referred to as the Square Knot) is unreliable and unsafe as a bend. It should never be used for that purpose.

The Overhand Bend is quick and simple to tie, and it is used sometimes when the rope or string will not need to hold a heavy load. It is not generally considered to be very safe or secure, and it can be difficult to untie after it has held a load. However, it's possible that the Overhand Bend with long tails has some advantages for climbers (according to some climbing websites).

The Sheet Bend and the Double Sheet Bend can be useful for tying ends of cloth together, but they are generally considered to be too weak and unreliable for rope or string.

The Carrick Bend is generally considered to be strong and secure, but it might be difficult to remember how to tie it properly if you don't use it very often.  It is displayed incorrectly in a number of books and websites, and it can be very unsafe if it is not tied properly.  It is usually very easy to untie, which makes it a good bend for string.

The Fisherman's Knot (Angler's Knot, Englishman's Knot, True Lover's Knot, etc.) is easy to remember, easy to tie, and it results in a small, clean, nice-looking knot which is less bulky than most of the other bends. However, it can be difficult to untie if it has held a heavy load.  The Double Fisherman's Knot is generally considered to be strong and secure, but it can be very difficult to untie.

The Ring Knot (Water Knot, Tape Knot) is easy to remember because it is simply a rethreaded Overhand Knot, and it results in a nice-looking knot. It is fairly easy to tie and dress, and it is a fairly strong and secure bend, but it can be difficult to untie after holding a load. It is also recommended when tying together webbing (or tape), wet materials, rubber materials, and so on.

The Figure-Eight Bend (Flemish Bend) is fairly easy to remember because it is simply a rethreaded Figure-Eight Knot, but it is not as quick to tie and dress as the Ring Knot. It is also bulkier than the Ring Knot. Due to its twists and turns it has more internal friction than the Ring Knot, and therefore it is stronger and more secure. For this reason, climbers often prefer the Figure-Eight Bend (with some type of Stopper Knots) over other bends for situations when lives are at stake.  The "Abnormal Figure-Eight Bend" is tied like the Overhand Bend, except that a Figure-Eight Knot is used instead of an Overhand Knot.  The general consensus among climbers seems to be that the "abnormal" version is not a very reliable bend. For example, when the ropes are pulled in opposite directions then it can cause this knot to distort and become unsafe

The Alpine Butterfly Bend, Ashley Bend (ABOK #1452), Hunter's Bend (Rigger's Bend), and Zeppelin Bend (Rosendahl's Bend) are all based on interlocked Overhand Knots, and they are all considered to be strong and secure bends. However, the Alpine Butterfly Bend has some potential advantages over the other three bends. For one thing, the other three bends are "unforgiving" in the sense that if you pass one end of rope through a loop in the other end of rope from the wrong direction, or if you curve the second end of rope upwards when you should have curved it downwards, or if you cross the second end of rope on top of itself when it should have crossed behind itself, then you will not end up with the bend that you were trying to tie. In contrast, the Alpine Butterfly Bend is very forgiving. It doesn't matter which way you pass the second end of rope through the loop in the first end of rope, and it doesn't matter if you curve the two ends of rope upwards or downwards, and it doesn't matter if you cross the two ends of rope on top of themselves or behind themselves. The only thing that matters is that the two ends of rope form interlocked loops which are mirror-images of each other (just like the wings of a butterfly are mirror-images of each other!), and that they both pass through the center of the knot together (i.e. in the same direction). This makes the Alpine Butterfly Bend very easy to remember how to tie properly.

Most bends should only be used with two ends of rope that are about the same thickness (which bends are exceptions to this rule?).  However, two ropes of different thicknesses can be tied together using interlocked loop knots, such as Alpine Butterfly loops, Double Dragon loops, Figure-Eight Loops, Bowlines (i.e. the Bowline Bend, ABOK #1455), etc.

Dave


roo

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Re: Brainstorming Session: Bends
« Reply #2 on: November 03, 2005, 09:59:02 PM »
Without agreeing or disagreeing with what you have here, I think this discussion is far too broad and will quickly become cumbersome to follow and make people's eyes glaze over.

A lot of this info has been discussed before, but if you really think some bend hasn't been discussed enough, post a question about that one bend, and give people time to add their observations.
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Brian_Grimley

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Re: Brainstorming Session: Bends
« Reply #3 on: November 04, 2005, 02:14:45 AM »
Dave,

There is an interesting report (.pdf) on testing knots (bends) that is here: www.bwrs.org.au/research/documents/1%20main%20paper.pdf . It is titled "Knots for Use in Canyons".
SS- Edit - Dead link New link to .pdf  http://www.caves.org/section/vertical/nh/52/PreferredKnots.pdf
What surprised me was their conclusion about the "Alpine Butterfly" bend. Their report said that this knot "could easily be tied the wrong way resulting in the knot possibly undoing under load ... " (see pg. 18 ). They dropped this knot from further tests and don't recommend it for abseiling.

I have yet to figure out how to tie the "Alpine Butterfly" bend the wrong way so that I can demonstrate this failure. Oh well, I will find out someday.  :)

All the best - Brian.

« Last Edit: June 04, 2013, 02:01:05 AM by SS369 »

Dan_Lehman

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Re: Brainstorming Session: Bends
« Reply #4 on: November 04, 2005, 02:40:39 AM »
Quote
The Reef Knot (sometimes incorrectly referred to as the Square Knot) is unreliable and unsafe as a bend. It should never be used for that purpose.

It's perhaps the best bend for rubber bands, and has been used and recommended
for webbing/tape by climbers/cavers (French?)--I was shocked to see such in some
in-use tape, but on playing around with it find secure (& asymmetric).

Quote
The Sheet Bend and the Double Sheet Bend can be useful for tying ends of cloth together, but they are generally considered to be too weak and unreliable for rope or string.

?!  These knots are in common use, often with some end-securing mechanism,
and often in similar becket-hitch forms.

Quote
The Carrick Bend is generally considered to be strong and secure,...

... though w/o any clear data to support this--just the parroting of knots books!
Quote
... but it might be difficult to remember how to tie it properly if you don't use it very often.  It is displayed incorrectly in a number of books and websites, and it can be very unsafe if it is not tied properly.  It is usually very easy to untie, which makes it a good bend for string.

There are various things shown under the label, and perhaps more often so than for
other knots, yes.  As for string, I find it rather fiddly to tie the lattice-form, and am
not much practised at any other.

Quote
The Ring Knot (Water Knot, Tape Knot) is easy to remember because it is simply a rethreaded Overhand Knot, and it results in a nice-looking knot. It is fairly easy to tie and dress, and it is a fairly strong and secure bend, but it can be difficult to untie after holding a load. It is also recommended when tying together webbing (or tape), wet materials, rubber materials, and so on.

There is a difference in knot-form for rope (round material), intended to be symmetric;
in tape, the commonly shown knot is asymmetric, with interior/exterior sides,
though the knot can be arranged to be symmetric (which makes it a tad longer &
less *fat*).  (Alas, indications are that the part that breaks is the exterior SPart,
and the part the slips in some stiffer tapes is the exterior end, which implies
choosing between strength vs. security (in theory).)

Quote
The Figure-Eight Bend (Flemish Bend) is fairly easy to remember because it is simply a rethreaded Figure-Eight Knot, but it is not as quick to tie and dress as the Ring Knot. It is also bulkier than the Ring Knot. Due to its twists and turns it has more internal friction than the Ring Knot, and therefore it is stronger and more secure. For this reason, climbers often prefer the Figure-Eight Bend (with some type of Stopper Knots) over other bends for situations when lives are at stake.  The "Abnormal Figure-Eight Bend" is tied like the Overhand Bend, except that a Figure-Eight Knot is used instead of an Overhand Knot.  The general consensus among climbers seems to be that the "abnormal" version is not a very reliable bend. For example, when the ropes are pulled in opposite directions then it can cause this knot to distort and become unsafe

It doesn't work so neatly in tape.  I'd say it's stronger for being able to retain less
sharp bending of the SPart, but YMMV on data on relative strengths:  AMGA (?) opines that
the Fig.8 & Ring Bends are equally strong.  But, they don't show WHICH form of either
bend is actually tested, and of course not how it was set (assuming perfect forms were
used for both--often the Fig.8 is tied asymmetricly).
Prefer "Offset" to "abnormal"--the former objectively descriptive, the latter not
necessarily so (the normal way to join rappel ropes is with an abnormal Ring Bend,
by such nomenclature--"Offset Overhand Bend" is preferred (or "Offset Ring...")).
And one canyoneer continues to use the Offset Fig.8 well aware of some of the climbing
troubles with it--indeed, having seen the ropes of one fatality (Mt.Zion), which he
described as "cables" (i.e., quite stiff).
But the warning I think should be given; the alternatives are readily available!

Quote
... However, the Alpine Butterfly Bend has some potential advantages over the other three bends ...

Hmmm, I don't want to chase all of that rationale, but tying a knot correctly
isn't all so
hard for the others.  Some of the tying methods I've seen for these knots are the
problem, getting two clever by half, IMHO.  I start with one Overhand and reeve the
opposite rope into it accordingly.  Now, the PABPRES has a whiz-bang way of tying
the Butterfly which gets him a hotter first sip of his coffee, fine.  In the course of
regular usage, one can get good at whatever method.  (-:

Quote
Most bends should only be used with two ends of rope that are about the same thickness (which bends are exceptions to this rule?).

The OOB (Offset Overhand Bend) used for joing rappel ropes will often be called upon
(or could be) to join diff.sized ropes (7mm + 10mm, say); there is a particular
orientation that should be used here (thinner rope outermost).
Sheet bends & derivatives of them & Lapp Knots are useful in thick-thin unions.
Other bends can be adapted sometimes with minor variation.
Flexibility & surface friction are important characteristics of "similar" along with
diameter--often more so, if dia. diff. isn't great.

--dl*
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merickson

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Re: Brainstorming Session: Bends
« Reply #5 on: November 04, 2005, 03:42:15 AM »
The Bowline Bend will join different diameter ropes.  

The Sheet Bend is a good bend. (Better if doubled) But, I do not trust it to hold two slack ropes together. Actualy, I doubt any unloaded bend, but the sheet bend is particularly bad.

The extreme symetry of the Zepplin bend makes it easy to learn.

I use bends less than any other class of knot.

DaveRoot

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Re: Brainstorming Session: Bends
« Reply #6 on: November 04, 2005, 04:29:50 AM »
Quote
A lot of this info has been discussed before, but if you really think some bend hasn't been discussed enough, post a question about that one bend, and give people time to add their observations.

Exactly, there have been some discussions about some bends, and who knows how much of that information has been lost due to the 200-day lifetime of the posts on this forum.

The intention of this thread is for collecting the knowledge, experience, and opinions that people have accumulated (related to bends, in this case), gathered in one place.  I'm hoping that the IGKT (or some "authoritative" body) will create a fairly comprehensive and practical resource where people can get accurate information on knots, so I started this topic as a place where that information can begin to be gathered.  If such information is adequately compiled elsewhere without need of discussions and clarifications and corrections, then this thread is redundant.  ;D


Quote
There is an interesting report (.pdf) on testing knots (bends) that is here: www.bwrs.org.au/research/documents/1%20main%20paper.pdf . It is titled "Knots for Use in Canyons".

What surprised me was their conclusion about the "Alpine Butterfly" bend. Their report said that this knot "could easily be tied the wrong way resulting in the knot possibly undoing under load ... " (see pg. 18 ). They dropped this knot from further tests and don't recommend it for abseiling.

I saw that report recently and had the same reaction you did!


Quote
tying a knot correctly isn't all so hard for the others.  Some of the tying methods I've seen for these knots are the problem, getting two clever by half, IMHO.  I start with one Overhand and reeve the opposite rope into it accordingly.

A lot of people (perhaps even the majority of people?) rarely tie knots in rope or string, so it's helpful if a secure knot is easy to remember how to tie properly.

Dave

roo

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Re: Brainstorming Session: Bends
« Reply #7 on: November 04, 2005, 08:28:27 PM »
Dave, Google the rec.crafts.knots group.   The discussions there do not disappear after a certain number of days.
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drjbrennan

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Re: Brainstorming Session: Bends
« Reply #8 on: November 04, 2005, 11:42:14 PM »
I've been very impressed these past few months with the Zeppelin bend. I tied it in some paracord, to keep my keys bunched together, in all that time it has shown no signs of loosening or distortion, I have read about it's security and I have found it a very reliable bend.

Another favourite at the moment, is the 'Simple Simon Over' because of it's ease of teaching to others, I believe it is a strong and reliable bend, unless you know better?
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