International Guild of Knot Tyers Forum

General => New Knot Investigations => Topic started by: knot rigger on April 18, 2015, 06:09:30 AM

Title: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 18, 2015, 06:09:30 AM
I may have discovered (invented?) a new way to tie the alpine butterfly knot.  Please check out this youtube link:

https://youtu.be/SsnzExoETgk

The closest I have been able to find to "my" version of the ABK is in Knotting Matters 8: a version of tying the ABK by Rob Chisnall, which is similar, but slightly more complicated.

I'd love your collective feedback

cheers
andy

PS. At the suggestion of Aplineer, I've re-worked the video slightly, to clarify the method of tying:

https://youtu.be/0wupL8dPTzw
Title: Re: a new way to tie the butterfly loop?
Post by: roo on April 18, 2015, 07:14:07 AM
I may have discovered (invented?) a new way to tie the [butterfly loop].  Please check out this youtube link:

I'll just say that I'm fairly proficient with knots and I managed to mess up the method for nearly the first dozen attempts.  It's easy to miss the little twist of the left hand as the right hand is moving around.  Then again, maybe it's just too late in the evening.   ;)

I notice that if you accidentally reverse the loop twist of the very first step, you end up with an evil imposter knot for the butterfly loop, namely the half-hitch loop (http://igkt.net/sm/index.php?topic=1892.msg13064#msg13064).  In light of this, I would recommend more conventional methods.

Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 18, 2015, 08:58:51 AM
There's a more ergonomic and visually simpler way (actually two ways) to tie the ABK on a hanging line and also ensure that one cannot tie roo's favourite knot, his so-called evil imposter.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 18, 2015, 09:11:51 PM
Thanks for all the feedback.

One question for the group,  is this indeed a new method of tying the ABK?  Has anyone seen it before?

As far as merit goes, let me reply

Roo:
 Perhaps in the light of morning you may find this method easier?  ;)  I don't think a video is the easiest way to learn a new knot, but it's certainly the easiest and quickest way to get the idea out to this board.  I'll work up a traditional storyboard instructions for tying, and post it as well.  As far as tying it wrong goes... well, you can tye most knots wrong and get disastrous results, tying it correctly is the trick.  Of course if a knot very easy to tie wrong, and difficult to tell if you have, then there is some risk, and the knot in question may not be very useful for that reason.  Is that your assessment of this method of the ABK Roo?   You did identify the "trick" with this method: beginning with the left hand pointed thumb down is the key.

on a lighter note Roo: I'm perversely pleased that this version gave a little challenge to such a knotting expert

Xarax:
Perhaps you could clarify what you mean by the knot being oriented the "wrong" way.  A primary benefit of the ABK as a mid line loop is that it may safely be loaded in either direction.  Do you mean that this method doesn't accurately form the ABK?  If so, I disagree.  I've compared this method with traditional methods, and haven't been able to find any structural difference in the finished loop knot.  Maybe you're seeing something I am not, in which case I would appreciate your clarification.

Alpineer:
The two methods you mention of tying the ABK: would those be the hand wrapping, and twisting methods?  Or are there two other better ways that I don't know of?  I find that which method one ties the ABK is usually a matter of which way one was first taught.  There are drawbacks to each of the two "traditional" methods of tying the ABK.  Two criticisms of the hand wrap method are:  1. it is difficult to tie a large loop with this method (a large loop being a useful technique for certain rope access techniques) 2. if the rope should come under unexpected load while tying the hand wrap method, you're hand will likely be injured, which is why most search and rescue personnel avoid the hand wrap technique.  For the twisting method: This method requires multiple grasp and release moments to form the twist, and to pass is through the doubled loops... which I find awkward (at best) and often lead to the attempted tying falling apart, or too errors in the tying.  Also, if tying this method of the ABK at height, with a lot of rope weight below you, the challenges of the twisting method are magnified.

It's likely that "my" method has drawbacks as well, some of which you three have already picked apart to some degree.  I do think it's benefits address the drawbacks of the two traditional methods of tying.  The more I use is, especially while working at height, the more useful I have found it to be.

Thanks again for all the input,  please keep it coming.  And I would be especially thankful if anyone can tell me if they have encountered this method previously.

thanks
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 19, 2015, 02:43:53 AM
Xarax : are you asserting that because of the asymmetry of the ABK that loading the loop from one direction is inherently weaker than from the other?  I have never seen any data to suggest that, and if you have, please share with me where I may find it.

It seems to me this criticism of the ABK, based on asymmetry, would apply to any butterfly knot, regardless of what method is used to tie it. Would you agree with that?  Or, do you have some special criticism for this(possibly) new method of tying the ABK.

Thanks
Title: Re: a new way to tie the butterfly loop?
Post by: roo on April 19, 2015, 04:45:41 AM
Of course if a knot very easy to tie wrong, and difficult to tell if you have, then there is some risk, and the knot in question may not be very useful for that reason.  Is that your assessment of this method of the ABK Roo?
I think other methods do a better job at either forcing the tyer to make the correct move or if incorrect moves are made, they result in obvious failure or even accidental success.

Quote
  There are drawbacks to each of the two "traditional" methods of tying the ABK.  Two criticisms of the hand wrap method are:  1. it is difficult to tie a large loop with this method (a large loop being a useful technique for certain rope access techniques) 2. if the rope should come under unexpected load while tying the hand wrap method, you're hand will likely be injured, which is why most search and rescue personnel avoid the hand wrap technique.  For the twisting method: This method requires multiple grasp and release moments to form the twist, and to pass is through the doubled loops... which I find awkward (at best) and often lead to the attempted tying falling apart, or too errors in the tying.  Also, if tying this method of the ABK at height, with a lot of rope weight below you, the challenges of the twisting method are magnified.

It's possible you may be thinking of another hand wrap method, but I've never had any problem with controlling loop length with the two standard methods (http://notableknotindex.webs.com/butterflyloop.html).  It's just a matter of leaving the structure open at the right time as you pull material.

The right time for the coil method is at the initial pull to the right.  The right time for the twist-fold method is represented by the down-pointing gray arrows in the second step (http://notableknotindex.webs.com/butterflyloop.html).

I do wonder about people who are worried about the line suddenly seeing severe load while they're tying.  Trying to reduce hand exposure to such a scenario via the method of tying seems to me like only looking down the barrel of a loaded gun for a second rather than five seconds.  I'd much prefer to eliminate that risk.  I do notice that in the method you present, your left hand is in the rope for a long time, relatively speaking.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alanleeknots on April 19, 2015, 07:11:17 AM
Hi All,
       Thanks for sharing your video Andy, Sometimes it is the ideas of another that can instigate sparks of creativity
       and I dare say, even private appreciation.
       Here I like to share my method to tie this beautiful butterfly loop with you. https://www.youtube.com/watch?v=MRnoevwqYto.
 
       謝謝  alan lee.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 19, 2015, 05:36:31 PM
Hello all,

I am still curious if any of you have seen or read this method of tying the ABK before.

now, to reply to some specific points:

Quote
  Yes, because, when loaded from the one end, the Standing Part s first curve is almost two times as wide as when loaded from the other end. At their X-shape crossing ( clearly visible when the knot is viewed from one of the two "flat" sides ), the one segment goes "over" the other, and that makes the curve which incorporates the "over" segment ( and encircles the "under" segment ) wider than the curve which incorporates the "under" segment. At this first curve the knot bears 100% of the load, and, presumably, a wide, gentle curve is always stronger/more evenly loaded than a narrow, sharp one, therefore the first curve is the weakest link of the knot s structure. ( However, the point of rupture is, most of the times, different from the point of maximum strain... )

Xarax, I follow you're thesis that there is a Stronger and a Weaker loading side of any ABK.  First, it looks to me that the stronger side, with the wider internal knot bend, is pointing up (to the standing end) in my video.  Therefore, the stronger side is taking a load should you load the loop of the knot.  Am I missing some detail that you are seeing?

Quote
  Simply because there are no data, for any knot, anywhere !  :)

The CMC rescue guide states that the alpine butterfly has a efficiency of 75% when the loop is loaded, and 57% when pulled end to end (as a butterfly bend would, or the ABK used to isolate a damaged section of rope).  I've seen similar efficiencies posted in other resources as well.  In reading dozens of books, attending multiple professional trainings, and working with many experienced riggers over the years, I've never encountered the idea that there is a right and wrong way to load a ABK.  I would say that conventional wisdom is that they are both equal, or that the difference is so negligible as to be disregarded.

Of course, conventional wisdom could be wrong.  In the multiple sources I can find stating the efficiency of the ABK, none of them specifically mention testing the left hand and right hand loading of the loop.  I had considered this due to the fact that there is no meaningful difference, rather than inattention on the part of the testers.  You, yourself, mention the important point that a rope with almost always break just outside the body of the knot (a fact widely and generally noted).  Given that fact, it is mysterious how the internal structure of the knot affects the strength.

I've read multiple theories of what makes knots weak, or strong.  And while there does seem to be some agreement, there are also contradictions (as I'm sure you're aware) and I believe that the only reliable way of measuring knot efficiency is through break testing.  I have access to a break testing rig, and when I have time, I intend to test your thesis that the left and right hand loading of the ABK, have a significant difference, I'll let you know.

In the mean time, I'll stick with conventional wisdom.

on to Roo:

Quote
I think other methods do a better job at either forcing the tyer to make the correct move

I agree with you about this, although I do think the point is worth discussion.  I think that this "new" method of tying the ABK would be useful to "expert" users who tye this knot regularly, know it well, can reliably inspect a tied version to insure it's tied correctly.  It has advantages over the two traditional methods, in my opinion.  At the very least, it's useful for impressing your peers over beers after the gig :)  I don't think I would teach this method to someone who didn't already know the ABK.  The "coil" method is probably best for that.

Quote
I do wonder about people who are worried about the line suddenly seeing severe load while they're tying

While working at height, any reduction in risk, however slight, has merit. It is a subtle (but worthy) distinction between having three wraps of rope around your palm for 10 seconds vs. having a loosely formed loop around your fingers for two seconds.  As far as sizing of the loop: it is possible to form a 5 foot long loop in the ABK for a Y hang anchor, or rope re-direct, it's just very awkward.  The twisting method is superior in this application, but with that much rope to pass, it can be clumsy and awkward to complete the "fold" of the knot.  I believe "my method" can be better in this (admittedly very specific, and somewhat limited) application.

finally to Alan:

Quote
Sometimes it is the ideas of another that can instigate sparks of creativity
       and I dare say, even private appreciation.

It brought me great joy to watch your video of your method of tying the ABK.  The loop appears almost as if by magic, and has a wonderful element of theatricality to it.  I'm greatly pleased to have been able to connect with a fellow knot aficionado in China!

Thanks to all of you for taking the time to watch the video I posted, and to share your thoughts with me.

andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 19, 2015, 09:06:05 PM
Quote
Simply because there are no data, for any knot, anywhere !  :)

Xarax,

I thought this link might interest you

http://l-36.com/rope_articles.php

page 21 of the first link in the list has some interesting observations regarding the tightness of a bend internal to a knot, and how it affects knot strength.

cheers
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 19, 2015, 09:54:41 PM
Hi knot rigger,
A while back I studied the problem of tying the ABK on vertical lines under tension. However, I'm rethinking my initial post. Your method may be as/more effective than my methods at managing the weight of the rope below the knot to-be-tied. I'll have more to say on this, but I must go out in the sun. Later.

alpineer
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 20, 2015, 12:18:52 AM
hello again

Alineer:

Quote
A while back I studied the problem of tying the ABK on vertical lines under tension

I would be greatly interested in seeing, or hearing from you about, your studies of this issue, and what conclusions you once drew, as well as any new thoughts you have about the method I started this tread with.  Thanks :)

Xarax:

 
Quote
  1.
   It "states"  :), but it is not referring to a single ( = even ONE ) experiment which corroborates that conjecture.   
   Such "statements" should not be considered more seriously than any conspiracy theory - and we all know very well that the internet has multiplied the production of conspiracy theories on everything, it had not eliminated them !

I trust the guys at CMC, and in my opinion, you would do well to trust them as well.  Here is a link to a link to their testing:

http://caves.org/section/vertical/nh/59/Rescue%20Knot%20Efficiency%20Revisited.pdf

When I have a little more time, I'll be happy to look up some other testing data for you, if you like.

Quote
3.
   ...dozens...many...multiple... never encountered... but you have just said it : "there is a Stronger and a Weaker side in the loading of any ABK ".

you actually misquote my earlier post there:  here it is unredacted:

Quote
Xarax, I follow you're thesis that there is a Stronger and a Weaker loading side of any ABK.

you're assertion that there is a weaker and stronger side to the ABK is a thesis which may or not be true.  as we both agree, the only way to know for sure it to do some break testing

Quote
I do not expect that you would like to BET on this ( because I do... :) )

I would be happy to make a gentlemanly wager with you.  Lets refer to you're "stronger side" as the right handed side of the loop, and the other side as the left handed.  I wager my copy of Jeff Jepson's Knots at Work against whatever you think is fair, that the difference in efficiencies between the left and right handed sides of the ABK is less that 5%.

now I just need to find some line I don't mind breaking :)

cheers
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 20, 2015, 07:40:44 PM
Xarax

Are you backing away from our wager now?   ;)

I think, perhaps, we've just had a little miscommunication, so let me clarify:

My wager is that the two sides of the ABK are essentially the same strength, and your position (as I understand it) is that the two strengths are different.

If you win, you win my copy of Knots at Work, and if I win, I get something of equal knot nerdy value from you.

I'll do the break testing, record the data, and provide you (and anyone else) the results.  I know you only trust numbers, not people, but in this instance you'll have to trust me to do the testing, and be honest about the results  ;)

So what's the threshold between same strength and different strength?  I propose that a 5% difference in breaking load between the sides, or less, should be judged the "same" strength, and anything above 5% different.  So, if the lefthand side breaks at 66% efficiency (33% strength reduction) and the righthand side at 72%, then you win!  We agree that 6% is a meaningful difference (for the purpose of the wager).

I have long length of a lightly used 3mm sampson double braid (i'll look up the exact specs) which I'll do the testing with.  It is used, so it won't be a perfect measure of breaking efficiency, but it will suffice for a comparison purposes.  All the knots will be tied, dressed and set by me, as identical as I can make them.  I'll tye an equal number of samples with a lefthanded loaded ABK, and with a righthanded, as many as I can get from the sample rope (which is something like 100' long).  The breaktesting rig consists of a chain puller connected to an analog dynamometer.  I pull each sample until it breaks.

do we have a bet?

cheers

oh yeah, PS.  yes the double fisherman bend is stronger than rest!  Somewhat surprising.  Three things that I find interesting in the CMC report

1. the material of the rope, nylon or polyester, affects the efficiency of the knot, which stands to reason, but is often overlooked
2. they state that their broken samples often broke in the knot (which is contrary to what I most often read, that a rope breaks just outside the knot)
3. The figure 8 bend is relatively weak, which is counterintuitive to most people, given that the figure 8 loop is so widely trusted
Title: Re: a new way to tie the alpine butterfly knot?
Post by: Dan_Lehman on April 21, 2015, 01:46:58 AM
  There is no ( = there can be no ) symmetric single TIB loop !
  It would be nice if one could actually prove this, rigorously=mathematically..

Firstly one has to be specific in what constitutes the
supposed impossible knot.  For I can refute the assertion
if having_one_eye and being symmetric is the goal,
except insofar as you might point to parts of my
"solution" as being (degenerate) unused "eyes" !
--of which there'd be two.   ;)


--dl*
====
Title: Re: a new way to tie the alpine butterfly knot?
Post by: Dan_Lehman on April 21, 2015, 01:55:31 AM
Sometimes it is the ideas of another that can instigate sparks of creativity
Indeed!  Sometimes --rather often, I find-- when one attempts
to illustrate (by pen & paper) a knot, the arranging of its parts,
the fiddling of this going here and that there, ... instigates the
"What if ...?!" thinking that arrests the recording of the extant
knot and sends one into explorations of what else, of what if ... !
(And one might end up with TWO (or more) unrecorded knots
to do, instead of one done.)   :P

Quote
Here I like to share my method to tie this beautiful butterfly loop with you.
https://www.youtube.com/watch?v=MRnoevwqYto.
 
       謝謝  alan lee.

PLEASE NOTE that Alan's knot has as different geometry
than the OP's, in which the legs of the eye cross within
the knot body rather than abutting each other as in so
many of the available illustrations and in the OP's.  In part,
this arises from torsion imparted during certain of the tying
methods --i.p., of the "twirly flop" old method.  Wright &
Magowan, who introduced this knot to mountaineers,
specifically called for this crossing.

As for the question of strength & orientation,
my surmise is that the crossed-legs version is stronger
than the other, and that between which end, it might
not matter much, in both cases.  (I disagree with X's
assertion of curvature in the OP's case --it seems a
1dia turn either way.)


--dl*
====
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 21, 2015, 02:41:59 AM
except insofar as you might point to parts of my "solution" as being (degenerate) unused "eyes" ! --of which there'd be two.   ;)

   Yes, I know... You would had been more successful as a lawyer than as a knot tyer.   
   Of course, if I had been so naively cunning to dare to present any single eye loop with a second unused, redundant pseudo-eye gawking around, I would had been "keystroking", and "filling lines" !  :)
   We have discussed this issue some time ago - in case you have forgotten it, read :
   http://igkt.net/sm/index.php?topic=4425.0

...yes, some *ends* of my *singlEye* knot would be bights, as you point out.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 21, 2015, 03:13:51 AM
...the crossed-legs version is stronger than the other...
( I disagree with X's assertion of curvature in the OP's case --it seems a 1dia turn either way.)

   Noope - In the "common" dressing, without crossed-legs and with the two Standing Parts ( as seen from the one of the two "flat" sides ) parallel to each other, we have an X-shaped crossing : at this area, the one segment of the Standing Part engulfs the other. The diameter of each first curve is determined by the paths of both legs of the U-shaped turn, the leg before and the leg after the tip of the "U" : so, it is determined by the direct continuation of the Standing End, before the tip of the first curve - where, indeed, there is no difference between the two curves -, AND by the continuation of the Standing End after the tip of the U-turn, where we see the difference I am talking about. In order to be able to go "around" the segment of the line which passes "under" at the X-crossing, the segment of the line which passes "over" has to follow a wider path, that is, to trace a more gentle curve. The segment of the Standing Part which passes "under" makes an 1 rope diameter turn, while the segment of the Standing Part which passes "over" makes an 1 + 1 = 2 rope diameters turn - because the later has also to encircle the former.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 21, 2015, 05:00:18 AM
   
   Of course, if I had been so naively cunning to dare to present any single eye loop with a second unused, redundant pseudo-eye gawking around, I would had been "keystroking", and "filling lines" !  :)
 

Your quip merits at least two of these  :) xarax.  :)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 21, 2015, 04:17:29 PM
Well xarax, you've naively misunderstood my comment completely! "These" refer to ":)" It was just my way of applauding your sense of humour (or was it pure sarcasm?) in this particular case.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 21, 2015, 04:57:02 PM
Well xarax, you've naively misunderstood my comment completely! "These" refer to ":)" It was just my way of applauding your sense of humour in this particular case.

  You have used a naive syntax !  :)  A pronoun of a smiley !  :)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 21, 2015, 09:01:16 PM
Hi knot rigger,

I think your method is well thought out. After a bit of playing around it became apparent that you have addressed what is perhaps the most important consideration regarding a vertically oriented line - that it can be under considerable tension - by virtue of it's own weight - where the knot is to be located. The method is only fully appreciated when much of the rope's weight hangs below, where the common "Handwrap" method is a fail. Your method has good flow and feels good in the hand - i.e. ergonomics - once one is familiar with it, which doesn't take long. 

Your method provides an effective means for isolating the weight of the rope without having to relieve the tension by means external to the tying process.
N.B. Any risk(examples?) of body parts getting caught or injured requires management prior to tying.

Your method elegantly avoids unwanted friction during the tying process. Other methods require mitigation. 



P.S. It would have been better had the tying process been shown even more slowly in the middle portion of your video, allowing the viewer more time to see the process clearly and also make it easier to stop and study.

P.P.S. Got a name for your method?
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alanleeknots on April 22, 2015, 02:25:15 AM
Hi All, Andy I use your idea and have create another method to tie the Butterfly loop, see if you like it or not.
          https://www.youtube.com/watch?v=prUHG_peCy8

          謝謝  alan lee.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 02:30:50 AM
Alpineer:

Quote
1) Your method has good flow and feels good in the hand - i.e. ergonomics - once one is familiar with it, which doesn't take long.
& ...Your method elegantly avoids unwanted friction in the tying process.
2) P.S. It would have been better had the tying process been shown even more slowly in the middle portion of your video, allowing the viewer more time to see the process clearly and also make it easier to stop and study.
3) P.P.S. Got a name for your method?

1) Thanks, I agree :)

2) You're right!  I intend to work up a traditional "knot book" storyboard type tying instructions.  And I can certainly re-work, or re-do the video.  Thanks for the suggestion.

3) no, not yet. 

"It is hardy necessary to name a knot, but it assists materially in finding it a second time it the occasion arises" ABOK pg 174, as quoted for ABOK #952

"andy's method" seems a little vain.  Inspired by Brion Toss' method of naming (moku hitching, strait bend, St. mary's hitching)  I had thought of perhaps naming it where I discovered it perhaps.  It came to me underwater, at my job working as a rigger with the "O" show in las vegas.  "scuba butterfly"?  "O butterfly"? "underwater butterfly"?  all of these names are amusing, but not very descriptive !  I was playing around with practicing this Hybrid method:

https://www.youtube.com/watch?v=QeKLU_6NLv4

when I came upon (came up with?) my new method.  Underwater the rope floats around, and a loose version of the "hybrid hand wrap method" floated into something like the final method I've come up with.

"modified hybrid"? "underwater hybrid butterfly"? are awkward as well as un-descriptive.  As a nod to my profession, as well as imitation intended as flattery of B. Toss again (rigger's hitch ABOK #1735), I thought "rigger's butterfly" has a nice ring to it.

  As you point out, the most useful thing about this method is mitigation of the tension due to rope weight, an application most useful to riggers, rock climbers, arborists, and rope access technicians. "rope weight tension mitigation method" is also amusing, but quite a mouth full! "rope access butterfly"? "SRT butterfly"?  I live in vegas, so "Red Rock's butterfly"? also sounds good to me, and is riffing off the "yosemite bowline". 

It's not really a new knot, so does it even deserve a new name?  The other (informal?) names of ABK methods (coil, or handwinding method, and twist and fold method) are really describing the motion involved in tying the knot.  I'm not sure what the key motion is in my method.  The trick to discovering it, and to tying it, is to start with the left hand thumb down, or "backhanded"  So "backhanded butterfly" or "backhanded method of tying the ABK" could be contenders.  "backhanded" has a somewhat nefarious connotation, which has a somewhat perverse appeal to me.  But tying a negatively connotated adjective to such a noble and trustworthy knot seems unsavory to me.

In the end, names of knots, and methods of tying them are really up to the people that use them.  Even if I have invented a new way of tying my old favorite, whatever I call it has little relevance to what the name may eventually be.  (you know the story of "Blake's" hitch I imagine)

So, Alpineer, I would like your help deciding on a name.  You (so far) have been the only IGKT forum member to see the merit in this method, or at least the only one to says so. (sorry, alanlee liked it as well, and I am very fond of his method).  So, do you have any suggestions on what to name this new(?) method of tying the ABK?  Of course, anyone else in the group, that has positive input in what to call it is welcome to chime in as well.

cheers
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 02:37:43 AM
Quote
Hi All, Andy I use your idea and have create another method to tie the Butterfly loop, see if you like it or not.
          https://www.youtube.com/watch?v=prUHG_peCy8

          謝謝  alan lee.

Alan,

You have again filled me with joy at watching your video :)  I really like both your methods.  In the new method I like how you catch the standing end with your left finger especially.

我很榮幸

(sorry if google translate slaughters that translation)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 03:54:00 AM
Quote
P.S. It would have been better had the tying process been shown even more slowly in the middle portion of your video, allowing the viewer more time to see the process clearly and also make it easier to stop and study.

Alpineer (and others) let me know what you think of this revised video

https://youtu.be/0wupL8dPTzw

I put a one second freeze frame in at a few key moments. If you thinks it's better, I'll update my original post and put it at the top of the tread.  If you think it still need improvement, let me know and I'll keep working on it.

thanks
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 22, 2015, 05:13:56 AM
Yeah, that's better Andy.
I also like "bracketing" fore and aft with real time demos to illustrate the ease and speed of tying.

Regarding the naming of this method: Take your time. Of course, I'm happy to contribute.

Thread drift alert! I have two friends who are currently down in Red Rocks on a 12 day climbfest . They won't want to come home.

Cheers,
alpineer
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 22, 2015, 05:39:07 AM
  I was playing around with practicing this Hybrid method:

https://www.youtube.com/watch?v=QeKLU_6NLv4

when I came upon (came up with?) my new method. 

Shades of Synchronicity, Batman! I'm the author of that method. I confess to wondering, after watching your video, if you'd seen mine!
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 06:02:00 AM
Quote
I'm the author of that method.

FANTASTIC!

You deserve some credit for this new method, then.  If not for your video (and the pool at O) I never would have come up with the new method.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 22, 2015, 06:08:04 AM

when I came upon (came up with?) my new method.  Underwater the rope floats around, and a loose version of the "hybrid hand wrap method" floated into something like the final method I've come up with.
 

There's heavy irony here; that your discovery took place in a water bound environment where gravity has minimal effect on Planet Earthians but works so well where it, i.e.gravity, has a major effect. :)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 06:17:11 AM
Xarax:

I come to the decision that I must decline our proposed bet.  I fear that the precision of method I have to break test the ABK would not meet your 3% or less difference in breaking efficiency condition to the wager.  Or to put it another way: you're too damn picky  ;)

On that topic, I feel that a 3% difference in breaking efficiency of two sides of a knot, or two knots is so slight as to be disregarded in most applications.  Even 5% is essentially the same to me!

As I rule of thumb, when I'm figuring out safe working loads for rigging involving knots, I figure that all knots reduce the breaking strength of the rope by 50%, adding an additional margin of safety.  As you know, the number of variables that affect knot efficiency are so numerous, that an accurate.. down to 3%.. real life known breaking strength of any rigging system is largely unknowable.  Or at least so complicated to compute that it would become counterproductive.

I am interested in your knot booklet, and would be happy to purchase a copy when you have it ready.

And, I intend to do the break testing we spoke of, and I'll post the results here for all to see.  Please be patient, it may take me a week or so to complete the testing.

cheers
andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 06:27:45 AM
Quote
I have two friends who are currently down in Red Rocks on a 12 day climbfest .

Alpineer, I sent you a private message about your friends  :)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: agent_smith on April 22, 2015, 11:06:58 AM
Quote
The CMC rescue guide states that the alpine butterfly has a efficiency of 75% when the loop is loaded, and 57% when pulled end to end

Hmmmmmmmmmm.

Strength is irrelevant.

For rope rescue and general climbing applications, knot strength matters least. What matters most is:
[ ] security
[ ] stability
[ ] jam resistant
[ ] and a 'new' concept (from mobius) that has long been understood but rarely documented - verifiability.

Note that I have not arranged these in any particular order of importance.

I also wish the knot could be referred to simply as a 'Butterfly knot' as it was previously known per Wright and Magowan (Note: Originally known as the 'Lineman's rider' per AA Burger 1914).

Mark

Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 22, 2015, 11:32:17 AM
... the knot could be referred to simply as a 'Butterfly knot' as it was previously known per Wright and Magowan
 ( Note: Originally known as the 'Lineman's rider' per AA Burger 1914).

   Where did this "Alpine" come from ?
   
   Strength is irrelevant.

  OK. When they will come to rescue us, I will let you go first ( provided you grasp the loop with the weaker knot, of course, because knot strength is irrelevant to you ), and then I will try my chances with the other one... :) 
Title: Re: a new way to tie the alpine butterfly knot?
Post by: agent_smith on April 22, 2015, 12:46:10 PM
No problem xarax.

I have always wanted to travel to Greece and climb there (eg Kalymnos) - I have read a lot about climbing in the Greek islands and it looks absolutely spectacular. If I visit - i would like to meet you and take you on a climbing adventure :)  See also: http://climbgreece.com

By the way, Sterling 11mm diameter abseil rope has a typical MBS of 31.1kN (thats over 3 metric tons) - even with a worst case scenario of 50% loss of strength due to a poor knot - you still have over 1.5 metric ton remaining. As an example, I weigh 100kg.
Sterling dynamic rope example ('Evolution Velocity'): http://www.sterlingrope.com/c/climbing_dynamic-ropes_9-8mm-evolution-velocity?action_type=switch_product&selected_cat_keys=1114670.46335.1114274.0.0&selected_product=1d60eff37814c55515ec6ef2334af5c8&redirected_post=1   NOTE the absence of any MBS / Ultimate tensile strength data!
[ ] Another popular climbing rope: 'Beal Joker' http://bealplanet.com/sport/anglais/corde-joker.php      Note again lack of ultimate tensile strength data!

Tie-in knots dont cause rope failure - the main culprit is falling over a sharp edge - thats a very bad thing for a rope. Another issue is cyclical loading over a rough/abrasive/sharp edge as can happen when a fixed rope rubs repeatedly over the said rough/abrasive edge (caused by the cyclic bounce of ascending or descending).

When I take falls in lead climbing, the thought that runs through my head is whether my gear placements will hold or whether my rope will run over a sharp edge. I'm never concerned about % strength remaining due to the tie-in knot on my harness.

Mark


Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 22, 2015, 01:20:29 PM
   You know much better than me that nowadays very few people climb with an 11 mm rope...
   Also, knots can also be tied on the much thinner personal escape ropes ( I have read that many people use 5mm ! ) - and there is always the possibility a single rope will be used by a rescuer and a rescued, that is, a load of two persons. You should also take into account the dynamic aspects of the loading, because the load and/or the vehicle on which it is attached by the rope moves, and the speed and direction of this motion may change abruptly.
   However, I was not talking only about climbing and rescue ropes... Knots on ropes are used by riggers in transportation, lifting and construction work, in mooring lines, in fishing lines, etc. You should not suppose that the safety factors on all outdoors activities are as high as in climbing. You can never know how strong a gust of wind or a wave will be - so, if you can chose from more than one "similar" - regarding every other safety characteristic and factor - knots, it is reasonable to select the strongest of them, just in case. A strong knot does no harm...
   Ask a fisherman if he believes that the strength of the knots he ties on ins lines are irrelevant or not ! Of course, if you are not hungry, and you also wish to offer one more chance to the poor hungry fish, you tie the weakest knot you know...  :) 
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 22, 2015, 01:46:34 PM
   Do nt take me wrong... I am not saying that the strength of a knot is the first thing that will make me chose the one knot or the other !  It is most probably the very last thing - but it is not irrelevant !
Title: Re: a new way to tie the alpine butterfly knot?
Post by: agent_smith on April 22, 2015, 01:53:05 PM
Xarax,

11mm (7/16 inch) diameter low stretch rope is very popular and is the gold standard for vertical rescue and industrial rope access work. Fire rescue teams use 13mm (1/2 inch) diameter rope which has an even higher MBS.

Dynamic climbing ropes are getting thinner - I like to use a Beal Joker but Sterling USA also make great dynamic ropes.

In the context of the original poster, it appears to me that he works at height (maybe rope access and some rigging with cranes) and might also do a bit of climbing??? The Butterfly knot he posts about is mostly used in rope access work and also climbing applications (including rope rescue). I dont think he was referring to fishing line or fishing applications.

I standby my assertion that strength is not a critically important factor in modern kernmantel ropes (either EN1891 low stretch or En892 dynamic).

What matters most is what I alluded to in my previous posts - ie security, stability, verifiability and resistance to jamming.

...

Do you live anywhere near Kalymnos?

Mark
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 22, 2015, 02:52:45 PM
  13mm is NOT 1/2 inch !  :)
  I had pointed out that your calculations were based on an 11mm rope, while now, as you say, even ordinary climbing ropes are getting thinner. A 7.8 mm rope has half the <area> of an 11mm rope ( so, presumably, half the strength, too ) - and you had also ignored the factor of dynamic loading. And a 5.5mm personal escape rope the one fourth of that... So your 1.5 metric tons of strength become much less, and your 100 kilograms of weight become much more.
  Personally, I am not interested where a knot may be used, and/or by whom - even whether it will be used, by anybody, or knot !  :) :)  I am interested in each and every possible simple knot per se - as a structure, a mechanism, a physical object.
   Have you ever measured the area of a triangle ? I suppose you did, but you had not used the formula which derives the area of the triangle from the lengths of its sides - and I am sure you do not consider the existence of this formula "irrelevant" to geometry. Recently, a generalization of this formula was offered for the volume of a polyhedron, where all the faces are triangles - and this proved the theorem that every such polyhedron has a constant volume, even if it is flexible ! You can squeeze it and transform its shape, but its volume remains the same.
   No, we do not need to know which knot is stronger of which, only to use this knowledge, in general, and to use this knowledge to do a particular job, in particular. We want to do our job as correctly and accurately as we can, and our job is to learn about knots as much as we can. If everybody, everywhere, does the same, then there will be much less accidents ( and possibly no murders at all !  :))
   ( There are thousands of rocky islands in my neck of the woods  :) - I am sure we will find one to test the strengths of our knots !  :) You will climb, I will watch and rescue... )
Title: Re: a new way to tie the alpine butterfly knot?
Post by: agent_smith on April 22, 2015, 04:25:57 PM
Sorry Xarax, I was 0.3mm out. In Australia, we are fairly easy going in nature and it is normal to round up to 13mm.

It is common to say that a half inch is 13mm (rule-of-thumb).

To be exact; Half inch = 12.7 mm

I'm not going to continue any further debate about about this matter as it is getting further off topic.

I do hope that future knot reviewers spend less time discussing pure % strength and focusing more on security | stability | resistance to jamming | verifiability | .... :)

I came across a board gaming group called HAMTAG the other day. Acronym for 'Half As Much, Twice As Good'.  I am transposing this concept toward keeping things as simple as possible - that is; less convolution, less bulk, simplicity, it just works.

having said that, examining raw strength data can give us insights into the relationship of knot structure and trying to pinpoint the localised region of rupture when rope is pulled to failure. But I maintain that raw knot % strength reduction in relation to the same unknotted rope is really not a crucial factor in human life support applications (like climbing, abseiling, caving, vertical rescue, etc).

For example, I use #1410 for retrievable abseils (rappel systems where you need to retrieve your ropes from below). In a raw pull test - this knot would yield low % strength figures. And yet, it is 'fit-for-purpose' - it is the best choice to ensure ropes will retrieve around a 90 degree edge. Strength is not important - what is important is being able to retrieve your ropes. I have already alluded to the dangers involved with stuck ropes. It is a nightmare scenario - I remember wanting to climb Great Trango tower in the mid 1980's (Karakorum Himalaya) - only to learn of the Norwegian tragedy during their epic descent. This spooked me and my team mates and we switched to a satellite pinnacle of the Ogre group. My point is that #1410 is a 'weak' knot - but it works well (it wont cause the ropes to suddenly and catastrophically fail). I have often descended in a tandem configuration on this end-to-end joining knot - meaning 200+ kg. The knot works.

Mark



Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 22, 2015, 05:46:04 PM
   To be exact; Half inch = 12.7 mm

   Therefore, if you want to round it up, 1/2 inch is 12.5 mm, not 13mm.
   Therefore, your rounding was 0.5mm out - 4%  :)

...a crucial factor in human life support applications ( like climbing, abseiling, caving, vertical rescue, etc ).

   Please, read my previous post more carefully, again.
   Knots are utilized by humans ( like numbers do...), but knot tyers can also study them for their properties as knots, independently of their applications ( like mathematicians study numbers, independently of their usefulness in counting apples... :)) . You can design, built and use wheels to go to the next village and steal the other chief s wife, but you can also study the properties of the circle per se. And pi, you know, should not be rounded to 3...  :)
   Anyway, knots are NOT used only in "human life support applications", by "climbers", etc ! To learn who needed most, and contributed most in the evolution of practical knots, read the very first sentence of ABoK !  :)  The absolute strength of a knot is not "nonsense" or "irrelevant", because there is always the possibility of an unexpected, uncontrollable, excessive loading, which will test the properties of this-knot-assisted structures beyond the "safety factors" ( those structures may be just scaffolds made of ropes, knots and bamboo poles, used now, as we speak, at construction sites in China and NorthEast Asia...).
   You are a climber, and it comes natural for you to "see" the knots merely as means to your beloved end, so you are interested mainly in knots utilized for climbing, and mainly in the properties of those knots which are useful in climbing  - the hammer and the nails ontological relation, you know... :)

  Strength is not important - what is important is being able to retrieve your ropes.

  In THIS particular application ! In other applications, the priority relation may differ, or even be the exact opposite.

   The knot works.

   So what ?  :)  Almost ALL knots, even the most dumb ones ( like three-four overhand knots or half hitches, the one after the other, for example ) will "work", in most cases... Do not limit your view in what a knot can do, "see" what a knot is independently of the particular application - and even independently of any application ! Knowledge has a "value", which may be transformed into a "price" hundreds of years after it is acquired - or never ! 
   Every even integer number can be expressed as the sum of two prime numbers. NOBODY will "use" this conjecture ( still unproved ), ever ! However, thousands of people, for the last 250 years, who study numbers, are "wasting" their lives trying to "see" the truth of this most simple fact, beyond any "practical" reason.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 22, 2015, 08:06:38 PM
Hi guys, 

Quite a debate :)

agent_smith, I work as a rigger in the entertainment industry, mainly acrobatic rigging currently, but my experience includes arena, theatre, circus, hemp-house, fall arrest, and ropes access rigging.  I have some limited hands on knowledge of sailing and arborist rigging as well, as theatre rigging borrows from many other fields.

I agree with you that strength is not the only consideration in a good knot.  But perhaps not the least important.  I would use the term inspection, or inspectability, instead of verifiability, but I understand what you mean.

As far as #1410 goes, I personally wouldn't allow it in a ropes access environment, or for lifting heavy loads overhead (regardless of design factor).  It doesn't meet my criteria for stability.  I do know that it is widely used, and I understand why you haven't used it's common (usa common) name :)

I consider myself fairly well read on the topic of knots, but haven't come across  "Wright and Magowan"  Could you tell me the name of their work, so that I could find a copy?  Thanks.

Lastly,  what do you think of my method of tying the butterfly?  Is it original, and does it have merit? 

as for you Xarax:

I am seeing, more and more, that we have different points of view on knots.  I wonder if you've ever used a knot for a practical application, or if they are just objects for you to admire and dissect?  Knots came into existence to do a job, to serve a purpose.  I judge a knot by how well it serves a purpose, even "decorative" knots serve a purpose, and most were invented by sailors to do a job, the fact that they are pretty is an added bonus.

You've said a lot in this thread, but you haven't told me if you think my new method of tying the ABK has merit, of if it is original.

Thank you both for your input, I've greatly enjoyed reading your posts

andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alpineer on April 23, 2015, 03:48:08 AM
Alpineer:
The two methods you mention of tying the ABK: would those be the hand wrapping, and twisting methods?

Well, yes and no. They are ergonomic adaptations, or re-interpretations, of how the traditional methods are typically depicted. The hand-wrap version is closely related to the "Hybrid" method as it uses one less wrap than the trad.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: Dan_Lehman on April 23, 2015, 07:25:13 PM
  13mm is NOT 1/2 inch !  :)
  I had pointed out that your calculations were based on an 11mm rope, while now,as you say, even ordinary climbing ropes are getting thinner.
A 7.8 mm rope has half the diameter of an 11mm rope ( so, presumably, half the strength, too ) ...
Evidently, you outnumbered yourself!   :o   ::)
(11/2 < 7.8, well less.)
You must've intended "... the material/volume",
which presumably implies strength.

In common rope parlance, I think that much of rope
sizing is based on "nominal" sizes, with specifics coming
from weight-per-100' or whatever.  Oddly, in rockclimbing,
ropes now are specified by fractions of a millimeter!!!
This must seem ludicrous to other rope users!  (IMO, yes!)
For one thing, just making such an exacting measure
(fraction of mm) seems dubious.  (In the good ol' days,
it was 9 & 11mm, 3/8 & 7/16th inches.)


--dl*
====
Title: Re: a new way to tie the butterfly loop?
Post by: alpineer on April 23, 2015, 07:55:12 PM


I notice that if you accidentally reverse the loop twist of the very first step, you end up with an evil imposter knot for the butterfly loop, namely the half-hitch loop (http://igkt.net/sm/index.php?topic=1892.msg13064#msg13064). 
Title: Re: a new way to tie the alpine butterfly knot?
Post by: xarax on April 23, 2015, 08:09:41 PM
  Evidently, you outnumbered yourself!   :o   ::)

  Lost in the copy and paste... Obviously, I intended to write, and meant, "area", not "diameter". THAT is the meaning of the "too", too !  :) Strength depends on the cross-section s area, not the diameter, of course.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 23, 2015, 10:33:09 PM
So I've found out this method is (as I suspected) not new, and is know to some folk out there.  I have by no means exhausted the possible forums to post this method, but I did find some arborists in the uk to whom this method is know.  One guy described learning it back in 98! At an arborist convention.

If I find out more, I'll post it here

Andy
Title: Re: a new way to tie the alpine butterfly knot?
Post by: alanleeknots on April 25, 2015, 06:41:48 PM
Hi All,
         Last time I tie the Butterfly loop on a vertical line, this time I use the similar method and tie it on a horizonal line, it work out
         quite well too. Andy, I have to thanks you, if I didn't see your video, I may not have these two videos.
         https://www.youtube.com/watch?v=xD_DovrBfwc
         
         謝謝  alan lee.
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 28, 2015, 02:18:34 AM
I've posted the results of my break testing of the ABK in the "practical knots" section of the forum.

My conclusion is that the strength of the ABK is symmetrical, there is not a weaker and stronger side of the knot, as proposed by Xarax.

I've attached the pdf to this post as well.  I have a larger file (400kb), containing pictures, which I can provide to anyone interested.  Or I'll post it on the forum if anyone has a suggestion of how to do it (the max attachment size is 100kb)
Title: Re: a new way to tie the alpine butterfly knot?
Post by: knot rigger on April 28, 2015, 02:58:43 AM
An interesting point that knots in smaller line may be more efficient than in larger line.

I may be able to break test some larger diameter line in the future.  If I manage to, I'll post the results.