Dual-loop Butterfly tying

[mcjtom]

There is a wrap-over-hand method of tying the dual-loop Butterfly (and the single one as well).  Is there a way of converting the regular (single loop) Butterfly to a double-loop one?

[agent_smith]

Is there a way of converting the regular (single loop) Butterfly to a double-loop one?

It depends on which variant you are referring to?
One might also assume that you are referring to a 'TIB' transformation?

There are 2 known double eye variants...
The 'Girth hitched Double Butterfly' can easily be transformed into its dual eye geometry from the base #1053 Butterfly (via TIB - without access to either end).

As far as I am aware, the other double Butterfly cannot be transformed from the base #1053 Butterfly structure via 'TIB' methods.
Although, knot masters such as Alan Lee or Xarax might direct their minds to this challenge and figure out a way to achieve such a transformation (via 'TIB' method from base structure).

Note that both variants have very different geometries (refer to my image for details).

[mcjtom]

Thank you Mark - I had no idea that there are two 'versions' of double eye Butterfly.  Do they both have similar properties?

[Dennis Pence]

There are more than two "dual loop" variations on a Butterfly.  Ashley himself gave one way to transform a Butterfly (which he called a Lineman's Loop) into two splayed loops.  See ABoK #1100, where he gives the wrong name for the knot you start with (a Single Bight Loop Knot) but he gives the correct reference number (ABoK #1053).  You can also find this in    Phil D. Smith, Knots for Mountaineering, 1953.  Available at 
         http://www.paci.com.au/knots.php   
Smith labels it no. 19 Twin Loops (a method for reworking a Butterfly Loop to get two loops).  Brian Toss in Knots for Boaters, 1990, calls it a Double Lineman's Loop. 

However, this double loop knot works best if the two standing parts come out of the knot parallel to one another.  You can pull them in separate directions, but the spread knot doesn't seem that great.  The versions that Mark gave above work better for spreading.

[Dennis Pence]

If your complaint is simply that you do not like to tie a Butterfly with a hand wrap method, here is a generalization of the "twist-and-flop" method that is given by Bushby and Ashley [ABoK #1053] that will give a Double Butterfly.  I tried to label things much as Bushby did in his beautiful diagrams.

See also the excellent article by Richard Delaney
   https://www.ropelab.com.au/the-awesome-alpine-butterfly/
where he has a delightful video showing how to tie what he calls an "Alpine Bunny" starting with a regular Butterfly.  This effectively shows how to transform a Butterfly into the Girth Hitch Double Butterfly with the loops going through the ring in a pulley.

[mcjtom]

Cheers for that, Dennis!

[agent_smith]

There are more than two "dual loop" variations on a Butterfly.

This comment is entirely dependent on how you wish to precisely define what a 'Butterfly eye knot is!
In my personal view, #1100 'Double Splayed Loop' from Ashley is not a 'Butterfly'.
Also the knot at illustration #19 'Twin loops' in Phil D Smith's book isn't a 'Butterfly'.
In both cases, the knot is derived from a #1053 Butterfly - but this is not the same as saying that it is a Butterfly.
I also note that both authors were careful not to assign the name 'Butterfly' to their illustrations.

From a geometric standpoint (which is sort of like looking at its DNA fingerprint) - A 'Butterfly' consists of 2 inter-linked overhand knots of opposite chirality.
And, a 'Butterfly' can be through-loaded (biaxially, from SPart-to-SPart) while remaining secure and stable.
As far as I am aware, a 'Butterfly' is jam resistant in biaxial through loading profile.

The derived dual eye knots from Ashley and Smith are not stable in a biaxial through loading profile.

Furthermore, the geometries depicted by Ashley and Smith are actually a type of 'Bowline'.
Look closely and you will see the nipping loops.

...

Interesting note: The 'Karash' eye knot can be derived from #1047 F8.
But this does not mean the Karash knot is a Figure 8 knot.
In fact, the Karash eye knot is a pseudo/virtual Bowline (nipping structure is based on a #206 crossing hitch).
So this is another example where a derivation can differ markedly from its starting base.

[Dennis Pence]

Inspired by Richard Delaney's way to transform a regular Butterfly into what he calls an Alpine Bunny (Girth Hitch Double Butterfly), I came up with the following way to transform a regular Butterfly into a Double Butterfly.  At first, I thought it was different from the Double Butterfly above, so I started to call it version B.  But then I saw how it could easily be transformed into version A.  When I tie a Double Butterfly with the hand-wrap method, I am not sure which version I get, and I do not think it really matters.

[agent_smith]

Hello Dennis,

I've been distracted by too many other things in life... and have only just had time to come back and revisit your work.
I must say that I am very impressed with your technical creativity!

You have proven that it is indeed possible to derive both double eye versions of a 'Butterfly' (beginning from base #1053 Butterfly).

This is just brilliant in my view

I would like to ask you a question if I may...

Did you derive this TIB tying method independently?
Or, was the tying method already existing in some obscure literature?
Please note that I am not attempting to insult you or to denigrate you!
I just need to be 100% sure - because I am writing a technical paper on #1053 Butterfly - and I would like to acknowledge you as the discoverer of this ingenious TIB tying method.
What you have achieved is remarkable in my view...
Thank you for your consideration...

EDIT:
I've attached an image showing how a pulley can be attached to the so-called "Girth hitched double Butterfly' (via TIB transformation from base #1053 Butterfly).
This is a very useful technique for vertical rescue technicians and rope access technicians.
Its simple and quick.

With the other double eye Butterfly variant, it would be nice if a similar method would work to add a pulley (via TIB transformation from base #1053 Butterfly).
I haven't attempted the procedure as yet... just putting it out there for you or others to find a way
I'll have a crack at it later...

[Dan_Lehman]

That pulley-swivel attachment knot is neat.

But for what other reasons is a double-eye, NSUE/midline
Eye Knot wanted?  --for one can dispense with the asymmetric
butterfly and go with a *symmetric version* (#1408) or with
#1452, among others.  These work well for using the two eyes
as one --with only one loaded, the other can draw too snug to
the knot body; used as twins, that doesn't happen.

--dl*
====

[agent_smith]

But for what other reasons is a double-eye, NSUE/midline
Eye Knot wanted

Rope access technicians and vertical rope rescue technicians work in a diverse range of environments
and contexts. The ability to quickly and easily create a mid-rope anchor point (via a TIB through loadable knot), and also the ability to
add a pulley increases the options that are available to the operator.
Furthermore, the 'Butterfly' and its double eye variants are biaxially through loadable, which does not
disturb an already deployed vertical rope's alignment. The deployed rope can also be tensioned (ie loaded),
without adverse effects (the reduction in MBS due to the tied Butterfly is not critical).

As for your 'NSUE' acronym - not sure of your precise intended meaning? 'Non Symmetric ...?

As for #1408 - have you found a way to make this knot TIB (Tiable In the Bight) - that is, TIB as an mid-line TIB eye knot?
I am of the view that the eye knot form of #1408 is not TIB?

Same issue with #1452, if this is tied as an eye knot, I was of the view that it isn't TIB?

Are you suggesting that #1408 and #1452 can both be tied (with an eye) via TIB method (and have double eyes) - and be through loadable?
This would be quite remarkable...

EDIT NOTE:
I've attached an image showing TIB midline variants of #1425A Riggers bend and the Zeppelin bend.
However, neither of these structures are 'Butterfly' knots. The 'TIB Zeppelin' isn't 'easy' to tie... (in my opinion).
The 'TIB Riggers bend' is easy to tie, but I don't think it will find utility with rope access or VR technicians.
I think the double eye variants of the 'Butterfly' will find utility with these user groups...
NOTE: The 'Girth hitched double eye Butterfly' has a different loading effect on the knot core. Each 'eye' is
actually independent. Compare this to the other double eye variant of the 'Butterfly' where the the 'legs' of
each 'eye' distribute load across the knot core more evenly.

[Dan_Lehman]

But for what other reasons is a double-eye, NSUE/midline
Eye Knot wanted

Furthermore, the 'Butterfly' and its double eye variants are biaxially through loadable,

Again, it's a SINGLE "axis" of tension running through the knot
(on it's S.Parts, eye legs unloaded here).

As for your 'NSUE' acronym - not sure of your precise intended meaning? 'Non Symmetric ...?

"NSUE" (French) = "TIB" (English) :: made to both get
other than English into the nomenclature
 ("nouer' sans utiliser les extre'mite's")
AND
to avoid the problematic "bight" --which just
doesn't have a happy (=consistent) existence.

> As for #1408 - have you found a way to make this knot NSUE
> - that is, TIB as an mid-line TIB eye knot?
> I am of the view that the eye knot form of #1408 is not TIB?
> Same issue with #1452, if this is tied as an eye knot, I was of the view that it isn't TIB?
EDIT NOTE:
I've attached an image showing TIB midline variants of #1425A Riggers bend and the Zeppelin bend.

And these have dual eyes, opposed sides of the knot
(and thus more like the insect than others --nb!).   

Probably tying in similar method, lay out a big "Z" / "S"
in the what-some-might-call-"bight"-but-not-others
... rope where the knot's wanted,
and then work with the U-parts (some..."bights"...)
qua single end-parts to tie the desired knot,
having this share-bight-leg/part in middle
to mind and work around.

Yes, I was amazed/surprised/delighted to see these
knots take form; big surrounding of parts by the S.Parts
so must be in this gentle curving pretty kind to the rope.
But the eyes really are best used as one,
just to prevent the collapsing of a collar if around an
UNtensioned S.Part.


--dl*
====

[enhaut]

@mcjtom
Please excuse me I have to go off topic to salute Mr.Lehman

@Dan_Lehman
It is interesting to note that I (a native French speaker) didn't come to know about the term "NSUE" until I read your post.
I take the liberty to insert the definition to provide some other meanings.
The English translation is italicized.

[agent_smith]

Whether you like it or not, English is the defacto language for science and research papers.
Link: https://www.researchgate.net/publication/329655421_The_Use_of_English_Language_in_Research

I am a native English speaker - meaning English is my first language.

I will therefore stick with communicating concepts/ideas/discoveries in English.
I suppose with the prevalence of cancel culture  and woke ideology, (ie the tendency to call out others for anything you disagree with),
its probably just a question of time until I get cancelled

Anyhow, on topic (sort of)...
The term 'TIB' (Tiable In the Bight) works for me - there aren't too many 'edge cases' where the concept is muddled.
I usually define 'TIB' as follows:
A knot is TIB if it can be formed without access to either end. The reverse also applies; it can be untied without access to either end.
The key underpinning concept is .... without access to either end.
Another acronym... WATEE (without access to either end)!
I'm content to stick with English and use 'TIB'.

...

The main concept behind the original post and I think most of the follow up posts is in relation to an eye knot that fulfills the following criteria:
1. Is TIB.
2. Can be 'through loaded'.
3. Have dual eyes that are superposed (adjacent/side-by-side) - and can be loaded together.

When I use the phrase 'through loaded'... I mean:
Loading is in axial alignment with both SParts, which are 180 degrees opposed,
so that load transmits through the knot core in a straight line pathway.

This definition requires the presence of two (2) SParts (standing parts).
And the SParts must be in axial alignment.
Load propagates from one SPart, passes through the knot core, and continues through to the opposite SPart.
Load can be bi-directional (coming from, or going in both directions).

Not all knots can sustain this type of 'through loading' profile (or biaxial through loading).
#1053 Butterfly can... which makes it very useful to rope access technicians, and other users groups who engaged in roped sports.
I have used the term 'biaxial through loading'... to make it clear that both SParts are involved.
Its not just a case of having the knot axially aligned... it also the fact that both SParts play a role.
It is also implied by these definitions that a 'TIB', through loadable eye knot can also exist mid-line.

Anyhow... I'm acutely aware that language and definitions are on trial here... and this is a technical knot forum;
and so when we start to drill down to granular details, there will be differing opinions.

Firmly on topic:
#1053 Butterfly is capable of sustaining a 'through loading' profile - without jamming or distorting.
 Key points:
1. The Butterfly can be transformed into a double eye variant - beginning from the base structure, without untying it.
2. There appears to be only two (2) double eye variants of the Butterfly (this is not conclusively proven).
3. It is possible to attach a pulley to one of the double eye Butterfly variants (the 'Girth hitched' variant).
4. It is not clear to me if a pulley can be attached to the other double eye variant of the Butterfly (needs to be proven if possible).

Dan Lehman has raised the issue of #1408 and #1452... suggesting that these knots can exist in 'TIB' form with double eyes, and be through loadable.
That is, #1408 and #1452 can exist mid-line, without access to either end, and be capable of sustaining a through loading profile.
If this is true, then it also needs to be confirmed if a pulley can be easily attached (in the same manner as with the 'Girth hitched' double eye Butterfly).

Happy to discuss - since this is a technical knot geek forum

[KC]

Another definable consideration:
Angle of pull on the eye/pulley, inline to the length of the rope distorting graceful flow of BFly the most
vs. lateral/cross-axis pull across the length of the line, distorting BFly the least, easiest untie too.
(but at worst angle structurally for column of length of line in trade)
.
Will go with a single axis of tension on (opposing)length of the line pulls.
A pull direction from center to each end, in opposing directions as then collectively an axis proper.
>>the gun shot, and it's kickback, each starting at the initial point in opposing directions as collectively a loaded axis.
>>just as a tug of war across great rope is a 1D single axis of antagonistic/opposing pulls, Equal (forces) & Opposites(directionally).
can not have 1 direction of force without the other, to make 1D line the minimal force form
>>no 0Dimensional force that is a point w/o wife/pair; as must have E&O and potential oppression in direction for change to then have force of linear 1D(loaded rope line, gun shot) or radial of 2D(capstan or winch)or3D(explosion) forces, but no 0D force.