Double loop knot variation

[tansel]

Hello everyone,

I would like to present to your views a double-loop knot that I obtained while practicing in the cockpit of my boat. The geometric visual, photos and construction method of the knot are in the attached links.

As far as I looked in The Ashley Book of Knots (Ch.12: Double and Multiple-Loop knots), I could not find this knot. Although it is similar to No.1088 (Sheepshank Knot) and No.1089 (The Hitched Tom Fool's Knot), I hope that you will see the difference in the knot I presented when you compare the visuals.

Unfortunately, I did not have the chance to measure the strength of the knot with test devices. However, I tied my 38 ft. boat to the cleat on the pontoon from both sides and was able to untie it without any difficulty after two very windy days.

I would be happy to hear your answers and opinions on whether this knot, which I think has a Bowline topology, has been made before, if so, what its name is, and also the use of the knot and its behavior under load.

Best regards

NTT-TR-Double-Loop-Bowline-Variation-Diagram.png
https://1drv.ms/i/c/d03f8f395aaac30a/EWELt4VILBJKo7grvP405DQBwRLGw04JKyujNyz5npxXMQ?e=pTRCvK

NTT-TR-Double-Loop-Bowline-Variation-Photo-1.jpg
https://1drv.ms/i/c/d03f8f395aaac30a/Eel5kSmeP7FElz-vuPAQuswB8qf4yHLWt4xg7ZXwVVVjtw?e=LCCcjc

NTT-TR-Double-Loop-Bowline-Variation-Photo-2.jpg
https://1drv.ms/i/c/d03f8f395aaac30a/EcorabndeWBEnD29fulGDigBp9v_jJcFUN1KZiqyIAfJgA?e=e0hTmQ

NTT-TR-Double-Loop-Bowline-Variation-Sequence.png
https://1drv.ms/i/c/d03f8f395aaac30a/EfSJsMJD0RpDqtrQzzW08wEBMdFjhk6iFEEEFAPHhtDj0w?e=3txO3J

[agent_smith]

Thank you for your presentation 'tansel'.

Its definitely not a 'Bowline'.
The title of 'Bowline' is reserved for a class of eye knot that:
1. Have a nipping loop that is loaded at both ends; and
2. Have a proper collar structure (where both legs of the collar enter the nipping loop from the same side).

It is possible that it is a Quasi Bowline.
This is because there is a nipping structure (not a nipping loop).
The left eye links to the right S.Part and vice versa.

There is a common communicating segment linking both eyes.
I'm not sure of the knots principal intended purpose? Perhaps you could clarify?

I would also comment that 'strength' is largely irrelevant.
More important metrics are:
[ ] stability
[ ] security
[ ] resistance to jamming
[ ] footprint
[ ] amount of rope consumed in forming the knot

EDIT NOTE:
As for this being a new discovery, this will take time to figure out (please be patient).
Only in the fullness of time will all the facts come to light and enable us to make a determination.
Part of the issue is that some great knot tyers are sadly absent from this forum.
I am of course referring to Xarax, and also 'Knot saver', and 'Luca'.
It saddens me that they are no longer contributing directly to this forum anymore.
Others have also disappeared over the years.
Mobius was a fine contributor - and he gave us the fabulous 'Mobius Butterfly'.

[Dan_Lehman]

Its definitely not a 'Bowline'.
The title of 'Bowline' is reserved for a class of eye knot that:
1. Have a nipping loop that is loaded at both ends; and
2. Have a proper collar structure (where both legs of the collar enter the nipping loop from the same side).

The above might be Agent_Smith's limitations, but they are
not my criteria for being a bowine.  I'll regard your
knot as being in the BWL neighborhood, at least;
and not worry about the verdict on it, anyway.

I tried this in some fine venetian blinds cord,
and recommend that each eye be turned/folded
back to tuck out the opposite side,
thereby removing the concern with the eye side
that runs through the original know w/o bending.
Modified as suggested, it seems pretty robust
to various loadings.

Thanks,
--dl*
====

[agent_smith]

Trying not to derail this topic thread...
Dan, there are constraints on what defines a particular knot 'family'.
That is, knots will have certain geometric characteristics which align them to a particular family/genus/species.

If we dont have metrics to define knots, then we could be free to define a knot in any way we feel like.
This would lead to confusion.
There has to be a set of agreed rules as to how to classify a knot.

In the case of 'Bowlines', there are indeed certain geometric features that all 'Bowlines' share.

Principal to all 'Bowlines' is the presence of a functional nipping loop.
Note the use of the term 'loop'.
The nipping loop must be loaded at both ends.

The second part is in alignment with Xarax postulate on the importance of the 'proper collar'.
It is here where you might disagree.

In the double eye knot presented by 'tansel' - it has a nipping structure.
I say 'structure' because it isn't a loop - its closer to a crossing hitch (munter hitch).
Also, the S.Parts are oppositely linked to each 'eye'.
That is, the left S.Part links to the right 'eye' (and vice versa).
This means: The nipping structures are only fully activated when both S.Parts and both eyes are loaded simultaneously.

There is no 'proper collar' per Xarax postulate.

I therefore regard this presentation as a Quasi Bowline.

[Dan_Lehman]

I tried this in some fine venetian blinds cord,
and recommend that each eye be turned/folded
back to tuck out the opposite side,
thereby removing the concern with the eye side
that runs through the original know w/o bending.
Modified as suggested, it seems pretty robust
to various loadings.

Actually, the robustness I found in the above knot
with one further revision :: have the two S.Parts
exit together between/within the elbow-2-elbow
connection they are initially beside --which will
of course soften that material bending.


Thanks,
--dl*
====

ps : 

In the case of 'Bowlines',
 there are indeed certain geometric features
   that all 'Bowlines' share.

And which god created the stone tablets you choose to read?!

For the OP, he raises little issue re this aspect,
and I'm with him on the littleness of it,
and we don't need more nominal "bowlines".

[agent_smith]

Again, not trying to derail this thread about a potential new discovery.

Dan, all of the links provided by 'tansel' include the word "Bowline".
In his text narrative, he also mentions 'bowline'.

Okay - I am not irritated by this in the slightest.
I am simply responding to 'tansel' in a technical manner.

This is a technical knot geek forum - right?
And so I am giving my perspective.

And so I am sharing my understanding of what a 'Bowline' is - given 'tansel's' use of that term.
There is nothing sinister going on here!

...

I have analysed the double eye knot presented by 'tansel'.
I have declared it to be a 'Quasi Bowline'.

And you (Dan) appear to concur via your statement:

I'll regard your knot as being in the BWL neighborhood, at least

Here you stop short of declaring the presented knot to be a 'Bowline'.

Again, I would remind Dan; What is the purpose of this IGKT knot forum?
My understanding is that this is a forum for deep technical discussions about knots.
And in 'New knot Investigations' (which is where I am replying and commenting),
I am giving my technical opinion.

And my opinion is that the presented double eye knot is a Quasi Bowline.
Tansel has not fully described what his intended application might be?
That is, what application(s) might this eye knot be employed for?

It has a communicating common segment - which affords a degree of adjustability.
How does this adjustability compare to the doube F8 eye knot (Ashley #1085)?

[Kost_Greg]

Hello tansel welcome.

You might want to have a look at the following bend structure i have attached.

I'm not sure about its name, but in my view, it's probably Abok#1451.

I have actually illustrated it in a way that's coordinated with your double loop.

If you omit the common line for a moment in your knot, whereby the two eyes are communicating and transpose the bend structure, meaning that the tails are designated as SPs, and vice verca, you will find out that your core geometry, falls under this bend topology.

Xarax has thoroughly investigated  this bend as well as the derived loopknot (Abok #1451 mirror).

Link: https://forum.igkt.net/index.php?topic=4013.0

This is the closest structure to your presentation i have tracked down, but that doesn't mean that it is not original i seriously doubt whether your knot has been recorded before.

Perhaps you were not aware of this bend, but in my view, you have managed to turn a symmetrical bend into a TIB, EEL, bowline-like, double loopknot with an interlocking crossing knot core topology, opening new ways of exploration and i'm highly interested to dive into this field. 

[Dan_Lehman]

I'm not sure about its name, but in my view, it's probably Abok#1451.

And I think among Roger E. MILES's "60 Symmetrical Knots",
but I'm w/o book in typing ... to confirm.

If you omit the common line for a moment in your knot, ...

... you get a dandy 2-Tangle's set of *knots* to explore.
Given the symmetry, half of the 8 eye knots will match
the other half.

Xarax has thoroughly investigated  this bend
as well as the derived loopknot (Abok #1451 mirror).
Link: https://forum.igkt.net/index.php?topic=4013.0

This isn't so thorough :: take the Tangle tour of letting
each end play the S.Part role to its two possible eye knots
(again, symmetry halves our number from 8 to 4),
and the Joints of 1-v-A, 2-v-B, & 1-v-B (or = 2-v-A).
And perhaps other things (the 1-v-A+B, 2-v-A+B, um,
"knot hitches" (would be "Becket H." for the BWL tangle).

Perhaps you were not aware of this bend, but in my view, you have managed to turn a symmetrical bend into a TIB, bowline-like, double loopknot with an interlocking crossing knot core topology, opening new ways of exploration and i'm highly interested to dive in this field.

Good eye!

(Which shows how discovering a "new" knot can lead
to --per Tangle checking, among other things-- a lot
of further work to do (in the interest of seeing what's
out there) :: the Tangle is just sitting there, newly
revealed, awaiting trying on Loading Profiles.)
<sigh>


(-;

[agent_smith]

Of course, any analysis and/or comparison must point to
the fact that this double eye knot has a communicating segment.
That is, the 'eyes' are linked to each other via a shared communicating segment.

It reminds me of #1085 Double F8 eye knot (which also has a communicating segment).
This enables both eyes to be adjusted.

The adjustment mechanism is different in a #1083 'Portuguese Bowline' (more limiting in which directions it can be adjusted).

In a 'Spanish Bowline' (#1087), there is also a communicating segment - similar to 'tansels' presentation.

[tansel]

Hello again,

Thank you very much for all the answers, comments, reviews and suggestions. I admire your approach to knot analysis. Since my knot background is based on scouting/leadership and some sailing experience, my level of knowledge is well below what this guild offers about knots' analysis. Therefore, I will keep quiet for a while and continue to follow your reviews and suggestions.

Meanwhile, I posted a similar presentation to the one I made here on IGKT's Facebook page at about the same time. Antoni Maksymiuk, a member of the Facebook group, posted a form he obtained while trying out my knot as a comment. Later, I tried the same and visualized it. When the knot is in relaxed form, tight pulling from both ends gives it this form - two loops, locked. Links:

Screenshot of Antoni Maksymiuk's comment: https://1drv.ms/i/c/d03f8f395aaac30a/EZ2TsFcnFVtIo7nklGrygI0Bo3AnRIN9BlnctxOMDohmRg?e=yTdHlq
My trial: https://1drv.ms/i/c/d03f8f395aaac30a/EVKK_Y1NIsNOuzD_bS8nhIAB53MwKdOHbAqMeyZQXuM84A?e=Amt4bl

I would also be happy to hear your opinions on this form of the knot.

In addition, I created some visuals to explain the node stages more clearly and to help the members of this forum in their various works. Links:

Sequence with numbers and notes: https://1drv.ms/i/c/d03f8f395aaac30a/EWNY445dJiJPhO7Ijk1VIeEBmKxxTGA8Nh9MdHx2uH1VHg?e=wM4nEO
Sequence with numbers only: https://1drv.ms/i/c/d03f8f395aaac30a/EbOQc092hPFGqrA9Nbwahy4BNtfE4mgaT5D6BQx-lWloWw?e=fl4W2W
Sequence (plain): https://1drv.ms/i/c/d03f8f395aaac30a/ERm4GPak1ltGiB_sPxd64CgBNgxw5hwuedzoLwSygXZ47g?e=ZVEyg2

Thanks again & happy knotting

[tansel]

I tried this in some fine venetian blinds cord,
and recommend that each eye be turned/folded
back to tuck out the opposite side,
thereby removing the concern with the eye side
that runs through the original know w/o bending.
Modified as suggested, it seems pretty robust
to various loadings.

Hi Dan,

If possible, a visual of this change would be very helpful for my understanding.

[Kost_Greg]

You should have expected some sort of distortion, more specifically, when bi-axially through loading the knot from SP to SP, because your SPs are linked directly to both crossing knot collars (the rope segments which encircle both eyes).

Nonetheless, this loading profile of your knot, appears to be remarkably more stable compared to your previous one, with two fixed, non-communicating eyes (loops) this time that are linked with a dual U fold formation or an S shape formation if you prefer.

I tend to believe that this very double loopknot which you originally introduced as an end of line profile at your first post, is afterall, an inline (midline) double fixed eyeknot.

I would guesstimate that your first presented configuration, is just an alternative dressing state of your final, stable, inline formation (equivalent example: Abok 1439 Carrick bend has two forms, the dressing state and the stable state).

As for the eye loading profile, at first glance, i would suggest the following loading combinations.....

1)left SP, lower eye.

2)right SP, upper eye.

These loading options appear to maintain the U-fold formation (the respective straight, common rope segment through which both eyes are linked in your first example), which is now heavily constricted by the SP in question.

However, one has to investigate all possible eye loading directions to determine which is more stable.

[Dan_Lehman]

I tried this in some fine venetian blinds cord,
and recommend that each eye be turned/folded
back to tuck out the opposite side,
thereby removing the concern with the eye side
that runs through the original know w/o bending.
Modified as suggested, it seems pretty robust
to various loadings.

(using Agent_S's image above, which is handy)

The left eye crosses behind the left S.Part;
fold this eye back across the S.Part
(bring eye towards you & then to the right
 to thus wrap around that S.Part).
And now tuck it out right on top of the right
eye.
Then take the right eye in similar tucking out
to the left side.
This puts a turn in the "communicating" part
between the two eyes, I think satisfactorily removing
a problem.

As for the further modification, of tucking the two
S.Parts out beside each other through those sharply
bent center parts, the course should be clear enough
to find.

--dl*
====

[Dennis Pence]

Sorry to be so slow to see this!  I agree with reply #6 that the knot bears a close relationship to ABoK #1451 (which Dr. Harry Asher calls a Corrick Bend in his Alternative Knot Book because he finds it closely related to a Carrick Bend).  Actually, this new Tansel Double Eye Knot is most closely related to the full transposition of the Corrick Bend (the free end and the standing part are switched for both ropes).  See replies 46 and 47 in the general discussion about the abstract relationship between bends and eye knots. 
https://forum.igkt.net/index.php?topic=7509.45

This new midline knot is not included in the list of related eye knots there because the connection between the two free ends goes through the knot structure to form the two loops.  I like your new knot a lot!

[Dan_Lehman]

... (which Dr. Harry Asher ... in his Alternate Knot Book =>"AlternatIVE"

  I like your new knot a lot!

Back to fiddling stuff here, with something more substantial
--and easier for me to discern & manipulate-- than v.blinds cord.
The knot seems pretty robust, and I'm going to look
at it for serving as an "Opposed-Eyes Knot" --something
(the purpose, i.e.) popping up in just one caving lecture,
to my searching, which is odd if indeed there's practical need!?).
Hensel & Gretel (EKFRopework) call it "Eye Bowline";
Ashley maybe copying them calls it "Sister Loops" --neither
book offering a raison d'etre (the caver's idea is an anchoring
eye and a rigger's attach-to eye, with one end loaded for
abseil & ascent).


Thanks,
--dl*
====