Author Topic: What defines a Bowline? - structure, characteristics, topology  (Read 126477 times)

KC

  • Exp. Member
  • ****
  • Posts: 185
    • latest project
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #360 on: November 16, 2017, 11:40:58 AM »
To my eye;
The 'braids' pull away from eye if well set; the turNip pulls into eye.
>>Thus, i think we can see turNip pulls more across SPart deforming it, than braids pulling along roman column length of SPart.
The braids and other friction hitch type builds preserve the 'sanctity' of pure inline SPart, as HH/turNip bases outrightly deform SPart.
As the pull along SPart can be made to stand further from mount it can be shown:
A>Doesn't pull across
B>slants SPart less
C>eventually can visualize as extra leg of support/ load sharing thru deforming parts, rather than all force thru or even at major deformity.
.
Whereas ; in a standard Bowline, all the force hand-off from both legs of eye to 1 SPart seems at one point,
>>in braids version the hand-off from  dual to single seems more gradual,where would seem to be more favored/forgiven.
.
The braid side is an theoretical extension of RT around SPart; giving back some strength of simple Turn deformity; limiting some  the  raising of tension beyond load, to allow less usable capacity 'strength loss'.
.
Final deformity braids assumes before breaking may be a reason not to work or perhaps, in a glass fiber concept(to me): back pressures of major turNip deformity coming thru line overloading only later after braids add load??!!?  Very Interesting in any aspect!
.
Braids Bowline is more secure, gives nice look and weight to end of line (but then also stiffened area that can leverage against line); but yes the main target for the extra 'labor and materials' is strength; these are only side attributes to that un-hit target.
.

.


Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~

SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1799
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #361 on: November 16, 2017, 02:09:11 PM »
KC,

You have the SP straight through the braid, in your graphic (Thanks for it.), and that doesn't show what I had devised and thought at the time that I did my pull tests. The SP should be crossing with the pre-collar parts.
Hopefully the picture attached will show what I mean and where I had marked the parts to be able to inspect  during and after the pull.

SS

KC

  • Exp. Member
  • ****
  • Posts: 185
    • latest project
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #362 on: December 11, 2017, 01:43:40 PM »
Over the weekend i found rather favorable results with this lacing strategy.
>>except 1 piece of stiff cord i had single piece of
>>but this strategy did prove weaker in it 2x
.
using:several small line types/several paracord:
Tied in 1 end as i've shown;
Tied on other end with Standard Bowline with Overhand Stopper
Each Bowline eye had a matching carabiner to it;
>>pulled between truck (frame pull) and tree.
.
Also had as safety:
much longer(than test eye2eye line) line to same carabineers;
>>to catch kickback of eye2eye line snapping
.
Offered even truck pull until line break, no jerk/impact action.
>>small Toyota p'up, small lines is my present testing radius.
Rope-n-Saw Life
"Nature, to be commanded, must be obeyed" -Sir Francis Bacon
We now return you to the safety of normal thinking peoples.
~ Please excuse the interruption; thanx -the mgmt.~

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #363 on: August 23, 2018, 12:54:40 AM »
per Derek:
Quote
So, how about this :-

    A Bowline has the following key aspects:-

   
[ ] A Bowline has two defining internal components, these being a Bight Component and a Helical Nipping Component, plus two defining external components, these being a load bearing SP and a load bearing fixed loop.

[ ] A Bowline may contain other components, but these must not change the form or function of the two key internal components.

[ ] The Bight Component collar must encircle the SP in order to stabilise the Bight Component, although in use the collar may become distorted and lead to eventual failure of the bowline - this is a continuous progression through various degrees of Bowline viability.

[ ] The legs of the Bight Component must be secured by and within the Helical Nipping Component.  This action provides the negative linear cogging function within the knot and is a critical aspect of knot functionality.
    One of the Bight Component legs must be a loop leg.
    the remaining Bight Component leg is normally the WE, but may be reworked to enhance security, but must not change the form or function of the defined key internal components.

[ ] The Helical Nipping Component must be loaded on both ends.  One end must be loaded by the SP, the other must be a loop leg.  The helical Nipping Component may range from an overlapped helix, through a spectrum of degrees of openness.  In use, the helix may continue to open if the bight legs are drawn through the grip of the Helix, eventually leading to loss of viability as a fixed Loop Knot and conversion to a Noose.

[ ] This definition is based on ABOK #1010, but does not extend to incorporating the Eskimo 'Bowline', wherein the Bight collar does not encircle the SP.

It incorporates a considerable amount of flexibility, yet retains the core essence of the Bowline.  The price is that the Eskimo will probably have to become known as the Sheetbend Loopknot ....

Derek

With a few modifications to your chosen terminology, this is largely what I and others have been advancing for some time (but maybe you did not see this?). Problem areas are highlighted in red font.

The nipping structure (or nipping component) - in the common #1010 Bowline - takes the form of a jam resistant helix that is loaded at both ends and is TIB (Tiable-In-the Bight). To Ashley's eye, all 'Bowlines' contained this type of nipping component.

Things get difficult when we see nipping components that take a different form to a helix. For example, there is #206 Crossing hitch and #559 Marlinspike hitch. Both of these structures are TIB and can be loaded at both ends and remain jam resistant.
In my view, it is possible to construct a virtual Bowline from a nipping component that takes the form of #206 and/or #559. The word 'virtual' meaning "in the likeness of" or, "a close representation of".
The use of 'TIB" as a qualifier for a nipping component assists in narrowing the potential for other eye knots to claim the title of 'Bowline'.

In my view the illustration at #1016 (in 'ABoK') is a clue to Ashley's mindset - and shows a [previously functional] nipping loop that, due to a transformation, has become non-functional. I think Ashley recognised that the nipping component needed to be loaded at both ends and be free to encircle and clamp both legs of the collar. In #1016, due to the transformation, the nipping loop has lost functionality. And that (in my view) is why Ashley was hesitant to call it a 'Bowline'. Xarax has also advanced that a nipping component (or nipping 'loop') is most effective when it begins at the continuation of the SPart (standing part).

A further qualifier for a nipping component is that it must freely be able to encircle and clamp both legs of the collar (which you prefer to conceptualize as a 'bight'). When this condition is satisfied, it is said to be 'functional'.

The collar does not need to encircle the SPart (standing part). It performs a U turn around it (not a full circle). This U turn may be performed at the crossing point formed at the juncture of the SPart and the ongoing eye leg (ie so called 'Myrtle Bowline'). The SPart acts as a bracing post.

The 2 legs of the collar may enter the nipping component from opposite directions (in the common #1010 Bowline, both legs enter from the same side).

Xarax is working on a theory about 'PET' (Post Eye Tiable) qualifier - but I am unclear as to how far he has progressed with respect to its completion. In earlier theories, it was advanced that all 'Bowlines' are PET.

With respect to your phrase 'degrees of openness' (re a helix) - a more accurate descriptor is degree of overlap. If the helix were to 'open up' (which I understand to mean spread apart so that there is no longer any contact between the overlapping segments) - it would no longer be functional.

I disagree with your proposition re the so-called 'Eskimo Bowline' (which is an anti-Bowline).
All the necessary building blocks are present - just all in an 'anti' direction relative to the common #1010 Bowline.

And; your use of the term 'loop' may be fluid and diluted - because a loop is a geometry that is not well defined in knotting literature. Some may argue that what you conceptualise as a 'loop', is more apt to be described as a fixed 'eye' (analogy is an 'eye bolt'). The concept of 'loop knot' is likely heavily influenced from the days of Ashley - and has become entrenched. To challenge that paradigm is to invite risk - because the concept of 'change' can induce feelings of fear, and in some cases, outrage. It is a human condition to fear change. And so, to substitute the phrase 'eye knot' for 'loop knot' could ignite fear and outrage. I think that knotting terminology needs to be better defined.

I am currently working on a revision to my analysis of Bowlines paper. I have a rich source of material and ideas to inject into that paper.
« Last Edit: August 23, 2018, 02:43:41 AM by agent_smith »

DerekSmith

  • IGKT Member
  • Sr. Member
  • *****
  • Posts: 1518
  • Knot Botherer
    • ALbion Alliance
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #364 on: August 23, 2018, 03:45:51 PM »
My actual proposal went like this (numbered now for clarity) - without the exclusion of line 6, which I am confident was only a transcription error.


  • A Bowline has the following key aspects:-
  • A Bowline has two defining internal components, these being a Bight Component and a Helical Nipping Component, plus two defining external components, these being a load bearing SP and a load bearing fixed loop.
  • A Bowline may contain other components, but these must not change the form or function of the two key internal components.
  • The Bight Component collar must encircle the SP in order to stabilise the Bight Component, although in use the collar may become distorted and lead to eventual failure of the bowline - this is a continuous progression through various degrees of Bowline viability.
  • The legs of the Bight Component must be secured by and within the Helical Nipping Component.  This action provides the negative linear cogging function within the knot and is a critical aspect of knot functionality.
  • One of the Bight Component legs must be a loop leg.
  • the remaining Bight Component leg is normally the WE, but may be reworked to enhance security, but must not change the form or function of the defined key internal components.
  • The Helical Nipping Component must be loaded on both ends.  One end must be loaded by the SP, the other must be a loop leg.  The helical Nipping Component may range from an overlapped helix, through a spectrum of degrees of openness.  In use, the helix may continue to open if the bight legs are drawn through the grip of the Helix, eventually leading to loss of viability as a fixed Loop Knot and conversion to a Noose.
  • This definition is based on ABOK #1010, but does not extend to incorporating the Eskimo 'Bowline', wherein the Bight collar does not encircle the SP.

It incorporates a considerable amount of flexibility, yet retains the core essence of the Bowline.  The price is that the Eskimo will probably have to become known as the Sheetbend Loopknot ....

Derek

Quote from: Mark
With a few modifications to your chosen terminology, this is largely what I and others have been advancing for some time (but maybe you did not see this?). Problem areas are highlighted in red font.

Or perhaps I have always held this view but not expressed it with sufficient clarity or with the appropriate terminology ?

Of the five exceptions you have highlighted within the definition, three of them relate to my use of the term Loop Knot, presumably in contradiction to your preferred term Eye Knot.  I have to say that I admire your fortitude and persistence in your attempt to justify the renaming of all Loop knots as Eye knots.  But isn't it about time that you accepted the fact that even on here, the majority of knotters reject your arguments attempting to support the change and are telling you that we will continue to call Loop knots by the term we all understand - Loop knots.  Some, including myself, have acknowledged that a specific subset of Loopknots justify the additional sub classification of Eye Knot, when they are small, with parallel legs and suitable for the inclusion of a Thimble.  Without anything new of significance to add to your rationale for such a significant change, I would urge you to consider getting back into step with the majority.  To persist with your
 fixation is only adding unjustifiable confusion.

Of the remaining two problems, the first is my use of the term 'encircle' describing the need for the bight turn to contain the SP.  I have to admit, that the term 'encircle' contains an inference that the Bight collar FULLY encircles the SP.  Would you feel better with 'contains' or 'encloses'?  The Bight Component has three sub components :- the Turn subcomponent (AKA collar) and two Leg subcomponents.  While identifying these parts of the Bight Component has value, it is critical to understand that the Bight Component functions within a knot as an entity.  You focus often on the Collar legs, with the emphasis being on the Collar subcomponent, but in function, the Turn (or Collar) has only the function of retaining the orientation of the Bight legs.  Having been restrained by the Bight Turn, the Bight Legs are then able to perform two critical functions within the Bowline.  The first is to keep the Nipping Helix Component in the correct orientation and to resist the propensity of the helix to rotate and open.  It achieves this from the tension between the external Loop Leg and the Turn around the SP.  The second, and perhaps the most critical part of Bowline performance is that it provides the only significant source of negative linear cogging in the whole knot.  There is a lesser amount of negative rotational cogging with the nipping turn, but without the negative linear cogging between the bight legs, the Bowline is fatally compromised.

Hopefully from this description you will see that it is the Bight that is critical, not just its 'collar'.  [NB this is born out by observations in the wild where loading has led to extension of the Bight such that the Turn (Collar) is virtually flapping in the wind, yet the knot defies decomposition.]

Quote
The 2 legs of the collar may enter the nipping component from opposite directions (in the common #1010 Bowline, both legs enter from the same side).
If I understand your above statement, it indicates that you have had no perception of negative linear cogging.

Quote
With respect to your phrase 'degrees of openness' (re a helix) - a more accurate descriptor is degree of overlap.

A helix, even when there is zero gap between its coils does not have any overlap.  Therefore using the term 'overlap' to describe how far apart the coils have moved is counter intuitive.  By talking about 'overlap' you are moving from the spectrum of plain helix forms into the far end of the Nipping Component spectrum where the nipping turn starts to become a Simple Hitch which is present in many Bowline examples and to a very large extent provides its own end loading - i.e. it does not need external loading from the loop leg.  Although I accept this end of the spectrum, I doubt you do.

Finally, might I make a request - that you first develop a robust understanding and definition of The Bowline i.e. #1010.  Not just one that describes the idealised knots of your excellent photographs, but a definition and understanding robust enough to apply to the vast array of #1010's that are created every day, and which morph under usage and in different cordages encountered in the wild.

Then you might be sufficiently aware of what The Bowline is, to be justified in encompassing other knots into that definition.

Derek

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #365 on: August 24, 2018, 02:56:42 AM »
per Derek:
Quote
But isn't it about time that you accepted the fact that even on here, the majority of knotters reject your arguments attempting to support the change and are telling you that we will continue to call Loop knots by the term we all understand - Loop knots.

This is a phenomena known as 'social proof'.
Link: https://en.wikipedia.org/wiki/Social_proof

I am happy for you to conceptualise an eye knot as being a loop knot and having a loop.

Quote
If I understand your above statement, it indicates that you have had no perception of negative linear cogging.
I have significant doubt that you understand what my level of understanding is.
Your reference to my perception is biased from your own viewpoint. You are being challenged and your mode of reaction is normalised to defending your own viewpoint.

Quote
Finally, might I make a request - that you first develop a robust understanding and definition of The Bowline i.e. #1010.
Interesting comment - but predictable.
You feel that you are being challenged - so you are compelled to devalue the theories and understandings advanced by your perceived opponent.
Some of these feelings are linked to the notional concept of change - and the idea of change can evoke strong emotions in some individuals.

Although the notional concept of 'change' (in this case) may be misplaced.
Two parties with differing perceived viewpoints can be mirrored on a global scale with the analogy of different national ideals and indeed, even within national boundaries as political parties with differing viewpoints. Usually, when the parties are willing to take a different viewpoint, many aspects may in fact be the same, just clothed in a different language.

If I may make a request of my own... taking an adversarial approach to arguing a theoretical concept is going to lead nowhere. Using social proof to advance support for your own arguments is invalid. Perhaps a collaborative approach may yield more positive outcomes?

You are welcome to write a theory of your understanding of what constitutes a 'Bowline' - and I would be happy to insert it into my upcoming revision to my 'Analysis of Bowlines' paper.
« Last Edit: August 24, 2018, 02:58:13 AM by agent_smith »

B.P.

  • Full Member
  • ***
  • Posts: 25
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #366 on: August 25, 2018, 10:35:10 PM »
In my view, it is possible to construct a virtual Bowline from a nipping component that takes the form of #206 and/or #559

Hello agent_smith,

I hope you didn't miss this thread : http://igkt.net/sm/index.php?topic=6151.0

Thank you for the paper about bowlines, I read it many times before my publications on the present forum.

I also share, probably among other things, your interest about tests and terminology.

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #367 on: August 26, 2018, 03:03:41 AM »
Quote
Hello agent_smith,

I hope you didn't miss this thread : http://igkt.net/sm/index.php?topic=6151.0

Bonjour B.P. !

Note: Bonjour is virtually the limit of my French speaking skills  :o

I replied to your other post.
I like your creation very much - it has an elegant geometry (in my opinion).

I have tendered my opinions in that thread...but:
I have used the phrase 'virtual Bowline' to describe your creation.

I think Derek would strongly request that I add a qualifying remark to practically all of my posts on this forum that:
"None of the information tendered by agent_smith represent the opinions or views of the IGKT or its members".
I might need to add a 'tag line' to all of my future posts with words to that effect so as not to raise too many alarm bells!

I had attached a very specific meaning to my use of the word 'virtual' as follows:
 Almost or nearly as described, but not completely or according to a strict definition.
 Almost a particular thing or quality.
 Almost, but not exactly or in every way.


First order Bowlines (or Bowlines of the first order), have a nipping structure that is based directly on a helix that is loaded at both ends (and TIB).

My use of the phrase 'first order' or; 'of the first order' is my invention (and does not represent the opinions and views of the IGKT). Mind you, having to insert this disclaimer each and every time is tiresome - because it could be argued that every post on this forum does not represent the views of the IGKT or its members (obviously, its just one persons opinion)!

Anyhow, I am writing an update to my analysis of Bowlines paper - and I would like to add your creation to that paper (with your permission!).

The updated paper will attempt to classify all 'Bowlines' as follows:
1. First order Bowlines (or, Bowlines of the first order)
2. Virtual Bowlines
3. Anti-Bowlines

I have come under heavy friendly fire from Xarax for using the word 'virtual' - because he strongly feels that in the modern age, it has become associated with computer generated imagery.
I have countered Xarax by stating that as long as I provide a glossary to define each term, the meaning should be as I intended.

Wish me luck!

EDIT NOTE: There is something wrong with viewing attached images - I think the webmaster ('mistress') needs to investigate. Uploading new images also seems to be problematic...
« Last Edit: August 26, 2018, 03:06:28 AM by agent_smith »

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #368 on: August 28, 2018, 03:15:48 PM »
PART 1 of 2

#1033 Carrick 'loop' has always interested me.
This particular eye knot should not be confused with the #1439 derived Carrick eye knot.
They look very similar - but not quite.
The #1033 structure does not have a uniform over-under-over-under weave pattern.
Also, it does not undergo a transformation when load is applied - it retains its form.
And furthermore, there is no #206 'Crossing hitch' structure (as with #1439).

In my view, a possible scenario is that Ashley was not aware of the #1439 derived eye knot - because if he had held both knots in a side-by-side examination, he might have spotted the subtle difference. And so, because #1033 (for all intents and purposes) had the 'appearance' of the #1439 Carrick structure, he decided to attach the title 'Carrick' to its name.

It is my own view that #1033 is more aligned to the family of 'Bowlines' than it is to the 'Carrick bend'.
However, it isn't one of the 'first order Bowlines' (or 'Bowlines of the first order).

I am of the opinion that it could fit within a class of 'Bowlines' called 'virtual Bowlines'.
This is a descriptor I had devised - largely due to dissatisfaction with alternative descriptors such as 'pseudo Bowlines', or 'para Bowlines', or 'quasi Bowlines'.

I intend the term 'virtual' to have the following meaning:
  Almost or nearly as described, but not completely or according to a strict definition.
  Almost a particular thing or quality.
  Almost, but not exactly or in every way.


And the term 'First order Bowline' (or 'Bowline of the first order' - examples include: #1010, #1013 etc):
  Of major importance or significance.
  Used to denote something that is excellent or considerable of its kind.
  A thing having the highest status in a group.


...

The bottom 3 images are EN564 Sterling 8mm cord at the following load milestones:
[ ] 1.0kN
[ ] 2.0kN
[ ] 4.0kN
(each successive image doubles the load)
No instability or insecurity was observed up to 4.0kN peak load.
« Last Edit: August 29, 2018, 12:22:34 AM by agent_smith »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3764
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #369 on: August 28, 2018, 10:31:20 PM »
It's the initial geometry/(non-)setting that is the challenge
--i.e., NOT to (over-)tighten but to leave the tail's circuit
through the initial turNip *relaxed*.  For to tighten it in
most any way will want to bend one or the other ends
leading into the central nipping loop.  Your images show
such nice stability!  --and not seen is the vast openness
of the collar around the outgoing eye leg.

Thanks,
--dl*
====

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #370 on: August 29, 2018, 12:49:00 AM »
PART 2 of 2

I have attached a side-by-side comparison of #1033 Carrick 'loop' versus #1439 derived Carrick 'loop'.
In my previous post, I had tendered a theory that Ashley did not examine [a] corresponding eye knot derived from #1439 Carrick bend.

I'm not even sure that he had outlined a theory about the correspondence between 'bends' and 'eye knots' (aka loop knots). Note that this 'correspondence' with the eye knot form can take on different forms according to which ends go where.
Although, given that Ashley did insert the word 'carrick' into the name of #1033, he presumably understood some level of 'correspondence' between bends and eye knots - but did not expand upon it. I seems that Harry Asher may have been among the first to try to expand the theory?

I am of the view that #1033 has a closer affinity with the family of 'Bowlines' than a 'Carrick bend'.
And indeed, #1033 has a functional nipping structure that takes the form of a single helix that is loaded at both ends (and is 'TIB'). Both legs of the collar are fully encircled and clamped by the nipping structure.

Xarax has pointed to his dislike of the 'collar' in #1033 - and of course, this is one of the structural characteristics why #1033 cannot be regarded as a 'first order Bowline'. The other being that the legs of the collar enter the nipping structure from opposite directions.

It does (in my view) meet the definition I tendered for 'virtual Bowline'.
  Almost or nearly as described, but not completely or according to a strict definition.
  Almost a particular thing or quality.
  Almost, but not exactly or in every way.
« Last Edit: August 29, 2018, 04:40:36 AM by agent_smith »

B.P.

  • Full Member
  • ***
  • Posts: 25
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #371 on: August 29, 2018, 01:33:55 AM »
Quote
Hello agent_smith,

I hope you didn't miss this thread : http://igkt.net/sm/index.php?topic=6151.0

Bonjour B.P. !

Note: Bonjour is virtually the limit of my French speaking skills  :o

I replied to your other post.
I like your creation very much - it has an elegant geometry (in my opinion).

Thanks again

I have tendered my opinions in that thread...but:
I have used the phrase 'virtual Bowline' to describe your creation.

I think Derek would strongly request that I add a qualifying remark to practically all of my posts on this forum that:
"None of the information tendered by agent_smith represent the opinions or views of the IGKT or its members".
I might need to add a 'tag line' to all of my future posts with words to that effect so as not to raise too many alarm bells!

I had attached a very specific meaning to my use of the word 'virtual' as follows:
 Almost or nearly as described, but not completely or according to a strict definition.
 Almost a particular thing or quality.
 Almost, but not exactly or in every way.


First order Bowlines (or Bowlines of the first order), have a nipping structure that is based directly on a helix that is loaded at both ends (and TIB).

My use of the phrase 'first order' or; 'of the first order' is my invention (and does not represent the opinions and views of the IGKT). Mind you, having to insert this disclaimer each and every time is tiresome - because it could be argued that every post on this forum does not represent the views of the IGKT or its members (obviously, its just one persons opinion)!

Anyhow, I am writing an update to my analysis of Bowlines paper - and I would like to add your creation to that paper (with your permission!).

Obviously you don't really need any permission, it's your paper, nevertheless you have it  :)


The updated paper will attempt to classify all 'Bowlines' as follows:
1. First order Bowlines (or, Bowlines of the first order)
2. Virtual Bowlines
3. Anti-Bowlines

I have come under heavy friendly fire from Xarax for using the word 'virtual' - because he strongly feels that in the modern age, it has become associated with computer generated imagery.
I have countered Xarax by stating that as long as I provide a glossary to define each term, the meaning should be as I intended.



Like I already told you on the topic "2 keys knot - Noeud a deux clefs" :
I think that I need more time to study these questions, hoping to find (my) answers to share

but I'll maybe share questions too   ::)

Wish me luck!
I wish you the best, courage and luck.

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #372 on: August 29, 2018, 01:52:34 AM »
per B.P.
In relation to the use of the term 'virtual'...
Quote
Like I already told you on the topic "2 keys knot - Noeud a deux clefs" :

Thanks B.P.

Like I stated elsewhere, the key to understanding is to have a glossary of terms.
As long as the author of a paper supplies clear and succinct definitions, all should be good.

It is up to the reader of the paper to either ignore those definitions or, to interpret them in the way the author had intended.

As I also pointed out, some readers may subconsciously apply their own interpretation regardless of what the author had intended. How do you deal with these type of people?

NOTE: ...please understand that my reply is not intended as a 'fight'! We are not sitting face-to-face in a normal human interaction. Its just typed words on a keyboard.
I am simply engaging with you on an intellectual level :)
I used the quote function to aid in meaning and to give a context for the discussion.
We are just discussing concepts... nothing bad or sinister here!

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3764
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #373 on: August 29, 2018, 11:15:55 PM »
My actual proposal went like this (numbered now for clarity) - without the exclusion of line 6, which I am confident was only a transcription error.


  • A Bowline has the following key aspects:-
  • A Bowline has two defining internal components, these being a Bight Component and a Helical Nipping Component, plus two defining external components, these being a load bearing SP and a load bearing fixed loop.
  • A Bowline may contain other components, but these must not change the form or function of the two key internal components.
  • The Bight Component collar must encircle the SP in order to stabilise the Bight Component, although in use the collar may become distorted and lead to eventual failure of the bowline - this is a continuous progression through various degrees of Bowline viability.
...
  • This definition is based on ABOK #1010, but does not extend to incorporating the Eskimo 'Bowline', wherein the Bight collar does not encircle the SP.

It incorporates a considerable amount of flexibility, yet retains the core essence of the Bowline.  The price is that the Eskimo will probably have to become known as the Sheetbend Loopknot ....

Derek
...
Hopefully from this description you will see that it is the Bight that is critical, not just its 'collar'.  [NB this is born out by observations in the wild where loading has led to extension of the Bight such that the Turn (Collar) is virtually flapping in the wind, yet the knot defies decomposition.]

Quote
The 2 legs of the collar may enter the nipping component from opposite directions (in the common #1010 Bowline, both legs enter from the same side).
...
Finally, might I make a request - that you first develop a robust understanding and definition of The Bowline i.e. #1010.  Not just one that describes the idealised knots of your excellent photographs, but a definition and understanding robust enough to apply to the vast array of #1010's that are created every day, and which morph under usage and in different cordages encountered in the wild.

Then you might be sufficiently aware of what The Bowline is, to be justified in encompassing other knots into that definition.

Derek

Which means you cast out "the Myrtle" (eye knot) as being
a *bowline*, as it lacks --critical for you-- the bight component
(except for the eye).

IMO, the sole critical/defining component is the central
nipping loop.  But even in this simplicity things get complicated
in considering loading and distortion, which you recognize.
But IMO what can be seen/chosen as the *bowline's* essence
is the nipping loop (my "turNip") and its effect at forming
a knot (fortunately, realized prior the introduction of HMPE
slick cordage!).  And given this recognition, there are many
wonderful & simple things that can be done.
Somewhere amongst sets of "bowlines' come those in which
there is something rather different than the simple "turNip"
--e.g., two of them, or a clove hitch-- which then puts this
definition into question; and also the deformation of the loop
into more open helical form (I just got s a few more photos
of Knots In the Wild of such deformation).

<sigh>

--dl*
====

agent_smith

  • Sr. Member
  • *****
  • Posts: 993
Re: What defines a Bowline? - structure, characteristics, topology
« Reply #374 on: August 30, 2018, 07:42:01 AM »
per Dan Lehman:
In relation to 'Bowlines'
Quote
IMO, the sole critical/defining component is the central
nipping loop.

and...

Somewhere amongst sets of "bowlines' come those in which
there is something rather different than the simple "turNip"
--e.g., two of them, or a clove hitch-- which then puts this
definition into question

I agree in principle with you.
I believe that it is possible to classify all 'Bowlines' by the geometry of their 'nipping structure'.
It may be more accurate to describe this central nipping component as a 'nipping structure' or 'nipping component'.

So for example, we could look to all of the primary Bowlines illustrated by Ashley - all of which have a nipping structure that takes the form of a helix ('loop') that is loaded at both ends (and is 'TIB'), fully encircles and clamps both legs of the collar and is jam resistant. And structurally, this nipping loop exists at the juncture between the SPart and the ongoing eye leg.
These primary Bowlines include; #1010, #1012, #1013, #1080 etc.
They also have a collar that performs a U turn directly about the SPart.

When the nipping structure doesn't take the form of helix/loop - for example, a #206 Crossing hitch or #559 Marlinspike hitch - it is no longer a member of the class of primary Bowlines.

I had used the term 'virtual Bowline' to identify these type of eye knots that have a nipping structure that doesn't take the form of a helix/loop but nevertheless still meets all other criteria such as 'TIB', loaded at both ends, and fully encircles and clamps both legs of the collar. And I had intended the term 'virtual' to have a specific and restricted definition.

With regard to #1033 Carrick 'loop' - this eye knot has a nipping structure that takes the form of a helix/loop and meets all other criteria (eg TIB, loaded at both ends and fully encircles both legs of the collar, jam resistant, etc)).
Where #1033 differs is the structure of its collar (which Xarax laments isn't a proper collar) and the fact that both legs of the collar enter the nipping loop from opposite directions.

I have tested #1033 Carrick 'loop' to 10kN using EN564 Sterling 8mm cord - and it remains stable and jam resistant. After 10kN load, it was easily untied.
« Last Edit: August 30, 2018, 07:43:35 AM by agent_smith »