Author Topic: What defines a Bowline? - structure, characteristics, topology  (Read 123136 times)

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #375 on: August 30, 2018, 09:10:27 AM »
@ Dan
Quote
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).

Indeed Dan, this restrictive definition should indeed cast out just about everything but #1010.  This is because it is my attempt to take'one bite of the proverbial Elephant'.  It has been my experience that complex problems may sometimes be resolved by seeing if they can be sensibly broken down into manageable portions (such as my approach to considering a 'nub' as a functioning set of Components).  Of course, some problems can only be understood 'in toto'. but even for these 'holistic' problems, the process of understanding the functionality of sub components may sometimes help in grasping the larger picture.

Once we have formulated a definition that works for The Bowline (#1010), and can be seen to work for the knot at work - 'in the wild', then we have a tool that will allow us to understand how the Bowline works - what makes it 'a Bowline'.  When we have this cornerstone in place, it is reasonable to consider other arbitrarily designated 'Bowlines' by seeing how the definition must be expanded to accommodate them.  In taking that step we give ourselves the opportunity of seeing  what other (self evidently NOT Bowlines) are let into the classification, thereby destroying any value to the definition.

So yes, the definition was deliberately aimed at #1010.  If it works and is found to be robustly acceptable, then we have at least one bite of this 'Elephant' under our control and ready for the next bite.

Derek

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #376 on: August 30, 2018, 09:33:52 AM »

IMO, the sole critical/defining component is the central
nipping loop. 

<sigh>

--dl*
====

Here Dan, I have to admit to a problem.

The nub of #1010 has but two components - the Nipping Helix Component and the Bight Component.

Without both of these components the knot does not exist.
Without the Nipping Helix, the bight legs cannot generate negative cogging and the knot flows out.
Without the Bight legs to bind on, the Nipping Helix collapses and without the Bight collar to stabilise the Bight Component the helix torsion simply twists the bight legs and turns itself into straight cord.

So the clarity I am seeking is to understand what aspect of these functions do you see that leads you to conclude one component to be more elemental than the other?

Derek

siriuso

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #377 on: August 30, 2018, 01:46:21 PM »
Hi dear all,

In my opinion, Carrick Loop ABOK #1033 is not TIB.

yChan

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #378 on: August 30, 2018, 03:58:52 PM »
per yChan:
Quote
In my opinion, Carrick Loop ABOK #1033 is not TIB.

But we already know this!
I am not sure what point you are trying to make? Are you are suggesting that being TIB is a pre-requisite for the title of 'Bowline'?

For example, the #1010 primary Bowline also isn't TIB.

siriuso

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #379 on: August 30, 2018, 04:06:04 PM »
Hi Mark,

Your threads mentioned that it is TIB.

yChan

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #380 on: August 30, 2018, 04:40:45 PM »
Quote
So the clarity I am seeking is to understand what aspect of these functions do you see that leads you to conclude one component to be more elemental than the other?

I understand the reasoning that underpins Dan Lehman's comment.

I personally do not see one component being more 'elemental' (or of higher structural importance) than another (within a 'Bowline'). I hope that Dan concurs!

The nipping structure is (almost without exception) formed first.
The nipping structure is key in terms of jam resistance - and all Bowlines (by definition) - are resistant to jamming.
Once the nipping loop is formed, all 'working end' maneuvers are performed through and around it. Essentially, it is the central building block from which the rest of the knot is built.

Removal of the nipping structure, causes [a] 'Bowline' to cease to exist.

Of course, there are other components that also need to be present - in order to complete the entity we regard as a 'Bowline'.

It should be possible to classify 'Bowlines' according to the type of nipping structure with due regard to the position and orientation of the collar.

EDIT NOTE:
I intentionally omitted the Spanish Bowline (#1087) and Portuguese Bowline (#1072) due to space restrictions and 100KB imposed file limit. To be clear, Ashley did identify these 2 structures as deserving of the title 'Bowline'.
I will also add #1074 (Bowline with a bight) in a future upgrade to my Analysis of Bowlines.
« Last Edit: August 31, 2018, 02:49:27 AM by agent_smith »

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #381 on: August 30, 2018, 04:46:38 PM »
per yChan
Quote
Your threads mentioned that it is TIB.
If I did specifically state (in clear and unambiguous words) that #1033 Carrick 'loop' is TIB - then it is either a typo or a miscommunication.

#1033 Carrick 'loop' isn't TIB.

Can you please point me to the threads / posts where I used specific language to declare #1033 Carrick 'loop' to be TIB? (I want to go back and delete that reference).

Thanks...

siriuso

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #382 on: August 30, 2018, 06:13:58 PM »
Hi Mark,

They are in this post :
Reply #370 para.6 and Rely # 374 second last para.

yChan

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #383 on: August 30, 2018, 09:06:11 PM »
So the clarity I am seeking is to understand what aspect of these functions do you see
that leads you to conclude one component to be more elemental than the other?
Partly, I don't think this is a pertinent question,
in that it suggests that we seek some Trvth of Things
rather than a way to talk about them --an invention
for a purpose, not something Out There 2 B discovered.

But, playing along with some *real* rationale for what
I said, I suppose one can point to concentration of forces,
and even other aspects --perhaps PET (post-eye tying)?--
that support such ranking.
For me, though, it really was just about what it is I want
to have a group of; and so I see this simple "central nipping
turn" as that, and for that component to work, there needs
to be stabilization by the tail's return knotting --but THAT
need not be only a bight.
(Then, though, I am also willing to walk away from the
mere "turNip" for like structures, even non-PET ones,
with, well, "likeness" to the simple loop.  For this, it
might be that I come up with some nominal distinction.)


Quote
Without the Nipping Helix, ...
And here I want to push back against the helix aspect
of the "central nipping loop", because it is a helix
of necessity rather than *ideal* (one might be able to
avoid this by reeving through hollow braided rope!),
and should the helix open much,
then I don't like classifying it as a "bowline" --though
I have pointed out that quite obvious #1010 bowlines
have lost their essence in this way, into "pile-hitch
nooses"
!  --a matter of force, & transformation.
<sigh>

But, really, I have AIMED for stabilizing a rather open
helix, and don't find it quite so "nipping" as a loop,
for, being open, there isn't the compression of one
side vs an opposite.
Would that things were black'n'white, present or not,
rather than sometimes tenuous dependent upon loading,
but ... such is life/knots.

Back to the top point, though :: what is it we want from
our nomenclature?  Yours seems to give us so little in
denotation, almost no collection; mine reaches to a group
of "like" knots, and maybe by a Xarax rule they are further
constrained to be PET?!  And then the water bowline
maybe gets in with some relaxation of pure "nipping turn",
and the "cloverhand bowline" has *attachment*/proximity
to this grouping though it's not PET ("cloverhand" being an
overhandoriented to resemble the clove h.; and
which for the eye knot seems to offer some slack-security
and nice curving of the SPart).


--dl*
====

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #384 on: August 31, 2018, 12:03:02 AM »
per yChan:
Quote
They are in this post :
Reply #370 para.6 and Rely # 374 second last para.

Thank you yChan. I appreciate that you have taken the time to look into this issue of 'TIB'.
I went back and closely read what I wrote.
You have applied an incorrect interpretation of what I wrote (sorry).

If you read it again (more carefully) - you will see that the reference to 'TIB' is in direct relation to the nipping structure.
I did not declare the entire knot to be TIB.

I would like to emphasize (for the record) - that it is a conditional requirement that all 'Bowlines' have a nipping structure that is 'TIB'.
There are other conditions that also apply - TIB is just one of them.

May I make a request from you please?
Can you go back and delete your posts which allege that I stated that #1033 Carrick 'loop' is TIB?
Then I can delete my specific replies.
This will tidy up this thread so there are not unnecessary posts adding clutter.

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #385 on: August 31, 2018, 01:38:11 AM »
from Derek:
Quote
Once we have formulated a definition that works for The Bowline (#1010), and can be seen to work for the knot at work - 'in the wild', then we have a tool that will allow us to understand how the Bowline works

Not surprisingly, others have already advanced a working definition that permits certain knot structures to be awarded the title of 'Bowline'.
The primary Bowlines had been illustrated by Ashley at #1010, #1012, #1013, #1034 1/2, #1072, #1074, #1080, #1087 in 1944. There is universal agreement that #1010 is a Bowline (ie it is the 'standard' or 'common' Bowline).
All of these structures share the same fundamental structural components.

Quote
In taking that step we give ourselves the opportunity of seeing  what other (self evidently NOT Bowlines) are let into the classification, thereby destroying any value to the definition.

Having trouble with interpreting your intended meaning with this last (italicized) statement.
Did you mean; "so as not to disturb or set aside the meaning of 'Bowline" ?

Or, did you mean;
"In taking that step, we give ourselves the opportunity to exclude knot structures that do not meet the definition of a 'Bowline' - so as not to destroy or dilute that definition".  ??
Can you clarify?

Destroying the value of [a] definition that defines a 'Bowline' could only occur if that definition was flawed to begin with.
But I do understand your point... we need to first arrive at a definition that is correct (or as accurate as can be).

I have difficulty with your requirement that the onus of proof is reversed - re your comment that:
Quote
For me, Ashley puts forward the ideal set of descriptors.  I believe to use any other lexicon, it would be first necessary to produce a case which faults the Ashley statements

I believe that reversing the onus of proof would have the effect of restricting and narrowing future opportunities to re-examine old concepts and hinder innovation and creativity. And, it could provide a convenient excuse for closing ones mind to new ideas.

I see parallels with the definition of a 'loop'. G Budworth and B Toss appear to differ in their conceptualization of a 'loop' compared to C Ashley. H Asher strongly implied that a 'loop' can have S or Z chirality (and so did Brion Toss - although he phrased it as clockwise / anti-clockwise). C Ashley appears to have overlooked chirality.
Therefore, a 'bight' cannot have any particular chirality - that is, a 'bight' cannot have an S or Z form; only a 'loop' can have this property.

Budworth, Toss and Asher all came from a later era than C Ashley - and have attempted to shed new light on knots and knotting.

The nipping structure of [a] 'Bowline' is essentially formed first - and then all remaining maneuvers of the 'working end' feed through it and around it to complete the 'Bowline'.
The nipping structure is the fundamental reason why all 'Bowlines' are resistant to jamming (because it is 'TIB' and therefore topologically equivalent to the 'unknot' - as well as being freely able to encircle and clamp both legs of the collar).
« Last Edit: August 31, 2018, 02:51:21 AM by agent_smith »

alanleeknots

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #386 on: September 03, 2018, 01:15:47 AM »
Hi All,
         Many years ago I create this knot here, at that time still very green, not so sure, I didn't post it to the forum.
                has been sitting in my unfinished work folder since then.
          Now have a look at it again, I found it no a bad loop at all, nice looking, look like bowline, have a bowline nipping loop,
                 like bowline's collar. but the tail didn't go back to the nipping loop.
            So what it belongs?  謝謝 alanleeknots.
         

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #387 on: September 03, 2018, 01:58:54 AM »
Thanks for presenting this creation Alan :)

Yes - it does have a nipping structure that takes the form of a helix/loop that is loaded at both ends, 'TB' and jam resistant.
However, as you have already pointed out, "The tail didn't go back through the nipping loop"

This would rule it out from being awarded the title of any class of 'Bowline' (either primary Bowline, virtual Bowline, or anti-Bowline).
The collar (aka 'Bight Collar') has 2 legs, and both of these 'legs' must be fully encircled and clamped by the nipping structure.
Since one of the legs is outside of the nipping structure and isn't clamped by it - it is excluded from being identified as a 'Bowline'.

Also, I note that it is vulnerable to 'ring loading'.

It should be possible to work on this structure to improve its resistance to ring loading - and maybe devise an alternate geometry so that the nipping structure can encircle and clamp both legs of the collar.

alanleeknots

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #388 on: September 04, 2018, 09:21:09 AM »
Hi All,
          Mark thanks for your reply .I know it is not a pure bowline, that's why I ask "what is this knot belong"
          This knot does have a bowline nipping loop and nip on one eye leg, Not so sure, do this knot qualify for half bowline.
 
Quote
and maybe devise an alternate geometry so that the nipping structure can encircle and clamp both legs of the collar.
          About this knot here, have nothing wrong with it, No too complicate to tie, easy to untie after heavy load,
           offer little more secure on the tail. Even though I am too fancy about it, we don't need any change or modify here.
          It's just another valid knot that does exist in the knot land, If I make any change on this knot "Knot God" may not forgive me.
               謝謝 alanleeknots

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #389 on: September 26, 2018, 02:15:36 AM »
Some more work I have been doing in the lead up to the next (updated) version of my 'Bowlines Analysis' paper...

I had advanced that all 'Bowlines' can be classified according to the geometry of their nipping component.
The term 'nipping component' has a strict definition.

1. It is topologically equivalent to the 'unknot'
2. It is TIB (Tiable In the Bight) - which relates to #1 above
3. It is loaded at both ends
4. It fully encircles and clamps both legs of the 'collar'
5. In the primary Bowlines, it takes the form of a helix or twin helix
6. The compression force exerted by the nipping component is directly proportional to the load
7. It exists between the SPart and the ongoing eye leg
8. It has a particular chirality - which may be S or Z form.

The nipping component is fundamental to all 'Bowlines'.
All initial tying maneuvers feed through the nipping component - indeed, it is formed first to allow all subsequent maneuvers to be made.
The jam resistance of all Bowlines is closely related to the function of the nipping component.
« Last Edit: September 27, 2018, 03:01:39 PM by agent_smith »