Author Topic: What defines a Bowline? - structure, characteristics, topology  (Read 134512 times)

DDK

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #210 on: August 28, 2011, 04:40:14 PM »
The task of classifying, naming or defining can be a difficult one, but, has been done before and in many areas of interest.  I found some interesting comments in the wiki pages on categorization and library classification.  http://en.wikipedia.org/wiki/Categorization   http://en.wikipedia.org/wiki/Library_classification

For example, an alternative to hierarchal ("tree") organization termed "faceted classification" allows for multiple classifications of a set depending on one's focus. http://en.wikipedia.org/wiki/Faceted_classification

On the wiki for categorization was a section labelled "Miscategorisation" which struck a chord with me.  "Miscategorization can be a logical fallacy in which diverse and dissimilar objects, concepts, entities, etc. are grouped together based upon illogical common denominators, or common denominators that virtually any concept, object or entity have in common. A common way miscategorization occurs is through an over-categorization of concepts, objects or entities, and then miscategorization based upon over-similar variables that virtually all things have in common." (see http://en.wikipedia.org/wiki/Categorization, as of August 28, 2011)

DDK

xarax

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Concepts and explorations of knotting : What defines a Bowline? - structure, cha
« Reply #211 on: September 13, 2011, 02:09:39 PM »
   The somewhat naive definition of the bowline, based upon the elements of a simpler or a more complex TIB nipping loop and a "proper" collar, has its problems as well. The first one was pointed out since the very beginning of this thread, and has to do with the "crossing knot"-based loops. We can not exclude those loops from the bowline family, without been forced to do the same to the Eskimo bowline - and I believe that this is a unacceptable high price to pay.
  Now, the second, more difficult problem has to do with the shape "8" bowline, also presented previously in this thread, under the telling title "to be or not to be a bowline".(1) I think that if there might be a plausible argument in favour of Dan Lehman s view of the bowline - that the collar should not be considered as an independent element, but only in relation to its entanglement / stabilizing function with/on the nipping loop - this shaped "8" bowline-like loop is the best I can think of. What can be said about the nipping loop(s) here ? Is there one nipping loop or two ? The second/higher part of it encircles the RIM of the collar, AND the standing end ! What can be said about the collar ? It encircles the standing end, AND the eye leg of the bight !  In short, a complete mess !  :) Derek, my friend, Ιδού η Ρόδος, ιδού και το πήδημα ( hic Rhodus hic saltus ) !  :)

1) http://igkt.net/sm/index.php?topic=3233.msg20079#msg20079
 
« Last Edit: September 15, 2011, 09:33:41 AM by xarax »
This is not a knot.

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #212 on: September 15, 2011, 06:40:03 AM »
I've followed this thread for some time and I think that this quote comes close to what I have been thinking.
There is only one bowline (not "a" bowline but "the" bowline) - ABOK #1010 for ease of reference.

And what of Ashley's so-called (-disparaged) "left-handed bowline"?
--hardly much of a change from one to the other, here (and there
is the case of the seized (or spliced) tail such that the collar is an eye)!

Quote
If a knot capsizes under extreme conditions into a different knot (as opposed to falling apart) then it should have a different name in my view BUT excluding a formation designed to capsize as in making a carrick bend by reeving the end and then pulling into shape.

But note that this capsizing can be a gradual change of geometry
per force, not necessarily the all-or-none sort employed by the
lattice-tying method for the carrick bend --and who should regard
those drastically different structures as the same *knot* (as we
bump into the undefined "knot" once more)?!

--dl*
====

[ 2011-09-21 edit : 'from on to' => 'from one to']
« Last Edit: September 21, 2011, 05:39:09 PM by Dan_Lehman »

Dan_Lehman

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #213 on: September 15, 2011, 07:03:29 AM »
   The somewhat naive definition of the bowline, based upon the elements of a simpler or a more complex TIB nipping loop and a "proper" collar, has its problems as well. The first one was pointed out since the very beginning of this thread, and has to do with the "crossing knot"-based loops. We can not dispense with the exclusion of those loops from the bowline family, without been forced to do the same to the Eskimo bowline -- and I believe that this is a unacceptable high price to pay.

[Exclude "exclusion" and it reads correctly; or replace "dispense with" with "admit".]   :)

I say we are bound to face difficulties on account of the
varying geometry of knots per load, per material, per setting;
things are not per-fect!  And we face the issue of what to make
of *knot* --a challenging definition or set of definitions yet to be made.

Now, how should we see the knots presented by photographs here?
We have two stages --set tightly, set loosely & "capsized", or at
least in a different geometry.  (I do not show a regular bowline
here, for surely that is known well enough.)
To those who would insist on seeing both of the eskimo bowlines
as, well, both being *A* (named) *knot*,
do you think the same thing in the case of the (capsized) bowline ?
--for it is arguably a similar change to the commonly seen knot
as is the "Ec" version (to the "E" --in my filename) to the eskimo b. .
(I confess to needing to turn this knot around and scrutinize it
in order to identify it --such a hard turn the tail-side eye-leg makes!)

.:.  So, I see the eskimo bowline as one, like the also cited carrick loop (#1033),
that straddles the boundary I'd like to keep as a *bowline's* essential
quality --a turNip .  And, yet, even this  structure is problematic, as the
helix (it's never a perfect circle (well, nearly never : one could do so w/some
loosely-braided cordage by tucking through the lay, I suppose!)) widens
--when must one call "enough!!"  That is a per-degree differentiating that
eschews some bright line of demarcation.


Quote
Now, the second, more difficult problem has to do with the shape "8" bowline,
also presented previously in this thread, under the telling title "to be or not to be a bowline".
(1) I think that if there might be a plausible argument in favour of Dan Lehman's view of the bowline
--that the collar should not be considered as an independent element, but only in relation
to its entanglement / stabilizing function with/on the nipping loop --this shaped "8" bowline-like loop
is the best I can think of.
What can be said about the nipping loop(s) here ? Is there one nipping loop or two ?

How about zero!  Again, looking to the turNip as the base, where
the eye delivers force into the loop, one doesn't have that here,
with the would-be "loop" more a "turn", not *encircling* the nipped parts
so much.


--dl*
====
« Last Edit: September 21, 2011, 05:41:57 PM by Dan_Lehman »

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #214 on: September 15, 2011, 10:31:05 AM »
... we are bound to face difficulties on account of the varying geometry of knots per load, per material, per setting;

Brrr. You do not like making life simpler, do you ? One is trying to learn swimming into his bathtub, and you throw him into the ocean, to get the whole idea...

do you think the same thing in the case of the (capsized) bowline ?

   No, I do not think so. There may be only one (final) stable version of a knot, or more (intermediate) ones, because the geometry seldom varies continuously - but in discrete steps. All those stable versions should be considered as different knots, because the geometry is noticeably different. "Capsizing" may occur due to a lighter or heavier loading, by the tier or the load, it does not matter. The one or more geometrically different stable forms that the knot takes as it is loaded more and more, should be considered as different knots, I believe.

the boundary I'd like to keep as a *bowline's* essential quality --[the]turNip.

This is a road one can take, it is true, to simplify things : Keep the nipping structure as simple as possible, and allow all other things to be more complex. I tried to walk on a different road, allowing the nipping structure to be as complex as desirable, and keep the collar, its formation, as an individual structure, procedure, separated from the nipping loop conceptually - as well as temporally.

How about zero!  Again, looking to the turNip as the base, where the eye delivers force into the loop, one doesn't have that here, with the would-be "loop" more a "turn", not *encircling* the nipped parts so much.

  Yes, if you insist in thinking in terms of the simplest possible nipping structure, the "turNip" as you call it, you will probably not be able find any of them here...If you think in terms of complex nipping structures, that can squeeze the working end/tail into their hug from many sides - in the tier s and the load s effort to secure the tail/loop - you would see one twisted - or two consecutive - nipping loop(s), that resembles the shape of an "8"- hence the name given in this contraption.
   I do not think that this bowlne-like-or-not fixed end-of-line loop is much related to the Eskimo bowline, although here we have also - a part of - the nipping structure encircling the eye leg of the bight. It was produced by the collapse of the double, crossed coils loop with a Myrtle collar, but, as I have said, that should not be a factor to determine what it is now, in this stable state.
    I have not said that "you" would have any problem in defining if this loop is a bowline or not...but "i" do have, and it is a major one...A collar that looks like / is, neither a "proper" collar, or a Myrtle collar, leaves me in a odd in-between no man s land...
This is not a knot.

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #215 on: September 15, 2011, 01:48:04 PM »
the "Ec" version

   An Eskimo crossing-knot based bowline, of course. See the attached pictures. Also see (1)
1) http://igkt.net/sm/index.php?topic=3467.msg20145#msg20145

   (The first picture of reply#216, with the three capsized bowlines, should have been be made by Photoshop, or by some rare favour of the universe that was never ever offered to me ! I have visited hundreds of harbours, looking for something like this, in vein...
« Last Edit: September 15, 2011, 01:49:47 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #216 on: September 21, 2011, 06:03:29 PM »
the "Ec" version

   An Eskimo crossing-knot based bowline, of course.

???  It is that, presumably in the tying, for both of what I present,
but the results --my point, for comparison-- differ in regard to what
central knotting the SPart makes : it is the crossing knot only in
the thick rope, and much a turNip in the 3/8" line.  For me,
that divides the generally started knot between groupings,
with only the latter regarded as "(anti-)bowline".
And the capsized bowlineS ...

Quote
(The first picture of reply#216, with the three [?!] capsized bowlines,
should have been be made by Photoshop, or by some rare favour of the universe that was never ever offered to me !
I have visited hundreds of harbours, looking for something like this, in vain...
...
are put as corresponding different results to that general
tying, where one would prefer to put the results into
different groups.  Btw, I think that there are but TWO
capsized bowlines --not the rightmost one, which has
the tail emerging in the wrong orientation to the tail-side
eye leg; it might be something got by tying a sort of
*granny'd surgeon's bend* and then capsizing that
(i.e., tail wraps SPart and then is tucked out through
the turNip in the opposite direction).   !?

Have you looked at mooring lines of such size?
I see this (in one locale, mainly) so much that I came
to wonder if it was intended --for how could one do this
to such a degree of frequency, otherwise?  But I don't know ... .
(I even salvaged such a knot (like the leftmost orientation)
from the trash, and have it for a souvenir, study item.)
I believe that I also found such a capsized structure in
some thinner line, but for the most part, no; and I have
seen photos of yachting lines under tension with quite
loose collars, uncapsized.


--dl*
====

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #217 on: September 21, 2011, 08:04:08 PM »
the results...differ in regard to what central knotting the SPart makes : it is the crossing knot only in the .... and much a turNip in the....

  I would be glad if you could elaborate on this a little more. With the help of some "accidentally" taken pictures of knots, in your indoors - or the outdoors - wild, and some plain English I could possibly understand - with the help - or not -  of the Google translator. :) I think that you really believe you have pinpointed some/the(?) crucial difference, but you have not reached a point of understanding that would enable you to express your view with the required clarity and simplicity. It is one thing to "see"  something for yourself, and another thing to be able to define something, so other people will potentially be able to see the same thing...

one would prefer to put the results into different groups.

  If we could put the results into different groups - knowing exactly what we are doing, and why we are doing this and not something else - then this would be a proof we already have a definition of the differences, would nt it ? Unfortunately, for the moment, I believe/my humble two pence opinion is we/"I" have not.

Have you looked at mooring lines of such size?

   Not really. The mooring lines that are used for recreational sailing boats (up to 60 ft LOA) are much smaller, and the materials used are, most of the times, lightweight contemporary synthetics. Perhaps this makes them prone rather to slippage than to capsizing - meaning that, under heavy loading, they would probably slip before they would have had the chance to capsize. Also, I happen to live near by a sea that has not strong currents or high tides, that would possibly justify the use of heavier lines. ( However, I had not seen something like this in any of the the many harbours - some of them with commercial fishing boats, too - of Normandy, Oslo, Dublin, or Amsterdam I have recently visited... :). I wonder why I am sooo unlucky...)
« Last Edit: September 21, 2011, 08:06:50 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #218 on: September 22, 2011, 09:04:45 PM »
the results...differ in regard to what central knotting the SPart makes :
 it is the crossing knot only in the ....
 and much a turNip in the....

  I would be glad if you could elaborate on this a little more.

Isn't it obvious?
In both of my photo'd cases for the "Eskimo Bowline",
the SPart is *collared*; but in the one case it is so by its
own continuation (this I call the "crossing knot" structure),
in the other (of which I have two photos, from two sides)
it is by the tail's wrapping.  In the latter case, I see the variously
tight helix as reasonably regarded as a turNip and thereby
qualifying *bowline* classification; but in the other case,
I regard the base of the knot as a crossing knot and prefer
to let that different structure build its own grouping.
(They both lie in a grouping of "PET" (post-eye [formation] tiable) eyeknots.)

AND a point to note it that these differences can be ameliorated
by degree via setting & loading, just as for eye knot #1033.
I cannot wait for some sharp boundary --that might not exist.

--dl*
====

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #219 on: September 22, 2011, 11:01:13 PM »
Isn't it obvious?

   Not to me... Horses for courses. I may be thirsty, I may even be able to smell  the water, but I can not see it...
   I see the double, crossed-coils nipping loop and the loops based on it. In this structure, we have also one section of the standing part, the second loop, going around another section of the same part, the first loop. Is it a crossing knot structure ? Of course not. However, if this same structure capsizes, it is turned into a more or less typical crossing knot...
   Let us imagine a hypothetical structure, where there is a normal, simple nipping loop, with a closed helical form, AND there is a "continuation" of one section of the  standing part, that makes a "second" turn around another section of the standing part. Is this one-nipping-loop-after-the-other a crossing knot ?  Is the 8 shaped bowline-like loop a crossing-knot-based loop, even if the "first" loop looks more like a tight "turnip" than a lower part of a 8 ? 
 
AND a point to note it that these differences can be ameliorated
by degree via setting & loading...
I cannot wait for some sharp boundary --that might not exist.


Please, do not tell this to all those people who already suspect / believe that "theoretical" discussions do not lead to any concrete, practical conclusions !   :)
« Last Edit: September 22, 2011, 11:07:59 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #220 on: September 24, 2011, 07:24:19 AM »
Isn't it obvious?
I see the double, crossed-coils nipping loop and the loops based on it. In this structure, we have also one section of the standing part, the second loop, going around another section of the same part, the first loop. Is it a crossing knot structure ? Of course not. However, if this same structure capsizes, it is turned into a more or less typical crossing knot...

I'm lost on what this is (i.e., I don't follow this description).

Quote
...  AND there is a "continuation" of one section of the  standing part,
that makes a "second" turn around another section of the standing part.
Is this one-nipping-loop-after-the-other a crossing knot ?

I don't know, here again, but the turNip is loaded *directly* on
both ends, unlike the *loop* section of the crossing knot --where the
away-from-SPart end turns around the SPart, and then is loaded.
That is my point of distinction/separation/classification (re "bowline").


Quote
AND a point to note it that these differences can be ameliorated
by degree via setting & loading...
I cannot wait for some sharp boundary --that might not exist.


Quote
Please, do not tell this to all those people who already suspect / believe that "theoretical" discussions do not lead to any concrete, practical conclusions !   :)

Who might these be?
The "leading to ..." wasn't questioned, as I recall; only the
Are we there, yet? aspect.  And I was bent on encouraging someone
to not fear isolation in this "explorative",  theoretical tent --knowing
that it would lead (to various interesting places, even practicality).

--dl*
====
« Last Edit: September 27, 2011, 06:22:34 AM by Dan_Lehman »

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #221 on: September 24, 2011, 03:51:57 PM »
   I'm lost on what this is (i.e., I don't follow this description).
...the turNip is loaded *directly* onboth ends, unlike the *loop* section of the crossing knot --where the away-from-SPart end turns around the SPart, and then is loaded.

OK, perhabs it is my mistake.( I find it difficult to verbally describe a knot, in any language...)
Describe those 2 pairs of knots using your words and terms, and tell me if they are crossing-knot bowlines or not, and, if some are but some are not, why is this so. 
« Last Edit: September 24, 2011, 03:52:35 PM by xarax »
This is not a knot.

xarax

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #222 on: September 24, 2011, 04:19:10 PM »
In this structure, we have also one section of the standing part, the second loop, going around another section of the same part, the first loop. Is it a crossing knot structure ?

   I do not believe that anybody can deny the obvious fact that this double "turnip" is a "turnip" ! (See attached picture). However, here also

the SPart is *collared*... by its own continuation (this I call the "crossing knot" structure),
This is not a knot.

xarax

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #223 on: September 24, 2011, 05:23:53 PM »
  The double, crossed-coils based loop - that we probably have to / are obliged to classify within the bowline family of knots, as it resembles the common double bowline so much -  can be capsized/deformed into an 8 shaped loop, that looks more like a crossing-knot based loop. ( See the attached pictures, for the un-collared loops). The transformation here is more continuous than we might had wished: There are many intermediate stages, depending upon the loading and the material used.  So, where exactly the initial bowline is turned into a crossing-knot based loop ? A definition is all about naturally discovered or artificially set - for whatever purpose- boundaries, is nt that so ? If we do not have a boundary, can we have a definition, or only some hands-waving vague description ? 
« Last Edit: September 24, 2011, 05:34:04 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Concepts and explorations of knotting : What defines a Bowline? - structure,
« Reply #224 on: September 25, 2011, 05:20:33 AM »
In this structure, we have also one section of the standing part, the second loop, going around another section of the same part, the first loop. Is it a crossing knot structure ?

   I do not believe that anybody can deny the obvious fact that this double "turnip" is a "turnip" ! (See attached picture).

Hmmm, it's at least something beyond the turNip --as is the
simple double-turn version of the double bowline .

But most clearly it is NOT "However, here also ..."
the SPart is *collared*... by its own continuation (this I call the "crossing knot" structure),
,
but is collared in the usual way, but the tail bight.   :o
--"a proper collar"!  (What are you thinking?)

--dl*
====