Author Topic: What defines a Bowline? - structure, characteristics, topology  (Read 134756 times)

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #75 on: July 26, 2011, 07:09:23 PM »
  Derek, with all respect, you are confused about this matter !
 
   Fig 39 shows a hitch, indeed, because the "two legs are highly asymmetrical, in looks as well as in function." The one leg is over the other,"it is squeezing the other, so the one crosses the other, it passes above the other." This is the elementary mechanism of "the riding turn". The riding turn is one of the five basic elements that we meet in practical knots.
   In your second and third picture, you do not specify if the free end is loaded or not. If it is NOT loaded, we have half hitches indeed, because "When a bight has only one of its ends loaded, it is a hitch."  Now, if those legs ARE loaded as well as the others, ( i.e., both free ends of the knots are loaded ), the part of the knot you think it is hitch, it is not : it has both its legs loaded, so it is a nipping loop.  
   In ABoK#160 and #161, as well as in the test "bowline" I have submitted to you, and every bowline everywhere in the universe, we do not have hitches, we have nipping loops. Plain and simple ! I now understand how one can be blinded, even if he has the best intentions, as you do ! Read my lips :
 
1. The nipping loop is not a hitch. When a bight has both its ends loaded, and it is nipping a line that goes through it, it is a nipping loop. When a bight has only one of its ends loaded, it is a hitch. BIG, HUGE difference !  :)
2. ...A hitch has its second leg pressed under its first leg ( on some other tensioned rope strand or rigid surface).

snip...


Hi Xarax,

Well, yes, we can agree that I am confused...

I am confused that anyone can suggest that the Bowline's only significant component is the ShC.
I am confused that you would define the half hitch in Fig 39 as 'highly asymmetrical'
I am confused that you see in Fig 39 one leg "crossing and passing over the other", yet you don't see that this is true for both legs.
I am confused that you are calling "the riding turn" an elementary mechanism when its Force Vector Analysis is hugely complex.
I am confused that you question the loading of the end in the 'second and third pictures', when Fig 39 is clearly loaded  and is defined as a half hitch - someone else's definition, not mine.
I am confused that in ABoK#160 and #161 you claim them not to be hitches when Ashley states " the hitches are in the standing part."

But most of all, I am confused that you seem to be closing your mind to the fact that while a single turn (xStC) is a nipping loop and may not be a hitch, a Hitch by contrast is also (and I believe likely to always be) a nipping loop

What are we arguing about? The ShC functions as both a hitch and a nipping loop...  If it didn't then ring loading would end the life of a Bowline in short measure.

Derek

xarax

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #76 on: July 26, 2011, 08:39:59 PM »
   I am afraid, Derek, that you are confused, indeed, and firing the one bullet right after the other will not save you ... :)
   So, I will take your bullets, one by one :

1. ."I am confused that anyone can suggest that the Bowline's only significant component is the ShC"
1. Yes ! NOBODY can suggest that the Bowline's only significant component is the ShC (except you, of course !  :)). There is no hitch component in the bowline, neither the so-called "Shc", the hitch component of the Sheet bend, nor any other. The Bowline has two components : The main is the nipping loop, and the secondary is the collar. You try to explain the bowline in terms of the Sheet bend, in vein. The bowline is a Gleipnir with a collar, plain and simple .

2. "I am confused that you would define the half hitch in Fig 39 as 'highly asymmetrical'"
2. Yes ! The half hitch of Fig 39, and any other half hitch in the universe, is highly asymmetrical, because :
a. The second end is not loaded as the first
b. The one leg is over, or under, the other, the one leg squeezes the other on some rigid surface, or a tensioned line.

3."I am confused that you see in Fig 39 one leg "crossing and passing over the other", yet you don't see that this is true for both legs."
3. Yes ! The "first" leg is over the second, but the "second" leg is under the "first", by definition...  :) So, the two legs are not symmetrical, neither in looks, nor in function. The "first" squeezes the "second", but the "second" is squeezed by the "first", by definition. Asymmetry. The one is loaded, while the other is not. Asymmetry. The difference with the situation of two legs of the collar are so big, you can hide beneath it !   :)

4. "I am confused that you are calling "the riding turn" an elementary mechanism when its Force Vector Analysis is hugely complex."
4. Force Vector analysis in flexible materials ? Ok, publish your scientific essay, and I promise I will read it... Leaving this in the field of serious science, where it does belong, let us go to the "riding turn". I am afraid "I" am NOT obliged to publish a Nobel-prize winning essay on this, ( like you are, for the "Force Vector Anaysis" of the "xStC", "ShC", etc....), because, fortunately, everybody already knows and understands what a riding turn is.  :) The one segment of rope makesaturn around the line/pole, and passes over the other, remember ? Now, if it is the most elementary knot mechanism, or can further be reduced in an even more basic concept, this is debatable, of course, but do not try to mix the weaknesses of my theory with those of yours !  :) We are talking about your theory now, that considers the half hitch as "symmetrical" relatively to its two legs !  

5. "I am confused that you question the loading of the end in the 'second and third pictures', when Fig 39 is clearly loaded  and is defined as a half hitch - someone else's definition, not mine."
5. Yes ! I was not supposed to know what the author of a sketch was meant to show. I have asked you to define it, and I have answered what happens in BOTH cases, the case where only the one free end of the knot was supposed to be loaded, and the case where both free ends were supposed to be loaded. Is that such a strong argument, that you feel you have to fire it towards me ? If it is, what can one say for the weak ones... :)

6. "I am confused that in ABoK#160 and #161 you claim them not to be hitches when Ashley states " the hitches are in the standing part.""
6. Yes ! The second structures of the ABoK#160 and ABoK#161, when and when only the one free end is loaded, they are hitches. When and where both ends are loaded, they are nipping loops. I have repeated this simple distinction a hundred times now, so you can not fail to listen it ! What is happening, Derek ? You are feeling so weak, that you are asking for help from your big brother ? You start citing the scripts  ?  :)

7. "But most of all, I am confused that you seem to be closing your mind to the fact that while a single turn (xStC) is a nipping loop and may not be a hitch, a Hitch by contrast is also (and I believe likely to always be) a nipping loop"
7. Yes! I am not going to split hairs to save face, as you do. A hitch is a hitch, and a nipping loop is a nipping loop. The fact that the hitch squeezes the pole or the rope around which is tied, does not make it a nipping loop, because it is highly asymmetric in its legs, the one leg being loaded, while the other is not. On the contrary, the nipping loop is symmetric in its legs, and both legs are equally loaded. Use any Sanskrit script you wish, like this "ShC" proto-indo-European one... :) Something should not be defined as a hitch and a nipping lop at the same time, otherwise our theories will serve less than astrology...We make a useful distinction and definition, even if there are similar mechanical functions in both our entities. I do not think that there is anybody that will fail to see those simple distinctions I have repeated again and again ( to use your style of the #1 argument... :))

What are we arguing about? The ShC functions as both a hitch and a nipping loop...

   If that is so, why do you use this "ShC" entity ? If it is a Chimera, a Janus, a double-edged sword, forget t ! I will not help us explore, explain and define what is a bowline, because it can do anything !
   On the contrary, the simple thing I have said is sufficient to classify the loops into bowlines and not-bowlines, whithout any such ambiguity.
   1. The "collar" is a collar, it is not a hitch, neither a nipping loop. The bowline has one, at least collar, made by a bight of the eye leg of the bight end.
   2. The "nipping loop" is a nipping loop, it is not a hitch, neither a collar. The bowline has one, at least, nipping loop on the standing part.
   3. The (half)  hitch is a hitch, is not a nipping loop, neither a collar. The fact that it does constricts the pole or the line around which is tied, does not make it a nipping loop. The fact that it does make a U-turn around a pole or a line, does not make it a collar.
« Last Edit: August 12, 2011, 05:25:34 PM by xarax »
This is not a knot.

knot4u

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #77 on: July 26, 2011, 09:40:53 PM »
Is there a way to quantify things here?  This thread reminds me of freshman year Physics 101 in undergrad.  There was a lot of "talking" before the test.  At the top of that test, the professor gave us one arrogant formula:  F=ma.  The average score on that test was about 40%.  One unassuming student got a 100% and messed up the curve.  Suddenly, everybody wanted to pay attention to that kid.  The application of physics principles silenced a lot of the noise.  Likewise, we have got to find a way here to settle knot disputes with mathematics and scientific principles.

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #78 on: July 26, 2011, 09:43:17 PM »
I am confused that anyone can suggest that the Bowline's only significant component is the ShC.

Perhaps it should be taken that we are conjecturing what will be
held to constitute >> a *bowline* (-type knot) <<.
"The" bowline is most spare --loop + bight.  Now, I am happy to see
the family of like knots be those that bind with the former,
and which might be maintained/stabilized in a variety of
ways (so that the turNip has effect).

Beyond this, I look to something one might call a "false" or
"<some better adjective>" bowline when the continuation
from the turNip does not go directly into an eye leg
(e.g., it might collar the eye legs and feed back into the
knot (which would pique X.'s angst about the hitch vs. loop
distinction, though the continuation would have some tension)).

I don't see the bight-collar as defining (and if it were, it is quite
limiting to knots that I'd see --e.g., Myrtle-- as family members).

(It's not a matter of Right/Wrong here,
but of viability/usefulness of the definitions.)

--dl*
====

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #79 on: July 26, 2011, 10:57:29 PM »
My Dear Xarax,

It was not a barage of bullets -

it was a plea for understanding - mine or yours or ours...

Derek

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #80 on: July 26, 2011, 11:24:34 PM »
Is there a way to quantify things here?  This thread reminds me of freshman year Physics 101 in undergrad.  There was a lot of "talking" before the test.  At the top of that test, the professor gave us one arrogant formula:  F=ma.  The average score on that test was about 40%.  One unassuming student got a 100% and messed up the curve.  Suddenly, everybody wanted to pay attention to that kid.  The application of physics principles silenced a lot of the noise.  Likewise, we have got to find a way here to settle knot disputes with mathematics and scientific principles.

Hi K4u,

When I started to attempt to categorise knots based on their component parts, I had in mind my chemistry background, and naively thought that a knot could be described much like a molecule - by defining its component atoms and describing how they were arranged.  But over time I realised my error.  In chemistry, a Sodium atom is always a Sodium atom with exquisitely fixed properties, but in a knot, any component can morph and slew through an infinite continuum of forms - from an identifiable hitch, through a hitch / turn hybrid, through to a turn, and exhibit all those properties in turn and in part simultaneously by degrees.

Sadly, the more I study knots, the more I believe we are further than ever from a Science or Physics of knots - certainly, I do not possess a mind capable of taking us there.  But I do not give up hope that the scratchings and searching for understanding that we do today, will offer some chance in the future for some bright mind to make a breakthrough.  To that end all our confusion and mumblings may have some value.

On the particular issue at hand, there is little chance of moving forward, because the arguments proposed are simply opinions, and every one is valid although each might be at odds with the other.

Mark asked - "What defines a Bowline?" - I have answered that with my opinion, but that is all it is - a single persons opinion, my definition.  Someone else defines a Bowline differently and there you have an equally valid opinion and definition.

Unfortunately, the question has a very familiar counterpart - 'How long is a piece of string?'

Derek

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #81 on: July 26, 2011, 11:40:30 PM »


(It's not a matter of Right/Wrong here,
but of viability/usefulness of the definitions.)

--dl*
====

Good point Dan, and it falls directly in line with the tight definition I have offered for a Bowline and a slightly less tight definition for Bowline Variants.  The usefulness then is that we describe a relatively small group of knots with similar attributes.  If by contrast we opt for a far more 'flexible' definition - then for example if we were to define a Bowline as a knot which has a nipping loop, then as this can be found in the vast majority of knots (by little or large), then just about everything becomes a 'Bowline' - and what is the usefulness in that?

Derek

NB  I have offered a definition from the 'components' perspective - but Mark did not make the question that narrow - are there any other aspects of what we perceive as a Bowline that can be added to the definition in order to confine the group size and hence improve usefulness.

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #82 on: July 28, 2011, 12:39:54 AM »


(It's not a matter of Right/Wrong here,
but of viability/usefulness of the definitions.)

--dl*
====

Good point Dan, and it falls directly in line with the tight definition I have offered for a Bowline and a slightly less tight definition for Bowline Variants.  The usefulness then is that we describe a relatively small group of knots with similar attributes.  If by contrast we opt for a far more 'flexible' definition - then for example if we were to define a Bowline as a knot which has a nipping loop, then as this can be found in the vast majority of knots (by little or large), then just about everything becomes a 'Bowline' - and what is the usefulness in that?

Derek, I think that by your criteria, the Fig.8-based knots become
*bowlines*, as their SPart's initial geometry fits your SBCore, and
at least the one with a simple bight-collar finish fills the bill.

In contrast, my & X.'s criterion of the turNip excludes these,
for the closure of that nipping loop in the 8 is more akin to the
locked-off end in the sheet bend  than the loaded-not-locked
continuation (into an eye leg).
.
.
.
But it might be that we need to see some considerable set of
prospects run through the various criteria to see what we think
of what emerges, in order to get a better feel for what we've
wrought in our criteria.

Now, there can be indicated infinities of things so classified
in some rather pointless extents (e.g., if the dbl. bwl is
a *bowline*, wouldn't a trpl.bwl be so --add one wrap?
... and when does that knot-building Add-A-Wrap ever cease
to qualify?  (It gets silly, though, nearly immediately!)
So, mere number needs some qualification.
Yes, though, one can get such a big field of *bowlines* that
one has then to subdivide into many sub-classes of *bowlines*;
but maybe this is yet preferable to a bunch of classes of the
first order which one might have some desire to see related
as kinfolk by some other means?

Xarax seem willing to regard the crossing-kinot-based knots
as nipping-loop bwl.s, while I want them distinct,
even though pointing out that that carrick loop can be seen
to reside in either camp --and in some fuzzing in-between state--
depending on how it's set.


Btw, you keep neglecting Mytle --your old flame, no less!-- :
where would you classify that?  (I call it *bowline*; X. will find
it short of a "proper collar".)


--dl*
====
« Last Edit: July 29, 2011, 06:38:58 AM by Dan_Lehman »

xarax

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #83 on: July 28, 2011, 01:35:25 AM »
  Now, there can be indicated infinities of things so classified in some rather pointless extents (e.g., if the dbl. bwl is
a *bowline*, wouldn't a trl.bwl be so --add one wrap?... and when does that knot-building Add-A-Wrap ever cease
to qualify?  (It gets silly, though, nearly immediately!)
   So, mere number needs some qualification.

  All families of knots are infinite, if you do not put a limit on the number of tucks, or the number of crossings. The family of bowlines is not infinite, if we consider only the practical knots. In that sense, if we put a reasonable upper limit on the number of nipping loops and the number of collars of a bowline ( say two, for example ), the number of practical knots that belong to the bowline family remains big, but finite...

... seem willing to regard the crossing-knot-based knots as nipping-loop bwl.s, while I want them distinct

   No, I am not willing, I am obliged to do so...I would love to throw them out, but I can not see how, without throwing out the baby, too : the complex, "improved" TIB nipping loops, as the Pretzel, the Constrictor/Transom, ( and their "inverted" forms ), in short, any structure tied on the standing part, topologically equivalent to the unknot, that can efficiently nip/constrict/secure the tail - with the help of a "proper" collar  :), of course ! I want a better definition of the nipping loop, which would possibly exclude the ugly "crossing knot", ( and the Karash loop that is based on it ), but, for the time being, I have not any...However, I would not go as far as Derek Smith, and try to analyse further the nipping loop itself, in its various similar forms, into some even more elementary parts, that might have somethng common with similar parts of a particular hitch, or not. The nipping loop is no hitch, even if the hitch, too, constricts the pole or the line around which it is tied.
« Last Edit: July 28, 2011, 10:28:05 AM by xarax »
This is not a knot.

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #84 on: July 29, 2011, 06:48:19 AM »

... seem willing to regard the crossing-knot-based knots as nipping-loop bwl.s, while I want them distinct

   No, I am not willing, I am obliged to do so...
I would love to throw them out,
but I can not see how, without throwing out the baby, too :
the complex, "improved" TIB nipping loops, as the Pretzel, the Constrictor/Transom,
( and their "inverted" forms ), in short, any structure tied on the standing part,
topologically equivalent to the unknot, that can efficiently nip/constrict/secure the tail - ...

Hmmm, I see no reason to make the definer "UNknot";
leave as the turNip --a requirement that the loop feed
into the eye, to be directly tensioned thus.  The crossing knot
violates this with its turn around the SPart --*indirect*.

(But I think that I've been too casual on my considerations
of the Dbl.bwl, water bwl, and so on, where the turNip
feeds something else, not the eye; it might be that one
must allow more than the turNip --some like structures.)

--dl*
====

xarax

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #85 on: July 29, 2011, 08:30:42 AM »
the loop feed into the eye, to be directly tensioned  
The crossing knot violates this with its turn around the SPart

   But so does the nipping loop in the case of the Eskimo bowine ! You don t expect me to throw out this baby, do you ?  :)
   I believe that the (first)collar should be tied around the standing part, on whatever side of the nipping loop it can. : If it had happened to the rabbit / working end, to enter into the nipping loop from the one particular side, it can only make a U-turn around the standing part and go back into its nest by a collar around the one particular end of the nipping loop. If it had happened to enter into the nipping loop from the other side, it can only make a U-turn around the standing part and go back into its nest by a collar around the other end of the nipping loop. The nipping loop is there, on the standing part, waiting for the rabbit to pass through it from whatever side, make a U-turn around whatever end/leg of the nipping loop it can, and return into its nest. If the rabbit happens to enter from the one particular side of the nipping loop and exit from the other side, it can only go around the one particular end/leg of the nipping loop. If it happens to do the opposite, it can only go around the other end/leg of the nipping loop. I am not willing to sacrifice this symmetry of the rabbit s path, in relation to the nipping loop, AND throw the Eskimo bowline baby out, with the dirty water, the "crossing knot" and the Karash loop.
« Last Edit: July 29, 2011, 09:38:06 AM by xarax »
This is not a knot.

DDK

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #86 on: July 29, 2011, 05:58:23 PM »
What defines a bowline?  To this point, convention which has led some fixed loops to be labeled bowline and others not.  When a formal definition is desired and sought by committee, it resembles this thread.  :)
 
I might point out that much of what has been proposed would appear to invite substantial subjectivity. The elimination of this subjectivity would be objectionable to most of us.  For example, one way to eliminate subjectivity would be to consider each fixed single loop as a looped version of a knot or bend and all double loops as variations of their single loop counterparts.  Thus, the bowline, dbl. bowline, and Eskimo bowline are bowlines as they are Sheetbend Loops.  The Karash single loop and its variations are Karash Sheetbend Loops, and so, are not bowlines.

I did not say you were going to like this.  I was merely pointing out what the elimination of subjectivity is going to look like.  Otherwise, the spinning of wheels does have its benefits as a number of interesting topics and ideas have been discussed.

DDK

xarax

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #87 on: July 29, 2011, 06:29:56 PM »
...one way to eliminate subjectivity would be to consider each fixed single loop as a looped version of a knot or bend

   If THAT has anything to do with "objectivity", no wonder what "subjectivity" looks like !  :)
The end of line loops are loaded entirely differently than their "corresponding" bends. So, the bowline has nothing in common with the Sheet bend, and, of course, it is not a "Sheetbend loop" ! Not even Derek Smith said anything like this...
   I prefer a live camel from a dead horse... :)
« Last Edit: July 29, 2011, 06:39:58 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #88 on: July 30, 2011, 02:42:00 AM »
I might point out that much of what has been proposed would appear to invite substantial subjectivity.
The elimination of this subjectivity would be objectionable to most of us.

Not sure I follow this.  What we're trying to do is
to be objective --to establish a rule in the face of what
has been somewhat haphazard naming.

Quote
Thus, the bowline, dbl. bowline, and Eskimo bowline are bowlines
as they are Sheetbend Loops.

Well, the 3rd is a *reverse* sheet bend --yes, it can be seen
as having in a sense the same formal shape, but on
setting it is quite different (as Xarax remarks, more of a
crossing knot-based eyeknot, not with a turNip base).

And, so, yes, Xarax, I do expect the Eskimo Bwl. to be thrown
out of the *bowline* set.


--dl*
====

DDK

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #89 on: July 30, 2011, 05:05:20 AM »
Both xarax and d.l. picked up immediately on several of the objectionable sacrifices that an unambiguous and non-subjective nomenclature of fixed loops might suffer from.  Namely, for the example that I gave, the ignoring of the loading of the ends, knot element mechanics and functionality (and likely a few others).  This was, in fact, one of my points.  Will there always be a slippery slope without accepting some objectionable (to some) limitations?  I will be pleased to find it not true as it would be like having our cake and eat it too.

DDK
« Last Edit: July 30, 2011, 05:15:39 AM by DDK »