Author Topic: What defines a Bowline? - structure, characteristics, topology  (Read 134717 times)

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #240 on: June 27, 2012, 04:10:26 AM »
One secondary, yet essential function of the collar, is to keep the nipping loop retain its closed loop shape

Indeed, and I maintain that there isn't anything "secondary" to this

  " Secondary" function, only in comparison to the primary function of the collar : to help the nipping loop prevent the slippage of the tail - because that is what any end-of-line loop ( indeed, any knot ) is supposed to do ! To firmly attach the tail on the standing part. How does the collar achieves this ? By just being a collar, i.e. a U turn around a stable element, such as the standing end - in the case of the common bowline - or the eye-leg-of-the-standing-part - in the case of the "Eskimo" bowline. ( The U turn of the Sheepshank is not a collar, it is a bight in mid air...) What an ingenious invention of the human species was this U turn ! However, as said, the primary element of the bowline is the nipping loop, and this is clearly revealed in the cases of the collar-less " half-bowlines' , the ABoK#160, the " Hitch series" and , of course - how did I forget to mention it ? - the Sheepshank.

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #241 on: June 27, 2012, 05:24:28 AM »
Adding some photos to illustrate key theoretical concepts:

Quote

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Re: Myrtle Hitch not in ABOK?
? Reply #12 on: October 17, 2009, 05:41:06 AM ?
Quote from: Andy Asan on October 16, 2009, 06:21:56 PM

    Dan, which one is the Myrtle, and which one is the Anti-Bowline?


The left one, if properly oriented/dressed, is an anti-bowline (my term);
you show it in odd (dis)array, instead of with the *bowline*-characterizing
(and here "bowline" in inclusive of "anti-") nipping loop of the S.Part.  The
right one is easier to see, it being in better form.

ORRRRrrr, just referring to your righthand image, loading the right end
makes an anti-bowline, loading the left end a bowline (Myrtle).

The sheepshank has elements of a bowline but, it is not a bowline on account of no fixed connective eye loop.

The photo of the 'Myrtle'? is poor (from a previous post in this forum) - I will re-photograph it in high resolution.

The Carrick loop ("ABoK #1033") also has elements of a bowline but is not a bowline on account of the nipping turn not encircling the bight component and applying equal tension on both legs of the bight. However, it does have a fixed connective eye loop.

The Eskimo bowline fulfills the criteria to be awarded the title of 'Bowline'. It has a bight component that is encircled, gripped and stabilized by the nipping turn component.

I note Dan Lehman's point re the servant and master - that is, the bight serves to stabilize the nipping turn. It is true that if the bight is removed from the nipping turn - the nipping turn no longer encircles and grips anything. I still take Derek Smith's view that you need both components to form a bowline.

Note: (added)... the images of the 'Myrtle' and sheepshank are not meant to imply qualification for the title of 'Bowline'. I am simply presenting the images to show the (possible) presence of a 'bight' component and a 'nipping turn' component.
...




« Last Edit: June 28, 2012, 10:34:47 AM by agent_smith »

Dan_Lehman

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #242 on: June 27, 2012, 07:13:38 AM »
Adding some photos to illustrate key theoretical concepts:

Quote
    Dan, which one is the Myrtle, and which one is the Anti-Bowline?

The left one, if properly oriented/dressed, is an anti-bowline (my term);
you show it in odd (dis)array, instead of with the *bowline*-characterizing
(and here "bowline" in inclusive of "anti-") nipping loop of the S.Part.  The
right one is easier to see, it being in better form.

ORRRRrrr, just referring to your righthand image, loading the right end
makes an anti-bowline, loading the left end a bowline (Myrtle).

The image given for "Myrtle Anti-Bowline" is grossly misleading
as to the nature of the knot --more resembles (in its open form)
a crabber's eye knot in implying a mere "U" in the SPart
vice a nipping loop (which tends towards a helix).  AND it wrongly
fuses the names of distinct knots.  (The tail for Myrtle enters the
nipping loop as does that for the common bowline and then differs
by making just a loop-wrap/turn vs. bight/collar ; whereas the
entry is from the opposite side for an "anti- [hence this prefix!]
bowline".

Swapping which *side* of the tail-wrap gets loaded, as I've indicated
in my quote, nicely swaps between the two knots, as the one works
well with the tail finishing towards the eye, the other (Myrtle) away
(re stability, nip).



> The sheepshank has elements of a bowline but,
> it is not a bowline on account of no fixed connective eye loop.

Well, duh, yes; which brings an unmade criticism : that THIS
aspect is most fundamental ( = "#1") of the definition (and
could well be overlooked in presumption).

Quote
The Carrick loop ("ABoK #1033") also has elements of a bowline
but is not a bowline on account of the nipping turn not encircling the bight component
and applying equal tension on both legs of the bight. However, it does have a fixed connective eye loop.

Well, you'll not sell this perspective to me.  It fits my definition
of "bowline" fine, if not hauled to the point that the "nipping
loop" becomes a crossing knot base.

Quote
The Eskimo bowline fulfills the criteria to be awarded the title of 'Bowline'. It has a bight component that is encircled, gripped and stabilized by the nipping turn component.

Here, too, there are disturbing variances for those who care to look
and explore differences in setting --loose can see "loop"=>"helix"
(well, it's always that, but more so); tight ... crossing knot base.

Quote
I note Dan Lehman's point re the servant and master - that is, the bight serves to stabilize the nipping turn. It is true that if the bight is removed from the nipping turn - the nipping turn no longer encircles and grips anything. I still take Derek Smith's view that you need both components to form a bowline.

But what I said wasn't removing the bight entirely, but just removing
it from "collaring" the SPart --which goes also against X1's remark :
Quote
the primary function of the collar : to help the nipping loop prevent the slippage of the tail
... By just being a collar, i.e. a U turn around a stable element
--
is that a sheepshank shows that this "U"/bight could-be "collar"
can be deprived of the asserted stabilizing (or U-turn-around...) functions
and a knot still works, from the behavior of the nipping loop alone.

Now, I see that I, too, once had stronger feelings for the "collar" bight,
and thought about naming *my* "Lehman8" "bowlinEight" on
account of a more easy-to-pry loose collar of the fig.8 base than
is normally the case (it being now a single strand, of the base component,
and not also a "rewoven" twin).  But then I thought otherwise, and am
not compelled in recollection to relent : no, the strong characteristic
of *bowline* to me is the nipping loop --at least I see that as a good
binding aspect for some named genus/family/order of knots, which
at the moment I'm feeling fits "bowline" (and "anti-bowline", with
thus "bowline" overloaded).


--dl*
====

ps:  I quite agree that continuing the dormant thread was the right thing
to do, vs. starting a new one only to have to refer to all this one's ideas.

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #243 on: June 27, 2012, 11:01:28 AM »
Hi Mark,

As you were the creator of this thread, I would hope other members would be happy enough to have you develop it further.

Well done on your 'Analysis of Bowlines' document.  It is a nice piece of work.  I would make one comment which is hopefully constructive - you publish a strength test on the EBSB, declaring it to be ca 73% to 77% which implies that the knot is a significant improvement over the basic bowline.  But then one notes that the calculation is performed against the declared minimum rope strength - not the actual rope strength, so these results will have been overstated by some amount by which the tested rope actually exceeded the declared minimum value.  You would have made this test a little more valuable if you had included a test on the basic bowline under the same test conditions so a genuine comparison could have been made if indeed the EBSB is stronger than the basic.

It has made interesting reading going back over this topic again.  I learned a lot from other posters, but I am afraid that I still cannot countenance the concept of a Myrtle bowline or a Sheepshank bowline, so to preserve my sanity I will abstain from further discussion on the subject.

Derek
« Last Edit: June 27, 2012, 12:51:34 PM by DerekSmith »

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #244 on: June 27, 2012, 01:28:13 PM »
Let me try to re-phrase some things, in order to better express what I believe about the matter.

The sheepshank has elements of a bowline, but it is not a bowline on account of no fixed connective eye loop.

The sheepshank has elements of a bowline, but it is not a bowline on account of no collar .


The Carrick loop ("ABoK #1033") also has elements of a bowline, but is not a bowline on account of the nipping turn not encircling the bight component and applying equal tension on both legs of the bight.


The Carrick loop ("ABoK #1033") also has elements of a bowline, but is not a bowline on account of the collar not being like the common bowline s "proper" collar.

[the collar and the nipping loop =] the servant and master - that is, the bight serves to stabilize the nipping turn.

   Thy collar is not just "a bight" , it is a loaded bight, a U turn of the working end around a stable element. So,

   This loaded bight = collar serves to :
1. Help the nipping loop keep the tail from slipping through it.
2. Keep the nipping loop retain its closed loop form, and do not degenerate into an open helix.

( I think that the #1 function is more important /primary than the #2, but this is not such an important thing anyway. It may be only a matter of semantics.)

It is true that if the bight is removed from the nipping turn - the nipping turn no longer encircles and grips anything.

An obvios missunderstanding looms here.

The (loaded) bight that we call collar can well be removed from the nipping loop, as a loaded bight - the nipping loop will continue to encircle the eye-leg-of-the-bight, i.e, only the one strand, that which was one of the two legs of the collar before that removal. When I say that we may remove the collar, and be left with a half-bowline, I mean remove the second leg of the collar, the "proper" tail. 

   Both the ABoK#160 and the Sheepshank are " half-bowlines"  in the sense that they have no collar - but, of course, there is something left, that the nipping loop encircles and grips:)

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #245 on: June 27, 2012, 01:58:58 PM »
the point that the "nipping loop" becomes a crossing knot base.

The problem is that this "point" is, in fact, a grey area.

   If we would allow ourselves to go beyond the common nipping loop, and consider instead any nipping structure ( that is topologically equivalent to the unknot and can be untied at exactly the same time the tail is removed  from its passage through it,  in other words, a " nipping structure + collar" compound knot that can be untied in one step) - then we can achieve a more general definition of the bowline. Of course, doing this, we run on the reverse problem ; how do we can now rrestrict that definition, so it does not include too many end-of-line loops that do not resemble the common bowline at all.

...which goes also against X1's remark :
Quote
the primary function of the collar : to help the nipping loop prevent the slippage of the tail
... By just being a collar, i.e. a U turn around a stable element

I have explained what I mean in the previous post.
I wouldn't describe as nipping loop a bight that encircles nothing but thin air , of course, - as I do not describe as collar a bight that encircles thin air ( The Sheepshank s bight(s)).\
When I say " we can remove the collar" from a bowline, and leave a half-bowline that has only a nipping loop in the place where the bowline was before this removal , I mean ( and, indeed, I could not have meant anything else, could I ?) to remove the one leg of the collar, the "proper" tail - so the loaded U turn around the standing part or the eye-leg-of-the-bight is not loaded, not U turn around something any more !  :)

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #246 on: June 27, 2012, 02:14:01 PM »
Hi Mark,
 a Sheepshank bowline
so to preserve my sanity I will abstain from further discussion on the subject.

 :)

   ( I had said " ABoK#160" "half-bowline",  and Sheepshank "half-bowline",  in purpose !
   Please, reconsider your abstain - I am convinced that knots bring us close to insanity, indeed... but, at the same time, they keep us from falling into it - iff they are tied and dressed properly !  :)
« Last Edit: June 27, 2012, 02:16:42 PM by X1 »

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #247 on: June 28, 2012, 02:39:49 AM »
Quote
What happens in a bowline if, intentionally or by accident, one of its two essential elements, the collar, cease to exist altogether ? Will this half-bowline still be capable to hold some loading ? This is a somewhat far-fetched measure of the security of the bowline, but I think that is not completely irrelevant. The thought that a knot would still function adequately well - at least for some brief moments. and when loaded with a small only percentage of its maximum capacity - even if/after it is severely de-structured, brings piece to mind...

An interesting proposition.

I did take a sequence of photos at various milestone loadings of a Bowline ("ABoK #1010") - up to 10kN force then stopped.

Although I am dissatisfied with the photos - because I should have taken them from the 'front' (ie the front as defined by Dan Lehman - which properly shows the operation of the nipping turn) - I also could have woven those darn little tracer threads into the knot structure as per Dan Lehman. However, the act of sewing and the fine motor skills and effort required to weave those tiny threads are a PITA! (I honestly believe that Dan invented the idea of the cotton threads purely to cast his cruel sense of humor on poor unsuspecting fools such as myself who are willing to do his bidding).

My next effort at photography will show the Bowline from the 'front' - and I hate to say it, I'll weave those cotton threads (I will chant a curse to Dan while threading my needle) - and hopefully finally come up with some useful photographic data.

But, of greater interest is the idea from X1 (alias our esteemed colleague xarax) and I will attempt to cut various sections of the structure (eg collar) with a razor sharp blade while under load. Hopefully the act of cutting will not place my life at risk should the knot suddenly explode in my face! If I don't post back here again, it probably means that I am in heaven looking down upon X1 and smiling  :o

Mark

« Last Edit: June 28, 2012, 02:42:48 AM by agent_smith »

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #248 on: June 28, 2012, 06:38:13 AM »
I will attempt to cut various sections of the structure (eg collar) with a razor sharp blade while under load.

  This is a catastrophic idea / action ! :)  Are you sure you are going up, to heavens ?  :)

  If not, I would suggest to simply untuck the tail / second leg of the collar, ( pull it out of the two nipping loops - so leave those nipping loops encircle and grip only the one, the first leg of the collar, the direct continuation of the eye-leg-of-the-bight ), and then measure what percentage of the initial maximum load of the complete bowline this "halved-bowline" can now bear.
  (I expect that we will be surprised by the numbers in the cases of the Water bowline and the Gith-hitched bowline. I also believe that the initial separation of the two nipping loops would  matter quite a bit. If they are placed close to each other in the first place, they will have a greater chance to remain close to each other during the whole phase of the loading. In such a case, the " half-bowlines" would be able to withstand a much heavier loading, I guess. ).
« Last Edit: June 28, 2012, 06:44:07 AM by X1 »

agent_smith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #249 on: June 28, 2012, 10:29:14 AM »
Quote
It has made interesting reading going back over this topic again.  I learned a lot from other posters, but I am afraid that I still cannot countenance the concept of a Myrtle bowline or a Sheepshank bowline, so to preserve my sanity I will abstain from further discussion on the subject.

Derek

Heh Derek,

The only reason I posted images of the that weird structure called a 'myrtle' and the sheepshank was purely to show some more bight components and nipping turn components. I certainly did not intend to suggest that these structures are 'Bowlines'.

I am continuing to look at structures that have these core elements (ie bight + nipping turn) - simply so I can test the theory and see if it holds up.

In my view, the primary features of a Bowline include:
1) possessing a fixed connective eye loop.
2) does not jam under load and can be easily untied - even after a high loading event

If the specimen knot cant meet these first 2 criteria, it wont even be a contender for 'Bowline'.

The sheepshank is instantly dismissed - it doesn't pass the first test (no fixed connective eye loop).

As for the 'Myrtle' - that photo I uploaded is an abomination...I lifted it off the IGKT site - because I couldn't find any other images. I will re-photograph my own tying effort and re-present it in a proper orientation in accordance with Dan Lehman's notion of 'front' and 'rear' view.

Essentially, I am clinging to your theory regarding the bight component and the nipping turn component since it appears to me to be logical and elegantly simple. By adding the above 2 criteria, it appears to me to be a reasonable working hypothesis. As you know, all theories have to be tested.

I guess what I'm saying is that your absence from further commenting would be a significant loss...

Derek Smith:
Quote
I would make one comment which is hopefully constructive - you publish a strength test on the EBSB, declaring it to be ca 73% to 77% which implies that the knot is a significant improvement over the basic bowline.  But then one notes that the calculation is performed against the declared minimum rope strength - not the actual rope strength, so these results will have been overstated by some amount by which the tested rope actually exceeded the declared minimum value.  You would have made this test a little more valuable if you had included a test on the basic bowline under the same test conditions so a genuine comparison could have been made if indeed the EBSB is stronger than the basic.

Fair comment... from memory, I had a tight budget and limited time during the period of these original tests. I purchased a limited quantity of accessory cord - and had to make some hard decisions on how best to utilize that quantity. I did consider performing break tests on "ABoK #1010" as a control, but didn't proceed because I also wanted to test the Rosendahl/Zeppelin + a few other knots. In the end, I ran out of time and cord and the tests ground to a halt. Also, a series of 3 pull tests is not sufficient - I should have performed at least 5 x tests to get a better statistical sample. Again, I went with 3 tests for the same set of reasons i outlined above (ie limited quantity of cord, limited time, limited money...). In any case, at least I was able to compare the 'EBSB variant' breaks against the manufacturers stated MBS...so it least I've got something of a (tiny) data set. I will try to find some time (and cordage) to go back and perform a control test on "ABoK #1010"...

Mark

« Last Edit: June 28, 2012, 02:32:49 PM by agent_smith »

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #250 on: June 29, 2012, 08:19:52 AM »
Hi Mark,

Thank you for the compliment, but I am sure that I cannot contribute much more of value of your challenge.

When I first read your post title, I felt there was an answer and after much discussion, arrived at the proposal outlined back in post #164

1.  A Bowline is an end of line [note 1] fixed loopknot {.EyeKnot}
[note 1 - a Bowline may be tied inline on a bight, in which case the bight is considered as an inline device to create a doubled 'end of line' element]

and carry on a little with :-

2.  A Bowline is defined and described in ABoK as 1010

3.  A Bowline construction comprises a load line, a knot, a fixed loop and an end

4.  A Bowline knot has two components, a Half Hitch Component connected to the load line and a loop leg and a Bight Component connected to a loop leg and the end [note 2]
[note 2 - the Half Hitch component transfers load into both loop legs through the turn element and the high nip force generated causes frictional entrapment of the end.  The Bight component acts as the core for the Half Hitch component and stabilises it via its bight collar made around the loaded line]

5.  A Bowline's Operational characteristics are :- ...

6.  A Bowline's Usage characteristics are :- ...

7.  A Bowline's Historical characteristics are :- ...

8.  A Bowline's Aesthetic characteristics are :- ...

9.  ...


But now I realise that had your question been 'What defines THE Bowline (#1010), the above answer might have held, but when it comes to answering your actual question 'What defines A Bowline', then I am afraind I have to opt for a perhaps more cynical answer --

i.e.  A Bowline is defined by - History and the whimsy of the trade or user that names it.

As if by way of demonstration we have proposals of the Zeperlin Bowline and the Myrtle Bowline, let alone the whimsy from Dan and Constance of the 'Sheepshank Bowline'.

Anything can be called a bowline and if then pressed into use, the name will stick irrespective of structure, characteristics or topology.

It would be nice to think that the combined 'Knotterati' of the venerable IGKT could make 2012 the year to propose a consistent definition for Bowline and Bowline Variants, and in doing so take a large step forward in cleaning up a little of the chaos which litters the historical naming of knots.  Driving our standard into the ground and declaring that henceforth members of the IGKT would only use the term Bowline to describe knots which complied to xyz...  but perhaps even that one step would require the wearing of 'seven league boots' by most of our illustrious members.

Still, enough on the topic of definition, could I turn briefly to the thorny subject of the importance of the bight component, and your proposal to take a razorblade to a loaded #1010.  Instead, could I suggest that you simply make up #1010 with a very long bight collar (ca 10 diameters).  If you then load this knot SP to Bight loop leg, the colar will pull up and form a normal Bowline.  If however, you load the SP and the nipping loop leg, then you willl see the nipping loop rotate the bight legs into a nice slipping noose arrangement.  What you will have seen is the mode of failure for the Bowline when the bight collar becomes excessively elongated and the loop is then subjected to ring loading on the nipping loop leg.

Conclusion == the bight collar is an absolutely essential part of the Bowline knot.

Derek

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #251 on: June 29, 2012, 09:20:11 AM »
An interesting example of how loading can / will influence a basic knot structure is given by the Eskimo



The standard SB Core loaded from the SP into the side arm of the nipping turn, converts the nipping turn into a Carrick component which in turn holds and is stabilised by the bight collar.

We might denote this knot as a 'Half Carrick loop knot' which is a very close sister to the one in which the bight component is replaced with a round turn which then creates the Carrick/Myrtle loop knot.

Or if we are feeling perverse, we could call the Eskomo a Half Carrick Bowline and its sister the Half Carrick/Myrtle Bowline.

But then, as the Myrtle is the working shape you get when you load a simple Carrick, we might have to call the latter of these two loop knots the Half Carrick/Half Simple Carrick Bowline...

But then again, as the Myrtle is most easily made by making a Constrictor and passing the WE through the constrictor loops before pulling it up, we might have to call the Myrtle the Constrictor Bowline... which would make the Eskimo sister knot into the half Carrick/Half Constrictor Bowline...

Ho Hum

Derek

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #252 on: June 29, 2012, 10:57:46 AM »
I suggest that you simply make up #1010 with a very long bight collar (ca 10 diameters).  If you then load this knot SP to Bight loop leg, the collar will pull up and form a normal Bowline.  If however, you load the SP and the nipping loop leg, then you will see the nipping loop rotate the bight legs into a nice slipping noose arrangement. 

   However, if you load the SP, and both the standing " bight loop leg"  and the " nipping loop leg at the same time, ( i.e, the "eye-leg-of-the-standingpart" and the " eye-leg-of-the-bight" , if we use your terminology), you will see what I mean. You will see how the ABoK#160 "half-bowline"  works, and how the Sheepshank "half-bowline" works, and how the "Hitch series" works !

   ( P.S. And this will prove to you that the bowline can work even if the legs of the collar are not crossed in any degree, and remain parallel to each other right after the U turn of the collar. So, there is no hitch element in the bowline, if we are looking for such an element in the tail - and there is no hitch element in the bowline, if we are looking for such a hitch element in the nipping loop either - because, of course, the nipping loop is a nipping loop, it is not a hitch ! 
   The bowline does not have a hitch in it.
   The bowline is a close relative of the Gleipnir, not of the Sheet bend.
   I argue for some obvious simple things with my wife for 35 years now. I guess I can bear to argue with Derek the next 35 years, for the bowline !  :) :)))
« Last Edit: June 29, 2012, 11:14:17 AM by X1 »

DerekSmith

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #253 on: June 30, 2012, 09:47:56 AM »


   However, if you load the SP, and both the standing " bight loop leg"  and the " nipping loop leg at the same time, ( i.e, the "eye-leg-of-the-standingpart" and the " eye-leg-of-the-bight" , if we use your terminology), you will see what I mean. You will see how the ABoK#160 "half-bowline"  works, and how the Sheepshank "half-bowline" works, and how the "Hitch series" works !

   ( P.S. And this will prove to you that the bowline can work even if the legs of the collar are not crossed in any degree, and remain parallel to each other right after the U turn of the collar. So, there is no hitch element in the bowline, if we are looking for such an element in the tail - and there is no hitch element in the bowline, if we are looking for such a hitch element in the nipping loop either - because, of course, the nipping loop is a nipping loop, it is not a hitch ! 
   The bowline does not have a hitch in it.
   The bowline is a close relative of the Gleipnir, not of the Sheet bend.
   I argue for some obvious simple things with my wife for 35 years now. I guess I can bear to argue with Derek the next 35 years, for the bowline !  :) :)))

Hi Constant,

You have demonstrated a number of things quite nicely for me here.

First - you have called ABoK #160 a 'Half Bowline'.  In Ashley's description of of #160 he states "the end is easily pulled through the hitches whenever it is necessary to adjust the length" [emphasis mine].  Now if Ashley can see that these two components are hitches, and I see they are hitches, why can't you?  And if the 'Half Bowline' has a hitch component in it, then presumably so does the whole thing- vis #1010.

Second, without meaning to cause offence or antagonism, I think you may have missed my point re the colar experiment.  Mark was going to take a razor to the colar of a loaded #1010 to demonstrate if the collar had any function within the knot.  If the collar was not there, then even pulling up both legs as you advocate would result in the demonstration I proposed, i.e. the knot would collapse into a noose, while load on the end leg would simply pull it out of the knot because shedding load in the collar turn around the SP is an important part of #1010 functionality.

Finally, you agree with my earlier statement that this thread is a matter of opinion, or rather a matter of differing opinions, and while some of my opinions have been revised by accepting rational arguments, some 'others' remain obdurate and indifferent to rational argument, and while you and your lovely wife have the stamina to bicker over 'simple things' for 35 years,  you will not find my dear Constant that I share your tenacity nor your good wife's patience.

Derek
« Last Edit: July 01, 2012, 09:46:50 AM by DerekSmith »

X1

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Re: What defines a Bowline? - structure, characteristics, topology
« Reply #254 on: June 30, 2012, 11:28:43 AM »
In Ashley's description of of #160 he states "the end is easily pulled through the hitches whenever it is necessary to adjust the length" [emphasis mine].  Now if Ashley can see that these two components are hitches, and I see they are hitches, why can't you? 

   I believe that repetition is the mother of all learning, but I also believe that exceptions prove the rule ... :)

   You have a theory, inherited from Ashley, that the bowline is related to the Sheet bend. No surprize here : A whole generation of knot tyers had inherited the same theory - I dare to say: they were brainwashed by this theory. To support this theory, you have discovered a hitch where there is only a nipping loop. Of course, now you can not say what a nipping loop is, and you have to call any nipping loop "a hitch"... I would nt be happy to be in your position - but your tenacity is impressive, indeed - that is for sure -, so I suppose you will elaborate this theory a little more, so it will start to look a little more plausible.

Well, I have said time and again that Ashley was wrong on this - as God himself was wrong, when He said that the ratio of the circumference to the diameter of a circle is 3 ( speaking about the dimensions of the circular basin at the Temple). I do not have to prove that π is not 3 for you to accept my point, do I ? :) One can not really argue with a mathematical theorem.

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 !  :)

The false theory of the close relation of the Bowline with the Sheet bend was, in fact, initiated by Ashley, who had not paid much attention to ABoK160 and ABoK#161 as structures that could be evolved even further : that is why he missed the Gleipnir ! Had he met the Gleipnir, I am sure that he would have seen its close relation with the Bowline, at once.
   The Gleipnir proved that the primary element of the Bowline is the nipping loop, and the secondary element the collar. If we did not know the Gleipnir, ( and the ABoK#160 and ABoK#161 ), we would be justified to see the relation of the Bowline with the Sheet bend, indeed, a relation that is more remote and less important that the relation between the Bowline and the Gleipnir.


    I have stated time and again this simple distinction :
    a. A hitch has one leg loaded and one not, because the second leg has gone under the riding turn, and has escaped as a free end. The hitch is asymmetric.
    b. A nipping loop has both legs loaded, to a more or less same degree. The nipping loop is symmetric.
    a, b., not even c ! SO simple...

   Of course, we can find cases where the distinction is not so clear, where the second leg of a "hitch" which should not be tensioned, is not a free end either. Also, we can find cases where the second leg of the nipping loop leaves the crossing point with the first leg at a much larger angle - so it is not loaded as much as the first leg any more. Generally, the "hitch" is a more vague term than the "nipping loop" . In ABoK#1821, Ashley is calling even a complete overhand knot tied around a ring as a "Half Hitch".
   What I have stressed is that the " nipping loop"  is a very fundamental element of knots, and it should not be confused with the " hitch" - which is another fundamental element. At a hitch, we have the one leg going UNDER the second, so the one leg is not loaded ( or it is now much less loaded) than the other. At a nipping loop we have two legs that touch or cross each other at a point- most of the times - but they remain loaded at about the same degree as they leave this  point.

So, any "half-bowline" DOES NOT have a hitch in it, and this is true for the Glkeipnir, the ABoK#160 and the Sheepshank. And if the Gleipnir, the ABoK#160 and the Sheepshank do not have a hitch in them, so, presumably, the whole thing , vis#1010, does not have a hitch  in it either.

If the collar was not there, then even pulling up both legs as you advocate would result in the demonstration I proposed, i.e. the knot would collapse into a noose,

The ABoK#160 and the Sheepshank do not have a (loaded) collar. Do they collapse into a noose ?

while some of my opinions have been revised by accepting rational arguments, some 'others' remain obdurate and indifferent to rational argument

I wonder what are the "some" and what are the "others" ! :)
(The fact that you feel you have to refer to a line in a holy bible as some kind of " proof", tells something about the " rational"  :) character of your arguments. )

Constant
« Last Edit: June 30, 2012, 03:23:48 PM by X1 »