Analysis of Bowlines paper uploaded for review and comment (PACI website)

Knotting Concepts & Explorations
381

Hello knotsaver,

Many thanks for feedback - and yes, I wasn’t all that pleased with my attempted re-write of that page (Myrtle). Derek’s S and Z twists were not entirely satisfactory to me - I was looking for another analogy/description…and you’re right in what you say so it ought to be included. Opposite chirality (eg left-right instead of left-left).

And yes, I forgot to include commentary re the other major effect of the collar - is that it aids in maintaining a stable nipping loop - without the collar, the bight kinks and folds down which in turn causes the nipping loop (a helix) to degenerate.

Also, may I include you as a contributor?

Thanks,

Mark

382

Dan,

That is beneath you. You know full well I have not ruled out any effect of the collar, and you also know full well what I actually stated, but to refresh your memory, here it is again –

The Bight is very important in a Bowline because it counters the turning moment created by the loaded Nipping Helix. The bight collaring the SP offers a small degree of stabilisation of the Bight in low load situations.

Besides, this, with or without collar, you would not catch me “–rap[ing] off of Yosemite’s famous walls” with any form of #1010, and I have made the point many times before that I would NEVER climb with the Bowline as my safety knot.

Having said that, Oh what I would give for just the chance to rap down those amazing faces - sadly though, not to be… and if I tied up any of my dogs with any form of Bowline, they would chew through the rope in seconds - ‘Very Important Collar’ or not.

Seriously though, obviously the bight ‘collar’ has to be anchored somewhere, and the Bowline is such a minimalist knot, there is very little elsewhere to park it. But the thrust of my statement was to challenge Mark, or any other Knotbotherers, to come up with a viable reason for giving the collar such importance, and the argument so far given of ’ All Bowlines have a collar ’ is circular, and does not cut it as being more functionally important than the function of the bight legs, without which there would be no knot, and then we would see just how ‘Important’ that collar really is…

Derek

383

VER 2.4d is ready for download.

Change log:
page 12 + 13 (some minor changes to include detail of the collar)
page 14 + 15 (added new wording to include details about the collar)
page 26: complete re-write (Myrtle content)

Feedback / comments are welcome.

Mark

384

Hi Mark,

The stress certainly seems to be getting to you, so my advice to you is - Calm down and enjoy the Project.

I did not give you any form of ultimatum - I ASKED you - with a please, to remove my name from the document. Thank you for doing this for me.

I offered you an alternative statement regarding the Bight component which redirected the priority from collar to legs, but acknowledged the lesser function of the collar in stabilising the bight into the nipping helix. I am pleased to see that you are now also adopting this position in point 4. above.

That blood you see in your eyes must be the ‘red haze’, because you have turned a simple request to generate substantiation for the emphasis placed on the collar being ‘Very important’, into the suggestion that I am ‘demanding you supply proof’. Absolutely not the case… mostly because I don’t think anyone can supply such proof, so it would have been stupid of me to demand anything of the sort.

So, just a confirmation - I am not demanding anything, nor threatening any ultimatums.

Getting on with the present two points of contention though - Collar importance and Capstan effect - this lovely emage you provided earlier -

http://igkt.net/sm/index.php?action=dlattach;topic=4480.0;attach=20421;image

supplies all the proof needed to put both areas of contention to bed.

Capstan Effect :- If there were any significant capstan effect in this knot, then one leg of the collar would be under more tension than the other - this would be apparent as one side being tighter and shorter than the other. No such effect is seen, demonstrating that in this cord, there is no significant Capstan effect at the collar.

Important Collar Effect :- The two major components of this working knot are the nipping helix and the Bight legs - they are both under load and the knot would cease to exist if either were not present. By contrast, in this example the collar is dysfunctional. However, in a working knot, loosening and lateral forces are countered by the presence of the collar. It has a function, just not as important a function as the nip and the legs.

Derek

385
The stress certainly seems to be getting to you, so my advice to you is - Calm down and enjoy the Project.

Your invention of some imagined situation is wrong.

That blood you see in your eyes must be the 'red haze',

Another interesting and imagined situation… the only red haze I see is the effect of rubbing my eyes after staring at a LCD computer screen for too long.

…

The ‘wonderful’ image you like to keep recycling actually proves the importance of the collar and how it functions as a ‘bracing post’ for the bight. I would suggest you have a look at page 14.

In reply, I also like to recycle my own image (attached).
The question is: Is it a Bowline?

This question is what I call a reversal of the onus of proof. And I like asking this type of question because it alters ones perspective.

If you answer ‘No’ - there must be a reason why. And your answer would be interesting.

If you answer ‘Yes’ - this would indicate that your requirements to fulfill the definition of a ‘Bowline’ differs markedly from the standard #1010.

For me, the answer must strictly be in the negative - because without a collar, the nipping loop will become unstable and then collapse and fail (because the bight is not braced against the SPart, it will kink and fold - which in turn triggers the collapse of the nipping loop).

I also commented earlier that I have yet to see a Bowline that has no collar - although one may regard this observation as too simplistic - at the same time, it is surprisingly powerful.
If indeed such a Bowline (with no collar) exists - I would very much like to see it.

Mark

386

LOL - OK, point taken.

I also commented earlier that I have yet to see a Bowline that has no collar - although one may regard this observation as too simplistic - at the same time, it is surprisingly powerful. If indeed such a Bowline (with no collar) exists - I would very much like to see it.

http://igkt.net/sm/index.php?action=dlattach;topic=4480.0;attach=20460;image

By your current definition in 2.4d, no this is not a bwl. because it has no collar.

By the definition I offered earlier, no it is not a bwl. because it has no bight component stabilised against the SP.

So can we take this exercise one step further. Take a standard #1010, but make it with a long WE. Now cut off the SP and make it the WE and load the SP.

Exactly the same knot, but we have just swapped the function of the SP and WE.

Is this now a bwl.?

Derek

387
Take a standard #1010, but make it with a long WE

This part makes sense.

Now cut off the SP and make it the WE [b]and load the SP[/b].

This part doesn’t (in red)…

Did you mean; “and load the eye while holding the new SPart (formerly WE)”?

388

@ agent
Your paper is well written, the layout and the photos are great; but for me its too much on the conservative side. Things evolved. #1010 was the first stage of the rocket let’s move on please.
In putting too much insistence on the strict definition of the bowline we are gonna miss the “what the bowline have morphed into”
The bowline is a butterfly.

My two cents;

A bowline consists of ;
a S Part (single,double,triple…)
a nipping loop ( any kind of, simple, doubled or helicoidal)
the loop (single double triple…)
a collar (single double triple or helicoidal) after the returning eye-leg is nipped we got to secure the tail dont we? Plenty clever solutions have been found your paper demonstrates a few.

I would say that any loop depending on a nipping mecanism (any) structure who hold the tension without loosing its primal function deserves the name;

So that why your Project should by entitled;

“Analysis of the bowline and its derivatives”

389

I think that you have two components and a result,
in a sense. A bowline is an eye knot (I don’t know
what an “unfixed” eye is --or is it what should be
called “noose”?!), and what distinguishes it from other
such knots is what we’re debating. Your list above
approximates what I’ve said. (One might think we
could leave it at “nipping loop”, for it that were NOT
stabilized, that would not BE !)

About the Myrtle (p. 26) you say: "The structure is stable....This occurs when the 'returning eye leg' enters the nipping loop from the SPart side (in the same way that a standard #1010 Bowline is formed)."
Yes : the distinction cited is one I use to separate "bowlines" from "anti-bowlines", nothing more; and stability of these you cite is just as you describe (and IMO the anti-bowline can fare better with the same-handed loops, though it's inferior to having them opposite-handed; the [i]Myrtle[/i]-like knot is worse).
(this reminds me the 'Boobash' (Boobashley? Boobasher? :) ) ABoK #1445).
Though that name doesn't occur there, does it!?

I more or less took AshER to task on this (or meant to),
and so expand “Ash” with an “er” not “ley”, after I confirmed
my assessment with testing in which his alleged okay knot
slipped so much that the tester gave up on it!
(tested in 1/4" laid nylon rope)

–dl*

390
I also commented earlier that I have yet to see a [i]Bowline[/i] that has no collar
?! Isn't that because you've [u]defined[/u] "bowline" to have a collar --and filter out anything else?!

Otherwise, Myrtle qualifies --or why not?
MY position (tentative, to see what falls in/out and
so on) is that it’s good to define/articulate/identify
the set of knots that have a “central nipping loop”,
for which I’m willing to use the name “bowlines”.

too simplistic
Mr. LanguageMan here : "simplisitic" has pejorative sense, and thus "too" is unwanted; "simple" would work.
If indeed such a Bowline (with no collar) exists - I would very much like to see it.
... So can we take this exercise one step further. Take a standard #1010, but make it with a long WE. Now cut off the SP and make it the WE and load the SP.
Occam cuts off your "cut off" :: simply (not "simplistically", nb!) put, load #1010 in reverse --by the tail vs. the eye, and see whether that tickles your fancy!

Firstly, NB : one has to define --this doesn’t come with
“1010”/“bowline”(!)-- on which side of the eye does
the newly loaded tail pass !! (This sort of thing pops
up if wanting to mathematize the knot into a
closed loop.)
.:. Orient the tail-to-be-S.Part so that it crosses over
the eye legs as it would from the position it is drawn
into by the pull of the S.Part --in the direction one would
take it in making the “Yosemitie” finish; this way one
gets more of a loop than helix in the newly become
nipping former collar/bight!

In either case, IMO, this reversed bowline wants
to flaunt a helix and not a loop, but tight setting
might staunch that, to some degree, anyway.
And it counts as a (pseudo/quasi?) “anti-bowline”
as the “returning eye leg” enters from the side
of the nipping loop of the “ongoing eye leg” unlike
for #1010.

It’s hardly “Exactly the same knot,” but AS we have
just swapped the function of the SP and WE.

Is this now a bwl.? Well, IMO it can be forced to hold,
at least in this small cord I’m working with now, a nipping
loop, though that does want to open.

Now, as for a “collar”, hmmm, I think not?
The nipping loop is held more or less in position
by the nipped tail. And I think this is your point?!
(good show)

BTW, such a knot has been presented in KM and was
discovered by me on my own, with the simple aim of
choking the base of a nipping loop and stuffing it
with diameters to both swell it and stabilize it. It
perhaps was shown with a slip-bight so stuffed,
in hopes of quick untying?!

–dl*

391

Sorry, it was late and I was not clear.

I meant simply exchange the functions of the WE and the SP.

In doing so, we now have the bight collar around the WE and a nipping helix which is loaded only by one loop leg. The SP no longer has a bight collar, and instead feeds into the nipping helix as a bight leg, on its way to a bight collar around the WE.

Would I be right Mark in assuming this reversal of leg functions now fails your definition on p. 12 (2.4d)

Derek

392

Yes, the stability of the eye is a result, the friction forces acting in the completed (well tied) bowline determine the fixed (not slipping) eye.
The friction forces are generated between contacting surfaces and now I see Capstan effect everywhere in a standard bowline.

  • In a well-tied (standard) bowline the nipping loop doesn’t lay on a single plane (the bight (and especially the collar) makes the nipping loop do a torsion) and the returning eye leg goes through a “chicane” (a double deflection) in the nipping loop (Capstan effect in the nipping loop?).
  • The nipping loop has two degeneration tendencies:
  1. the helix can open up
  2. the nipping loop can roll (walk).
    (Without a collar) the first degeneration occurs when the ongoing leg (the nipping loop leg) is loaded much more than the return eye leg. The second degeneration occurs when the returning eye leg is loaded much more than the ongoing eye leg (I could draw a picture of the experiment I made).
    In a well tied standard bowline these events don’t occur and the load of the standing end is distributed between the ongoing eye leg and the returning eye leg (Capstan effect of the nipping loop?)

No, the name doesn’t occur there. I was referring to this
http://igkt.net/sm/index.php?topic=4480.msg36276#msg36276
:wink:

ciao,
s.

393
Would I be right Mark in assuming this reversal of leg functions now fails your definition on p. 12 (2.4d)

Derek

I get the distinct feeling that you are attempting to extract a sort of confession from me for a “aha” kodak moment.

Your argument is non-sensical - as it implies a loading profile that simply doesn’t exist - it is only a thought experiment and not a good one at that. It is like asking me to saw one wing off a plane and then ask me if it can still fly (and then declaring you were right all along). An aircraft needs 2 wings (left and right) to remain stable in flight - that’s the way its designed - aerodynamic lift is generated by both wings - and lift is perfectly in balanced in level flight. Spoilers on the wings can alter this lift. Look what happened to space shuttle Columbia when it lost one of its wings…

The Bowline is an eye knot - and the eye is intended to serve as a connective interface to something…like a tree, a climbers harness, a carabiner, etc. The SPart is intended to be subjected to load. The same can be said of #1047 F8 eye knot and one can also conduct thought experiments with that knot - and subject it to non-sensical loading profiles to circumvent the eye.

To answer your specific question, this loading profile isolates the eye…and effectively mimics the core function of a Sheet bend (although the Sheet bend can be tied with tails oriented same side or opposite sides - with same side orientation being the standard practice). I have already stated that in my personal view, there is no ‘nipping loop’ in a Sheet bend since it is not loaded at both ends.

A better argument is to examine some knot structures that cause people to stop and think - and scratch their heads. Like the #1017 Angler’s Loop perhaps?

Another area that is more worthy of attention is the various nipping loops (I refer to them a ‘loops’ and not ‘turns’). Budworth also appears to suggest that a ‘turn’ - eg a Round turn and 2 half hitches is formed around an object such as a post, a tree, a bollard, a rail, etc. I have not seen this structure called a ‘round loop and 2 half hitches’… it is always 'round turn and 2 half hitches.

Note: With regard to the bight performing a ‘U turn’ around the SPart in a Bowline, in this case - the phrase ‘U turn’ is referring to a maneuver and not a turn in the strict definition of wrapping around an object.

I am currently struggling with a nipping ‘structure’ based on a constrictor hitch.

And some are not satisfied with a nipping ‘structure’ based on a Munter hitch…

Mark

EDIT: Another puzzling ‘Bowline’ - is #1057 and #1058 (in ABoK). I do not know why Ashley referred to these 2 structures as ‘Bowlines’. I do not see evidence of a ‘nipping loop’ (which is loaded at both ends and can freely act to compress all material enclosed within it) in either knot - and so it immediately must be disqualified from having the title ‘Bowline’.

394

???
I don’t follow this at all.
If one begins with #1010 but then reverses that
by loading the tail vs. the eye (so that the 1010 S.Part
is now unloaded, qua tail),
one has (variously, but it taking care to set snug…)
–THE NEW PARTS NOW USED IN NAMES THAT FOLLOW–
the (new, mind) S.Part making a nipping loop
(albeit one more prone towards opening into a helix)
that nips the tail,
and its ongoing eye leg on-goes,
and returns to surround & so choke the nipping
loop at its crossing point,
and then tuck out through the nipping loop to hold.

I see NO BIGHT ANYthing (in the reversal).

–dl*

395

I didn’t see it as nonsensical, and it’s a loading that
defines a NEW knot, one that could be started from
the bowline --and one that, as I emphasized earlier,
wasn’t completely defined by Derek as the “long” tail
must cross the eye one side or the other.

What I find nonsensical is Derek’s description of what
his recipe yields : I don’t follow his words, there.
What I do see, which fits his point --as I also noted
previously–, is that the reversed bowline has its
nipping loop NOT stabilized by any collar but by the
draw of the "choking turn around its crossing point
(depends on that tail-to-SPart orientation) and the
nipped tail (which part had been 1010’s SPart).

But I don’t follow any logic that somehow by doing
this reversed loading one can lay claim to “bowline”
or cite that knot’s parts in discussing the new as
though they continue to exist as they were.

I also don’t follow your interpretation of what Derek’s simple
recipe yields, either:

To answer your specific question, this loading profile [b]isolates the eye[/b]... and effectively mimics the core function of a [i]Sheet bend[/i] (although the Sheet bend can be tied with tails oriented same side or opposite sides - with same side orientation being the standard practice). I have already stated that in my personal view, there is no 'nipping loop' in a Sheet bend since it is not loaded at both ends.
"isolates the eye and ... mimics the ... sheet bend" ??? No, it loads the 1010 tail VICE the S.Part in opposition to the eye. And with reasonable setting, the once collar becomes a nipping loop; the once nipping loop becomes some wrap-around-&-tuck structure.

WhaTHEck is everyonElse DOING out there? :o ::slight_smile: ???

–dl*

396

Here is one that may generate some interest… #1080

The question is: Does it have 1 nipping loop or 2 nipping loops?

397

It has one - because only one is loaded both ends.

Derek

398

Well Derek, you see - I find #1080 to be a very interesting structure.

I personally only see 1 nipping loop.

But I’m not sure if you are just saying there is 1 (but really think there are 2 nipping loops)! The requirement that both ends of the nipping loop be loaded is my theory (and I think Xarax’s). But I have a distinct impression that you disagree - and that’s fine. So that’s why I think #1080 is interesting to analyse.

To me - if this can be definitively answered, it would help us to make forward progress.

Mark

399

It worries me Mark that you think I am trying to trap you with, as you call it, an “aha” Kodak moment, or that I am lying over there being one or two nipping loops - why would I do that? How would it carry our search for clarification forward?

Yes, you have stated that the definition you intend to use is that both ends of the nipping helix must be loaded, and in the example in point, there is only one structure that satisfies this requirement.

I have stated and given examples of how clamping one end of a nipping helix is sufficient to generate a nip if the unclamped end is loaded (the misplaced capstan effect). but in this knot example, the second helix is loaded only by the second loop, its other end is neither clamped nor loaded, so it fails not only your definition of a nipping helix, but mine as well.

[NB as the return leg of the second loop enters the nip of the nipping helix before making its own turn, it is probable that this second helix is not loaded on either end]

Is this answered sufficiently for you to feel confident that I am not attempting to lead you into some logic trap? But then, if I was being that clever, and did manage to prove some point to you - would that not be a good thing? A step forward towards consensus.

But, one aspect of the Bowline I will put forward, is that - the Bowline contains a nipping helix that must be loaded by the primary source of load, i.e. the SPart. i.e. the greatest load differential available should be impressed across the primary gripping engine of this knot.

Derek

400

VER 2.4e is ready for download.

A major re-write and re-organisation.

Several new images added and some older images replaced.

Still a work in progress…

Mark