Author Topic: Simple lock for the bowline  (Read 114689 times)

xarax

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Re: Simple lock for the bowline
« Reply #90 on: October 08, 2011, 07:09:17 AM »
you misunderstand, even in reply here to the simple statement "the knot becomes effectively and end-2-end joint"(emphasis added : 2 /= 3).

  Caveat lector : When we tie and untie knots, we solve problems our brain was not evolved / wired to confront with. It is only natural we feel able, and proud  about this, but there is a trap : we tend to believe  that we are the only ones capable of understanding, and everybody else misunderstands every existing thing and every said word. ( A "komvos"(2), often leads us to a "kompos"(1) ("wonder what that is, eh?") :
http://igkt.net/sm/index.php?topic=3602.msg21052#msg21052  :) )

  I am afraid you have misunderstood  what I have said  :) : During ring-loading, we should examine a loop as a midline bend with three(3) limbs, at different angles with each other. The knot effectively becomes a midline joint/bend, not  an end-to-end joint/bend (emphasis added : three (3) limbs, 3 # 2 ). Both eye legs are loaded, and, of course, the standing part is also loaded ( not  slackering - any limb that was loaded in the first place, remains loaded, and is not  slackering), although loads vary with angles and friction forces induced by the encircled object on the two eyes. That makes ring loading a difficult thing to test accurately ( emphasis added : a difficult thing for me...).
« Last Edit: October 08, 2011, 07:23:03 AM by xarax »
This is not a knot.

SS369

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Re: Simple lock for the bowline
« Reply #91 on: October 08, 2011, 02:37:47 PM »
Since we cannot test each and every scenario's input of loading(s), I suggest that if you tie a loop/eye knot and it is in tension, for the simple sake of testing its possible aversion to ring loaded influences, just spread the eye with your hands. Perform this spreading un-tensioned as well.
This simple test will give you indications of the tangle's resistance to coming undone. (Yes, not very scientific.)

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alpineer

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Re: Simple lock for the bowline
« Reply #92 on: October 08, 2011, 05:53:22 PM »
I believe the proper and most efficient loading profile to test for the effects of ring(eye) loading is "end to end". Introducing a third parameter (i.e. tension on the S.Part) only serves to minimize or mitigate the effectiveness of the test.

alpineer     
« Last Edit: October 09, 2011, 09:22:34 AM by alpineer »

SS369

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Re: Simple lock for the bowline
« Reply #93 on: October 08, 2011, 06:06:26 PM »
hello alpineer,

please expand on what you've just written please. "End to end" can mean a few things.

Mostly, the eye will be loaded while the SP is in tension and a ring load is the spread of the eye during use.
Of course there could be times that only the eye will be spread and possibly with force, so I believe there is a case to sufficiently test that as well.

I am not of the opinion that the knot should be rated necessarily on its performance as a bend of the eye legs with a third leg (un-tensioned perhaps). But. if it does indeed pass this aspect, then all the better.

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xarax

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Re: Simple lock for the bowline
« Reply #94 on: October 09, 2011, 12:40:14 AM »
   I believe the proper and most efficient loading profile to test for the effects of ring(eye) loading is "end to end". Introducing a third parameter (i.e.tension on the S.Part)

   I have never used a common bowline as a binder - around one round object, or around a bundle of many objects - and I believe that this is not a knotting situation which the bowline end-of-line loop is supposed to confront. If I anticipate that, at some instance, the angle of the eye limbs will be greater than, say, 120 degrees, I use an Eskimo bowline. Why we should test the bowline in unrealistic situations ? The primary element of the bowline is the nipping structure, be it a simple nipping loop, or a more complex one. This nipping structure does not function with an unloaded/ untensioned standing part, so what is the point of testing what is left of the bowline in this hypothetical unrealistic situation, where the two other limbs are loaded, while the standing part is not ?
   (What makes much more sense, is to test the bowline with the one eye leg un-loaded / un-tensioned, because it might well happen to the other eye to be caught somewhere, and bear the whole load of the loop by itself. In crowded harbours, it happens to many bowlines to be tied around the same bollard or ring, the one on top of the other, so that their bights are tangled, and the standing part and one eye of one or more of them are their only limbs that are loaded simultaneously. Moreover, because of the not-so-rare fact that a bowline will not be able to revolve freely around a bollard, the tensioned limbs can be in wild angles the one relatively to the other, and to the centre-of-the-bollard on-dock / centre-of-the-bitts on-board axis.) Testing how a particular bowline holds when its three tensioned limbs converge at various angles on its nub, would be a useful test indeed.) 
« Last Edit: October 09, 2011, 05:12:50 AM by xarax »
This is not a knot.

SS369

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Re: Simple lock for the bowline
« Reply #95 on: October 09, 2011, 03:08:00 AM »
I have used a bowline around a wide board before and I feel confident that the angle exceeded 120 degrees. The load was not heavy and the task was completed. Yes, there may have been better knots for this task, but it was one of those times.....

So if there is divined a simple "lock" for the common bowline that happens to improve the ring loaded ability, then I would say that it is a winner.
And then the necessity of using another bowline form is unnecessary.

Would anyone say that this has been achieved with the samples offered so far?

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alpineer

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Re: Simple lock for the bowline
« Reply #96 on: October 09, 2011, 11:53:59 PM »
please expand on what you've just written please. "End to end" can mean a few things.

"End to end" as in simple 2 point loading from within the eyeloop; not involving tension on the S.Part. Note the two examples of this which were cited in post #89. "Ring loading" does not refer to loading the knot where the eye may have the physical form of a round(ish) structure, but simply refers to loading the eyeloop from within it's own boundaries. S.Part tension occuring simultaneously with ring loading only reduces the possibiliy of a knot failing as a result of ring loading. Or could there be exceptions?

alpineer
« Last Edit: October 10, 2011, 12:41:04 AM by alpineer »

SS369

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Re: Simple lock for the bowline
« Reply #97 on: October 10, 2011, 03:24:30 AM »
Hi alpineer,

I get what you're saying and I think that we can dream up possible scenarios where there could be circumstances that allow the eye loop to be loaded even with the SP tensioned. Lopsided loading in fact. As in, if the loop should snag as a load is raised or lowered, etc.

I am not too sure that ring loading dictates that the forces within the eye loop expand as the bowline in this thread is not necessarily a binder knot.

I can think of uses in construction or tree work that could have detrimental outcomes should the knot capsize due to ring loads.

Just a hypothetical here, but let's say a man has to lower a large tree limb, one that is well within the rope's capacity, but he needs to tie the loop almost snug to the limb. The angles of the eye legs would be fairly severe compared to "normal" use for the common bowline. The spread could cause the knot to loosen to the point of capsizing.  Doom.

If the simple lock serves the purpose of reinforcing this challenge, then all the better.

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xarax

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Re: Simple lock for the bowline
« Reply #98 on: October 10, 2011, 02:19:43 PM »
many recommend a strangle (though not by its proper name  :P  ). 

   A strangle knot as a collar of a bowline, can be tied in a number of ways. See the attached pictures for two variations of a "Strangle collar bowline". It may be seen as a complicated solution, but , conceptually, it is quite simple. The tail can pass through the nipping loop two times (A), or three times (B).
   On the next post, see the attached pictures for another loop, also with a strangle knot tied around a simple nipping loop. Although not a bowline  - we do not have a "proper" bowline collar here - this loop is also very secure, easy to tie and a good looking, compact knot.
« Last Edit: July 20, 2014, 08:18:21 PM by xarax »
This is not a knot.

xarax

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Strangle collar loop
« Reply #99 on: October 10, 2011, 02:22:42 PM »
   A bowline-like end-of-line loop with a strangle collar.
This is not a knot.

Dan_Lehman

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Re: Simple lock for the bowline
« Reply #100 on: October 12, 2011, 08:35:05 PM »
you misunderstand, even in reply here to the simple statement "the knot becomes effectively and end-2-end joint"(emphasis added : 2 /= 3).
...
  I am afraid you have misunderstood  what I have said  :) : During ring-loading, we should examine a loop as a midline bend with three(3) limbs, at different angles with each other. The knot effectively becomes a midline joint/bend, not  an end-to-end joint/bend (emphasis added : three (3) limbs, 3 # 2 ).  ...

I don't know why you make such difficulties!?
"ring-loading" is a defined term from rockclimbing,
and means what I said --the eye of an eye knot is
loaded from within, in opposition, as though one
had tied a round sling; the two *ends* are slack.
And I gave two examples of how this could occur
in practice, with one of them an advocated use(!).

Should you want to consider some other loading
that is a combination of ring-loading and normal
loading, well, fine with that; but don't presume to
hijack the term for this and then argue about others'
lack of comprehension.


--dl*
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xarax

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Re: Simple lock for the bowline
« Reply #101 on: October 13, 2011, 01:27:25 AM »
"ring-loading"[/i] is a defined term from rockclimbing

  For the bowline ? I was under the impression that rockclimbers do not use the bowline, so they would not have much to say about it... and they should not say much about it. And if Ithey do  use it, but use it as a binder, or in situations - like the two examples you provided - where it runs the danger to be reduced to something else,  then this is their fault, not the bowline s ! The bowline works because its nipping loop is tensioned, and its nipping loop is tensioned only iff- and because - the standing end and the eye leg of the standing part are both tensioned. If, momentarily, the standing end is slackering for whatever reason, the two eye legs are slackering too, so there is no danger that any load moves towards any direction.
   You stated that : "the knot becomes effectively an end-2-end joint". Well, the bowline that I know, and I have used as an end-of-line loop more times than any rock climber, never  becomes an end-2-end joint : fortunately, the waist line of the mooring bollards does not expand during the night !  :)

...you want to consider some other loading that is a combination of ring-loading and normal loading

   I do not want  to consider it, I have  to consider it, because it is the only thing it happens when the bowline is used properly, as an end-of-line loop, and not as a binder.

don't presume to hijack the term for this

   That was not my intention, but now you mention it, I think that I / we should !  :) Why do the rock climbers have the monopoly for a term concerning a knot they do not use, they do not trust, and they do not understand? Let them keep the monopoly for the fig.8 bend, which they use, they trust... but, again, they do not understand !  :) And let us be free to define what "ring loading" should mean, that would be related with what the bowline is, and how it works, when it is used properly.

and then argue about others' lack of comprehension.

   I believe you do not believe that it is sooo difficult, even for me, to test an eye-to-eye knot, don't you ? I was talking about my difficulties to test the many proposed solutions for a simple bowline "lock", in a most complex situation like the one we encounter many times, and is described here :

   To test this midline bend/joint, you have to control carefully the loadings on each  of the three limbs, because, in a real situation, they vary according to the angles they meet each other at the central nub, and  the friction forces they encounter around the - round or not - object...

... or in Reply# 94. So, how we can test those things for all those solutions ? And even if we could, even if we could exhaust all possible scenarios, what would this mean ? Suppose we could conclude that the bowline lock A, is holding better than the bowline lock B, in some situations described by the scenarios A1, A2, A3, etc.., while in some other situations described by the scenarios B1, B2, B3, etc, what is really happening is the exact opposite. How would we chose which solution we will use, if we can not anticipate the future situations ? And if it turns out that we can not decide how to evaluate the most usual scenarios, where there is "a combination of ring-loading and normal loading ", why should we consider the most rare "pure" ring loading scenario - even if it is very easy to test our candidates in the simple situation described by it ?
   It might be the case that there are many satisfactory "simple" locks for the bowline, but the decision which one we should chose is not a simple thing - not at all !  :)
   
« Last Edit: October 13, 2011, 01:31:41 AM by xarax »
This is not a knot.

Dan_Lehman

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Re: Simple lock for the bowline
« Reply #102 on: October 20, 2011, 09:55:39 PM »
"ring-loading" is a defined term from rockclimbing

  For the bowline ? I was under the impression that rockclimbers do not use the bowline ...

So, you were under mis-impressions.  The bowline has long been
used by climbers, and continues to be used --even in the face of
some strong opposition to it (and some confusion about what "it"
is --the advocates almost always mean using some precautionary
structure to prevent coming untied).  It is favored for being quick
to tie and easy to untie after loading, in contrast to the fig.8 eye knot.

Quote
don't presume to hijack the term for this

   That was not my intention, but now you mention it, I think that I / we should !  :) Why do the rock climbers have the monopoly for a term concerning a knot they do not use, they do not trust, and they do not understand? Let them keep the monopoly for the fig.8 bend, which they use, they trust... but, again, they do not understand !  :) And let us be free to define what "ring loading" should mean, that would be related with what the bowline is, and how it works, when it is used properly.

Dispensing with your misunderstanding, rockclimbers are who
introduced (Germans, i.p., I believe)  and defined the term,
to articulate a circumstance that could arise --"proper" or not.
And it is one that is general --for any eye knot--, not particular
to a bowline  (which simply is one with a particular vulnerability
to failing).


--dl*
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xarax

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Re: Simple lock for the bowline
« Reply #103 on: October 21, 2011, 02:39:01 AM »
rock-climbers are who introduced... and defined the term, for any eye knot--, not particular to a bowline

   That makes sense.  :) Rock climbers introduced and defined the "proper" use of the term "ring loading" for any eye knot :  An end-of-line loop is "ring loaded", if it is loaded as a binder, even if and while the standing end is not loaded at all. Unfortunately, the bowline* is not meant to work like this... and it does not work like this ! The generalization of the use of this term in the case of the bowline*, is simply wrong. The bowline* - and all the bowline*-like loops that are based on a TIB nipping structure to hold and secure the tail - 
...works because its nipping loop is tensioned, and its nipping loop is tensioned only iff- and because - the standing end and the eye leg of the standing part are both tensioned.

  So, a "proper" ring loading circumstance - where the standing end is not loaded at all - makes sense to many eye knots, indeed most of them...but not to the bowline*.                                     
  I might even dare to DEFINE the bowline*, as an end-of-line loop that is automatically released and completely untied,  if and when the bight is tensioned, while the standing end is not. The bowline* is a end-of-line loop that can not work as a pure binder. If the standing end is not loaded at all, the nipping loop is also not tensioned, it s not squeezing the tail any more... and a loaded eye leg of the bight would slip out of this loose nipping loop in no time.

* Here, with "bowline* ", I denote the common bowline - not the Eskimo bowline ( or anti- bowline ). The Eskimo bowline, (and all the Eskimo bowline-like loops that are based on a TIB nipping structure to hold and secure the tail ), when the eye legs are almost aligned to each other, or when the standing end is not loaded, works just like a Sheet bend ( with the standing end as the one tail of this Sheet bend). In that sense, the Eskimo bowline-like loops are suitable to withstand ring-loading, even in the case of a "proper", absolute ring-loading circumstance - when the standing end is not loaded at all.
« Last Edit: October 21, 2011, 11:31:34 PM by xarax »
This is not a knot.

xarax

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Re: Simple lock for the bowline
« Reply #104 on: October 21, 2011, 06:02:56 PM »
  Although not a bowline by any means, the Eskimo bowline-like "Double Harness loop"  shown at the attached pictures could serve as a end-of-line loop that can withstand a "proper" ring loading. Even if the standing end is not loaded at all, the loop can be loaded safely, as it is turned ino into the quite secure "short" Double Harness bend.
This is not a knot.