Author Topic: Simple lock for the bowline  (Read 103659 times)

xarax

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Re: Simple lock for the bowline
« Reply #60 on: September 29, 2011, 11:39:44 AM »
   A modification of the Columbus bowline "lock" (A), described at :
just tying an overhand around the SP in the place of the collar and tucking the working end down through the nip as usual.

, the Columbus bowline "lock" (B), as described at :
the same Columbus thing after the formation of a "proper" bowline collar, that is...the overhand knot [tied] around the eye leg of the bight, and retucked the tail of this overhand knot up, through the nipping loop, as usual. I feel that, doing this, we remain within the bowline family, ring loading is not aeffected, and our "lock" is not loaded too much, to a point it can be hard to untie. The problem now, of course, is that our lock is not even loaded enough, to a point it can remain tied  :) ,  but I think that, by retucking the tail through the nipping loop, this problem is somehow addressed.

   Do I like this solution ? Not really... Although it is a conceptually simple and an evidently secure solution, I feel that this overhand knot - as any overhand knot tied in the vicinity of the nipping loop - is just too much for this  knot, it makes the bowline s nub too bulky, and unbalanced : The one element/end of the bowline, the collar, is now much more convoluted/complex than the other, the nipping loop...If we want to improve the common bowline s security by making one of its two essential elements more complex than it is, I think that we should use a more complex nipping loop. Of course, this is equivalent of modifying the locking mechanism of the bowline, not adding a lock:) 

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DDK

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Re: Simple lock for the bowline
« Reply #61 on: September 29, 2011, 04:49:40 PM »
   If we let the tail of the half hitch, or of the overhand knot, pass underneath the standing end of the bowline, we have the knot shown in the attached picture. To my eyes, it looks a little more compact and neat than the original DDK s knot, but I do not know if its security is jeopardised, or improved in that way.

The similarities in the two knots we have presented include the initial "U-turn" of the working end and the use of a Half-Hitch/Overhand Knot.  In addition to the difference you mentioned regarding the tucking of the tail, some other differences I think I see are that the "U-turn is around a different section of the nipping loop and the HH/OH is wrapped around only one leg of the collar.  I think your knot does have a lower profile.  This knot and almost anything I tie which includes this "U-turn" and HH/OH seems to add security (from slipping).

Related Knot #1:  (edit: call it Bowline Lock WE RT 1, for working end, round turn #1) If instead of tying the HH in your knot, after the working end has gone through the collar, tuck the WE through the nipping loop.  In essence, the WE leg of the collar does a round turn around the rim of the nipping loop (so is nipped twice).  Looks sort of interesting as well.  I do notice that this round turn structure cannot be tightened independently from the tightening of the bowline collar like the HH/OH structures and the collar is a more open structure.

Related to Related Knot #1:  (edit: call it Bowline Lock WE RT 2, for working end, round turn #2) If the WE is not threaded through the collar but instead, the round turn in the WE is around the crossing point of the nipping loop, an OH knot is produced and can be tightened independently from the tightening of the bowline collar  This collar is less open than in Related Knot #1(edit:Bowline Lock WE RT 1).  Hmm, I probably ought to have some pictures here.

DDK
« Last Edit: September 30, 2011, 05:23:19 PM by DDK »

xarax

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Re: Simple lock for the bowline
« Reply #62 on: September 29, 2011, 07:13:05 PM »
Hmm, I probably ought to have some pictures here.

Yes ! :)
See knots related to your related knots, ar the attached pictures.
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DDK

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Re: Simple lock for the bowline
« Reply #63 on: September 29, 2011, 11:00:57 PM »
Thank you for the pictures.  BTW, how hard would it be for you to become right-handed?  just joking  :D 

S2 is the knot I was verbally describing above as Related to Related Knot #1 (edit: Bowline Lock WE RT 2)

S1 is not what I meant by Related Knot #1 (edit: Bowline Lock WE RT 1) in that you did not first take the WE of the standard bowline through the collar from the backside of the knot.  This configuration would be the same as starting with your Bowline with the HH/OH Lock and untucking the last tuck (see the last tuck marked in the picture below).  Then, from the front of the knot, tuck the WE through the nipping loop to produce the round turn of the WE around the rim of the nipping loop.

DDK
« Last Edit: September 30, 2011, 05:20:27 PM by DDK »

DDK

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Re: Simple lock for the bowline
« Reply #64 on: September 30, 2011, 05:39:29 PM »
Pictures of Bowline Lock WE RT 1 are shown below.  In the pictures, the gray marking is the SP, nipping loop and large loop leg connected to the nipping loop.  The blue is the WE, the collar and large loop leg connected to the collar.

BTW, I notice that the round turn does not produce an overhand knot in Bowline Lock WE RT 2 as I originally thought.  It can be tightened independently of the collar, but, its structure is more of a Granny Knot (WE and nipping loop both produce round turns around the crossing points of each other).

DDK

xarax

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Re: Simple lock for the bowline
« Reply #65 on: September 30, 2011, 07:10:23 PM »
   The way this tail winds around the rim of the nipping loop, is not my cup of tea ... I do not believe that it is now more secure that it was in all the previous solutions.
« Last Edit: September 30, 2011, 07:20:48 PM by xarax »
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DDK

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Re: Simple lock for the bowline
« Reply #66 on: September 30, 2011, 08:07:26 PM »
   The way this tail winds around the rim of the nipping loop, is not my cup of tea ... I do not believe that it is now more secure that it was in all the previous solutions.

Since the round turn of the WE cannot be tightened independent of loading the collar, the knot you show in reply #65 (what I call bowline lock WE RT 1) may be susceptible to loosening if shaken.  Under constant load (the more the better - to a point), this knot should be resistant to loosening and very resistant to slipping (WE has a round turn and is nipped twice).

DDK
« Last Edit: September 30, 2011, 08:11:14 PM by DDK »

xarax

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Re: Simple lock for the bowline
« Reply #67 on: September 30, 2011, 10:11:57 PM »
WE has a round turn and is nipped twice).

   When you pull the second leg of the collar ( the "WE") upwards, you see that this "round turn" rotates as a whole around its axis, and unwinds rather easily. This happens because the "two" points/segments of the tail where it is "nipped twice", move like one piece : if the first segment is forced to be set in motion towards one direction, the second can follow it and move towards the same direction, without having to overcome any additional friction force. This is the reason we never use a naked "round turn" as a final means to secure a tail - not without a half hitch right after it...
« Last Edit: September 30, 2011, 10:13:24 PM by xarax »
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DDK

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Re: Simple lock for the bowline
« Reply #68 on: October 01, 2011, 01:03:19 AM »
WE has a round turn and is nipped twice).

   When you pull the second leg of the collar ( the "WE") upwards, you see that this "round turn" rotates as a whole around its axis, and unwinds rather easily. This happens because the "two" points/segments of the tail where it is "nipped twice", move like one piece : if the first segment is forced to be set in motion towards one direction, the second can follow it and move towards the same direction, without having to overcome any additional friction force. This is the reason we never use a naked "round turn" as a final means to secure a tail - not without a half hitch right after it...

I have tried to reproduce your results of slipping to no avail.  I can only guess that you had little to no loading on the nipping loop.  Obviously, without substantial loading on the nipping loop, the tail of the standard bowline would slip very easily if one pulled on the second leg of the collar.  Which brings up the question: So, with the same conditions and materials you used, does the standard bowline slip?  My guess is the answer will be "yes and more easily".

As far as the positive cogging that you mention ("move like one piece"), I do see what you are referring to but I also see that there is substantial additional negative cogging present (so, I would disagree with your assessment that the round turn is "naked"). 

DDK                            edit: typo
« Last Edit: October 01, 2011, 01:37:50 AM by DDK »

xarax

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Re: Simple lock for the bowline
« Reply #69 on: October 01, 2011, 02:44:49 AM »
...little... loading on the nipping loop
...substantial loading on the nipping loop
...with the same conditions and materials...does the standard bowline slip?  My guess is the answer will be "yes, and more easily".

  Define "little", "substantial", "more"...  :) If any improvement achieved with the DDK s 3 is only marginal, who would use this "lock", and not tie some Janus bowline, for example, that requires the same number of tucks and amount of time ? Your previous two Janus solutions (DDK s 1 and 2) would also benefit from a more natural tail-legs relation  :) ( in those solutions the tail seems to be squeezed in between the two legs of the collar more effectively than in the DDK s 3).
   
« Last Edit: October 01, 2011, 02:51:07 AM by xarax »
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DDK

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Re: Simple lock for the bowline
« Reply #70 on: October 01, 2011, 06:09:56 AM »
...little... loading on the nipping loop
...substantial loading on the nipping loop
...with the same conditions and materials...does the standard bowline slip?  My guess is the answer will be "yes, and more easily".

  Define "little", "substantial", "more"...  :) If any improvement achieved with the DDK s 3 is only marginal, who would use this "lock", and not tie some Janus bowline, for example, that requires the same number of tucks and amount of time ? Your previous two Janus solutions (DDK s 1 and 2) would also benefit from a more natural tail-legs relation  :) ( in those solutions the tail seems to be squeezed in between the two legs of the collar more effectively than in the DDK s 3).

The observation of a configuration where positive cogging might occur is not of itself a strong reason to assume that this knot (Bowline Lock WE RT 1) might be only a marginal improvement (in preventing slipping) over a standard bowline.  Consider that, like a number of bends, both the Zeppelin Bend and Figure 8 Bend have configurations where positive cogging might occur.

Measuring the load required to pull on the collar leg which leads to the tail would be an informative test if the loading of the nipping loop was taken into account and controlled.  For example, the tail of the Heinz Prohaska's Double Bight (Janus) Bowline pulls completely out under this test if the nipping loop is not loaded.  What does that tell us about the security of the Janus Bowline?  I'd have to say it tells us very little.

Knot structure and mechanics do provide useful guiding principles.  Mentally summing up all of these effects, all the positives and negatives, is not possible in all but the simplest of knots if at all.

DDK
« Last Edit: October 01, 2011, 06:12:29 AM by DDK »

xarax

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Re: Simple lock for the bowline
« Reply #71 on: October 01, 2011, 10:28:08 AM »
The observation of a configuration where positive cogging might occur is not of itself a strong reason to assume that this knot... might be only a marginal improvement (in preventing slipping)

  I do not understand the infamous mechanism of "positive cogging", and the mechanisms that prevents/cancels it - as we have seen in the case of the retucked thief knots...However, I understand very well how easily a round turn unwinds when it is not accompanied by a half hitch... It is something as simple as the wheel !  :)

   For example, the tail of the Heinz Prohaska's Double Bight (Janus) Bowline pulls completely out under this test if the nipping loop is not loaded.

   I have never assumpted that we should test the bowlines with an unloaded nipping loop. You can pull the second leg of the DDK s 3 while you keep a "little" or "substantial" load acting on the limbs of the nipping loop - and you can pull it rather easily ! ( more easily than the tail of DDK s 1 or 2 ). Mind you that the tails of the Columbus A and B bowline locks of SS369 will not slip easily, even if the nipping loop is very lightly loaded, or even not loaded at all.
 
  Mentally summing up all of these effects, all the positives and negatives, is not possible in all but the simplest of knots if at all.

  I am afraid this is mostly true, for me at least.  So we have to test  those knots. Go on !  :)
« Last Edit: October 01, 2011, 10:30:44 AM by xarax »
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DDK

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Re: Simple lock for the bowline
« Reply #72 on: October 01, 2011, 03:09:32 PM »
I also prefer knots in which the lock can be tightened independent of the collar.  I would also agree that those knots which perform better under little to no load on the nipping loop would likely be better at not loosening from being shaken (while unloaded).  I mentioned that DDK s3 did likely possess this poor attribute when I first showed the knot.

Only more sophisticated testing can really help us understand its performance under high nip loading.  I mention more sophisticated because pulling on the collar leg connected to the tail while controlling the nipping loop is not nearly as straightforward as the typical strength tests that are done.  The payback would be to see, for example, exactly how effective is something like the Yosemite finish at increasing the load needed to pull out the tail. 

DDK

« Last Edit: October 01, 2011, 03:12:58 PM by DDK »

xarax

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Re: Simple lock for the bowline
« Reply #73 on: October 01, 2011, 05:52:18 PM »
Only more sophisticated testing can really help us understand its performance under high nip loading.

   There is an easy road to perform a more sophisticated testing : start  from a less sophisticated one !  :)

...how effective is something like the Yosemite finish at increasing the load needed to pull out the tail.

   Not very much, I believe. ( I do not like this solution, and I do not understand why it is so popular among climbers. I suppose there should be some relevant testings I am not aware of.)
« Last Edit: October 01, 2011, 05:56:28 PM by xarax »
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Dan_Lehman

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Re: Simple lock for the bowline
« Reply #74 on: October 03, 2011, 05:32:48 AM »
Pictures of Bowline Lock WE RT 1 are shown below.

FIRSTLY, I strongly urge knotters to treat the orientation
that here is labeled "back" as the PRIMARY one in which
to view a bowline --as it better presents the knot, better
showing the more interesting crossings (whereas the path
of the bight legs is pretty easy to comprehend, simple,
and they are behindmost in this view).
I really think that so much of the confusion about a bowline
comes from the bassackwards ubiquitous illustration of
the knot, typically --reversed, e.g., from how the sheet bend
is commonly shown.

Now, let me point out that what I've called "end-bound..."
is just this knot but with the extension wrap of the tail
doing something more useful : nipping and locking (as best
it is able, which isn't always so great/enough) the main
nipping loop (which is reciprocating).  Turn that tail over
the crossing point of the main turNip !
I prefer this in the double bowline body, where this extra
wrap will have 3 diameters within it (best approximating a circle).
But I have seen even that knot, tied in some recalcitrant,
firm, soft-laid, slick, thin (4mm?) polypropylene hold only
briefly, than all the round turns just simultaneously
loosened/expanded !!   :o  In this cord, the simpler knot
presented by Prohaska seemed to be a better solution
--it wasn't so snugly tight on setting, but the material
tried to spring open and was easily limited, as the sharper
turns made it want to open like scissor legs, easily resisted,
not expanding like a big eater's waist line.

--dl*
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