Author Topic: In Search Of The Holy Grail Bowline: A Bowline For All Reasons  (Read 27177 times)

SS369

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #15 on: March 22, 2013, 12:51:04 AM »
The knot was dressed as tightly as my hands could do,
using all the parts individually till I had the affair as snug as possible.
/ /
The biggest drawback, to me, is that after loading it to 300 lbs and then bouncing
using body weight, I had to use round nose pliers and a spike to untie it.

Which begs the question Why set the knot so tightly, of the collar?!
IMO, if you cannot untie any "X"-bowline --i.e., one with a "proper"
collar--, you've gone wrong in its setting --the collar being the
key to easy untying.  (Now, in some cases of heavy loading,
there could be some slippage in material whose diameter
has been reduced in tension such that upon the removal
of force the knot's strands *swelled* and left the collar
unusually tight around the returned-diameter SPart!)

"300 pounds" suggests a 2:1 pulley and body weight
--is that so?  --and a good pulley (I count my 5:1 as
rather poor, so need the bouncing to convince me that
I've at least surged towards its theoretical force (and
then realize that the crummy friction should hold it at
that extension/tension))?
It's certainly a force able to show effects that might
surprise one vs. manual loading, and make one take
care before testing some knot --if untying is desired,
without tedious use of tools (and even then)!

Quote
I believe that the double nipping coils
... aren't so well described as that, given the actual
geometry of the knot : that it's a helical part more
than some definitely circular turn, doubled.

Alpineer asks:
Quote
Were your findings the same for both the Dyneema and the nylon?

This surprises me : there was no "Dyneema" here, in any effective
presence for this sort of testing --i.e., it was core material, not
contributing the slickness of fibre to points of contact that
would show effect in mere stress testing.  (The stiffness of
the cord is another matter.)  Conceivably, the core can slip
within the mantle so that there is effect --and effect not
often suspected / recognized-- in full break testing, or maybe
in some repeated usage where the slippage accumulates,
but that requires such testing to reveal it.  (There have been
reports of a polyester/nylon sheath breaking and the hi-mod
core pulling out, e.g. ; or images where the core remains
intact at a broken sheath.)

The Brion Toss video I URLinked to previously (above) shows
bare HMPE 12-strand cord being tested.  He has one also
showing a dbl. bowline just slipping out through the nub,
collapsing the eye --a marvel to behold!


--dl*
====

Wow! A whole lot of responses!

I set my knots snug because that is what I believe I should do for all good reasons.
It is a standard that I use when I investigate a knot of any kind. From that base I can  determine things for myself. After that baseline/benchmark other forms can be looked at.

I don't personally feel that my snugging all parts of the knot equals over tightening them. One fall can exceed my hand strength easily in tightening a knot.

As for my load test method that you inquire about Dan. I have a three hundred pound weight that I mount to my "test" knot by means of a shackle (in the case of a loop) or other non-detrimental means in the case of other types. With the weight suspended I some times climb on the weight and bounce my 180 lbs.
This gives me an understanding to some degree of what the knot is going to perform like.
No pulleys are used so it's pretty much one to one.

I climb and abseil quite often and I take some testing to the crags, though generally I have backup as warranted.

And yes there was Dyneema (core material) present and included in my simple test. No, not to destruction as my pockets are not quite so deep. I do believe that a sheath can influence things and of course we count on them to do just that. Hopefully positively.
And hopefully someone with some naked material will jump in here and give it a go.

SS

SS369

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #16 on: March 22, 2013, 01:08:10 AM »
Back to the OP.

Hi Alpineer, I tied your offering in two more ropes. The ProTac 10.5mm static and 10.6mm Dynagym (both BlueWater).

I did the same test procedure that I do across the board, regardless if some might think it superfluous or wrong or excessive.

What I found is the ProTac liked conforming to this knot and the Dynagym did not. The latter's construction is very springy and I really had to work the knot into shape and it took more time than I care for. My opinion only.
Another thing I found, using this particular rope (Dynagym) is that if the knot is a even a bit loose the tail will pull easily out of the coils.

The way I did this was to dress and snug the knot (overly so)  :), and then worked it loose (not too) leaving everything dressed as you showed it. Then I pulled the leg opposite the tail and caused movement. I have found this to be a tendency of stiff, hard ropes. It effects many well known and cherished knots so.
Another good reason to "overly snug" knots.  ;)

Btw, both specimens untied relatively easy enough.

Attached are some pictures of the test media tangled your way.

SS


X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #17 on: March 22, 2013, 01:16:52 AM »
  Wow ! There is a miracle happening in the Forum !  :) Tests, and pictures of tested knots ! I can only keep my fingers crossed this will become the mainstream from now on ! We have too many knots, and too few tests - its time to balance the sheets. Thanks, SS369.

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #18 on: March 22, 2013, 03:20:36 AM »
Hi Dan,
Thanks for your responsesssssssss. It's going to take some time for me to respond to yours and others (in no particular order), even the ones I choose to respond to.
Cheers,
alpineer
« Last Edit: March 22, 2013, 10:38:49 AM by alpineer »

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #19 on: March 22, 2013, 01:31:27 PM »
   I am glad you have discovered this very tight, efficient double "nipping structure", that I have called " double, crossed coils nipping loop ". 

Hi X1,
   Look closer, please. This " double, crossed coils nipping loop " shown in your photo is not the same structure shown in my photos, the difference being the degree of torsion present in each. It's an important difference, at least in the context of the Bowline. Your photo shows the double loop nipping structure typically found in the Double Bowline re-formed into what I call a closed Elbow, containing 720 deg. of torsion. My photos show the double loop nipping structure I call an open Elbow, which contains no torsion. The essence of my claim is this, that the Open Elbow is the most efficient nipping structure (for the Bowline), exhibiting the highest level of the combined attributes of simplicity, security, stability, and untiability, and in the broadest range and nature of cordage. [edit]: add compactness to this mix


    Moreover, when one decides to tie such a double nipping structure, it is almost irresistible to proceed just half a step further,   

I find no irresistibility in myself to do such. I want simplicity, married with the other attributes I've listed above.

« Last Edit: March 24, 2013, 03:32:07 AM by alpineer »

X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #20 on: March 22, 2013, 07:18:31 PM »
   Look closer, please. This " double, crossed coils nipping loop " shown in your photo is not the same structure shown in my photos, the difference being the degree of torsion present in each.

   I do not look the knots, I tie them and try to feel the forces that run through their body, as if it was mine s !  :) This is an "intrinsic" "view", which can tell us things that are not shown in pictures. Imagine you are a snake, and you are knotted and pulled by your head and tail - what do you feel ?
   The geometry of structure is the same, obviously, but you are right, this is never the whole story - not even the most important part of it. I can feel that the torsion in the structure you show in much less than in what I show, indeed. However, I believe that this is another advantage of the later in relation to the former !  :) This torsion is beneficial to the gripping power of the two wraps, because it works as an invisible "skeleton", it stabilizes the form of the "coil tube", and it will not allow it to lose its initial symmetry when it will be loaded in this eccentric way it is to be loaded. Torsion is a very effective force, and that is why the torsion springs were used in tanks and the VW beetle !  :) It is a good thing, if we can use it to our behalf. I know that there is a common misunderstanding, that torsion "absorbs", in some way, the tensile forces, so what is added in torsion should be subtracted from tension. This is not correct. You can have torsion forces alongside tensile forces- a rope or a rod can be "twisted" AND pulled/pushed, at the same time, without the amount of the twist absorb, and diminish, the amount of pull/push.
   So, the test I propose to you is not visual, it is corporeal !  :) Tie the two structures with a lose collar, and "see" / "feel" what holds better.
   The twisted / torsioned rope segments of the wraps of the knot I show will be constricting the encircled body of yours, like the turns of another snake ! The head and the tail of this snake will almost cut you in two, with this scissors-like action - the one pulling towards the standing end, the other towards the tip of the bight.
   I had tried the "common" application of this crossed coils double nipping loop many times, before I had discovered the "Eskimo" version...I agree that the visual simplicity of the "common" version is very attractive, while the "Eskimo" version looks like a ...whatever. However, I was amazed by the constricting power of the "Eskimo" version - which also utilizes the L-shaped continuation of the standing part and the returning eye leg, the "handle" and the "step" which facilitate the job of the nipping structure - and that is why I had preferred it. I can assure you that I have a soft point in the simplicity of the knot structure, and I would nt hesitate to sacrifice a reasonable portion of gripping power, to retain it. However, here we have a GREAT difference ! The one structure can work even without the collar, as an adjustable loop, while the other is only stabilized by the collar - moreover, the nipping structure is much more complex than the collar structure, which remains rudimental ... This discrepancy between the amount the ante-eye and the post-eye knotted structures is something that bothers me, and I always try to tie bowlines where the rope segment will be almost as much convoluted in the nipping part as in the collar part. If I see a bowline where the one part is elaborated, and convoluted more than the corresponding part in the common bowline, while the other part is left unchanged, I sense that the design of this knot has not been finished yet !  :)

the Open Elbow is the most efficient nipping structure (for the Bowline), exhibiting the highest level of the combined attributes of simplicity, security, stability, and untiability, and in the broadest range and nature of cordage.

    I have tied many nipping structures, if not ALL of them, in a systematic way, I can assure you. However, I can not confirm what you say - and I very much doubt it. However, you can persuade me VERY easily : Tie all the structures I propose, test them, and report your results !  :) Your very high-flying tone about the "Open Elbow Structure" will lower a little bid, but, in the mean time, we will have learned many thing we still ignore .. :) Is this structure more simple than the Water bowline s or the Mirrored bowline s ? No, of course not, and I would nt even argue about it. Is it more secure ? We have to test them to tell. Is it more stable ? Here, my dear alpineer, I will resist my temptation to lough loudly. It is a most unstable structure, that has to rely in the collar structure s belt to remain in one piece! It imposes a great strain on the base of the legs of the collar - I almost "feel" the pain they feel ! My KnotGod, it is but a poor loop-sided fellow that needs the collar stick to walk ! Is it untiable ? Yes, it is - but have you tried to untie the Twisted Pretzel structure, for example, to see the difference ?  :) "Broader range and nature of cordage" are not of much concern... I tie and try the secure bowlines in climbing ropes, 9-12 mm, because those are the ropes that will be used, if any of those is going to be used as a replacement to the retraced fig.8 knot. I do not tie and try them on small, soft cordage, or on monofilament fishing line, for example, because I see no point of using a secure bowline in non-critical applications - the common or the "Eskimo" bowlines are just fine for them.

   I want simplicity, married with the properties I listed above.

   Simplicity is imperative to me, too.. But tell me, please, alpineer, do you really believe that the asymmetric 8 shaped structure you show, is really simpler than the Girth hitch of the Mirrored bowline, or the Constrictor of the Constrictor bowline ?  Have you tied MORE times this almost crippled 8 structure ( which is beautiful only in the eyes of a blind mother... :)), than a Cow hitch, or a Constrictor ? Simplicity is depending upon the amount of information of something, that is needed in order to store or retrieve it. May be the simple Clove hitch is simpler than the Constrictor, indeed - or the Water bowline than the Constrictor bowline. However, the "Open Elbow", or the "Pretzel", are not - they are more complex, and an indication of this fact is that they can be tied wrongly in more than one ways !
   Perhaps you have not noticed my argument about the difficulty of adding a second collar in this structure. Do you believe that such a modification would be redundant ?
   Now, it often happens that we come to see a cup that may look like it is made of pure gold - or that it IS made of pure gold, indeed. Is it the Holy Grail ? You can believe it - but the prudent thing is to not bet anything you have on this... :)
    I would also like an experimental comparison of this bowline to the "similar" Locktight bowlines tied by Dan Lehman - because I can not find why they would be very different. I prefer the U-turn of the eye leg around both legs of the collar as at the structure you show, that is true, but this might not be the whole story (1).

1. http://igkt.net/sm/index.php?topic=1234.msg8419#msg8419
« Last Edit: March 22, 2013, 07:34:47 PM by X1 »

X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #21 on: March 22, 2013, 08:25:09 PM »
   I have read my previous post, and I feel that it sounds too critical... :) So, I have to repeat that this bowline is a very simple, easy to remember and tie eyeknot, with a very tight double nipping structure, that deserves further, detailed examination and evaluation. I do not say it is no good ! - I only doubt that it is "the best", the Holy Grail ... because there might be no such thing, and because I have met a number of other tight double nipping structures, of about the same complexity, that are as secure and simple ( and perhaps even simpler) than this.
   One of my concern is that the nipping structure is much more elaborated / sophisticated / convoluted than the collar structure - which remains the old "proper" bowline s collar, in a knot that is meant to go beyond the common bowline... One possible way to do something about it, without spoiling the character and the simplicity of the knot, is shown at the attached picture. Another similar solution to the same problem is the slightly different "braided" collar structure, offered by the very clever and original "Braided bowline", by SS369 (1).

1. http://igkt.net/sm/index.php?topic=4283.msg26651#msg26651

P.S. The interested reader might notice that the shown bowline, as well as a number of other similar eyeknots, can be derived by a simple modification of the Sennit, the Symmetric Simple Sinon (SSS) and/ot the Vice Versa/Versa Vice/Reever bends. Usually, an untucking of a limb of the one side, which afterwards is forced to make a U-turn and be connected with a limb of the other side to form the eye, would be sufficient.
« Last Edit: March 22, 2013, 09:28:28 PM by X1 »

X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #22 on: March 23, 2013, 12:09:41 AM »
   So, if we wish to go one step further, we will ask ourselves : why does the second leg of the collar ( the tail ) has to follow the same, first leg s path ? In the "Eskimo" versions ( there are more than the one I have shown), it passes in between the first leg ( the continuation of the returning eye leg)  and the standing part. That is the place where it is squeezed harder, so it seems reasonable to try to replicate this situation in the "common" version as well.  See the bowline at the attached picture, which is a modification of the knot presented at the previous post. The interested reader would recognize the symmetric bend which lies at the core of this eyeknot - it was published in this Forum some time ago, and it is a modification of another member s similar but more complex knot.
   
« Last Edit: March 23, 2013, 12:17:46 AM by X1 »

X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #23 on: March 23, 2013, 01:37:56 AM »
double, crossed coils nipping loop ". Its great advantage is that it is very table, almost self-stabilizing, even without the presence of any "collar structure" ! However, I believe that this advantage manifests itself mainly in the case of the "Eskimo" variation, where the whole nub lies perpendicular to the axis of loading, not parallel to it.

  I understand that many people would not understand what I am talking about here ...so I have to show some pictures.  :)
  One does not see any collar in the double, crossed coils nipping structure shown in the attached picture, does he ?  However, the interested reader who does not only look at knots, but also ties them, would be surprized by the holding power of this structure, even in the absence of any collar, even when it is deformed  That is why I say that we should better place and manage to maintain the shaped "8" structure perpendicular to the axis of loading, not parallel to it - where it would not be stable any more, and would need the active presence of the collar to remain in one piece. If the collar, for whatever reason, gets loose, the "perpendicular" double crossed coils nipping loop would still hold, while the "parallel" double crossed coils nipping loop would open up, like a peeled banana !  :) In any crossing knot bowline, we mainly seek one, and one only thing : to keep the form of the nipping structure closed, without much aid by the collar, in any loading configuration. We can not suppose that the two eye legs will always be equally loaded, or even that they will be loaded at the same time ! The one leg can be caught up somewhere, and be forced to carry the whole load, while the other will get loose. A more self-stabilizing nipping structure would be able to maintain its integrity, remain closed, and hold during this phase, while a structure that is heavily depending upon a loaded leg, would be deformed and lose its gripping power altogether, if this leg happen to be loosened.

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #24 on: March 23, 2013, 07:11:07 PM »
   On Thursday a friend and I set up a pull-testing station in his back yard between two stout mature trees and at near ground level. Sorry, no photos. I forgot my camera. A ratcheting cable winch puller (1000 lbs. first layer capacity) was used to apply the forces, which were estimated as we had no means for measuring them accurately. But, really, all that we wanted from the tests was to see how well the Tresse Bowline resisted deformation under severe loading and thereafter how easy it was to untie. A large plastic tarp -  folded several times -  covered the entire setup when the forces were being applied. Even so, the high forces reached scared me, as this was the first time either of us has done something like this.   
   The tests were conducted in the normal loading mode. Only two tests were performed, one with 10.5?mm KM (brand unspecified) and the other with 4mm nylon accessory cord. The test pieces consisted of a Double Bowline tied on one end of each test piece and Tresse Bowlines tied at the other ends. The accessory cord was tested to near failure as best as could be judged [~600-750 lbs.], the knots were checked for movement and ease of untying, after which the knots were reset. The accessory cord was then loaded to failure, at which point the Tresse Bowline ruptured. Of course, the highest forces were reached when testing the KM and could have been as high as ~1000 lbs.
   The test results showed that the Double Bowlines and the Tresse Bowlines maintained their forms well under heavy loading and were similarly easy to untie.
   I would like to do more testing to gather some data points regarding movement at or near the knot. FWIW, I will also test the T.Bowline for ring-loading issues and see if I can get it to jam.

Cheers,
alpineer

The puller used was similar to this product.  http://www.texastooltraders.com/Contractor-Supplies/Pullers-Bars/Comalong-Pullers/Maasdam-CAL-1-1-Ton-Capacity-p8447136
« Last Edit: March 24, 2013, 08:11:32 PM by alpineer »

Sweeney

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #25 on: March 23, 2013, 10:16:53 PM »
The test results showed that the Double Bowlines and the Tresse Bowlines maintained their forms well under heavy loading and were similarly easy to untie.

Perhaps I'm missing something here but on the face of it the double bowline outperformed the tresse bowline in that the tresse bowline ruptured and the double bowline didn't. That would put the double bowline in pole position awaiting tests against say the EBDB? I have in mind something like the "knot wars" used for fishing knots but I don't have the kit to contribute to testing unfortunately.

Barry

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #26 on: March 24, 2013, 02:57:34 AM »
Hi Barry,
   I indicated in my opening post that the tresse bowline appears to be weaker than ABoK #1010. Commercial and sport fishermen and climbers... value many of the same characteristics in their knots. Where each discipline can differ is in what specific characteristics of knots they must necessarily place greater - or lesser - focus on. For a climber, the threat of a knot causing a line to fail from being overloaded is simply unacceptable, so climbing ropes are necessarily overbuilt, and knot strength becomes a lesser factor in knot choice because the required strength is always there in enough measure. Even a weak knot is strong enough for any task, but for other undesirable properties... it may not be used in certain applications.
  One could argue that strength is the most important of all cordage properties. Knot efficiency isn't a major issue concerning climbing ropes because of the high margins of safety built into them. So the focus on specific attributes goes elsewhere.
   Fishermen are at the other end of the scale (haha). Their lines must necessarily be of smaller diameter for several reasons, I would guess (bulkyness, weight, cost, stealthyness, manageability...). Fishing requirements don't allow for overbuilt lines with high strength margins, in fact, in the case of sport fly fishing the name says it all. The focus naturally tends toward knot strength efficiency to get the most performance from their lines.
   So, did you miss something Barry? No, not really. You read correctly. But so what. It is what it is. I'm just reporting my observations as honestly as I can. Why come to conclusions about a knot based on one parameter when there's a host of others to consider? I've just begun the quest to test and prove my claims in a public forum. Pole sitters don't always win the race!
   Everyone here has an opportunity to engage themselves in evaluating this simple adaptation to the standard Bowline.

Cheers,
alpineer 
« Last Edit: March 24, 2013, 03:35:14 AM by alpineer »

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #27 on: March 24, 2013, 05:55:20 AM »
My thoughts on Bowline security:
   It would be most desirable to get the security feature of a Bowline derived knot up front rather than at the tail end of the tying process. There's a human psychology aspect to my thinking on this. Considering reports of accidents implicating failed Bowlines, I suspect that most were a result of not tying a tail security feature.  Better for the security feature to be first - before tying the Bowline -  rather than last, regardless of whether you feel the need to do something with the tail -  i.e. if you remember to after being distracted, say, by the scenery around you ;), or feeling rushed or for whatever reason. Perhaps those accidents, and the bad press that followed the Bowline, could have been prevented.
   In the tresse bowline's case the first nipping loop is the knot's security feature, after which you're tying ABoK #1010.

alpineer
« Last Edit: March 24, 2013, 06:30:35 AM by alpineer »

alpineer

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #28 on: March 24, 2013, 07:10:37 AM »

X1

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Re: In Search Of The Holy Grail Bowline: A Bowline For All Reasons
« Reply #29 on: March 24, 2013, 02:03:05 PM »
   It would be most desirable to get the security feature of a Bowline derived knot up front rather than at the tail end of the tying process. There's a human psychology aspect to my thinking on this. Considering reports of accidents implicating failed Bowlines, I suspect that most were a result of not tying a tail security feature.  Better for the security feature to be first - before tying the Bowline -  rather than last,

   You have a point here. However, why not have a secure nipping structure AND a secure collar structure, at the same time ? Regarding good things, most of the time "two" is better than "one". Bowline is a knot made by two good components : the nipping loop and the collar. If we decide to go forward, it seems reasonable to me to use both feet / to improve the nipping loop AND the collar. When you replace the tyres of your car, either of the front or the rear wheels, you replace both of them, don't you ? I never use one single anchor, or one single mooring line - and I admit there is a human psychology aspect in my thinking on this !  :)