Author Topic: How much redressing makes a new knot?  (Read 14350 times)

Mobius

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Re: How much redressing makes a new knot?
« Reply #15 on: May 14, 2015, 03:39:51 AM »
Mobius I would say this is certainly a different loop than the usual one, but not a different knot.  (Others might add the qualifier "PART")  I'd have trouble saying you "discovered" even the loop, but you might have created awareness of its potential usefulness and if this configuration gets used a bunch, it's going to need a word to go with it, so sure, why not a name, but one that reflects its nature.  Oddly enough, your handle works quite well.. Mobius Butterfly Loop seems to be quite descriptive, although the spelling might be abrasive to somebody ;)

I was trying to be careful and not overstate my case, after all, I fully admit that all I did was fool around with a Butterfly Loop to get the knot I have shown. If the knot is deemed 'new' than I guess I might have "discovered" it. However, that is already quite a contentious issue, with good arguments on both sides. I don't care if the knot is new (in terms of the way it has been discussed here), just that it might be useful.

To me, it might prove useful/practical since many knot tyers already know how to tie a Butterfly Loop efficiently, so redressing that into a form potentially more suitable as an end loop is relatively easy. I am reasonably sure it won't jam in the form I gave, however I will do some trials later today and see whether my rope jams after being loaded.

Cheers,

mobius


Mobius

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Re: How much redressing makes a new knot?
« Reply #16 on: May 14, 2015, 03:43:09 AM »
Hello all!

Maybe one could see something very close to the Bull hitch within the geometry (and possibly something within the functioning?) of this fixed loop,so I decided to take a step forward (following a path that someone else opened) and try to realize a sort of Bull-Clove hitch version of this loop(below).
Actually I do not expect that this (completely untested) knot has a practical value greater than the simpler version (and I have not yet ascertained whether there is a method of tying, TIB or no-TIB that is acceptable in order to be able to be considered as a practical knot(but I had fun and ,after all,we are in "Chit Chat"!)

                                                                                                                           Bye!



Oh! Nice  :) Another good-looking loop to play with. Thank you for sharing.

alpineer

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Re: How much redressing makes a new knot?
« Reply #17 on: May 14, 2015, 04:42:48 AM »
This knot has been documented as being used to construct an easily adjustable, "self-equalizing" multiple loop climbing anchor. I can't find a link to support this, but IIRC it was on Peter Suber's Knots On The Web site, now possibly the largest collection of Broken Links on the Web.
« Last Edit: May 14, 2015, 04:45:07 AM by alpineer »

Dan_Lehman

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Re: How much redressing makes a new knot?
« Reply #18 on: May 14, 2015, 06:33:41 AM »
If anyone is wondering where my pictured knot came from, ...
Wasn't that the point --and, so, if they're NOT, ...!?
(Well, maybe they're a quick read, like Tex.)

Quote
... it was simply a redressed Butterfly Loop
Interesting, as --not seeing this as did Tex (to which
I can say that I do know that also Ashley's bends
#1452, 1408, (...?) also can *capsize* into themselves)---,
I tried to reconstruct it (wasn't clear to me, and I think
my over/unders differed), and then worked a reasonably
like knot into . . . the fisherman's/Englishman's eyeknot!

Quote
If this Butterfly Loop version is different/interesting enough to warrant a title
then 'Collared Butterfly Loop' might be a good descriptive name.
If it's different enough, then I'd not care to try
to liken it to what is differs enough from!
(Nor confuse over what constitutes "collars",
which IMO is something the original has,
and this one more dubiously so (hence jamming).


--dl*
====
« Last Edit: May 14, 2015, 06:45:49 AM by Dan_Lehman »

Dan_Lehman

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Re: How much redressing makes a new knot?
« Reply #19 on: May 14, 2015, 06:44:30 AM »
   Your original question is a very difficult one...
We have not yet defined what a "knot" is,
so how could we do the same for a "new" knot ?
Indeed!!
(But, in our state of understanding such as it is,
I think I"d see this variation as disctinct.)

Quote
   Knots that are topologically identical, may be geometrically very different, have different structures and structural characteristics regarding slippage, strength and jamming, "work" differently, and so be different knots. One can go as far as to consider topologically and geometrically identical knots as different, if/when, without any major change in their forms, they are loaded differently.
Further, one can note that different knottable media
tied in equal geometries as set with some modest,
equal tension, can behave differently upon full loading,
given differing characteristics of their media --one more
compressible, one more elastic, one more frictive, and
so on!

Also, in the case of the offset water knot --and likely
some other offset end-2-end knots--, the loading
can range across about 180 degrees of rotation of
the knot body!  --differing from extremes where one
or the other end makes a loop vs. forward arc.

Quote
A loop may retain its basic shape when it is loaded by the one or the other free end, but is it the same knot, or it is two different knots, which, when loaded, just happen to have a similar shape ?
This seems a clear case : different.


--dl*
====

Dan_Lehman

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Re: How much redressing makes a new knot?
« Reply #20 on: May 14, 2015, 06:55:52 AM »
The shape of the fig.8 bend will not change noticeably when it is loaded by the one or the other pair of ends, so we tend to think of the two knots as the "same" knot.
One can quibble re "noticeably" : I argue that in fact
the different loadings are quite noticeable, though
you might take a different sense for it and cite some
dramatic case.  (Of course, now, we first have to come
to some agreement about the general fig.8 form
we're differently loading!)  Of the "perfiect form" --which
I think Grog's Animated Knots presents--, loading
its "strong form" --my label for loading ends that will
bear against their twins, and which to the extreme ends
of the knot--, the knot will be compressed to appear to
be at about a 45-degree angle to the axis of tension;
loaded by the other ends, the knot remains roughly
aligned/parallel to this axis, and the outer reaches
show a lack of tension on these parts.

But, I think that all this is arguably within what you
might regard as substantially the same knot-appearance.


--dl*
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Mobius

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Re: How much redressing makes a new knot?
« Reply #21 on: May 14, 2015, 10:07:40 AM »
If it's different enough, then I'd not care to try
to liken it to what is differs enough from!
(Nor confuse over what constitutes "collars",
which IMO is something the original has,
and this one more dubiously so (hence jamming).


--dl*
====

That is fine, I haven't thought about the loops around the eye of a Butterfly being 'collars' , however I suppose they are. As for the 'butterfly' part of the name I gave, it was just a tribute to the Butterfly (where my pictured loop came from and some are saying still is) rather than saying the knot was different from a Butterfly.

Anyway, the name really doesn't matter to me, pick something yourself if you like ;) If others like it, they will use it.

(Note to self: suggest a name for the next knot I make something with 'Mobius' in it, names just seem to be plaguing me at present one way or another. Maybe watch out for the "Mobius Bowline" ;D)

Cheers,

mobius
« Last Edit: May 14, 2015, 10:09:20 AM by mobius »

Mobius

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Re: How much redressing makes a new knot?
« Reply #22 on: May 14, 2015, 11:15:58 AM »
I tried my knot out on my test rig again tonight.

I took the tension to 120kg in my 3mm braid and then released it. I watched the knot closely and the loaded side of the near symmetrical nub squeezed together a bit more than the unloaded side, though it did not move otherwise. There was no tail slippage as far as I could detect. I could untie the knot afterwards. I find just about any knot a bit difficult to untie after load in my 3mm material (eg. even a Zeppelin Bend), so getting it undone at all is something I suppose.

I was going to break-trial it again using the same piece of rope. I know that is not the way to do it really, pre-strained rope isn't a good idea. Anyway, the rope broke at a place well away from the knot at ~132kg. That gave another opportunity to untie it. Again I was able to do so.

So is it easy to untie? It gets a pass from me at the moment, though that assessment may be unreliable in other rope materials and sizes.

Cheers,

mobius
« Last Edit: May 14, 2015, 11:18:56 AM by mobius »

Mobius

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Re: How much redressing makes a new knot?
« Reply #23 on: May 14, 2015, 11:35:43 AM »

   Besides that, the shape of the Butterfly loop and the shape of Mobius loop, are NOT the same ! Mobius should had presented his knot without this funny angle of the eyelegs - if he had done that, and the eyelegs were parallel or at, say, 30 degrees angle, the "difference in shape" would had been more obvious - but it would not be THIS difference which would be the main reason those two knots are different : the main reason is that they are loaded differently, and the various segments of the knot inside the nub "work" differently.   

Please don't nit-pick about how I displayed my pictures. If you tie my knot and cinch it, the way I showed it is the way it wanted to sit. How many knots displayed in the forum are in significantly different forms than how they look when they are loaded... nearly all of them  :)

Cheers,

mobius

Mobius

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Re: How much redressing makes a new knot?
« Reply #24 on: May 14, 2015, 02:08:31 PM »
...   ( AND, you blurred the picture as much as you could  :), because it was so much out of focus ! Some better pictures, where you would had pre-load / pre-tighten the loop a little bit, before you take the picture, and its eye legs would not be spread out SOOO much  :), would be much appreciated. )

xarax, I assure you I didn't try to blur my pictures. They do not looked blurred when I look at them :) It was an old piece of rope I was using, is that why it looks blurred?

Have a look at the following picture, is it blurred to you? It's a new piece of rope and new background, is that better?

Cheers,

mobius
« Last Edit: May 14, 2015, 02:10:04 PM by mobius »

Tex

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Re: How much redressing makes a new knot?
« Reply #25 on: May 14, 2015, 03:15:50 PM »
... this knot PART is IDENTICAL to an ABK knot part.  There is no difference in dressing, certainly not before its loaded.

   I do not believe that we can say this. The "half hitch" and the "nipping loop" may be considered as having identical "parts", but they are not the same. If "difference in dressing" means "difference in shape", without any consideration of what is going to be loaded, and how, I think this "difference" is not what makes knots be the same or be different !  Structures are not determined uniquely by their shape. A dome and a fishing net may have the same shape, but they are altogether different structures.
   Besides that, the shape of the Butterfly loop and the shape of Mobius loop, are NOT the same ! Mobius should had presented his knot without this funny angle of the eyelegs - if he had done that, and the eyelegs were parallel or at, say, 30 degrees angle, the "difference in shape" would had been more obvious - but it would not be THIS difference which would be the main reason those two knots are different : the main reason is that they are loaded differently, and the various segments of the knot inside the nub "work" differently.   

Xarax I don't know if you actually aren't seeing this or if you have some purpose in refusing to acknowledge a fact.  There is no good reason raised at this point for there to be any disagreement about the facts of this knot part or these two configurations.  Nobody disagrees that this knot part can contort and behave differently under different combinations of tension and angle applied to  its 4 ends.  A 2x4 can support much more force loaded axially than beam loaded, and acts sometimes as a stud or as a joist .  A bolt is still just a bolt though if it shear loaded, or stretched, whether pre-loaded or not.   Arguing in a serious way about labels is a fools game.  I'd rather argue about facts.  The loading facts are not particularly in dispute(not fully understood either, but not in dispute) as far as I can tell.

But NOW you've gone and seemingly intentionally failed to clarify, refused to establish, or if I give you the benefit of the doubt, are maybe simply wrong about a simple fact, either because you actually don't see it or because you have some purpose which the fact does not suit.  While this might seem wise to you, dodging facts to me does not seem likely a useful way to find truth.  I think it's much more helpful usually to establish facts than to argue about words.

 The (false) fact I'm referring to the possible implication that this knot part, aside from loading or what exact angle we lay the ends at , is actually different, and that's just wrong.  If the loop is cut and the 4 ends are all cut the same length you cannot distinguish one knot from the other.  They are INDISTINGUISHABLE.   This is a fact and not open to interpretation of the minds eye or to any number of words of extreme wisdom.

I have one of each sitting on each of my two legs. I tied them both as regular ABL's, but capsized ;) one of them to the other form to produce it in the "right" way.  I have spread and opened each so that they clearly retain the essence of their dressing but are now easily vissible.   One has the loop toward me the other has the loop away.  They are now turn for turn, crossing for crossing, over for under exactly the same knot part.   If I cut all the ends short, there would be no difference at all and they will then simply be exactly the same knots.  I could take a picture, but what it would it prove?  That I can tie the same knot twice?  You have to do it yourself.

Without loading, this loop is just as happy to have its eye legs at the angle mobius shows as any other angle.    Yes the "butt cheeks" of the loop legs tend to slide apart, but that's true with normal loop loading or ring loaded, so is irrelevant. There are actually at least a few dressings for this knot within either of the "two" capsized "variations".  I don't think that changes their names, although I think it does change their properties, but if someone wants to give those different names too, I cannot argue factually against that.  It's impossible. 




Tex

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Re: How much redressing makes a new knot?
« Reply #26 on: May 14, 2015, 03:20:58 PM »
And, as I've said, I'm happy to call this loop by a different name, after all I cannot keep calling it "this loop", my vote, and it can be neither right nor wrong no matter how close to a Zen master one thinks they have become, is that it would contain butterfly as its middle name, but that is just my "vote" (maybe better to say it's what I'll call it for now since I don't need to take a vote about that anyway).

Tex

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Re: How much redressing makes a new knot?
« Reply #27 on: May 14, 2015, 04:44:37 PM »
I will also add that I'm pretty sure there have been plenty of cases in the wild where the ABL was loaded with all the loaded legs in in parallel, in fact it's quite normal.  The difference in those cases are that the legs leaving together would, being part of a loop have both been tensioned instead of only one, but the directions would not have been different.  If only one parent line is loaded and the loop legs are parallel, then it is guaranteed by 1st and second laws that the three loaded legs are all parallel (unless the knot is accelerating). If the unloaded parent is slack or made slack by the loop load, surely the angle of this dangling leg will not then be so relevant as the fact that it is not loaded.

So it seems to me the angles are not the real issue here at all in the difference in performance, but which of the 4 legs is not loaded is the issue. Of course angles matter more as the loop gets shorter/fatter/more ring-loaded/less parallel, but even then the only part that's hard to imagine ever seeing with the other knot is the which leg is unloaded.

Tex

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Re: How much redressing makes a new knot?
« Reply #28 on: May 14, 2015, 05:09:04 PM »
Well X if you have force on a stationary thing in 3 directions with equal force on two of those, then the third force must bisect the angle of the first 2.  It cannot be avoided. It is simple vector addition and that addition must add up to zero.  Now if those first two legs are parallel then the bisector is obviously parallel. The only way this can be not true is if the 4th line is in fact NOT unloaded, but has at least SOME load.  Sure, sometimes the 4th leg has some load.


Mobius

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Re: How much redressing makes a new knot?
« Reply #29 on: May 14, 2015, 10:49:54 PM »
   What can I do ? I have to take pictures of the Mobius loop by my blinded camera - and my blinding eyes...  :)
   Mobius, if you wish to finish this job, do the same thing you did for the Buttefly loop ( which has the same shape as the Butterfly bend ) in the cases of ABoK#1408 and ABoK #1452 bends.
   Veeery interesting !  :) :)
 

xarax, my photography skills are clearly less than yours. I'll resign my self to taking bad photos and you can fix them if you wish  :)

Thanks for these photo's they are great.