Author Topic: Gnat bend  (Read 9745 times)

Valentine

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Gnat bend
« on: October 26, 2013, 03:37:45 AM »
I was fiddling with some cord recently and made this:



I noticed how it seems to make a highly jam-resistant (if perhaps a bit insecure) bend, and considered whether a different hitch-based structure could increase security while still being very simple. With those goals, the gnat hitch came to mind, which produces the gnat bend:



It's symmetric, moderately jam-resistant (apparently to a degree similar to the gnat hitch), and remarkably non-streamlined for a knot of its simplicity. Thoughts?

Dan_Lehman

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Re: Gnat bend
« Reply #1 on: October 26, 2013, 06:48:33 AM »
I was fiddling with some cord recently and made this:
[a pull-together of cow hitches in discordant orientation]

I noticed how it seems to make a highly jam-resistant

Whoa, do not pass Go : I don't agree with this assessment
--looks/feels pretty jamming to me!  (Oh, I can loosen the
closing half-hitches, but not the central/opposed ones.)

Quote
It's ... remarkably non-streamlined for a knot of its simplicity. Thoughts?

I think that this is a remarkably uninviting characteristic
(like being "unlight for one's height") !!
 ;)

--dl*
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xarax

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Re: Gnat bend
« Reply #2 on: October 26, 2013, 10:54:30 AM »
   The advantage I see in this Fisherman-knot-like bend is that the individual links are "simpler", because they are topologically equivalent to the unknot, and not to the single or double overhand knot, as is often the case. So I think it should be considered as a relative to the Double Harness bend rather than to the Fisherman knot. A simple modification of the paths of the tails generates the bend shown in the attached pictures.
This is not a knot.

Valentine

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Re: Gnat bend
« Reply #3 on: October 26, 2013, 03:12:51 PM »
Whoa, do not pass Go : I don't agree with this assessment
--looks/feels pretty jamming to me!  (Oh, I can loosen the
closing half-hitches, but not the central/opposed ones.)
It does bind tightly on itself, but (with the ropes I've tried, at least), that doesn't inhibit untying. Once the supporting half hitches are removed, the central knot (a less-secure dressing of the knot called a symmetric sheet bend by xarax here) can be loosened easily by flexing the knot along the axis formed by the tails.

I think that this is a remarkably uninviting characteristic
(like being "unlight for one's height") !!
 ;)
Sure, for many practical purposes, and for for practical purposes there are better bends to be had. It does have niche possibilities though, given that it is at least functional as a bend. Its crazy zigzag-bowtie shape might be used when camping to weird out nearby Boy Scouts, for one. The open structure does make it fairly easy to pry the knot apart after loading, which can be problematic with knots that form more compact shapes (like this one, where the situation is the reverse of what you pointed out above: the knot is tightly constricted nowhere, but its compact rigid structure makes it somewhat difficult to untie).

Luca

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Re: Gnat bend
« Reply #4 on: October 26, 2013, 08:29:19 PM »
Hi Valentine,

(like this one,

I found in my hands this bend starting from the knot called "square antiprism" in the diagram in this post http://igkt.net/sm/index.php?topic=4655.msg30093#msg30093 ,and transforming it into a bend through the same process as a Blimp knot can be transformed into a Zeppelin bend.
It was done to note to me that can be obtained four variations of this bend("long" + "short" on the model of the Double Harness bend if the tails are not crossed, and over/under + under/over if the tails are crossed, if I understand correctly(EDIT: I actually have not figured out which is the fourth version, because, due to the symmetry type of the knot, the versions over/under and under/over seem to produce two symmetrical knots)).
Regarding the tendency to jam, at least for the simpler variation, or, better said, the more "spontaneous" version("long"), that you show, I agree with you, but I think it also depends on how the knot is set (if it is modeled by giving it the most compact form that may have,in fact can be very difficult to untie even after being loaded blandly),and of course on the type of rope which is used.
Personally, I noticed a similarity of this bend with the Hugo bend, but in fact it also resembles the Double Harness bend with opposite ends (if you want, just swap the direction "up / down" whereby the terminal parts of the two initial bights pass through his own standing parts, keeping the rest of the knot unchanged, and you get in this way the Double Harness bend).

                                                                                                                  Bye!
 
« Last Edit: October 26, 2013, 08:52:06 PM by Luca »

Valentine

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Re: Gnat bend
« Reply #5 on: October 26, 2013, 10:19:06 PM »
I found in my hands this bend starting from...
I found my hands on it by trying to recreate the loading pattern of an Ashley bend in a line-axis-symmetric knot.  I haven't tried different dressing arrangements of the tails, but it does seem plausible that they wouldn't jam as badly. However, the only practical use I see for this knot (when non-jamming and harder-jamming alternatives are available) relies on its ability to jam too solidly to pull the tails out by hand. In such a situation, it can still be untied by pulling one of the outer collars over its standing part and down the other side, which gives enough slack to open up the rest of the knot. The non-obviousness of this (and the non-trivial force needed) lets it serve as a padlock that resists casual tampering.

Luca

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Re: Gnat bend
« Reply #6 on: October 27, 2013, 02:18:49 AM »
Hi Valentine,

A couple of "variations on the theme"(the "theme" is "two not-interlinked initial bights") that could solve the jam problems of this bend: in the first the tails are simply tucked one time less(EDIT:this is the "fourth version" that I  have not understand in my previous post); the second is perhaps to be regarded as a mere "style exercise" which, if set in the appropriate manner, and it is not very easy, can lead to a bend based on two unknots that has some look and appears to behave like the Zeppelin bend, but that in practice one can not replace the Zeppelin with it unless one does not want to complicate his life!
These bends maintain the same type of symmetry of the Zeppelin bend to which also you perhaps have mentioned.
 It's just "for the collection",in the end this is not the section "Practical knots"!

                                                                                                                              Bye!





« Last Edit: November 03, 2013, 12:10:18 AM by Luca »

Dan_Lehman

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Re: Gnat bend
« Reply #7 on: October 27, 2013, 06:23:20 AM »
   The advantage I see in this Fisherman-knot-like bend is that the individual links are "simpler", because they are topologically equivalent to the unknot, and not to the single or double overhand knot, as is often the case.
But what advantage follows from this?
(One might see unknotted links as problematic
for tying --that they need holding in position, and so
on (not necessarily an issue, but ...).)

When I look at the images --the OP's, or those familiar
pretty ones, returned--, I see a twin bowlines end-2-end
knot begging to be realized (and with each tail taking
another tuck to put 3 diameters in the turNips).
 ;)


--dl*
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xarax

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Re: Gnat bend
« Reply #8 on: October 27, 2013, 04:47:12 PM »
  The advantage of simplicity for its own sake can not be overestimated. However, in the present case, one can also add that if one ( at least ) link of a bend happens to be topologically equivalent to the unknot, then this bend can be transformed into a potentially interesting PET eyeknot, and/or it can serve as a useful midline bend.
    Moreover, what can be considered as posing problems during tying, can solve problems during un-tying : a topologically simpler link can often be easier and faster to untie than a more complex one.
« Last Edit: November 01, 2013, 01:00:09 PM by xarax »
This is not a knot.

Dan_Lehman

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Re: Gnat bend
« Reply #9 on: October 29, 2013, 01:46:34 AM »
  The advantage of simplicity for its own sake can not be overestimated.
Perhaps, but I question that the unknot is everywhere
so simple : anything tied in the bight, afterall, is that,
but I've spent hours in rendering some long-entangled
jetsam pot line to the obvious unknot
--in short, *unknotting* it was far from simple!   ;D

The point about being "PET" is taken, but there, too,
it might be far from simple : indeed, one of the eyeknots
I've discovered of a bowlinesque form is something I only
know how to tie in the bight, as forming it in the PET
way is problematic (but also, I've been too lazy to try
to memorize a PETying method).

 ;)

xarax

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Re: Gnat bend
« Reply #10 on: October 29, 2013, 12:04:31 PM »
   We may consider such an interpenetrating bend, where each link is topologically equivalent to the unknot, as a junction of two marlinspike hitches : the tensioned standing end of the one link works as the rope-made toggle of the other.
   When we untangle the tail of the one link and pull its standing end out of the other link, the whole bend gets untangled as well. ( So, during *unknotting*, we have to do half of the "dumb" job we had to do during  *knotting* = another advantage. We just clean and free one end, and, ho, we get two clean free ends ! ) In fact, if we are able to pull out the tail of the one link while the bend is still under some tension, the corresponding standing end can be pulled out of the other link by itself, so the bend can work as an "exploding bend", the same way an "exploding hitch" works (1).   
 
   (*) A counter-example ( A Fisherman s knot - like bend, made by two interpenetrating slipped overhand knots ) is shown in the attached pictures. If we "pull the trigger" and "unknot" the one end, the bend can "explode", indeed, but the other end will remain 'knotted". 

1. http://igkt.net/sm/index.php?topic=4463.0
« Last Edit: November 01, 2013, 01:01:34 PM by xarax »
This is not a knot.