Author Topic: A noose-like hitch that can be untied after hard strain  (Read 37339 times)

xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #15 on: February 11, 2012, 12:53:26 AM »
   Maybe we can save this for another topic or a new topic.  Let's try to curb the tangents.

Sorry. I was forced to reply in such a lengthy balh blah because my original short comment was misunderstood repeatedly. Even if the knot presented in this thread does not slip with most materials, we can still evaluate its security, and try to find out if it is more or less secure than other knots, of about the same complexity.
« Last Edit: February 11, 2012, 12:54:34 AM by xarax »
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knot4u

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Re: A noose-like hitch that can be untied after hard strain
« Reply #16 on: February 11, 2012, 03:06:04 AM »
I'd like to get back to talking the knot in the original post and how it behaves in rope. It's intriguing.

I've tried it in various situations (e.g., paracord, boot lace, larger polyester, large diameter objects, small diameter objects). It has not slipped.

On the flip side, the knot does feel like it might jam in certain circumstances and materials. However, that's just a guess because I have not jammed it.

I'm guessing the knot might slip if the object has a large diameter (ring loaded knot) and is slippery. Again, that's just a guess because I have not gotten the knot to slip. If the business portion keeps behaving like a Marlinspike Hitch and doesn't capsize, then it shouldn't slip.
« Last Edit: February 11, 2012, 03:07:26 AM by knot4u »

xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #17 on: February 11, 2012, 04:53:58 AM »
It's a Marlinspike Hitch in which the standing end operates as the spike. That's nifty.
I have not gotten the knot to slip. If [it] keeps behaving like a Marlinspike Hitch and doesn't capsize, then it shouldn't slip.

   Perhaps the comparison to the Marlinspike hitch, which is not correct, reveals the problem of such hitches ( like the hitch presented in this thread, or the one I have shown at Reply#2, or at Ref. (1)). In all knots where the standing part penetrates the knot like a spike, (without being such  :)), what we see is that the standing part  is aligned too early and too much, the rest of the knot does not force it to curve a little, so it slips, as a whole, alongside it. This is not a problem when this "rest of the knot" is convoluted enough, like it is in the Buntline hitch or in the 'Buntline extinguisher" hitch, because there it does not run the danger to be untied when pulled by the eye leg of the bight. When this knot is too simple, like in the case of the hitch presented in this thread, the pull from the one end can be sufficient to make it unfold from its place around the aligned standing part, and be untied. The standing part is not curved even a little, so it will not be an obstacle to this trend. Only the compression forces from  the object, and the friction with the object s surface, can prevent this. I do not trust this one and only one line of defense against knot release. Who knows what will happen to this simple overhand knot after alternating pulls, when the compression forces from the surface of the object will shake it repeatedly ?
I would not trust this hitch unless I know that it was dressed tightly in the first place, it will remain under constant loading all the time, and that the surface of the object is not slippery itself, - and even then I would like to pull the free end from time to time, to be sure the knot remains tightly tied on the standing part  :).
   What we need is a hitch-noose where the pull from the eye leg of the bight can deform the standing part a little, so the formed curve will allow the rest of the knot to be entangled with/on it in a safer way - and also where the rest of the knot will be complex enough, so it will not run the danger to be untied when it is pulled by its one end. I think we should go beyond the single overhand knot, to a double overhand or a shape "8" knot, to have a sufficiently convoluted knot tied around/on the standing part.

1) http://igkt.net/sm/index.php?topic=3288.msg19765#msg19765
« Last Edit: February 11, 2012, 05:30:48 AM by xarax »
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knot4u

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Re: A noose-like hitch that can be untied after hard strain
« Reply #18 on: February 11, 2012, 07:16:59 PM »
   Perhaps the comparison to the Marlinspike hitch, which is not correct...

I said it's like a Marlinspike Hitch where the standard part is like the spike. I'll give you a chance to explain how that statement is incorrect. Actually, don't bother. I don't care.

roo

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Re: A noose-like hitch that can be untied after hard strain
« Reply #19 on: February 11, 2012, 07:48:26 PM »
I've finally decided to do a write-up on it:

http://notableknotindex.webs.com/gnathitch.html

Thanks to all for giving your thoughts on the matter.   :)
« Last Edit: February 11, 2012, 07:50:48 PM by roo »
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knot4u

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Re: A noose-like hitch that can be untied after hard strain
« Reply #20 on: February 11, 2012, 07:54:30 PM »
Cool, can you explain the name?

roo

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Re: A noose-like hitch that can be untied after hard strain
« Reply #21 on: February 11, 2012, 07:59:35 PM »
Cool, can you explain the name?
The small knot form reminded me of a little gnat.  Also, I see a "g" shape the tying process.
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knot4u

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Re: A noose-like hitch that can be untied after hard strain
« Reply #22 on: February 11, 2012, 08:11:17 PM »
The Gnat does fill a niche. I imagine tying a Gnat in many applications I would otherwise tie a Slipped Buntline, but want something smaller. While a Slipped Buntline is not big, a Gnat is a little smaller and does not require a slip. Actually, the Gnat seems to be actively opposed to the idea of a slip.
« Last Edit: February 11, 2012, 08:16:41 PM by knot4u »

xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #23 on: February 11, 2012, 08:39:52 PM »
I said it's like a Marlinspike Hitch where the standard part is like the spike. I'll give you a chance to explain how that statement is incorrect. Actually, don't bother. I don't care.

It is not like a Marlinspike Hitch. But you do not care.
When I try to explain what I think, I do not do it for one person, that may decide to care, or not care about something he does not know...I do it because I write what I believe it is true, for any present or future reader.
I know that there are many people who care only to learn the multiplication table by heart. So they believe they will learn how to multiply, and they even believe they will learn what multiplication is... and what mathematics is. Some of them will even go as far as to believe that parroting the multiplication table makes them great mathematicians !  :)
I try to understand things, knots, whatever, and when I believe I have understood something, I believe I have a duty to share my thoughts. I have tried all the possible arrangements of an overhand knot, a figure 8 knot, a Constrictor and a Strangle knot around the standing part, and I believe I know the advantages and the shortcomings of each solution. Whoever wishes to care about my experience, may learn something, or think about something else, and discuss it with me, so I will also learn something new. Whoever does not care, will not bother about anything, and "will live with this", proud and happy !   

 ( Off topic post, as an answer to an off topic post... :))
« Last Edit: February 11, 2012, 08:40:55 PM by xarax »
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Dan_Lehman

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Re: A noose-like hitch that can be untied after hard strain
« Reply #24 on: February 12, 2012, 04:47:35 AM »
Once security reaches 100% in rope (i.e., rope breaks before it slips), any additional data about security doesn't matter much.

Do not say this again !  :) It is a sooo false a statement ! If that was so, our life would be much easier, that is true -but unfortunately or fortunately, it is not.
...// ...
You tie two knots with/on a certain rope. They do not slip.
...
Two knots tied on the same rope material do not slip. Are they equally secure ?
Of course not.

Yes, they are, in that material.
All this expounding about the structure of a *knot*
is wasted energy, here, and beside the point of practicality.
It points to an issue on the definition of "knot",
with concerns I've mentioned before, about treating
*knots* as schemas for the formation of knottable
material, rather than as instances of something knotted.



Quote
The single most important factor is the structure, the geometry of the knot.
This geometry remains (almost) the same, when the knots are tied with any of the
usual ( not elastic ) materials. So, when we tie a knot with a very slippery material,
like a non-coated spectra/dyneema, a monofilament fishing line, a dental floss thread,
its structure remains the same.

It's not so simple.  Nor is friction the sole determinant of
behavior --vs. flexibility, cross-section stability, & springyness,
e.g..  I recall the EBDB looking worse in one springy slick
soft-laid PP cord and a Janus bowline seeming more secure,
which was contrary to behavior I found in other materials.  The
PP could too well simply loosen and enlarge rounded loops (of
the EBDB), but didn't so well enlarge the sharply elliptical
collars of the Janus bwl (where it tried to simply open, as
legs of scissors, and was immediately impeded by the central
nipping turns).
Quote
If ... we can find a slippery enough material where both knots do slip,
but the one slips less than the other ... , we can say that, tied on this X material,
knot A slips more than knot B, so knot A is less secure than knot B.
And this relation is going [NOT (you meant to say!)] to be reversed with any other material Z,
because it is the structure of the knot that is the single most important factor that dictates security,
and this structure will not change significantly when the knot will be tied with this Z material.
So, the relation will not be reversed.

And this conjecture about the inviolability of the significance
of structure is just that, and something I think I've seen
hints of contradiction for.

At this point in our understanding, it's hardly worth going
all keystoke krazy over.  (And, with the conjecture, can one ever
make a conclusion?)

The not-knot-tyer will jump and be eager to shout : But I am not interested in the security of my knot when tied on your slippery material ! I will always use this specific material in which my knot does not slip...so why I bother for any other condition ?

This goes too far.  One can have constraints on the domain
of knottable media one is concerned about; it will be hoped
that such constraints are kept in mind if media outside of
the domain should ever be the focus of knotting.

As for squeezing around the object,
note that this won't happen for other than *ring*
hitches --*spar* and beyond will tend to produce
choker-hitch sorts of openings on the side where
the noose SPart is, with quite a gap between where
the material hitches to itself.  Hence my suggestion
for friction hitches (forming the noose --though being
lousy for cinching to the object w/o assistance),
which can be set snug to the object.


--dl*
====

knot4u

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Re: A noose-like hitch that can be untied after hard strain
« Reply #25 on: February 12, 2012, 06:34:33 AM »
Who knows what will happen to this simple overhand knot after alternating pulls, when the compression forces from the surface of the object will shake it repeatedly?

You're viewing the Gnat Hitch as an Overhand? Do you also view a Half Hitch as an Overhand? Sure, there happens to be an overhand in there. However, the money is not in the overhand portion. For the Gnat, the money is in the part that resembles a Marlinspike. You're coming at this from a bizarre angle with all this talk about Overhands, monofilament, etc.

xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #26 on: February 12, 2012, 12:35:00 PM »
Two knots tied on the same rope material do not slip. Are they equally secure ?
Of course not.

Yes, they are, in that material.
All this expounding about the structure of a *knot* is wasted energy, here, and beside the point of practicality. It points to an issue on the definition of "knot",
with concerns I've mentioned before, about treating *knots* as schemas for the formation of knottablematerial, rather than as instances of something knotted.

It is really amusing what you try to pull out of your magic sleeve, to defend something that can not be rationally defended ( and which happened, just happened, to be something said against what I have said.. :)) Dan Lehman, you are such a good knot tier, and such a lousy lawyer... :)
So, a thief knot is a safe, secure, knot ! Because it can be tied with a material with which it will not slip! So, we can not say that a thief knot slips, but only that "a thief knot not-knotted on this material, may slip"  :) :). We can not say that any knot is slippery or not, because with some materials it will slip, and with some others it will not. There are no general characteristics of knots : All knots are equal in the Dan Lehman s Land of knots !  :) A "materialistic" approach, indeed ! :)
Gentlemen, do not talk about knots, they exist only in my imagination, they do not have structure, because they are not real : There are only things knotted on a specific material ... so we can not say "an overhand knot", because there is not such a thing. There is no structure of a knot, topology, geometry, lengthrope, etc. Oouaou ! What a relaxing simplification of the Word is this...We have managed to get rid of so many things with this "knotting material"invention, there are so fewer invariable qualities in nature, our life has suddently became so much easier... :)

The single most important factor is the structure, the geometry of the knot. This geometry remains (almost) the same, when the knots are tied with any of the usual ( not elastic ) materials. So, when we tie a knot with a very slippery material, like a non-coated spectra/dyneema, a monofilament fishing line, a dental floss thread, its structure remains the same.

It's not so simple.  Nor is friction the sole determinant of behavior --vs. flexibility, cross-section stability, & springyness, e.g.

That is why I said "usual"(sic), "non elastic"(sic) material. To speak about an (almost) same geometrical structure, when a knot is tied on different materials, we should pre-suppose that the material will keep, more or less, its circular cross section and will not flatten out completely, It will not be springy, etc.  Read my lips, when I was trying to spell out the simple thing I said above. When we use webbing or springy materials, we are talking about different things, that is obvious, and evident too, even to me ! :)

If ... we can find a slippery enough material where both knots do slip,
but the one slips less than the other ... , we can say that, tied on this X material,
knot A slips more than knot B, so knot A is less secure than knot B.
And this relation is going [NOT (you meant to say!)] to be reversed with any other material Z, because it is the structure of the knot that is the single most important factor that dictates security, and this structure will not change significantly when the knot will be tied with this Z material.So, the relation will not be reversed.

And this conjecture about the inviolability of the significance of structure is just that, and something I think I've seen hints of contradiction for.

Well, "I" have not ! And this is exactly what I have said, again and again, repeatedly :

   It had never happened to me, when a knot slip less and it is more secure than another, when those two knots are tied on a certain rope material, to slip more and be less secure, when those two ropes would be tied on another material !

If you point out to me two "knotted materials" tied on the same material, with the same structure,  where the A "knotted material" slips and the B "knotted material" does not, and then two other "knotted materials", tied on another material, with the "same structure" as before ( If I can say this...PLEASE, allow me to say this, just for once, for the last time, to describe what I mean...), where now the "knotting material" A will not slip, and now the "knotting material" B will slip, Iff you point me this situation, then, and only then, you would be able to start to argue on what I have said. I have seen , ( and you, as a knot tier, you have also seen, of course, but, as a lawer, you are trying hard to hide the crux of the matter...) that the relation "a knot A will slip, more than a knot B", or the relation "a knot A is more secure and safe than the knot B", is a relation independent of the material used . It depends mainly upon the geometrical structures of the knots - and those things do not change... and that is why they are called "structures', for Kant Land s god sake !

At this point in our understanding, it's hardly worth going all keystoke krazy over.

I tried to say one obvious, self evident thing, that an overhand knot tied around a tensioned, aligned standing part would be not such a good solution... because the overhand knot will run the danger to be untied quite easily, the structure of the overhand not is not secure and safe enough, and we would probably need something more convoluted, like a fig. 8 knot. I have also pointed out that I have tried all the possible configurations of overhand knots tied around the standing part of such hitches-nooses, and I have even given references and PICTURES of three such knots...which, of course, no participant on this discussion had ever seen, or tied or tried...And what do I listen ? That I can not speak of "knots", in general, because there are only "knotted materials", so the overhand knotted material, tied with/on the Titanic s mooring line, will not slip, is secure and safe ! Asta la vista, my dear Dan Lehman, I have hijacked this thread too much. The hitch presented is not bad, the ones I have also presented with pictures are not bad, but we better tie a "Buntline extinguisher " Constrictor-around-the-standing-part, or a Double overhand, Strangle neck instead.
« Last Edit: February 12, 2012, 01:20:48 PM by xarax »
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xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #27 on: February 12, 2012, 01:02:30 PM »
You're coming at this from a bizarre angle with all this talk about Overhands, monofilament, etc.

Try, just try, to be a little dubious about your understanding of what I have said and my "bizzare"angle... "All this talk" about Overhands, monofolament, etc.", might be, just might be, not such a nonsense you think it is. I have tried to answered to your questions, but you do not care, and you do not bother to try... Asta la vista, my dear knot4u, I am sure you will manage to understand something more in the future.
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Dan_Lehman

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Re: A noose-like hitch that can be untied after hard strain
« Reply #28 on: February 13, 2012, 05:47:42 AM »
Two knots tied on the same rope material do not slip. Are they equally secure ?
Of course not.

Yes, they are, in that material.  ...   It points to an issue on the definition of "knot",
with concerns I've mentioned before, about treating *knots* as schemas for the
formation of knottablematerial, rather than as instances of something knotted.

So, a thief knot is a safe, secure, knot ! Because it can be tied with a material
with which it will not slip! So, we can not say that a thief knot slips, but only
that "a thief knot not-knotted on this material, may slip"  :) :).  We can not say
that any knot is slippery or not, because with some materials it will slip, and with
some others it will not.  There are no general characteristics of knots :  All knots are
equal in the Dan Lehman s Land of knots !  :) A "materialistic" approach, indeed ! :)
(There are no apostrophes in X's land of keystroke kraziness!)

Did you miss the point about *knot* ?
If one finds a material in which the thief knot works well,
what is the point to decrying its use there --perhaps by urging
further searching ...-- where is suited?

Quote
The single most important factor is the structure, the geometry of the knot.

It's not so simple.  Nor is friction the sole determinant of behavior
--vs. flexibility, cross-section stability, & springyness, e.g..

That is why I said "usual"(sic), "non elastic"(sic) material.

Hmmm, now X. becomes aware of material, though he seems
to want it only with "general" characteristics, not liable to unsettle
a *structured* perspective!

Quote
And this relation is going [NOT (you meant to say!)] to be reversed with any other material Z,
because it is the structure of the knot that is the single most important factor that dictates security, ...

And this conjecture about the inviolability of the significance of structure
is just that, and something I think I've seen hints of contradiction for.

Well, "I" have not ! And this is exactly what I have said, again and again, repeatedly :

... so much so as to ignore that I have pointed to one
case where security was reversed.  Or that it seems to have
been (security vs. shaking loose), which is enough for me to
put doubt into such a broad generalization, knowing how
diverse knottable media is.

Xarax, you have gone gung-ho here (maybe "oauauao", whatever
that new utterance is, too) over something that is conjecture on
your part, and not wise, in light of how diverse knottable media
is.  Here is a simple case that I hope sheds some light on the
variability of *security*:
bowlines have been --and continue to be-- used for ages
in maritime use, without further precaution, for the most part;
their users laugh at suggestions that the knot will slip;
the knots can hold through to rupture, in testing;

but rockclimbers know to beware the bowline, because of
some well-publicized cases where it has slipped in the
sense of coming loose.

Now, I submit that if one put a shake test on a bowline
tied in some flexible, 12-strand HMPE (non-coated [and by this
I mean "not coated with urethane or other like treatment",
and NOT "unsheathed" --but, yes, it IS unsheathed/pure]),
the knot will do better than one tied in springy slick PP, or
smooth-slick-&-firmish kernmantle;
BUT, put to the test machine (same knots exactly!),
the not-shaken-loose(now) latter knots (*knots* as knotted
material) will hold to break,
whereas that in HMPE will slip out, spill.

Yes, this is different than your Knot-A & Knot-B scenario;
but it shows the vagaries of knot behavior, and in has specific
aptness to the OP who wants *security*, entirely.

Please don't read me as dismissing structure as important.
But we might come to --with improved, intelligent testing
and demonstration thereof of knot behavior across materials--
see some structures as preferable where materials are very
flexible, say, and other structures good in different cases
(and be less likely to try to find some universally *best*
structure).


--dl*
====

xarax

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Re: A noose-like hitch that can be untied after hard strain
« Reply #29 on: February 13, 2012, 10:28:28 AM »
(There are no apostrophes in X's land of keystroke kraziness!)

For a reply to this stroke of genius (or else  :)), see (1)

1) http://igkt.net/sm/index.php?topic=3784.msg22146#msg22146
This is not a knot.