I don’t have any experience with the gallows knot, but if it jams you might have your explanation there.
Fishing knots are designed to be tied in monofilament lines. The lines are cheap, you often have a lot of it and it doesn’t matter if it jams and you have to cut the line, as long as the knot won’t work loose.
Be careful about what you understand (and how you came to
do so).
I recall an old test report done in nylon hawsers in which bowlines
were interlocked simply and then united as with a square knot (but
all ends --the legs of bowline eyes-- loaded : and the point of the
testing was that the latter structure was stronger --which seems to
imply that the break came not at the bowlines but at their joining,
or did so in the weaker case. But it could be that (a) the joining
structure influenced bowline strength, or (b) the variation was
not statistically significant and the testers not clever re this.
(Break points are seldom reported, alas.)
Then, currently, there’s a YouTube video of the rupture of HMPE
1/8" ? line with eyes of splices run through loops of cordage,
not all so much thicker (doubled, in one case, I think). Well,
although HMPE suffers much strength loss in knotting, and so
you’d think would/could be affected by a hard bend such as
being reeved through a small soft eye, the breaks didn’t occur
there. Hmmmm!?
AND if the diameter spreads the eye widely, it increased the load
on the eye-legs and what the deliver into the knot, as well as
the exact geometry/angles of such parts; that could affect the
behavior.
In a test of the Scaffold knot (well, actually a Strangle noose,
one turn fewer) tied in 8mm Bluewater II low-elongation kernmantle
rope around a 'biner, the rope broke --at a high load-- in the NOOSE’s
S.Part (not the knot’s) at the point of entry, where the strangle was,
er, strangling it. --so the turn around the object didn’t make the
strength determination here; in thicker ropes, I’m not sure that
the same thing occurs (and have a vague tingling that some
testing of arborist cordage around a half-inch pin (about 1:1
nominal ratio (rope will compress)) there was evidence that the
knot broke --I’m not certain re this, though).
Anglers work with slippery fine material and so often employ knots
with many turns; you’ll see notes about some of these knots to
use fewer turns for thicker angling material, too.
Is the gripping force of the noose directly proportional to the number of its wraps/coils ?
I have tied 3 “mirror” nooses ,( I call them “8-nooses” ), with 1, 2 and 4 complete wraps, starting from a single, double and quadruple strangle knot. (See attached pictures), I have measured how easily one can pull the two free ends (placed horizontally in the pictures frames), or the two loops, apart from each other. My answer to the question posed above is : Not even close ! Having more wraps in our noose does not make it grip the loop leg(s) much more than having fewer of them.
However, the funny thing is that we had to wait some thousand years to discover a noose mechanism, even simpler than the strangle ( in fact, the most simple there can be), that blocks the line completely : the Gleipnir…
A morose use of our beloved knotting.
From what little I know of the hangman’s noose/collar the wraps do add friction not necessarily to make it grip much in the keeping open, but to resist the opening thereafter the fall.
More to the point is that it allows positioning of the coils that are there to add bulk to do the job of severe spine deformation.
The encircling of the neck for the reduction of life force could otherwise be done with simpler means.
I vote enough of this has been written about. IMHO
SS
I am sorry, SS369, that my (bad) sense of humour was so annoying. I edited my previous post so it does not contain any phrases that can be in disaccordance with our beloved field of knotting.
That 8-noose seems to make a good handcuff knot, better than the so-called “Handcuff knot” (ABOK #1140).
Dan_Lehman wrote: “No, what Ashley means --reading with the arrowed tying, dressing movement–, is that from the differently formed start one rotates the top turn around until the prior structure is achieved (which is something that is supposed to happen with the Uni on setting, in monofil).”<<
I’m puzzled to think of ABOK#1121 as merely an alternate way of tying ABOK#1120, a feat you said is “hard to achieve”, and I found to be impossible on my climbing rope (frankly, I don’t see how it is done). (Ashley did not restrict his remark to fishing or monofil). Perhaps Ashley was being witty in seeing a possibility of conversion and calling them the “same”. In any case, in unconverted practice the two knots are treated separately, and can be compared to each other with regard to strength – which was my original question.
Here is my drawing of the two nooses, which might make it easier to see how differently each handles loading stress.
Dan_Lehman wrote: “…I recall an old test report…”<<
Are you saying that practical experience so far has not produced any reliable generalizations here? Or even stronger, suggesting that properly controlled experiments with a variety of ropes, knots and object diameters, are unlikely to confirm anything significant on this head?
One of my difficulties is configuring an idea about fixed loops for slip loops.
The idea about a Fixed Loop is that, although both the knot and the loop bear the full load, each leg of the loop bears only about half the load, so the break is much less likely to occur at the loop than it is at the knot. Is this true (and, if so, the main reason why object-diameter is not likely to be significant here)?
This does not seem true of Slip Loop hitches because, although a Slip Loop knot is located at the end of the loop, the loop is not tied-off and equalizing in the same way as fixed loops. The whole (or almost whole) load flows around the object to the knot. So where is the “first curve” (the differential stress leading to breakage) located in Slip Loop hitches? Where the rope first curves around the object (and so the diameter of the object is significant)? Or does does the loop at first ‘equalize’ to pass the load along to the knot, and so, the first curve weakness is in the knot? Or does it depend on which first curve (around the object or in the knot) is smallest? Where do Slip Loops usually break?
Thank you for your comments.
I revisited the Snare Noose (ABOK #1118). This knot may be the simplest noose that doesn’t jam or capsize easily. In contrast, a Buntline and a Halter are simple but tend to be difficult to untie without a slip. A Figure 8 Noose (ABOK #1116) is a half turn simpler than a Snare Noose but tends to jam and/or capsize.
The Snare Noose has a niche where you don’t want to tie a slip or don’t want to tie additional wraps like in the Gallows Noose (ABOK#1121) or the Scaffold Noose (ABOK#1120).