This is how I see the world:
Upside-down, from DownUnder!
The notional concept a right Vs wrong (or strong Vs weak) method of tying
a Figure 8 connective eye knot (#1047) is more likely than not,
only for the realm of discussion and debate among knotting theoreticians.
There is no real-world practical application of the 'strong form' over the 'weak form'
of #1047 within climbing or rescue contexts.
As I have pointed out many times before, strength is irrelevant in climbing/rescue applications.
It might be relevant for the purpose of setting "high lines"
which will require high tension for staying closer to straight,
and if not needing *strength* of the knot for this, might need
preferable/easier untying of one vs. other versions.
Perhaps the "ease of untying" difference (is there...?) will
have (some) significance in other uses, too.
The 'ideal' knot is one that is secure and stable and doesn't jam.
Also (preferably) it can withstand loading from multiple directions (eg refer to 'wrap 3 pull 2' anchoring knot).
There might be some seen difference in
offset loading (aka "EDK")
between the forms, although there is now some advice to
avoid the
offset fig.8 in favor of the simpler and more
widely used
offset waterknot (overhand) already.
((
BTW/FYI : Clyde Soles introduced the name "offset overhand"
which I liked --esp. the "
offset" adjective, which is spot on
(such knots are NOT "flat"!)--, but I opted to go for "water knot"
as the least confusing name (not liking "ring bend" as this
knot doesn't *bend* to a ring; I no longer support Ashley's
desire to hijack "bend" for "end-2-end", as history used it
otherwise --a point that C.L. Day made).
Similarly, as an essential aspect of webbing/tape IS its
"flat"ness, I do not like "flat" vs. "tubular" for tape types
but "
solid" vice "flat" --again, to the point!)
))
A person can tie #1047 deliberately 'messy' - and it will still hold a falling climber.
NB : "messy" is a non-particular description! One messy
orientation and another one might be quite different in effect?!
NB-2 : "properly dressed" is sometimes advised, but is there
EVER any given specification to what this is, actually?!
(All I've seen is the further verbal guidance to avoid parts
"crossing over" each other, which is subject to interpretation.)
This goes to X.'s point about authors not having real knowledge
(in the No Author is Wrong challenge), but just parroting what
they've heard elsewhere!
TO THE POINTS WE DEBATE ("strong"/inner vs. "weak"/outer versions):
NB-3 : TWO sources --viz., CMC (3rd; & 4th?) & Dave Richards-- have
thought to test "
tied in the bight & "follow through" *versions* of the
fig.8 eyeknot !!! I believe that Agent_Smith has remarked at this,
as have I --that the knots (presumed to have been "dressed & set"
to whatever believed ideal the particular knot tester had, AND that
it was specific enough...-- that the knots cannot care about their
tying method : they are the same entanglement receiving force.
THIS IS A FAR LESS DIFFERENT CIRCUMSTANCE THAN "STRONG/WEAK"!!
And yet it was tested !!
It just would NOT occur to me to do this,
UNLESS
I had done some
in-the-field, practical, actual-factual empirical
research that revealed that there was a difference in
orientation (or a statistically significant bias) of result obtained
from the different tying methods. THEN, well, yes, test these
different *knots* !! But neither CMC nor D.R. give such thinking;
they just indicate tying method, for which there is no evidence
of differing results (and general guidance that results should be =) !!
(I find this amazing, appalling. Mostly, also, w/o remark or critique.)
... a 'dressed' form of #1047 ... behaves more predictably under load
and holds its form
... is in a vague way at least better specified
than the open-ended, who-knows-what, "messy" result.
Knotting theorists have long tried to pinpoint with precision the locality of knot rupture but to date it has eluded them. This in my view might be a prime driver for the subject matter of this thread.
Whoa, this K.T. has made some small effort to learn this,
and --speaking of "thread"-- has introduced the technique
of sewing into test specimens colored threads to mark the
locations at pertinent points of interest. (See attached!)
I think that I've seen clearly enough that it is the INNER
yarns/strand(s) of a part in a bend that by compression
break, and not the outer, presumed-more-stretched parts,
which was a commonly voiced theory (i.e., outer breakage).
One might see this in following the twist of laid rope where
one of three strands breaks, others stretch out intact, and
see that it leads to concave side of curve at rupture,
not the convex/outer side.
I'll attach two (elsewhere here previously posted?) pics
of such thread-marked tested knots --the ruptured one,
and the survivor eyeknot showing where the marked
spots were (likely) at point of rupture. (I'm thinking
that these qualify me for a Nobel Prize in Knotting.)
From a purely theoretical standpoint, narrowing down the precise nature of rope rupture in tensile pull-to-failure tests is interesting and helps us to learn more about the science of knotting. Altering the path of a curve/turn of rope within a knot might yield a few % points difference in strength - and this is exciting for theoreticians as it moves the science a notch forward.
But only if the testing comes with specifics of geometry
and so on, not merely --and as is common--
knot namesand test data, a not showing the pre-loaded geometry,
and the near-rupture geometry, and so on.
(I feel a lock on the Nobel!)
If someone posted news of a discovery of a new knot climbing tie-in knot that is:
[ ] easy to tie - ('easy' is based on an inexperienced climber attempting to tie the knot)
[ ] is secure
[ ] is stable
[ ] is easy to untie after high loading event (eg a 100 kg+ falling climber - who generates significant impact force)
... would be more interesting than pure theory about 'strong' Vs 'weak' form of #1047 (more interesting to me personally)
That is spelled 'L e h m a n 8' (and spells "Nobel") !
In the attached photos of tested knots (in Dyneema, 5/16" 12-strand),
a pink thread marked a point I thought likely for rupture, and a gold
thread led or trailed this, anticipating movement in tightening
--i.e., that the gold might move for rupture where the pink had been.
Some white threads are at entry points, to show how much
material is drawn out during tightening/compression (this is
quite INelastic cordage).
The
reverse fig.9 eyeknot was chosen over the common
one with this thinking : common one might benefit,
in usual
material/fibre, from some gripping effect, but in HMPE
the material is too slick for this,
so go instead for a form that seems to give a broader curve.
Note that the break point looks to be rather well around
this curve, maybe beyond the U-turn point, where the S.Part
bears against entering eye legs!?
In these cases, it will take more scrutiny to conjecture about
concave/convex side of curve vis-a-vis break point.
--dl*
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