I continue to have "database error" problem in posting,
even trying to paste text in small amounts (well, I couldn't
get to plural, as first attempt failed!)
Maybe this will go through, as my prior short "HELP" post did.
I was amazed to see the knot slip, sometimes breaking,
but a few times not; and how distorted it got, seemingly
first on the side with "pretzel"-shaped OH (timber_H-shaped
other half); AND that the #1408 version also slipped, with
some incredible snap-back of tail/eye-leg from a fully nipped
to less-well-nipped position. (Here, I THINK that the dressing
could've been done to make desired positioning more fully
set.)
In one case of a pulled-through Butterfly, with black markings
of exit points and eye center, one can see much abrasion
damage ONLY on the pretzel-OH side (and some bit of
*having-a-rough-time* effect on opposite side); and in
close-up of the abraded side, NB the red marker strands
showing that opposite-handed white strands in some
cases had broken away --so I take this as indication
of torsion effect.
I wonder how rockclimbing rope would fare --if it would
more or less deform as seen in the low-elongation-rope!?
--dl*
====
[NOW, I'll try to MODIFY-in my long text!?]
FAIR WARNING :: TEXT BELOW IS SLIGHTLY "STREAM
OF CONSCIOUSNESS"-LIKE --typing as I selectively viewed
the video, making some adjustments, but ... .
I've at least tried to help the presentation with some BOLD
notes of time & topic.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Thanks much for this alert; inevitable review/comments
follow (a lot to comment on):
Yeah, your paper --visibly your colors, blue rope etc.--
is cited for butterfly history in brief view prior Wikipedia
page (which from time to time has an Agent_Smith aroma).
Interesting :: in a soon-after testing [
5:29] of the knot in
through-loading, the eye nearly pulls all the way OUT !!!
--wow, I didn't think that there was that kind of slippage.
No, it's not easy to see the exact geometry of this case;
in some other, it looks as though the geometry might
be close to that suggested by W&Maggowan (whether
they did so because of perceived knot behavior, or
that they realized per the "twirlyloop" tying method
torsion would favor that geometry, I don't know).
At 06:25 one has a fair look at a seemingly ungainly
geometry of the knot --something's wrong in the
original, methinks :: W&M's geometry won't do this,
will it? (ack, maybe so!)
Then going for EK loading vs. through,
at 7:23ish one has
a half-decent albeit quick... look, and that geometry looks
to be roughly W&M's, though perhaps one could better
dress & set it into the W&M form a bit. ?!
LOADING THE OH-in-Pretzel end, not the minimal Timber H.
one.
ALSO AT 9:04, which is pretty close to W&M; but I think that
one could work parts a bit more *around* to a surer W&M
geometry --that what we see is a little outside of ideal
--but, wait, I'm tying in 6mm kern. before me,
it seems that he's pretty SPOT-ON in geometry --i.e., to the
point that slight adjustments are really beyond what one would
expect any user to indulge (and variety of ropes to get into).
(But in one case it betters an interior-loaded Fig.8 ek!)
BUT DAMN DAMN WTF?
DAMN,
9:08 and first under-load image shows a WTF??? formof knot --really cannot imagine how this came to be,
way lopsided, with an apparent double turn on left side ?!?!?!?
HUH??? (okay, I'm maybe learning but kicking & screaming...!
)
[[at
12:51 one gets a good l00k at butterfly transforming;
yeah, esp. the pretzel side distorts. (I gotta wonder about #1452
in this rope; AND of my discovered same-handed-S.Parts butterfly
--i.e., where, in twirlyflop tying, one gives an extra half-turn twist
to one side (only one side will do this (timber-hitch side, I just checked))
and so S.Parts JOINTLY TWIST tails/eye-legs ever tighter!?
]]
(If indeed it follows from the cited looks-good tying,
then it will be that the PRETZEL OH got way distorted,
the timber-h.-like one (yeah, there's an ABoK # for this)
holding form, looking fine.
my guess :: pretzel collar moves out and gets a sort of
half-wrap of its eye leg root; timber h. collar on its root
side is pulled leftwards (towards pretzel...) and makes
what looks as a double/twin wrap.
AT WHICH POINT THE
EYE SLIPPAGE OUT
IS >>> EQUALLY <<< TO EACH SIDE,
THE EYE-CENTER SHARPIE MARK STILL SMACK IN CENTER
--that's a surprise, but there must be much help in having
twin parts move together, so they do.
DAMAGED LEFT/Pretzel side :: I count 3 red stripes length
of eye leg to center mark; in starting knot, that point is
JUST into nub; it is seriously abraded at the end (and apparently
NOT so on other eye-leg-pulls-through side : recall, eye center
mark stayed centered! So, all that damage for THAT part
flowing around through the Pretzel positions, but not the other!?
at 9:25 in initial long-line views, one can count the red marks
either side of center mark; right/timber-h. side looks to be
a bit *ruffled* maybe, but not w/the obvious abrasion/chafing
on opposite, pretzel side --interesting!?
(could it be that torsion comes into play somehow with bias
to one vs. other end?!)
NB : Look at the RED fibers running unbroken, and more visible
because the white fibres once crossing them (opposite handed)
are busted away :: smells like torsion to me!AHHHHHH, thankfully he explicitly notes . . . : :
WHAT IF BUTTERFLY IS USED QUA END-2-END JOINT !! ?!
"oops" --well, at some serious loads,
but maybe not all so seriously out of bounds that might
say meet with arborist use in haul line, or in small cord
taken to a big job.
Egadz, these guys need to slow down and LOOK & think.
At 17:14 Ryan tries tying the knot by REEVING --using
an end.
Quite to MY liking, what he ties is #1408(which I regard as the *pure* Butterfly as it's symmetric,
same-handed S.Parts working jointly to twist the eye legs).
(His (still in yellow coat) tied-right check concluded "butterfly",
but what he's tied is #1408 and those "wings" are on opp. sides;
but he does get around to noting the #1408 form (and copies
another site's quartet of versions with #1408 --poorly dressed-
leftmost. (
Ryan later mistakenly IDs this as #1452.)
damn it, doesn't give a well-dressed #1408 a test;
the eye *roots* need to be twisted into axial plane
before the knot gets loaded. As it is, they seem to keep
just enough away from that that they can --amazingly--
snap away from further tight twist back to an earlier
state, repeating twisting (all the while the eye collapses).
THEN at 19:17 he wrongly cites #1452 --which is a better
knot than #1408 IMO, and I hope he gets around to testing
THAT, and understanding the intricacies of these knots <sigh>.
At 22:12ff there's brief RING-LOADING, but in tying the
butterfly for this the W&M dressing is lost, replaced by
what is likely the most common, "eye-legs-abutting"
(my term) dressing --left eye rooted into left OH,
right into right (no crossing, as per W&M).
Like some other interlocked OHes, the knots can capsize
. . . into themselves.
22:50ff
Ahhh, here's a test needing explaining :: loading TWO knots
so that each of the two (asymmetric, nb) ways of loading
the butterfly qua eye knot is used. (W/o knowing yet,
I figure timber-h. S.Part'd side wins. --nope)
Okay, my quick (ha!) review ends here.
Thanks again for the heads-up!!
Oh, we should keep in mind that for surer conclusions
about results/behaviors, there will need to be far more
"replicates" of the testing done. But here at least we
see SOME behaviors possible, and IMO surprising!
(Use USED (not abused, but what most users would have) rope,
and also dynamic, yachting, arborist ropes,
and see differences/likenesses !? !)
(-;
[Aha, Modify worked, where New Topic & Reply had "database error"s ?]
