[2nd half]-:
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About that Fig.8 loopknot (and bend): your advice to
ensure that the two strands lie neatly, and parallel beside each other with no twists round each other. Finally, check that there are two parallel turns at each part of the knot.
I've read elsewhere, and it's naively wrong. The what I call
flat orientation
of the knot (not to be confused with some sense of "flat" meaning "offset")
is impossible to maintain in material of a round cross section. You've violated
a piece of advice/direction(!) of some works to ensure that the SPart takes the "outer"
curve (you have the end doing this in the loopknot). But that advice is flat like
the image. Please see my drawing on Dan Britton's "Knot Knowledge" site.
www.iland.net/~jbritton/KnotPhotoContributions.htmlUpdated Link > www.pssurvival.com/PS/Knots/Knot_Knowledge_Photo_Illustrations_2004.pdfThe assertion re strength comes from Rob Chisnall's ORCAssoc. Safety Manual,
and is contradicted by Lyon Equipment's testing. Strength data sadly comes in
all over the map, so to speak, with little or no explanation of knot orientation, etc.,
to help make sense of it. But let's just call what I show the "perfect" form,
meaning "perfectly symmetric". (Yeah, so is that bogus "flat" form, but it's not
maintainable under tension; one can find some other symmetric forms that are.)
And, yes, you should find a few other loopknots of interest here as well.
As for "For safety a longer end is essential", I guess we can toss that misclaim into
PABPRES's disclaimer bucket. In fact, it isn't, unless perhaps one is in the habit of making
loose knots. Even then, if the end slips out of the last tuck, you're presented not
with spilling but Ashley's #1057 or 1058 (or some who-knows-what if you've tied
an *Imperfect* form). Some rationalize the purpose of the stopper knot to ensure
length of end. "You can't be too safe", and all that. For climbing, or any other
situation with fall potential, yeah, make it complete--for a snag on some protusion
to
ring-load the eye would capsize & spill the briefer knots; it could flype and
spill a full Fig.8, too (as has been demonstrated for the Offset Fig.8 bend), but there
one has a better fighting chance (esp. w/the back-up Strangle).
(It would be good to show this back-up knot TIGHT: to my great surprise, one
of the rec.climbing regulars (Dawn Alguard, who maintains a site of collected climbing
wisdom) admitted to having her back-up come untied!! It shouldn't.
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Re the Bowline ("Blw"): "two loops engage ..." => "a loop & bight are united".
--using those traditional definitions (which are oft' given but generally ignored).
The Bwl isn't so "identical", but
similar, as the Bwl loads both ends of the
"loop" (and one of the bight; the Becket H. is the reverse). I know what you
mean, but it's helpful to point out some difference, for folks are prone to make
bad deductions based on the notion of identicalness--the Bwl is more secure
on account of its loading, and assumes a different geometry.
That red-roped Yosemite Bwl irks me; for there are better ways, and that one has
some risk of deformation in tying, and isn't so good in stiffer rope.
For a decent secure-when-slack variation, bring the end around as you do
but cross over BOTH legs of the eye, then u-turn w/end (horizontally) and
bring it back under both legs, tucking it out between the R leg of the eye
and the parallel parts there (side of main "loop" and first turn of end).
Call it a doubly tucked Half-Hitch; it sufficiently binds the SPart to prevent
loosening when slack in many situations (such as climbing, where Bwl.s have
been known to loosen and even come undone).
The Dbl.Bwl (aka Round-turn Bwl) would be a good variant to show, as it's pretty
well know & appreciated.
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re Rolling Hitch:
Ah, geesh. There's the spelling issue noted elsewhere ('Bachmann', 'Klem').
And there there is a load of stuff parroted from knots books that is too far from
the mark for comfort. Slippage in friction hitches comes and goes with the vast
number of combinations of several factors (relative dia., coeff.s of friction, load,
construction, elasticity, setting). Frankly, I wouldn't trust this or the close relative
which you dismiss (though it grips better in some cases) in many cases w/o adding
a stopper--that finishing HHitch just isn't so secure, often.
You note that Ashley only once pictures the version you stress? Hmmm.
Friction hitches come in many varieties--some load mainly the top of a coil
(like what you dismiss, and the Hedden H.), some the bottom (Klemheist,
Bachmann (though Franz has many the other way round)). Arborists sometimes
use your dismissed version, with a full roundturn finish, upside-down (so,
loading the bottom of the effective coil). (The Prusik, I should point out,
largely loads the bottom of its ("upper") coil, as until that grips it will push and
release the near-to-load/"bottom" coil!) Your remark "would a climber reallly tie ..."
can be answered pretty matter of factly that a climber doesn't use THIS hitch
(seems that Carl Prusik's knot got them going, although the Rolling H. in its
various forms was around to be known).
For some pages w/many friction h.s, check out Gary Storrick's & TreeSpyder's sites:
storrick.cnchost.com/VerticalDevicesPage/Ascender/AscenderKnots.html
www.mytreelessons.com/www.mytreelessons.com/friction%20hitch-work%20in%20progress.htm[NOW, BACK TO FINISH THE PART 1 OF THIS MSG.! :-]
