New update has been uploaded...
It concerns me that you posit stability --as though something
needing minding-- to the trio of extreme/center orientations
of the
offset water knot :: IMO, we just don't know enough
about their influence; but we do want to make their existence
known!
(There might be something to the conjecture (mine,
on this writing) that by having two "pry-up" "arcs" in the
SParts, the mid-range orientation raises greatest vulnerability
to capsizing; the orientations with a "loop" (+ arc in opp.SPart,
of course) have this bit of resistance !?
)
(FYI, I go further in dressing & setting the
owc : I pull
the choking line's tail *up into* the expected curve of the
SParts, anticipating their draw on this important part by
setting it most in opposition/distance from where the draw
will rotate it --so, e.g., one would see NO slit of gap/space
at knot nub center as one can see in your mid-range image.
)
Dan, my response to duplication of #1410 (to create a 'backup')
is that the primary #1410 knot is under maximal load. However, the
duplicate #1410 is not under maximum tension. The primary #1410
always has a tendency to self-align and translate over an edge. My
concern is that the tailing duplicate #1410 backup is increasing the
overall footprint and could conceivably cause issues downstream
(it does not self-align in the same manner as the primary knot).
"Leaving long tails" --which is the commonly given advice--
can invite my challenge : "Rather, DO something with them
(with all that "left" material)!" Because the common advice
is given in anticipation of some sort of capsizing/"rolling",
and I'm not comfortable with asserting that that will be limited
and so within some unknown though believed length of tails.
In any case, one can imagine somehow that dangling tails
get slipped into mischief? --never heard of such, though.
I don't think that the knotted bulk (vs plain length of ropes)
invites anything bad; it won't need to "self-align", as it won't
be so oriented to snag (as the aligned base knot will lead to
the back-up from its top, away from edge/surface).
Since you appear to be a strong advocate for duplicating #1410,
Maybe esp. in cases of stiff ropes and mitten'd hands,
though perhaps in such an alpine situation there'd be
less advantage to offset aspects!?
(Tom Moyer also suggested by his limited testing that
the
grapevine can be poorly tied but yet work;
tensioning the knot IS presumed, at least. Forming an
offset water knot and then with tails OR with SParts
forming a 2nd, and setting to reasonable tightness & closeness
I'm surmising is a measure surer than tying many things;
the
grapevine's ability to be tied in halves (each rope
strangle-ing the other) remotely/clearly apart
(un-interfering; not requiring intricate interlacing)
is a good attribute similarly.
)
I am reaching the limits of what a photo can convey - camera angles are tricky to get right. Any further comments?
I was looking at some of those top-/tails-down views
and thinking "my, this can show how a thicker rope in the
choking position (bad) has a lot of material half way to
coming out around the thinner --which if in the choking
position might not be visible from under its thicker twin!?
- - - - -
Hmmm, some of us should perhaps go out into the wilds
and do a batch of drop-tests --can we muster up some
weight about 50-100# (noting as you do that the knot
is usually taking half a climber+pack's weight) !?
--do some shock-loading short drops;
--do some mild, like-during-abseil "bounces" to see if
anything worrisome appears to be happening (under
this relatively light, but cyclical loading)!?
--in a mixture of ropes (not only likely offset-knot users),
and tying goodness.
Maybe a quick-&-dirty batch of tests so done would at least
point to some orientation as indeed looking worse, as taking
a step farther from desired snugness & so on!?
Thanks,
--dl*
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