Yes, in its usual (i.e. book presentation) form, the Sheetbend is acknowledged as an 'end-2-end' knot.
But is this the only conformance that we will accept this structure as being the Sheetbend?
Rather, it is so
defined.
For example, will you permit the name if I now bend two cords,
but instead of e-2-e, I make an end-2-midline bend?
The knot still handles 100% of the loading, it simply has a 'very' long WE.
You make a mistake, well, presumption here that comes
out later :: simply, there are two ways to, um, *sheetbend*
this added line --i.e., to U-part it into a turn of the other
line, or to turn it into the other line's bight! (Just as we
should remark that to the extent that the
bowline is
the eye-knot correspondent to the
sheet bend there
remains a
2nd corresondent with U & loop constructs
in the opposite pieces of knotting!
Now, your millimeter-by-microgram moving from tail
to something w/tension is, yes, understood as pressing
the question about a black-&-white definition boundary.
Let me remind you that you're writing to one who has
ventured a cookie-cutter-circle view of a knotted *tangle*
where what goes on outside of there is immaterial to the
definitions of knot classes and so the "eye knot" might
not have an eye ! --just in your way of joining a 2nd
line into the first and loading it ... qua *eye knot* : one
end A (of piece A-B) opposing end B & end 1 (of piece 1-2),
end 2 being unloaded.
For an in-practice actual eye, the normal case is pretty
much equal tension on the two legs; some movement
of a boat e.g. with friction on a pile can alter this.
Now, in you example where there is no eye, there is
not sure/natural balance of tensions,
and the definitional challenge rises.
Rather than thinking here "What is
right?" we should
ease into "What (definition/nomenclature) will
best serve us?!
And I don't know the answer.
We might define canonical classes & their loading profiles
and do much work on these;
and also acknowledge --esp. if there are good, actual-factual
cases to address, not mere What ifs from an Ivory Tower--
the rough edges & compromised states in between.
Because the pure *eye knot* that you have tied in with
could somehow snag and become an e-2-e knot, like
it or not! --not while you're defining ..., but FALLING !!
But for now, no, a "sheet bend" is a known and well-enough
articulated e-2-e knot; taking that structure into other
waters will be to whatever extent going outside that
definition, and I don't think that the name should follow
on this chase.
--dl*
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