My interest in the Zeppelin Bend stems from explorations of failed bowlines.
!? How have you explored failed
bowlines ?
bitter ends,
Let's kill the "bitter" mis-use (it should refer to bitts);
"end" or, better?, "tail" will suffice, nicely.
As for (rock)climbers knowing about the
bowline,that is demonstrably not true, for all --hence some
of the issues your explorations might've found.
But awareness is growing (one hopes).
In looking at Ashley, Butterfly, Hunters (aka Rigger's) and Zeppelin Bends, I am impressed that whereas the first and third typically can jam, and the butterfly bend can be sometimes shaken free, the Zeppelin excels in all these areas.
The issue about the first "typically can jam" I hope
I've put to rest in a thread here, about 6 months ago?
There are various ways to dress the knot --which can
be varied per need--, including one dressing in which
there is no jamming. I've put this to some testing
in normal materials. And
SmitHunter's bend has a
simple version that pretty well resists jamming (just
cross the tails ...). Oh, by "Ashley", we should append
a qualifier to that --"1452". He also introduced #1408
and #1425, which are jam resistant (the first being
what I regard as a symmetric "butterfly").
As to your conjecture about opposed tails giving some
benefit to security, I don't buy it so much. There are
cases where tails move opposite each other, as well as
some cases where there is apparently some *assistance*
of slippage by ends moving together. Here, I think that
the security comes from a hard nip relative to the forces
on the tails (irrespective of their direction of pull). And
the slack-security (something Xarax seems to ignore,
as a quality aspect) comes from the particular angle at
which the tails reach their final tucks (so that they just
aren't so pulled towards loosening?!).
All that said, there are some quite simple
bowline extensions
that do well to add security, maybe even a bump of strength
--putting a 3rd or 4th diameter in the central nipping loop--,
so that rope users can meet their needs with that knot.
--dl*
====