"Heikki" wrote in message
...

But I saw a bowline failure last weekend! My knife lanyard is
tied with a
duobled figure-8 knot to the knife, and the other end is left
straight.
When rigging down our ship, I tied the other end to a loop in my
pocket
with a bowline. I kept the knife in my jacket pocket (folded) on
my right
side, and lanyard was tied to an upper pocket on the left. When
ever I
needed the knife, I could just grab the lanyard and yank it out
of the
pocket. This produced a load pattern with the line slack most of
the time,
with some hard pulls in between. After about two hours I
suddenly realised
that the bowline had come undone. The line was regular white
flag line,
double-braided, about 3mm thick.

I suffered that failure regularly too, and stopped using bowlines
in light line for attaching knives/marline spikes etc, switching
instead to round turn and (3) half hitches. Critical factors were
that the flag line was very smooth - even slippery - and
relatively stiff for its diameter, so tended not to jam up.

Never had a failure in heavy line though, even when the stress
cycle was similar (on a secondary bow line made up to a quay in
surging conditions).

Which all goes to confirm the importance of a particular type of
line and stress cycle when assessing which knot to use. There is
no 'universal' knot.
--
JimB
http://www.jimbaerselman.f2s.com/
Compares the cruise areas of Europe