Craig wrote:
> The lanyard on the Swiss seat is made from flat cord, tied in a loop
> with a square knot ...
DO NOT - I REPEAT DO NOT - EVER USE A SQUARE NOT to connect two end of rope
together unless you want (and are safe with) its ability to untie instantly.
Tied with a square knot, the Swiss seat should NEVER be the only thing holding
you up.
In the days of tall ships, sailors used the square knot (aka reef not) to tie
up
sails in a high wind (note that in this application, the knot is under
continuous
tension and is pressed continuously against the sail, and dozens of them
are used along the sail, so one failing is harmless). When the wind lessened
and
it was time to let out the sails, untieing was done by pulling on one end
to straighten one of the U's of the square knot, then simply sliding the
rest of the knot (which has been changed into two loops around the now straight
part) off the end. This is hard to convey in words, but amazingly easy to
do in reality!
In any use with varying stresses on a square knot, it has a tendency to do the
above on its own at unpredictable times! It can be stabilized by putting
lashings around the loose ends to the adjacent rope - but that also makes it
a semi-permanent knot.
A sheet bend is a simple and stable bend better suited to the task.
Climbers seem to prefer the double figure 8 bend - it's work to tie and
really hard to untie, but virtually nuke-proof as far as coming undone
accidentally.
Darrel KI6VY
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