Page 177 - Geoffrey Budworth, Jason Dalton "The Little Book of Incredibly Useful Knots"

Penberthy knot

Devised by Larry Penberthy and Dick Mitchell in about 1969, this is also known as the caver’s

helical knot. It is one of a number of sliding friction knots that evolved prior to the advent of
mechanical devices, and has the advantage that—unlike some others—it is not prone to
jamming.

Take a length of accessory cord and wrap a number of spiral turns around the main climbing rope

(1, 2). How many turns will depend on the user’s weight: too few and it will slip, but too many will
make it difficult to shift. Secure them with a bowline (see page 63) (3, 4, 5), adjusting the knot to
tighten the spiral turns around the rope (6). As with the turns, and depending again on the load,
too much or too little slack within those turns will render the knot hard to move or will allow it to
slip.