Peru2000 - Pusik system
The really amazing thing about tying Pusiks is how much cord
you need! In 5mm cord a double fisherman's knot with 1.5" tails
(a minimum) takes 12" of rope, in 6mm cord it is about 14".
A good reference is `Glacier Travel and Crevasse Rescue' by
Andy Selter (pub. 1990, The Mountaineers, ISBN 0-89886-250-7).
Basic requirement is two Pusik loops; I think it is best to
have one shot one (harness to rope) and one long one (feet to
rope). To get freedom of movement for clambering over lips
it seems best to have separate cords to each feet (like a Texas
System though in caving that usually means separate cords
and separate ascenders for each foot). The long Pusik is
placed on the rope below the short Pusik and the climbing
motion is sit-stand. On 9mm (or 8.6mm) rope
I prefer 5mm cord over 6mm cord and find that 3 turns in the
Pusik is good.
Short Pusik
16" length (32" circumference) seems to be a minimum, closer to
20" length is probably better. To make a 20" length Pusik
loop out of 5mm cord tied with a double fisherman's knot
requires: 20"+20"+12"(knot)=52"=4'4".
Long Pusik
The best length for this depends on the length of the short
Pusik and the length of the user's legs. The compromise is
between having it long enough so that you don't have to bend down
too low to move the Pusik and short enough so that the Pusik
doesn't bump into the short Pusik and restrict the step size
(big steps seem to be the best approach when climbing with
knots as opposed to mechanical ascenders).
So, for a person with 35" inside leg, a 20" long top Pusik,
and wearing plastic boots I came up with:
The approximate length of 5mm cord required to tie this is:
2x10"+9"(doubled fig8)+2x(37"+10"(loop knot))=123"=10'3"
In an attempt to generalize, I suggest a general formula:
2x10"+9"(doubled fig8)+2x(inseam+shortPusikLength-8")
Of course the ideal length is also sensitive to harness attachment,
boot size and preferred technique so I'd add a foot to the length when
buying cord!
Use
- Attach the short Pusik to the rope and clip to harness.
- Attach the 10" loop of the long Pusik to the
rope below the short Pusik loop
- The two small loops on the long ends of the long Pusik are
used to form noose-like foot-loops which cinch around the boots.
If the loops are made short enough so that the knot doesn't easily
fit through then the nooses will stay tied making life easy.
- Sit-stand, alternately moving the Pusik knots.
Weight: about 80g in 5mm cord.
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