*** Auto-Prussik Knot ***

Message : #21712651    From: Paul Lydon
Address : paul@palydon.demon.co.uk
Group   : Usenet.rec.climbing
Subject : Re: Rapelling Technique
Org.  : home in Brassington, Derbyshire, UK

In article tjs@brahms.udel.edu "Tim Schafstall" writes:

> >One more often unused technique to increase the safety of the rapell:
> >
> >Back up the belay/rapell device with a prusik attached to the harness.
> >Pull the prusik along with one hand as you rap.  Also good as a temporary
> >brake if you need to stop along the way.  Anyone agree?
>
> Yes, a backup prussik is an unused technique.
>
> Speaking as a caver, I know of no one who uses a prussik knot for a backup
> belay.  The reasons are:
>
>        1)  They create more problems than they correct, especially
>            if accidentally loaded (i.e. they are a bitch to unload)
>
>        2)  If you are out of control on rappel, you are more likely
>            to grip the prussik tighter than to let it go.
>
> There are other reasons, but these are the big two as far as cavers are
> concerned.  Perhaps climbers have a differing view....
>
> Tim S.

I have found that if you use what is often called an 'autolock' knot
(similar to Klemheist), which is formed by wrapping a prussik loop
around the rope (BELOW the descending device), say 4 or 5 times,
clipping a carabiner through both ends of the loop and then clipping the
carabiner to the harness leg-loop on the same side as the 'braking'
hand, this is very effective.

Hold the knot in your 'braking' hand and slide it down the rope. Let go
the knot, or relax your grip and it will lock off the rope below the
descending device. To continue simply slide the knot down the rope and
it will release. A prussik knot does the same job - but is very
difficult to undoe if loaded a lot.

Cavers usually use different descending devices when abseiling which
take into account the fact that the rope is often tied into bolts. I use
a Petzl 'Stop' which will only move while a large handle is depressed
and locks on release.

--
*******************************
* Paul Lydon                  *
* Brassington, Derbyshire, UK *
* paul@palydon.demon.co.uk    *
*******************************