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Topic Date User

Prussic while abseiling - above or below device? 1-Aug-2012 At 11:53:08 AM muki

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On 1/08/2012 IdratherbeclimbingM9 wrote:

>A bar tack in the end of a cinching strap has a different application
>to bar tacks sewing rated portions of a harness together though...
>☺
no doubt it does, but it's still a bar tack.

>Muki also wrote;
>>this covers me in many situations, unconciousness, lost control, no more
>rope, or damaged rope, and with knots in the ends, also uneven rapel on
>two different diameters or one of the two ropes bieng shorter, as when
>any of the above happen then the belay device is the first to fail and
>my back up riding above is then allowed to take over
>
>All good examples of why having a backup is often a good idea!
>
>As an aside, I have 'tested by practice for myself' the above-device prussik
>backup system in a controlled environment (read just off ground level out
>of a gum tree in the back yard), with unequal diameter ropes / unequal
>length ropes, and non tied off rope ends; ... & I found that it is actually
>possible to abseil off the rope (or one strand of it), without it fully
>engaging! The prussik locked off but not quickly enough due rope slippage
>under tension, to prevent the ensuing 'fall'.
>~> Tying stopper knot/s in ends of abseil ropes is a good idea!!
>☺
I would say stoppers are crucial for differing diameters on double rope rapells !
Due to differential slipage on decent, this could lead to both one rope ending earlier than the other, and when that happens most prusics fail as the two ropes then travel in opposite directions.