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Isc rope grab help


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4 hours ago, openspaceman said:

8mm, 9.5mm or 10mm?


Why double fishermans over a figure of eight or bowline?

There is a requirement by the HSE [or whoever] that when attaching cords, ropes, whatever to a carabiner that the knot binds down on the carabiner and cannot move about [thus preventing the carabiner being loaded in the wrong axis]



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20 hours ago, openspaceman said:

8mm, 9.5mm or 10mm?


Why double fishermans over a figure of eight or bowline?

Also functionally the double fisherman's is the most compact, secure without a backup stopper, and cinched down onto the crab is not adding slack to your system so you drop less after pulling the slack out. Or simple answer that's the way I was taught. If you're making prussic loops then double fisherman's is secure and I believe the only approved knot.


Friction cord diameter is a trade-off on usability and grip as 8mm is plenty thick enough to take the weight. Thicker is a bit easier to hold, may be smoother, but in general you want the cord thinner than the main rope else the knots don't sit evenly.


So I climb on 12.7 rope because I find it easier to grip, with a 10mm friction cord, works nicely. Some of the modern ropes are down to 11mm diameter, would be better with the thinner cord. Can also be a factor on the space for the knots, I have 8mm on my lanyard with a pinto pulley.


In the end there are too many combinations possible, some work better than others with different knots and you just need to try a few. This is either fantastic because you can find a lovely smooth combination that you can tune for your own weight and style, or a complete pain in the backside, depending on how you look at it.

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