Topic - Abseiling on single rope with pull cord
| by - Sean_J on - 05 Dec 2012
|Say i've got a 60m single rope, 10mm diameter so not exactly super-skinny. I want to make a series of full-length abseils on the rope, and i'm planning on using a pull cord to get the rope back. |
Question 1) What's a sensible diameter of cord to use? I was thinking 5mm, but i'm tempted by 4mm which is almost half the weight (11g/m instead of 20g/m). Breaking strains are 580kg/330kg for each cord diameter. As for length, something like 65m would probably be a good idea I assume (it might be that an ab station is reached on rope stretch, and the 60m single will stretch a bit under its own weight anyway).
Question 2) Where the 10mm rope is threaded through the top anchor, it is normally then tied with a fig-8 bight and a locking krab used to clip the bight back onto the downward strand, thus securing the single rope (and the pull cord is then tied to the fig-8 bight for retrieval). I'm thinking about the screwgate getting cross-loaded on the anchor(or rather, loaded in a direction perpendicular to the plane of the krab - think getting bent in half), maybe using a rap ring (30mm diameter solid aluminium round bar toroid, looks like a lower-off ring) would be safer - but more faff to rethread the next ab station as it can't be unclipped. I'm considering a maillon as a good method as well, but possibly also prone to cross loading. Any more thoughts on rap ring vs. screwgate vs. maillon? Just trying to figure out a safe and efficient system. And don't mention any fifi hook/skyhook method, not interested.
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