UKC

I've started running recently and I want to start combining the running with some climbing (10m-15m crags). For example I might get the train to Clapham and run to Twisleton Scar. I've been looking into running packs which seem quite good, but my 60m single is far too bulky and heavy to pack.

What I'm thinking is I could buy the 30m Beal Rando (a twin rope), weighing in at just over 1kg and set up the shunt on it. I don't really understand all the maths and forces though.

Do people think it would be safe to use the shunt on two strands of the Rando? If so, and more importantly, what about on one strand?

In reply to kev82:


I think it is best to check on the shunt box, or the PDF on Petzl.com nowadays. As far as I remember they have max-min diameters for using the shunt on double and single ropes. I suspect you might be OK double but not single, but check.

And if you haven't done it before you need some weight on the rope to get the shunt to slide. The lighter the rope the more this is amplified. Your pack and trainers might be enough, but I normally coil up the spare rope for weight - with a short light rope that won't be available.

In reply to TobyA:

You're right about the diameter, it is 10mm-11mm for a single rope. I've just tried a 9mm single which holds my weight, and some 6mm cord and that doesn't. I may have to experiment with this while on belay at the same time.

What about the fact it is a twin rope, assuming I was using both strands, is that a problem?

I know about having a weight on the rope. If my pack wasn't heavy enough, I'm sure I could find a suitable rock to put in it.

In reply to kev82: Below is a link to the information sheet for the Shunt:

http://www.petzl.com/files/all/technical-notice/Sport/B03_SHUNT_B035000A.pd...

As can be seen it is suggested for use on single ropes 10-11mm diameter or on double ropes 8-11mm so it will be fine for your rope.

With regards to climbing on a single strand of a double rope, I wouldn't recommend it, double & half ropes are designed and tested based on the assumption that 2 strands will be climbed on and both will absorb the energy of a fall.

In reply to James Goodwin:


It's beside the point of this question, but no; they are not. Half ropes are tested, not very logically, on their own but with lower weight. When climbing, it is highly likely that that one of your two half ropes will have to absorb all the force of your fall.