Ascending twin 8mm ropes

[grandma1]

I need to be able to ascend twin 8mm ropes. So what's the best way to do this? Will 5mm or 6mm prusiks work around both lines?

[catbirdseat]

Yes.

[lummox]

hedden knots will work too.

[catbirdseat]

I didn't know that a hedden knot was an upside down kleimheist until I looked it up. Interesting.

[specialed]

sketch.

[John Frieh]

The rule for prusiks is roughly 3 mm (or more) smaller than the rope you are ascending (you can sneak by with 2 mm in a pinch, but if the rope is wet you will get slippage... I have used a 6 mm prusik on a 7.8 mm rope and was fine). Also, if you settle on a prusik as you knot, use three wraps (called an improved prusik in NOLS books if you need a reference) as it will give more surface area contact. Perhaps I read it wrong, but are you are trying ascend both strands together/side by side simultaneously? I hope I am wrong, but if you are why? If you are following a pitch or coming out of a crevasse (or anything for that matter), have the leader belay you on one strand and you ascend the other fixed strand. Obviously not essential, but safer. There is no need have both strands running thru you knot (prusik, etc). Can I ask what you are doing?

[catbirdseat]

Sounds like what you might do if you got rappel ropes stuck, that is you rapped off and couldn't even get the ropes to move at all, hence you still have both ends.

[John Frieh]

I had this happen on Burgundy (with 8 mm twins). What my partner and I did was build an anchor, attach both ends to the anchor via figure 8s, climb with two prusiks attached to one of the two twins and placed pro (clipping the same strand both prusiks were on into the pro). This way if the rap anchor failed, I wouldn't "buy the farm." Also, if the rope became unstuck, I could then just rap from my position and clean the pro on the way down. Needless to say, neither of these things happened and after unsticked the rope (moving the knot to a better position so it could pull), I cleaned my gear on rap. Grandma1: if reascending stuck rap ropes is the reason for the question, climbing had a good article on it in the past year/year and a 1/2 you should look up. Hope this helps.

[catbirdseat]

This happened to me at Exit 32. It was just starting to rain as I got off rappel and rope wouldn't pull. The chains had shifted and pinched the ropes. It was an easy enough route that I could climb using a prussik as a safety over the wet rock. By the time I was back down, I was soaked to the skin. My partner, who had wanted to leave earlier, felt I got my just deserts.

[Superman]

desserts*

[catbirdseat]

Go look it up.