When you are using half ropes (8.5)(Not to be confused with twin ropes) , and alternating clips, and you establish a completely bombproof piece that you want both ropes to go through, can you clip half ropes through the same piece (i.e. the same biner) or should you add an extra biner to the draw and give each rope it's own biner? I have seen people do both and was wondering which is better/safer? Seems like running them both through the same biner could cause them to wear on each other. I dunno, maybe this is a a dumb question, just want some clarification. Thanks, and Cheers with dark beers!

-- Tea (mtea@ptc.com), December 17, 1998

Answers

If you are alternating clips, you should not clip both ropes into a single biner. The reason is that it's possible for the top rope to burn through the other rope at this biner if the top rope is loaded and sliding over the other rope. It's possible to do this, although I can't remember the exact geometry. It comes down to the fact that the ropes are clipped into different pieces of pro, so if you fall and a piece pops it creates a lot of slack in one rope but does not affect the other one.

I've never heard of an accident caused by this error, so it should not be high up in your list of concerns.

It is OK to clip both ropes through a single biner provided you do it on every clip (no reason you can't clip your half ropes as if they were twins). I often do this ice climbing, because there is usually very little rope drag ice climbing (no reason to alternate clips).

-George

-- George Bell (bell@advtech.uswest.com), December 18, 1998.

Because of the dynamics of falling and loading per fall factor, clipping both is nessecary for only about the first 30 feet after which the fall factor in most cases is reduced to an acceptable level for a 1/2 rope single strand or even a twin single strand. For a detailed technical explanation, visit the UIAA web site. Many of the Rope manufacturers also have detailed information on the technique. As well I prefer that my belayer use a dynamic belay rather than a static, to further reduce the load stress on both the rope and the first piece in the event of a fall. As well I place a shock absorbing device on the first piece. As the fall factor diminishes to an acceptable level this becomes un nessecary. note: a caution is nessecary to remind the leader to judge each situation. for eg. a dynamic belay may prove unsafe if it creates a potential ground fall situation. Understand your system and manage the risk, don't roll the dice.

Good

-- Bill Betts (bbetts@shaw.ca), February 12, 2004.