sorry to bring up such an old thread, but i've only recently got out of the dark ages and had some other questions i thought someone might be able to help me with:

#1
was ascending up a multi a couple of months ago, and an earlier party was coming down on us. they got their ropes stuck, and one of them used their guide as an ascender to get up (using both ropes together as a fixed line). so i've done my share of jugging with prussics, a few different types of full sized ascenders, rope men, and whatever it is called when you prussic around a big beaner, but was wondering if someone had a visual of how to rig the guide as an ascender.

#2
also, thought someone might be able to help solve a debate we were having earlier that day: is it safe to belay two different people up two different ropes (top rope) simultainiously using a standard ATC? (obviously keeping hands on the brake?)...while i'm at it, what about if we were trying to move, and the first up took off to lead the next pitch, while the latter was still coming up. probably would be a big rope mess, but what about that?

thanks in advance - S

Steve, #1 is a rig with the autoblock off the belay loop. Piton Pete gives an illustration but using the gri-gri. Using the guide/reverso/similar device is basically the same, but the gri-gri is far more manageable & you would need to manage a knot so you can treat a two strand standard rap as a one strand fixed to allow pull when you get to a safe anchor in a lower position.

#2 - I've actually done 2 with only munters (why? because I left my device at the anchor below). This takes practice, you can't ever take your hands off of both strands; this is something you really need to be solid with when it comes to belay technique -- it's slip, slap, slide times two and very fast. If a second falls, you really have no choice but to lock off strands -- a redirect would be helpful & recommended, if you can; even better are direct-anchor munters on separate biners.

Buddy rescue at this stage is risky to consider belay escape. So going with a basic ATC to belay two seconding climbers can turn into more than epic in a split second if your skills are not dialed in. But is it possible? Sure, you just don't have the auto-blocking rig. If the terrain is well within ability to simul-climb, using this technique works when climbing as a party of three.

Sending the leader up & belaying a seconding climber -- again, if you all could simul-climb anyway; it is possible -- but the trouble is if the seconding climber hangs, you could pull your leader off or short-rope them as you lock-off. So the risk is higher in this situation.

I would say, if the weather is moving in and you 3 had to get out of terrain, this rigging is possible to consider to try and get someone up to a safer anchor/terrain situation; but I wouldn't consider it as much an option if a fall due were likely due to terrain difficulty. You could also just have the leader short fix & keep the belay on the seconding climber independent until they reach to your anchor position.

If you didn't need to move a leader up as quickly as possible/simul-climbing wasn't likely either; what you could do instead is butterfly mid-line and use one rope and belay both seconding climbers. Use your second strand as a free tag-line if you needed to get down to them.