If you have three climbers and one rope, how would you manage it? I was thinking putting all three on rope at once... leader on one end, belayer at midpoint on a doubled-up bowline (which could be untied if the leader needed lowering) and third on the other end of the rope. What kind of pitfalls am I missing to this scenario?

If you are doing multi pitch routes and the pitches are longer than half the rope, I would tie both the seconds in closer to the end, maybe 20 feet apart, and have them simul-climb. This avoids the need to simul-climb with the leader and risk pulling the leader off if the second falls. The leader can finish the pitch and set up the belay before the next climber starts climbing.

Thanks. I'd assumed short pitches. Getting better with the search function, and also just found another post addressing a similar question. I think that'd work, so long as my friend doesn't pull my girl off the rock. She'd be pissed.
Guessing you'd want the second to clean normally, except maybe anything that protects from a pendulum, which the third would then clean...

Get another rope. Having two seconds on one rope climbing at the same time is a last resort kind of technique.

Based on this post and your profile, I'd suggest sticking to single pitch stuff and letting your friends toprope a bit, till you all develop more skill.

Put your girl on third ;)
BTW I like the butterfly knot for tying in to the middle of a rope:

butterfly Submitted By: David Houston on Jan 11, 2012

Johnny, I have to assume your third climber is someone you're trying to introduce to multipitch. You're profile also says your new to climbing and lacking experience. So I don't recommend trying this.

I'd beg/borrow/buy a second line for your third climber, you'll have a much better/safer time.

I've never done this myself, and i wouldn't try this without everyone in the team knowing what they are doing and being very comfortable with the climbing you're going to be on. Even on comfortable terrain, it'd be a last resort type thing for me - the only way to safety is up and i only have one rope. the second and third are in a way simuclimbing. Either one falling won't be horrific, but you could be in for a bit of an epic. If the third hangs or falls, the rope is going to stretch and the second is in for a nice suprise as they get ripped off the rock. There will be slack between the two, so its going to hit the middle climber hard. And if either one takes a bit of a swing it's going to be messy.

If you know the pitches are short, less than half the length of your rope, you can tie into and lead from the mid point of the rope and treat it like doubles or use single rope technique and treat the one end like a trail line, just make sure you know which end you're leading on, you don't want to accidently clip in with the un-belayed end.

I've actually climbed in a party of 4 before: I lead with two ropes and had one climber on a rope by themselves and 2 climbers on a second rope. We were actually remarkably efficient and even managed to pass a party of 2. There are 2 good options:

1) Use two ropes. Each climber ties in separately and climbs simultaneously slightly staggered or sequentially. If they climb simultaneously rope management can get tricky. If they climb sequentially it takes longer. There's also a bit of a problem on traversing pitches, as you need to protect both followers. This requires either placing separate protection or clipping both ropes into one piece. If you choose to clip both ropes into one piece, you need to be careful: either use twin ropes or make sure that one of the ropes will not be belayed so that it doesn't increase the load on the piece. Using two ropes has an advantage if you think it is likely that one or both climbers could fall, that way they won't be pulling each other off the rock.

2) Both seconds tie into the same rope. The strongest second ties in at the end, and the weaker second ties in with an alpine butterfly 15-20ft from the end. Both seconds climb together. Ideally, the last second (third) climber will not fall because if they do, they will pull the middle climber off. If the second (middle) climber falls, it will not affect the third climber. It is very important that the third climber maintains constant distance to keep too much slack from accumulating, but also doesn't climb too slow and hinder the progress of the middle climber. When the middle climber reaches protection, they simply unclip the piece and reclip it behind them. This leaves the third climber protected on the traverse and actually has the middle climber protected from any pendulum since they are effectively belayed on both sides. In summary, this method is good if your third climber is confident on the terrain, but not so good if they have a good chance of falling.

In either case, make sure you think about self rescue issues. Using two ropes gives you a lot more options. Putting both climbers on a single rope could substantially complicate a rescue should any one of the 3 of you become incapacitated.

Seems like belaying both 2nd and 3rd close to each other while simulclimbing would encounter exactly the type of risks you've listed above, thus the comment about my friend pulling my girl. Most times we would have two ropes available, but we're taking a trip where we have to fly and weight is a concern, so minimal gear. Don't even know if we'll be climbing at all.
My initial thought was to use the butterfly, but that would require clipping in with a locker. Thought the bowline (treating the bight as a single strand) would work better for the second. (but not if 2&3 are simulclimbing) If the pitch is only half a rope, then if I fell on lead, easy to lower me. If the second falls, easy lower. Likewise for the third. Only the pitches longer than half a rope would need to be creative for getting 2nd and 3rd up.
As to lack of experience, yeah. There's that. So far no one else is stepping up to climb with me. Guess something about me tends to sketch people out. Whatever. That said, my first goal is getting everyone home safe. 2nd is getting up the rock. Since we're still pretty new and will always be learning, I come here to ask opinions then think them over. We also tend to stick to easy stuff, well below our gym ability. So far, painting the living room and the lantern catching fire on the back of the truck have both been more nearly disastrous than climbing for us. That said, we're learning, we're damned slow, and what we've been climbing is generally not in a book. Probably better at tying knots than climbing, and fumble the gear a lot trying to place it, but sew it up anyway. It's a helluva lot of fun though.
Again, this is thinking single rope. If both followers were going to simulclimb, then maybe leading from the center of the rope would be fine. Only problem with that is if I fall and get incapacitated, they wouldn't be able to lower me if I'm beyond half the useful length. Anyway that would be an issue any time you lead past half the rope length wouldn't it... I'm not leading past half a rope length yet. blah blah blah. Dragged it way out....

Lots of "ack... don't do it... yer gonna die!". Yeah, well if that's the case, given all the "seek professional help" advice, then I shouldn't be climbing at all. But remember, I'm the dork in the helmet on lead in the gym in case I stick my foot behind the rope. I don't care what anyone else thinks, as long as I'm technically being as safe as I can. It's about balancing safety and personal responsibility against the risk of death or injury. You're there. You're climbing it anyway. So the goal is to reduce the risk as much as you can without looking up and running away. We're going to do it anyway, so we might as well get as many ideas as we can, vet them out, and reduce the risk as much as possible.
For all you know, we might go work it out on a fourth class mound, or the front yard to get a grip on what's going to work for us. Sure not going to head out after some kinda 11.
But hey, I'm doing that whole overconfident new climber b.s, huh? Guess I best go hide in the closet and cry.
Seriously, if we try anything it will be on easy routes below our ability. Why not discuss situations before you get into them? Why not even before you're technically capable? Gives you more to think about and consider. Self-rescue is a huge issue I think everyone should have some knowledge of before you ever get on a rock... but how many of you seasoned dirtbags have taken the time to practice it?
To that end, I prusiked up a 70ft wall tying backups every ten feet to get a feel for it before I could climb a
oh screw it

You'll be fine. Use either a butterfly or figure-8 on a bight with TWO locking biners, gates opposite and opposed.

If the pitches are less than half a rope length, tie the second in at the very middle. This way they will not be simul-climbing.

If the pitches are longer than that, you have two options: (1) put both climbers toward the bottom of the rope as previously described; or (2) tie the second climber in as close to the middle as possible.

The first option makes it easier for the two climbers to communicate. However, the second option means that the two won't be simul-climbing much of the pitch (the trade off also is that the first option is a bit faster for your team). If speed is not a concern, I recommend the second option. On a 35m pitch, the two will be simulclimbing for 10m instead of something more like 27m.

Put the strongest climber third, keep a tight belay, and climb something that is below the limit of the third climber (the second climber can thrash and dangle safely the whole way up).

So I'd only attempt this on pitches where once you've built your anchor and are off belay you still have over half the rope length down on the ground.

At that point, I have the middle person clip in with a locker to a bowline on a bight, then belay them up having them clean all gear except for directionals.

Once they're up, belay the 3rd like normal having them clean all remaining gear.


Super easy, really manageable, just make sure you're climbing short pitches.

David, I didn't explain it well. No simul with the leader. The leader sets up the anchor and puts the second on belay without pulling up any rope. The second climbs up, on belay. The third is not on the rope until the second is near the top, which reduces the amount of time the second and third are simulclimbing.