Let's assume you're on a multi-pitch sport climb with a pitch length of 40m and you know how to rappel using an ATC. The single rope you are climbing on is 50m. After 35m you are not able to continue. Let's assume the bolts are spaced 2.5 m apart.

How can you install a rappelling anchor if a) you or b) your belaying partner carries a second rope of 50m?

How can you then manage to rappel on the double-stranded ropes by connecting both ropes together down to your partner? You never want to hang on a single bolt.

  • I’m not sure you can do this without relying on a single bolt to ab off, unless you happen to have a piece of trad gear on you you’re happy to leave behind. However, if this is an emergency and you were relying on those bolts to protect you in a fall when climbing, you may have no choice but to trust them to ab off too.
    – Darren
    Commented Jul 26, 2020 at 7:38

3 Answers 3


By far your simplest and safest option is just to downclimb, cleaning your own pro as you go. Obviously you wouldn't enjoy doing this, but it would be very safe, and I'm not clear on why you wouldn't do it.

If you really don't want to downclimb the whole pitch, you have the option of downclimbing to within 25 m of the belay and then being lowered. You would need to leave two of your draws in place so that you were being lowered off of something redundant.

Your other options are going to depend on what gear you have with you. If you have even a few pieces of trad gear, you could see if you could get a piece in to allow you to aid climb past the crux and then continue the climb.

But let's say for the sake of argument that there is really some reason you have to rap off. Maybe your leg is broken. The self-rescue options are then going to depend a lot on what you have with you, and they will involve leaving behind at least some amount of gear. If you have a cordelette that's long enough, you may be able to build a redundant anchor using two of the bolts. If you have some trad gear, you can use that. If you're really desperate and have no cordage, I suppose you could temporarily tie in to two bolts, pull up the rope, cut off a piece, and use that to rig an anchor that you could leave behind.

One moral here is that you shouldn't start up a multipitch sport climb without a basic self-rescue toolkit on your rack, including stuff like a cordelette, a knife, some extra lockers, prusiks, some webbing inside your pack, and a few pieces of trad gear. A full trad rack is expensive, and not something you want to spend a lot of money on if you're a sport climber, but you can pick up a few nuts and maybe a couple of cams or tricams pretty cheap.

It's also a really bad idea to start up a multipitch route unless you're pretty certain that it's within your abilities. Multipitch is committing. Bailing off of a multipitch route can be difficult, impossible, expensive, and/or dangerous.

  • 4
    Down climb 35m? Who are you? Alex Honnold?
    – Darren
    Commented Jul 26, 2020 at 7:29
  • 2
    @Darren: Of course nobody wants to downclimb that far, but the alternative here is a complicated and difficult self-rescue situation that could be unsafe.
    – user2169
    Commented Jul 26, 2020 at 21:36

We hate to use the term "safer" in climbing, but here's a method to manage risk a little more appropriately.

Using this method, we'll never be off belay, and we'll never be trusting our life to a single piece

Evaluate your last point of attachment. We're looking for the best anchor that we can make. Realistically, that's likely to be the newest, shiniest looking bolt, because we're unlikely to have much else in this situation. In a perfect world, we find a tree or horn or thread to sling.

However, let's assume we're the simplest, most common, likely situation, we're just on a bolt, not incredibly trustworthy.

Call down to you partner to lower We're 35m in, and we've got a 50m rope. That's 50 feet of rope that we've got to work with. In this situation, lowering is going to be safer than rappelling, because we-

  • aren't trusting our life to a single piece. If the top bolt blows, we take a fall which isn't fun, but is to a piece which is ≈ only 8 feet lower, which is a 16 foot + rope-stretch fall, at most.
  • are still attached to our partner. That's going to be most ideal, because it's a useful method of redundancy

As we lower, we're trying to find a better spot to anchor Your belayer has 15m of rope left with which they can lower you. Once we've been lowered 10m, we'll be only half the rope length above the last anchor. As we lower, evaluate bolts. In a "perfect" world, you'd be able to replace the second highest quickdraw with a bail biner, then clean the rest of the draws on you way down to your destination. They key here is to have clear communication with your belayer regarding your intentions, so they can let you know how much rope is left.

As you approach the end of the rope, transition back to the end of the rope

  1. Once your belayer runs out of rope, pull on their strand to haul yourself back to the closest bolt
  2. Swap the quickdraw at your "new" anchor for a larger basket biner if possible, if not, we'll assume the bolt-side carabiner of the quickdraw is what we're going to refer to as the bail biner.
  3. Clip yourself to the bail biner with your tether, or another quickdraw (to your belay loop)
  4. Ask for slack, weight the attachment to the bolt.
  5. Pull a loop of the belayer's side of the rope through the bail biner.
  6. Tie a figure eight on a bight (or any other mid rope loop knot), clip it to your belay loop. (You are now on belay via this strand)
  7. Untie your rope-end tie-in knot
  8. Pull rope end through and down, pass it through the bail biner.
  9. Tie in at the end of the rope.
  11. Unclip and untie your mid rope loop knot, ask your belayer to take up all slack.
  12. Pull up on the anchor so that your tether/quickdraw attachment to the bail biner isn't tensioned, and your tie-in is.
  13. Unclip, lower.

Using this system, we can stay safely redundant with our attachment, and end up leaving (probably) 4 carabiners behind. You can get more carabiners. Depending on your level of comfort, you can leave more or fewer.

Once down to our partner, we can rig our system to rap the rest of the cliff

Either you or your partner has the other rope. Let's assume it is merely a tag-line. If it's a rated rope, this would still work, but you'll have more options.

  • Rated rope goes through rings
  • Join the two strands with an EDK (with several feet of tail/backed up, no need to be stingy)
  • Tie a mid rope loop knot between the EDK and the rings in the rated rope (Clove is fine), clip a carabiner to it and then also clip it around the rated rope (A "carabiner block")
  • Rap
  • Pull tag line
  • Rinse and repeat

You basically have 4 options

Aid climb your way up to the next belay
Pull on quick draws, step into a sling, etc. If you chose a route matching your skill level roughly, only a short section should pose a problem.

Down climb to the last belay
Most people consider downclimbing a lot harder than up, but it is still possible. If you cannot downclimb a section, it may be necessary to unclip and jump off (watch the terrain).

Create some redundancy and rappel
by adding a cheap piece, e.g. a stopper. Only possible if you can place protection (and carry trad gear in the first place)

Rappel off a single bolt
While this is discouraged in text books due to the lack of redundancy it is not as uncommon as a beginner might think. In fact, in alpine routes the safety standards are not the same as in sport climbing and many routes here in the Alps involve rapelling off a single bolt. There are also valley crags where this is still common practice. In an emergency situation, I definitely would rappel on a single bolt as well.
Your problem will be to get the second rope up. To do this, tether yourself into the bolt and let the partner knot the second rope into a loop of your rope. Now pull it until you have two ropes and rappel.
(Note that I consider this scenario kind of artificial. One rarely carries two single ropes and uses only one of them. If two ropes are used, these are half or twin ropes and one would start leading with both of them)

  • One rarely carries two single ropes and uses only one of them. Actually this is pretty common when you're climbing a route that you're expecting to rap off of at the end. The OP's scenario arises, for example, when the descent requires rapping down all the pitches of the climb, some pitches are longer than half a rope length, and you're leading on a single rope (which is the norm here in the US).
    – user2169
    Commented Jul 27, 2020 at 15:24
  • 1
    I would always take 2 half-ropes (or twin-ropes) for this. Why bother with another heavier single rope in your backpack when you can just climb with half-ropes? And if you really want to climb with a single rope because rope management is easier why not take something like a rap-line/rad-line/... for the second rappel-strand?
    – Manziel
    Commented Jul 27, 2020 at 15:37
  • I would always take 2 half-ropes (or twin-ropes) for this. Why bother with another heavier single rope in your backpack when you can just climb with half-ropes? Americans don't own half-ropes. They're not widely used here. And if you really want to climb with a single rope because rope management is easier why not take something like a rap-line/rad-line/... for the second rappel-strand? I've heard of such things, but I've never met a single person here who does that. One reason might be that the second rope is more versatile than a single-purpose cord you have to buy.
    – user2169
    Commented Jul 27, 2020 at 16:11
  • 1
    Rapping off a single bolt is not something that should even be considered in the OP's situation. The reason to rap off a single bolt is that you don't have a safer option available. That's the case in your alpine scenario, but it's not the case in the OP's scenario. And in the scenario you describe, the bolt was put there intentionally for that purpose, and other people have been using it for that purpose. A bolt in the middle of a sport route could be anything in terms of quality, and it can be difficult or impossible to detect it if there's a problem with it.
    – user2169
    Commented Jul 27, 2020 at 16:13
  • 1
    You can simply weight and bounce test it before committing to it (with all the other bolts as backup). If it holds, it should hold while rappelling. Of course this is rather a last resort solution but this is definitely a common practice with lots of maillons in bolts below the crux standing witness. For the rap line... I have none myself as I and e everyone I know will climb this with half ropes. But nobody would carry a single rope just for rappelling. Using half ropes has other advantages as well such as reducing friction
    – Manziel
    Commented Jul 27, 2020 at 21:01

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