Note - This post discusses techniques and methods used in vertical rope work. If you do them wrong, you could die. Always practice vertical rope techniques under the supervision of an experienced climber, and ideally in a progression: from flat ground, to staircase, to vertical close to the ground before you ever try them in a real climbing situation.
Scenario: You have a team of three climbers and one rope. You’re in moderate technical terrain - low fifth class rock with good climbers, 4th class with occasional “steps” of harder moves, a open big slab, or fairly steep snow. The terrain falls lies that in-between spot, ranging from “No prob, I can solo this!”, to, “Hmm, I think I want a rope!”
This might be a good time for end roping.
Look! It’s our friend Sticky! She’s back, and climbing with her 2 pals. Hi Sticky!
This is a technique often suited to alpine climbing, where you may have many pitches of easy to moderate climbing, and speed can become more important. It’s best not to use it on much anything higher than mid 5th class.
The leader heads out as usual, but the two followers tie in close to each other near the end of the rope. (End roping, get it?) The leader then belays up both followers at once.
The “end” follower ties in to the rope end as usual with a rewoven figure 8 knot. The “middle” follower, about 4-5 meters away from the end person, ties a overhand on a bight knot with a large loop of about 2 feet. (With the middle person on a large bight of rope, it gives them some freedom of movement. If the end person falls, the middle person may not be pulled off because of this loop. And, it means the followers do not have to be moving at the exact same rate.)
There are a few ways for the middle person to connect to the rope.
One is with what Freedom of the Hills calls a “double bowline.” (Now you knot-heads, don’t slam me because I used the wrong name. From what I can tell, this is not a double bowline in the generally understood sense, but that’s what I’ll call it for now. Got a better name? Email me.) Oh, and be sure and clip the tail with a carabiner.
Another option is to clip this bight of rope to the middle’s belay loop with two carabiners, opposite and opposed, with at least one being a locker. (If you are feeling a bit bold, one good locker with the carabiner properly aligned with no chance or cross loading is probably okay too. It's really up to your personal level of acceptable risk. Me, I like 2 carabiners.)
Cross loading the carabiners is the main thing we're trying to avoid here. There are several ways to avoid this:
Use the belay loop rather than the harness tie in points, as this minimizes tri-axial carabiner loading.
You can tie a clove hitch in the bight loop and crank that down on your carabiners.
You could use a nifty new locking belay carabiner, like the Black Diamond Gridlock, that has a clip that captures the carabiner so it can’t be cross loaded.
Or, if you have it, you could cut a few thick rubber bands from a bicycle inner tube (ideally a wide mountain bike tube), snap that around your belay loop, and then clip in a locking carabiner. The rubber band will keep your carabiner in the proper orientation, and avoid cross loading. Use another rubber band on the rope loop that clips to the carabiner.
Basic set up: overhand on a bight with 2 opposite and opposed carabiners.
Or: cut an bike inner tube, put it over the rope, then cinch it down onto the carabiners. Close up:
Add a clove hitch and cinch it down to hold the carabiners in place.
When you're done adding the bike inner tube, it looks like this:
Or, go with the sweet Black Diamond gridlock or similar carabiner designed to resist cross loading.
A few things to note:
You need to use a single rated rope, not a skinny twin or double.
If the last person falls, it’s likely they will pull off the middle person. Because of this, it’s best if the strongest climber of the two followers is on the end of the rope.
This is really only a safe system up to low fifth class for most people. If it gets much more challenging than this, you probably need to be using a different rope system.
Both climbers are ideally about the same fitness and skill level, because they both need to be moving at about the same speed.
If you're in an area where the rope is going to be potentially loaded over sharp rock edges, keep in mind that you could be putting a double load on the rope if the seconds fall together.
This works best if the route is pretty much straight up. If you start any kind of a traverse, a slip by either of the two followers will probably result in a fall for both of them.
Use some common sense. If the consequences of a fall are low, meaning the terrain is a slab or snow or not very blocky, and it goes pretty much straight up, and your climbing team is skilled enough for a very low chance of a fall, this is a technique that will probably work.