When and how to belay a rappel
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 a qualified instructor, 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.
A belayed rappel is something many climbers think might be helpful only with a nervous beginner who needs the extra reassurance of a belay, or maybe an injured partner.
There’s another application - when you're rappelling into unfamiliar terrain with the location of the next anchors uncertain or nonexistent.
If there’s a reasonable chance that the person rappelling can’t locate the existing anchor (or a suitable place to build one) and needs to climb back up, it's going to be much easier to do so if they can be belayed by a separate rope strand. So, think of it as not really safeguarding the way down, but more to safeguard the rappeller climbing back up, should they need to do so.
Here's one way to set up a belayed rappel with two ropes.
(The same method applies with one rope. In the photos below, where you see the ropes tied together, imagine that’s the middle mark if you were using one rope.)
Here's the complete set up, ready to go. Yes it is a little confusing, so let's break it down step-by-step in the photos below.
Step 1:
Pass blue rope through the anchors, tie it to the green rope with a flat overhand bend.
Tie a stopper knot in blue, toss the blue rope.
Be sure that your green rope is stacked neatly, or in a rope bag or something similar.
Step 2:
Clip a locking carabiner, HMS preferred, to the master point.
Tie a butterfly in the blue rope, and clip it to this locker.
(Some people get freaked out about three-way loading on the blue carabiner. Black Diamond tested this, and it broke at at around 21 kN, which is the rated strength of the carabiner under a normal load. So, under the body weight of one person rappelling, it's not gonna be a problem.)
Step 3:
First person rappelling goes on rappel, single strand, blue rope. (Harness and third hand / autoblock not shown for clarity.)
Rigging an extended rappel (not shown) or using a Grigri or similar assisted braking belay device is a fine idea, because both of these can be easily converted to an ascending system if needed, as we cover here and here.
Step 4:
Take a second HMS carabiner (yellow), and clip it to the first one.
Tie a Munter hitch on this second locker.
Tie a bight knot in the end of the green rope.
Step 5:
With another locker, the rappeler clips the bight knot to their belay loop. Alternatively, you could skip this carabiner and bight knot, and tie in with a retraced figure 8. (Harness not shown for clarity.)
Schweeeeeet, now you're ready to go. First person down raps on blue rope, single strand. Person above feeds out green rope through the Munter hitch.
If the rapper has to go back up for any reason, they have a top rope belay for any part they can climb, with the option of ascending up the rappel rope (or even getting an assisted hoist) if it gets steeper. Depending on the terrain, this is probably faster and less strenuous than prusiking both strands, which they would probably have to do if they didn’t set it up like this.
When the first person reaches the ground (helpfully pulling down all of the green rope on their way) the top person cleans the carabiners and raps normally on two strands.
Here's a close-up of the rigging.
Note for belaying a beginner . . .
Anytime you're working with beginners who are just learning to rappel, it can be a good idea to not only have a belay, but also some kind of releasable system on the rappel rope. If they freeze on the rappel, get their shirt stuck in the device, whatever, you can release the system and get them to the ground.
Here's a modified way to set this up: Instead of fixing the rappel rope with a butterfly, fix it with a munter mule overhand (MMO), with at least 2-3 meters of slack behind it. If the rappeller gets hair or clothing stuck in their device, you can tension and hold the rappeller on the belay rope, then release and lower on the MMO. This creates some slack in the rappel rope, so the blockage can be removed.
In a more formal instructional situation, you're probably going to have a set up with a completely separate belay rope that's not tied to the rappel rope, which makes any mild rescue shenanigans you need to do quite a bit easier. But the main method shown here is a good compromise when on a real climb and needing to improvise a bit.
