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.
Auto locking plaquette-style belay devices (such as the Black Diamond ATC Guide, and Petzl Reverso) have an additional secret trick - You can rig them as an ascender! We cover that extensively in this tip here.
Below is a photo of an ATC Guide in ascender mode. If you weight your harness, the yellow “blocking” carabiner will lock down on the rope.
OK great, so I have a fixed rope that’s locked off at my waist. Now what happens?
Well, you could go old-school, put on a foot prusik loop, step in it, and struggle your way up the rope. But, there is a more elegant solution. It does involve using a foot prusik, but in a clever way that lets you use a little mechanical advantage to climb the rope MUCH more easily!
Doing this is WAY better than the old school method of ascending a rope with two prusik loops!
As the saying goes, “Do you want to work hard or do you want to work smart?” Using mechanical advantage is working smart. Here’s how to rig it.
1 - Put a short prusik loop on the rope above your belay device. (If you happen to carry a micro ascender such as a Wild Country Ropeman, you can use that instead of the prusik.) Here we’re using a Sterling Hollow Block, a very handy bit of kit that works great as a prusik.
2 - Girth hitch a double length (120 cm) sling to the short prusik loop. This is your foot loop.
3 - Clip a carabiner onto the short prusik loop. This is the redirect carabiner.
Finally, clip the rope coming out of the bottom of your belay device through this carabiner on the short prusik. This is the genius addition to the system. It not only redirects your pull so you’re pulling downward, which is less tiring for your arm, it’s also creating mechanical advantage!
So, now you’re ready to climb the rope.
1 - Put your foot in the double runner foot loop, and slide the prusik as far up the rope as you can.
2 - Stand in the foot loop, at the same time pull down on the rope that’s redirected through the carabiner. Voilà, you’re lifting yourself with a (very) theoretical 3:1 mechanical advantage! The point is, this is LOTS easier than the old school method of going up a rope on two prusik knots!
Yes, this is a much better show than a tell. Watch the video below, starting at about 2:08, where the guide sets this up after checking on a crevasse rescue victim, and effortlessly goes back up the rope. Very cool!
A few comments . . .
You do NOT need to carry a long foot prusik loop to climb a rope. Improvise. A dedicated “foot prusik” is something most people use for crevasse rescue only, and rarely to never carried on a rock climb. Instead, use a short prusik as rope grabber and the added double sling as a foot loop.
Best practice in any kind of rope ascending is to have two points of connection minimum to the rope, in addition to being tied to the end. Your connection with the ATC counts as one. To make a second connection, simply tie backup knot(s) directly to your belay loop as you move up the rope. This can be an overhand on a bight, clipped to a locker on your belay loop, or as in the video, a clove hitch. Doing this means that if your ascending system fails in anyway, you will only fall to the last backup knot. The frequency of your backup knots depends on how gripped you are. :-)
As with any rope ascending technique, 90% of your muscles used should be your leg, not your arms. Even if this technique gives you a little mechanical advantage, do not think you're going to magically pull yourself up the rope with one hand. (In fact, the ATC is actually going to introduce a LOT of friction, so be ready for that. The 3:1 theoretical mechanical advantage won't be anywhere close.) So, stand up with your leg, and use your arm to pull through the slack rope created when you stand up.
If you’re on lower angled terrain, you may not even need the foot loop. Slide up the prusik, pull down on the rope, give a little upward thrust with your hips, and you will move up the rope. If you’re on anything close to vertical, you’ll probably want the foot loop.
The diameter and type of rope you were using can greatly affect how easy this is. A newer, skinnier rope with a slick sheath is going to work a lot better than an older thicker rope with a cruster sheath.
This is a stripped-down system that’s closely related to one used in big wall climbing. For aid climbing, one style of ascending uses a Grigri, a handled ascender and an aider to do pretty much the same thing. This gear is more expensive, bulkier and heavier, but overall gives a smoother and easier climb, which is pretty important if you're on a 3,000 foot wall. You can read about that technique here.