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. As your pull slack through, 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)
2 - Girth hitch a double (4 foot/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 biner 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 mechanical advantage! (Personally I think this is a 2:1, the guide in the video below calls it a 3:1, but it doesn’t really matter.) The point is, this is MILES 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 pretty much something you’d use for emergencies only, and you especially don’t need it 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 tie backup knot(s) directly to your belay loop as you move up the rope. This can 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 you 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. :-)
If you’re on lower angled terrain, you may not even need the foot loop. Slide up in the prusik, pull down on the rope, give a little upward thrust with your hips, and you will lift yourself up with mechanical advantage. If you’re on anything steeper overhanging, you’ll probably want the foot loop.
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.