The stairstep prusik
This system of ROPE Climbing Guide" href="/guide/min-inspection-of-rope.html">climbing the rope uses a separate sling for each leg. You can make a set of slings for yourself, and 25 feet (about 8 meters) of 6-milli-meter accessory cord is plenty of material for both of them. Getting the size right requires some experimentation. When all the work is done, you should end up with two slings—one as long as the distance from your foot to your ears, the shorter one as long as from foot to elbow.
Each sling consists basically of a single strand of cord, tied with equal-sized loops (1 foot long or so) at each end. One will be the prusik loop, used in attaching the sling to the climbing rope with a prusik or Bachmann knot. The other is a foot loop, large enough to fit over any footwear, including crampons and overboots. Add a slip knot to this loop to prevent tightening down on the boot and cutting off circulation (fig. 13-7a-c).
You need to incorporate one little difference in the longer sling. Leave a 5-foot tail after you tie the loop that will be used for creating the prusik. Tie a small overhand loop at the end of this tail. When you use the slings, clip this small loop to your seat harness as a safety strap to catch you in case both feet slip out of the slings.
Before you head out onto a glacier, attach the prusik loops to the climbing rope so the slings are ready for immediate use in an emergency (fig. 13-7d,e). Attach them at a point beyond where the climbing rope leaves the carabiner at your chest harness, the longer sling attached beyond the shorter. (Pass the long sling through the chest carabiner as well.) Shove the other end of the long sling under the belt of your seat harness. Put the
Stopper knot can be moved up or down on the foot loop to change the size of the loop as needed to fit boots with crampons
Fig. ¡3-7. The stair-step prusik: a, tying the foot loop with one half of a double fisherman s knot; b, climber prepared to walk out onto a glacier with prusik slings attached to climbing rope
Stopper knot can be moved up or down on the foot loop to change the size of the loop as needed to fit boots with crampons
Fig. 13-8. Ascending a rope using the stair-step prusik
Fig. 13-8. Ascending a rope using the stair-step prusik ends of both slings into your pockets, ready to be pulled out and slipped onto your feet when needed.
(If you are using mechanical ascenders instead of prusik loops to hold the sling to the rope, carry the ascenders on your seat harness and the slings in your pockets. After a crevasse fall, attach the ascenders to the rope.)
This is the sequence to follow if you need to climb the rope (fig. 13-8):
1. Take the foot loops from your pockets and slip thern over your boots, cinching up on the slip knots.
2. Stand up in the short prusik sling, putting all your weight onto it.
3. Lift the leg attached to the long prusik sling, then loosen the knot attached to that sling and slide it up the rope some 18 inches.
4. Stand up in the long sling, shifting all your weight to it.
5. Lift the leg attached to the short sling, then loosen the knot attached to that sling and slide it about 18 inches up the rope.
6. Stand up again in the short sling.
7. Keep repeating the process and you'll walk up the rope, somewhat as if it were a flight of stairs.
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