The single-pulley method theoretically doubles the amount of weight that each hauler can raise compared with using no pulley, though friction lowers this ratio somewhat. Because the method uses a length of rope that is separate from the rope going to the climber, it?s the hauling method to use if the accident rope is entrenched into the edge of the crevasse.

1. Find a rescue rope (the unused end of the accident rope or a separate rope altogether). This rope must be at least twice as long as the distance from the anchor down to the fallen climber. You can use the existing anchor system or a new rescue anchor.
2. At the point where the rescue rope will go over the lip of the crevasse, prepare the lip with padding, such as an ice ax or pack, to keep the rope from entrenching itself in the snow.
3. Double the rescue rope into a big loop. Affix a rescue pulley to the loop and attach a locking carabiner to the pulley. Leave the carabiner unlocked.
4. Lower the pulley and carabiner dangling from the loop down to the fallen climber. Have the climber clip and lock the carabiner into the seat harness. Confirm that this has been done. Check that all the climber?s equipment is secure and ready for hauling to begin. Have the climber clip the pulling side of the rescue rope into the chest harness, to help stay upright.
5. Assign a rescuer to attend to the slack that will develop in the original accident rope as the climber is raised. It?s critically important that this person pull slack through the friction knot so that the rope is always ready to accept the climber?s weight, in case the pullers slip or need a rest. If the fallen climber has removed his or her pack and clipped it to the accident rope, there will be considerable weight on the rope, and it may even require two people to take in the slack. The existing figure-8 backup knot to the anchor remains in the system while the slack is taken in; do not remove it.
6. With everything ready, the haulers start pulling on the unanchored end of the rescue rope. To somewhat ease their task, the climber can pull up on the anchored half of the same rope while the hauling proceeds.

Z-Pulley

The Z-pulley magnifies the muscle power of small climbing parties by offering a 3-to-1 theoretical mechanical advantage through the use of two pulleys. It can be set up and operated with no help from the fallen climber, making it valuable in rescuing an unconscious person.

1. Unclip the backup figure-8 loop from the anchor system and untie the knot as soon as haulers and fallen climber are ready for pulling.
2. If a prusik knot was used to attach the accident rope to the anchor system, assign a rescuer to tend the knot so that the rope slips freely through it as the rope is pulled in. If a Bachmann friction knot was used instead, the attachment should tend itself, and the front hauler can simply keep an eye on it to see that all is well.
3. Start pulling at a steady rate, either hand over hand or by holding tight and walking backward.
4. The hauling will soon bring the second pulley in close to the stationary pulley at the anchor. Stop hauling while the pulleys are still a couple of feet apart. If you pull them too close, the figure Z is collapsed and its mechanical advantage is lost.
5. Now that you?ve stopped hauling, relax your pull on the rope enough to transfer the climber?s weight back onto the friction knot at the anchor.
6. Reset the Z-pulley by loosening the friction knot that is linked to the second pulley and sliding it back down the taut line toward the crevasse lip once again.
7. Keep repeating the process from Step 2.

Piggyback Pulleys

To get even more mechanical advantage out of a rescue hauling setup, you can combine, or ?piggyback,? two systems.

First create your initial hauling system, either a single pulley or a Z-pulley. Now establish a second anchor some distance behind the main one, to handle the second hauling system. Attach the second hoist, again either a single pulley or a Z-pulley, to the accident rope at the point where the rescuers would normally pull.