Hey, this is a question for people who are familiar with/have practiced a counter weight abseil. I'm working on a checklist my own personal reference - I'd appreciate your thoughts. I've practiced this and it seems to work, but I've never had to use it on the rock. I'm particularly interested what MCI trainees are being taught on this.
Applicable conditions:
1. It is easier to descend than ascend.
2. The second cannot be lowered to the ground/ledge.
3. The second is incapacitated.
4. There must be a powerpoint (not built with the rope) and this must be in-reach.
5. The next anchor or ground is <half rope length away (single rope) or full rope length (double ropes).
6. Must not be on a traverse.
Alternative scenarios:
If you are climbing with double ropes and need to descend >half rope length (i.e. next anchor/ground >half rope length away), you will need to abseil to the second*, untie one rope, ascend to the belay, release untied rope, and join the ropes before abseiling in counterbalance. This may necessitate passing the knot (see passing the knot in counterbalanced abseil).
Prerequisite skills:
-Tied off italian hitch
-Releasable prussik (french ‘autoblock’ prussik, prussik + italian hitch tied off, mariner overhand)
-Abseil extension with french prussik
-Escape the belay (transition to italian hitch)
-Rescue spider (rope end or cord)
-Tandem abseil
Cautions:
-Avoid if loose rock present (moving ropes)
-If you cannot reach the ground in the first abseil, is there a suitable anchor below?
-Next anchor must be < half rope length (single rope). If not, unless you’re using half ropes, haul, then either shelter or ascend.
-Tie knot in end of rope
Steps:
1. Escape the belay and transition to italian hitch:
a. Back up and hands free
b. Create powerpoint if necessary (separate to the rope)
c. Releasable prussik on live rope (attached with locker to powerpoint)
d. Italian hitch (locker) on powerpoint (tied off)
e. Weight the prussik
f. Remove belay device
g. Take in slack on Italian hitch and tie off
2.Set up abseil (extended with autoblock) below italian hitch
3.Tie catastrophe knot below autoblock
4.Clip dead rope through a locking carabiner on powerpoint.
5.Remove italian hitch.
6.Get your abseil device close to the powerpoint carabiner.
7.Remove personal anchor / tie in knot
8.Release prussik (leave attached to live rope) and set up as releasable on belay loop.
9.Tie knot in end of rope (if not tied to harness)
10.Remove catastrophe knot
11.Abseil to second** and continue to anchor
12.Back up and hands free
__________________________________________________
13.Build anchor (if necessary)
14.Attach both persons (releasable) to anchor e.g. spider.
15.Remove seconds’ knot
16.Pull rope down
17.Rethread anchor
18.Tie knots in end of rope (if necessary)
19.Remove original abseil setup/prussik (nb you may want to do this after step 14).
20.Setup for tandem abseil
21.Release spider
22.Remove back up
23.Abseil
Repeat steps 13-23 (15 n/a) until grounded.
*Attend to injuries before proceeding.
**You may need to pass a knot, if using separated half ropes.
Post edited at 10:36