Post by kensmall on Apr 14, 2014 12:40:27 GMT -8
On p. 340, F8 says "The key to successful self-belay is to grab the shaft at the surface, so that you pull against the buried shaft." I can't believe that this has ever been more than very casually tested, and probably only when self-belaying on the ascent. Bellingham has now had a hard-snow practice for six years. In three of those years we have had fairly hard snow, well within the range of conditions where self-belay is a feasible technique. We ask the students to try the technique of grabbing the shaft to see if they can make it work. From what I can observe, they are generally able to do so when ascending, although in the years when the snow is fairly hard I think the grab is mostly done after the fall has been stopped and thus plays no role. With the softer snow we've sometimes had, I suspect the grab helps stop the fall. (Film footage that can be slowed down might show what is going on.) When descending (facing out, sideways, or doing a descending traverse) no one could do it at all consistently. The problem with calling it "the key" is that if you take the idea seriously, you are sometimes required to do something irrational: leave about 15 cm of the shaft out of the snow even if your experience with practice falls convinces you that in the conditions you're currently in, it will almost certainly fail but will succeed if you get the ax almost all the way in. (We ask students to take at least 20 self-belayed falls, pushing it to failure a couple of times by progressively leaving more of the shaft out of the snow.) I suggest that Freedom 9 say that this technique is a useful one when ascending snow that seems too soft for the ax alone to stop the fall unless the ax is all the way in. (Putting anything but a shorty ax all the way in on anything less than 45 degree snow is pretty awkward, leaving you uncomfortably bent over.) It should perhaps also say that the technique should be practiced in a safe environment.