Do some AMGA instructors teach top managed belays with ATC devices? I feel like this poses a lot of problems if you don't know how to use one. What if the climber needs to be hauled up before they reach the ground? what if there is no ground? how would you switch to lowering mode from plaquette mode while there is tension on the rope? I feel like all of these problems could be solved with a GriGri type device. Unless you are super quick with transitions with a loaded and unloaded ATC, there is a lot of room for error.
Good vid, Just a technical point. It is bad practice to clip into the shelf with nothing in the focal point, as per the tree set up. If the guide loads the system and the knot rolls he will fall.
I don't quite understand your point. If you dress the original knot well and the guide is not applying higher load forces to the shelf I think it is pretty unlikely the knot would roll especially with the bomber ledge he is standing on. Also, there is both the carabiner used to redirect the brake strand on the lower and the carabiner used to trap the rope for use in plaquette mode running through the focal point which would prevent the knot rolling to the point of catastrophic failure.
Hi Billjack, I am only referring to 1.37 to 1.57 of the video when there is nothing in the focal point. You are correct a well dressed knot, with long tails, not applying forces and the guide being on a ledge makes the knot rolling highly unlikely. However the correct way to teach using the shelf it is to clip a carabiner into the focal point first, thereby eliminating the possibility of the knot rolling even when the other factors are not correct. The situation in this video is exceptionally safe however a simple modification in the procedure was introduced after a guide in the Alps died due to a knot rolling while loading a shelf.
He is going hands-free for a moment to move the belay device into plaquette mode. The knot he ties backs up his autoblock hitch, as well as marks for other future climbers on this pitch where they started to climb so you don't lower the next person further than the first.
