NZcaver wrote:A tibloc in the harness maillon sounds very efficient in theory... but how would you attach/detach/downclimb? Not very practical!
I don't know...to attach when standing on solid ground, simply open the maillon, take off the Tibloc, put the rope through, put the Tibloc back on, and close the maillon. Downclimbing could be accomplished by pressing down on the top of the Tibloc to prevent the maillon from pushing the teeth against the rope.
For safety, the Tibloc would have to be on the rope at all times--after all, when rappelling, you never know when you might need to change over. In order to prevent the Tibloc from engaging, it would be necessary to push down on the Tibloc while rappelling. Surely nobody would push down on a Tibloc in panic, so this would also be a reliable automatic self-belay for rappelling.
Perhaps greater speeds could be achieved by adding a foot-mounted Tibloc. Holding one's foot at an angle would not remove the device, but it would cause minor sheath damage.
Unfortunately this system does not pass knots and rebelays, but this is not an insoluble problem. To climb past a knot with this system:
(1) Attach yet another Tibloc to the rope above the knot, on the short cowstail.
(2) Move the upper Tibloc up above that one, so now there are two points of attachment above the knot. Note that these Tiblocs, not weighted, may be subject to falling down by themselves repeatedly and should be pushed back up as many times as necessary if that happens.
(3) Press down on the top of the chest Tibloc to lower it enough that the upper and third Tibloc take up the weight.
(4) Untie the knot, attaching the lower half of the rope to yourself so as not to drop it.
(5) Attach the chest Tibloc to the upper rope (by feeding the upper rope's tail down through it) and set and weight it.
(6) Retie the knot, remove the third Tibloc, and continue ascending.
Anyway this is getting
so I guess I shouldn't ask you if you have any similar ideas for passing rebelays and switching from one rope to another with this system.