there was a guy at the brion toss workshop this weekend named manuel, who came all the way from puerto rico for the class. anyway, he wants to teach his girlfriend to footlock and was showing me a doubled-rope "treadmill" he sketched which looks pretty cool. if i can get his email i'll try to get him to post it. he basically had 120 ft of rope or so tied (yes, knots are a problem) into a big loop, then doubled and run through 2 double pulleys: one to hang from and the other to keep the falling end of the rope out of your face. the idea was the climber ties in w/a standard doubled rope triple prusik loop, and as s/he footlocks the rope advances so the climber stays in the same place (makes for easier coaching and less risk too). if i've got it right, the friction in the system to counter the climber's weight comes from a 2nd prusik attached to a becket below the main pulley, which is pushed up with the climbers prusik. make sense? the sketch was pretty cool. i'll see if i can get him to post it.
k.