Moderator: Tim White
RescueMan wrote:Gary was refering in that article to the old prusik-above method which has been widely discredited ... What this thread has been about is the "French Wrap", more commonly called the autoblock, below the descender.
One alternative that seems better than the chest Prusik (but still not adequate to me) was presented by Larry Penberthy in Off Belay No. 16, pp. 10-11. Since "The trouble with the chest/Prusik system is that a beginner [anyone - gds] may lose control, start to slide rapidly, panic and then grasp the Prusik even tighter, thus preventing it from working. It is contrary to instinct to let go of the rope to gain security". So, "At an MSR 'working' field trip, we devised a new method of security for rappel
The rope from above passes through a [rappel device] and then down to a security knot [Mr. Penberthy recommends either a Penberthy or a Penberthy-Pierson knot, not a Prusik - gds] attached to a webbing loop around one thigh [nowadays, attach to the harness - gds]. When descending normally, the braking (lower) hand grips the knot to prevent it from grabbing, and simultaneously applies enough friction to control the rate of descent.
"As the climber descends, the rope slides upwards through the security knot, and then through the friction device. If the climber lets go with his braking hand completely, the knot grabs and stops him. If he grips the control knot tightly in panic, the extra braking friction force stops him, assuming the friction device has a high enough friction ratio."
But there is a problem, and Mr. Penberthy recognized it: "CAUTION: The security knot must not be able to touch the [rappel device]. If it does, the security knot will not grab". My experience suggests that this disadvantage is enough to be a problem, so I do not use this technique.
Rescueman wrote:As for those of you who claim to dislike the autoblock safety while admitting to having never tried it, isn't that a bit like thinking sex is gross before ever having enjoyed its benefits?
cavegrrl wrote:...Personally, I would rather hang upside down, be uncomfortable and have to worry about harness hang while my caving buddies come and get me than to be laying in the bottom of a pit not having to worry about harness hang because I'm severely injured or dead waiting for my caving buddies to come and get me...
van wrote:Even in that rock-in-the-head scenario, someone using a Stop obviously doesn't need it. Someone using a well-tuned 6-bar rack, as Scott pointed out, doesn't need it (IMO, the ideal situation is when you are pulling bars down to move - not that I achieve that consistently).
Scott McCrea wrote:if a rack is tuned, set up and used properly, it is difficult to lose control, even if unconscious. BLANKSPACENote: emphasis added by Hank
Princess Butterfly wrote:On longer drops, ie Golindrinas, I put the FW between my legs because of the rope weight. This is the best way to do it if you have someone under you on a tandem rappel as well. The FW is nice to have on longer drops, especially when you have to manhandle 90lbs of ropeweight to drop a bar. Once you set the french wrap you are not going anywhere and can use both hands to pop a bar.
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