An autoblock (or autobloc or "third hand") is a rope device used in

climbing Climbing is the activity of using one's hands, feet, or any other part of the body to ascend a steep topographical object that can range from the world's tallest mountains (e.g. the eight thousanders), to small boulders. Climbing is done fo ...

and

caving Caving – also known as spelunking in the United States and Canada and potholing in the United Kingdom and Ireland – is the recreational pastime of exploring wild cave systems (as distinguished from show caves). In contrast, speleology i ...

for both

rappelling Abseiling ( ; ), also known as rappelling ( ; ), is the controlled descent of a steep slope, such as a rock face, by moving down a rope. When abseiling the person descending controls their own movement down the rope, in contrast to low ...

(downward) and ascending (upward). While rappelling, it slides freely down the rope when pushed downward by the hand, allowing a controlled descent, but jams in the event of a sudden drop or loss of control, stopping the descent. This prevents uncontrolled falls in the event of an accident in which the abseiler loses control of the rope. For ascending, it likewise can be pushed up the rope manually when unweighted, but jams and holds when weighted by the body. It is made using a

friction hitch A friction hitch is a kind of knot used to attach one rope to another in a way that is easily adjusted. These knots are commonly used in climbing as part of single-rope technique, doubled-rope technique and as "ratchets" to capture progress on a ...

around the rope, connected by a

carabiner A carabiner or karabiner () is a specialized type of shackle, a metal loop with a spring-loaded gate used to quickly and reversibly connect components, most notably in safety-critical systems. The word is a shortened form of ''Karabinerhaken' ...

to the climber's harness, and may be combined with other

climbing equipment A wide range of equipment is used during rock or any other type of climbing that includes equipment commonly used to protect a climber against the consequences of a fall. Rope, cord and webbing Climbing ropes are typically of kernmantle c ...

for further safety. For instance, it is typically used as a backup while rappelling using a tube belay device. The term autoblock is also used for a specific type of friction hitch, which is also known as a French prusik or Machard knot, named after its inventor, Serge Machard. Other friction hitches that can be used to build an autoblock system include the

Prusik knot A Prusik ( ) is a friction hitch or knot used to attach a loop of cord around a rope, applied in climbing, canyoneering, mountaineering, caving, rope rescue, ziplining, and by arborists. The term Prusik is a name for both the loops of cord used ...

Klemheist knot The klemheist knot or French Machard knot is a type of friction hitch that grips the rope when weight is applied, and is free to move when the weight is released. It is used similarly to a Prusik knot or the Bachmann knot to ascend or descend a ...

, and

Bachmann knot The Bachmann hitch (sometimes misspelled 'Bachman') is a friction hitch, named after the Austrian alpinist Franz Bachmann. It is useful when the friction hitch needs to be reset quickly or often or made to be self-tending as in crevasse and sel ...

. The Ashley Book of Knots #505.

References

External links

*
Backing up an Abseil
Climbing knots Climbing techniques Caving techniques {{Climbing-stub

See also

References

External links