A time-lapse panorama of a rock climber abseiling off a climb
Abseiling (/'æbse?l/ or /'?:pza?l/; from Germanabseilen, 'to rope down'), also known as rappelling (/?æ'p?l/ or /'p?l/) from French rappeler, 'to recall' or 'to pull through'), is a controlled descent off a vertical drop, such as a rock face, using a rope.
This technique is used by climbers, mountaineers, cavers, canyoners, search and rescue and rope access technicians to descend cliffs or slopes when they are too steep and/or dangerous to descend without protection. Many climbers use this technique to protect established anchors from damage. Rope access technicians also use this as a method to access difficult-to-reach areas from above for various industrial applications like maintenance, construction, inspection and welding.
To descend safely, abseilers use a variety of techniques to increase the friction on the rope to the point where it can be controlled comfortably. These techniques range from wrapping the rope around their body (e.g. The Dülfersitz) to using a custom built device like a rack. Practitioners choose a technique based on speed, safety, weight and other circumstantial concerns.
In the United States, the term "rappelling" is used nearly exclusively. In the United Kingdom, both terms are understood, but "abseiling" is strongly preferred. In Australia, New Zealand and Canada, the two terms are used interchangeably. Globally, the term "rappelling" appears in books written in English more often than "abseiling".
The origin of the term rappel in reference to the technique is attributed by Roger Frison-Roche [fr] circa 1944. Frison in turn attributed the techinique of abseiling to Jean Charlet-Straton [fr], a Chamonix guide who lived from 1840-1925. Charlet originally devised the technique during a failed solo attempt of Petit Dru in 1876. After many attempts, some of them solo, he managed to reach the summit of the Petit Dru in 1879 in the company of two other hired Chamonix guides, Prosper Payot and Frédéric Folliguet. During that ascent, Charlet mastered the technique.
Early Dülfersitz or body abseil technique did not require a harness or any equipment
Later double carabiner brake abseil technique used simple carabiner and sling as a harness
Another carabiner based abseil technique
The figure 8 belay device was one of the earliest specialized abseil device, which often required gloves. Now used mostly by military as it allows greater speed of descent.
Modern abseiling technique used by climbers uses belay device
Cave abseils can be long and might have to be done using ropes with varying degrees of friction. That requires specialized brake bar rack
Rescue-style (eared) figure eight descender and rope
Australian rappel -- Used in the military. The abseiler descends facing downwards allowing them to see where they are going.
Tandem or spider abseiling -- Used in climbing. Involves two climbers descending on the same belay device. This is useful in rescue situations when one of the climbers is incapacitated or the descent needs to be done quickly. The set-up is similar to a regular rappelling, with the incapacitated climber suspended from the descender (and backed up on the primary climbers harness).
Simul-rappelling or simultaneously rappelling -- Used in climbing and canyoning. Two climbers descend simultaneously on the same length of rope, where one climber's weight counterbalances the other. Generally the technique is considered less safe than the regular rappelling; however, it's useful in case of emergencies, or for rapping off opposite sides of a fin or spire where there are no anchor points. This is common in places like the Needles of South Dakota's Black Hills.
Counterbalance abseiling -- Used in climbing. This rescue technique is typically used by a leader to reach an injured second. The leader abseils off on one strand of rope, using the incapacitated second's weight on the other strand of the rope as a counterbalance.
Releasable abseil -- Used by guides. This safety technique allows a leader to descend with inexperienced abseilers. A rope about twice the length of the descent is anchored with a munter mule hitch. The client descends on a single isolated strand of the rope. If the client becomes stuck halfway down the guide will be able to unlock the other strand and lower the client to the ground using the hitch as a belay device. This could be useful if the client panics, or gets clothing or hair entangled in the descender.
Classical (non-mechanical methods), e.g. the Dülfersitz -- Used in emergencies. These technique are more dangerous than modern alternatives and only used when no other option is available. They involve descending without aid of mechanical devices, by wrapping the rope around the body, and were used before the advent of harnesses and hardware.
Fireman's Belay -- Safety backup. A partner stands on the ground below holding the rope(s). If the abseiler begins to fall they will be able to pull down on the rope to arrest the descent.
Abseiling can be dangerous, and presents risks, especially to unsupervised or inexperienced abseilers. According to German mountaineer Pit Schubert, about 25% of climbing deaths occur during abseiling, most commonly due to failing anchors. An analysis of American Alpine Club accident reports shows that this is followed by inadequate safety backups and rappelling off the ends of ropes.
Abseiling is prohibited or discouraged in some areas, due to the potential for environmental damage and/or conflict with climbers heading upwards, or the danger to people on the ground.