Simul-climbing (or using arunning-belay) is aclimbing technique where a pair of climbers who are attached by arope simultaneously ascend amulti-pitch climbingroute.[1] It contrasts withlead climbing where the leader ascends a givenpitch on the route while the second climber remains in a fixed position tobelay the leader in case they fall.[1] Simul-climbing is notfree solo climbing, as the lead simul-climber will clip the rope into points ofclimbing protection as they ascend.[2] Simul-climbing is different from arope team (which can involve larger groups) andshort-roping [fr] (used byguides with their clients), which are used for flatter terrain that doesn't typically need protection points.[3]
Simul-climbing is an advanced and potentially dangerous technique.[4][5] A fall by either climber is serious, and a 2019 article inOutside said "That's why there's a simple rule of simul-climbing: don't fall."[6] In simul-climbing, the strongest climber goes second.[1] Contemporary simul-climbers useprogress capture devices (PCDs) at some of the protection points so that if the following climber falls, the PCD will lock the rope holding the falling climber and preventing the leader from being pulled off.[2][7] While PCDs can control the consequences of a fall, no manufacturer of PCDs recommends their use for simul-climbing, and the falls from simul-climbing can place greater forces and stresses on the rope and/or the PCD than they were made to handle.[4][8] The second climber will also use anassisted braking device as abelay device which will auto-lock in the event of a leader fall.[2][7]
Simul-climbing is most commonly used by experiencedalpinists on very longalpine climbing routes so they can move quickly on terrain that both climbers are very comfortable with, but which is sufficiently exposed to require protection.[3][9][10] Examples are long sharp alpine ridges or aretes or easier-angled rock slabs andcouloirs (see images).[3][4]Alex Honnold andTommy Caldwell considered their ability to simul-climbgrade 5.10 rock climbing routes as critical to theiraward winningtraverse ofCerro Chaltén Group in 2014.[11] Simul-climbing has also been used in settingspeed climbing records onbig wall climbing routes such as onThe Nose onEl Capitan.[12] Speed simul-climbers can reduce the climbing time by three quarters by using fewer points of climbing protection (known as "running-out"),[6] but this has led to fatalities,[13] and concerns about the danger of the technique.[12] A safer alternative to simul-climbing for steep big wall routes is the technique ofshort-fixing, where the leader effectively sets up afixed rope for the second climber to ascend while the leader simultaneously continues up the next pitch using arope solo climbing technique.[1]
