This article is about belaying as it relates to climbing; in this context, belaying refers to the practice of controlling the rope fed out to a climber.
In climbing, belaying is the technique of controlling the rope so that a falling climber does not fall very far. While this task is typically assigned to a belayer, self-belaying is also possible as an advanced technical climbing technique. The term belay is also used to mean the place where the belayer is anchored; this would typically be a ledge, but may instead be a hanging belay, where the belayer is suspended from anchors in the rock.
Control of the rope is achieved through applying friction, which allows control of the speed at which the rope slides past the belayer. This friction is generally achieved by forcing the rope through tight bends and past rough surfaces. Usually either one thick rope (about 11mm) or two thinner ropes (about 9mm) in parallel are used; both systems have their advantages in different situations.
The person climbing is said to be on belay when one of these belaying methods is being used. Belaying is a critical part of the climbing system. By using a correct belaying method, the belayer can hold the entire weight of the climber by using relatively little force, and can easily arrest even a long fall. By using a mixture of belaying angle and hand-grip on the rope, a climber can be lowered gently by the belayer to a safe point where climbing can be resumed.
Climbers should wait for a verbal confirmation from the belayer that they are ready to begin. Usually the climber will ask "On Belay?" and wait for the belayer to reply "Belay On,". Once ready, the climber then follows with a "Climb Ready" or "Climbing". This is usually acknowledged by the belayer saying "Climb On."
During the climb, the climber may ask the belayer for "Slack", "Tension", warn of a "Rock!" or that they are about to be "Falling!".
At the top of the climb, the climber may elect to climb back down, be lowered down, walk back down, or set up a new belay point for another pitch. Whatever they choose to do, it must be made clear to the belayer. When the climber is in a safe position independent of the belay they will call "Off belay".
Silent belay communication is possible via tugging the rope. Though it is much more difficult, it may be necessary in storm weather.
To set up the anchor, the belayer should insert a relevant piece of protection (i.e. a nut or sling) into a crack below his or her body or around a nearby tree. The anchor will arrest any upward force produced during a fall, thus preventing the belayer from "taking off".
Unlike belays set up at the top of a climb, it is not usually necessary for belayers at the bottom to have more than one point of protection as long as the single piece is sturdy and safe - "bomb proof", as it were.
A belay device is a piece of climbing equipment that improves belay safety for the climber by allowing the belayer to manage their duties with minimal physical effort. Belay devices are designed to allow a weak person to easily arrest a climbers fall with maximum control, whilst avoiding twisting, heating or severely bending the rope.
A munter hitch is a method of belaying which creates a friction brake by tying a special knot around an appropriate carabiner. This type of belay, however, causes the rope to become twisted. It can also be used on double ropes, simply tie the munter hitch with the two ropes as if they were one.