Belay Devices

Most belay devices use a similar design principle –– an aluminum alloy plate or cone with two holes through the centre to accept ropes of various diameters. Devices are used to belay climbers and most can also be used for rappelling.

How Belay Devices Work

The primary function of a device is to provide enough friction to enable the belayer to lock off the rope. Friction reduces the amount of strength required to hold a loaded rope. In lead climbing situations, the rope trails from the climber down the route through various points of protection to the belayer. The rope passes through the belay device and through a locking carabiner that is attached to the belay loop on the belayer's harness. The belayer holds the free end of the rope, ready to feed out rope or catch a fall. When the device is rigged correctly and used with diligence, there is little chance of failure. By far, the most frequent failure of the belay is the result of mishandling or not paying attention.

Auto-locking devices

An auto-locking device (such as a Grigri) clamps down when the rope is loaded suddenly. The principle is similar to a car seat belt. The device assists the belayer in catching falls, it does not eliminate the need for the belayer to hold the free end and to pay close attention.

Safety Note: You should not use a belay device without proper training or close supervision until you demonstrate a reasonable level of skill. After all, you have your partner's life in your hands.