Belay Devices Explained

Friction is the key word here! The sole purpose of a belay device, used properly, is to create friction. If your climbing partner fell while climbing, and you were holding the rope with your bare hands, it would take enormous strength to hold the fall. In fact, it is nearly impossible. That is why we use belay devices.

The system pictured has three elements. First, the carabeiner. The carabeiner (always a locking one when used with a belay device!) is clipped through the black plastic loop of the belay device, and the loop of rope that was threaded through the device. The second element is the belay device itself. The loop it has on the bottom, clipped into the beiner, is there to assure that the belay devices can't travel up the rope while belaying.

The rope then enters the system. Notice one piece leaves at the right. This is where the brake hand always resides. The other end of the rope, that goes upwards, is where the climber is tied into.

In the event of a fall, all the belay has to do is pull the brake hand down to their side.

When the rope is pulled tight, and the brake end is down, it creates enough friction to keep the rope from moving. The most friction is created where the rope turns 180 degrees in the belay system, which are indicated in yellow. Belay devices are also used for rappeling. Examine the picture of the belay device below. It is an ATC.

Notice that the ATC has two slots for threading a rope. While belaying, you usually only use one, unless you are using a double rope system. Most often, however, both these slots are used when rappeling. A normal rappel set up goes something like this: after the climb is finished, the climber clips into the anchor. Then the climber threads the rope through the anchor, and pulls up one half of it. The half at the top is on the opposite side of the anchor than the half the belay was connected to. The half of the rope at the top is thrown down, so now we have a rope that is essentially folded in half over the anchor.

The climber then threads first one of the pieces hanging down through their belay device. Then the other piece that is hanging down is threaded through the other slot. The system now looks similar to the belay system picture above, but with two ropes. Remember, the purpose of a belay device is to create friction. You could try sliding down a rope with your bare hands, but it probably wouldn't feel to great, or work well either. The rappel system described provides plenty of friction. If you want to start sliding down the rope, you simply let off of your brake hand (which is holding both ropes now!). This reduces friction, which in turn lets gravity take over, and you slide down the rope. If you want to stop, you simply move your brake hand to the brake position while holding both ropes. As with belaying, when rappeling, don't let go with your brake hand, ever!

There are many different kinds of belay devices, but they all have the same basic design. When it comes time to get your own belay device, you might want to get an extra, or a figure 8 as a backup. A belay plate. This function the same way an ATC or belay tube will. The spring-like wire at it's base performs the same function that the ATC's plastic loop does.