The Petzl Gri Gri is a versatile auto locking belay device that can also be used to ascend or descend a rope. One widely touted disadvantage of the Gri Gri is that it can’t be used to double rope rappel. This is true, but as I’ll discuss, a Gri Gri can still be used to descend in many scenarios…
For sport climbs shorter than 1/2 of the rope length, a Gri-Gri can be used as shown in Figure 1 to lower oneself to the ground. The anchor must have chains or rings for this to work. This method is especially nice when the route is difficult to clean (read steep) because the climber can take both hands off the rope and still be locked off.
Single Rope Rap
A Gri Gri can be used to single rope rappel, but these would typically require fixing the top of the rope. Here are two methods to descend based on single rope rappels, but that don’t require one to fix the top of the rope.
1. Simu-Rap. Both climbers do single rope rappels on what would typically be a double rope rappel.
2. Rap on the “fixed” side of a double rope rappel. Refer to figure 2. The climber descends on the side opposite side of the anchor from the rappel knot. One could add a stopper carabiner if there was a question as to whether the knot could pull through (shown).
The Gri Gri can be used the descend in most circumstances that a double rope rappel is used. That said, I do not advocate using the Gri Gri as such, many times it simpler to use a normal tube style belay device and double rope rappel.