b. Seat-Hip Rappel. The seat-hip rappel uses a mechanical rappel device that is inserted in a sling rope seat and is fastened to the rappeller to provide the necessary friction to remain in control. This method provides a faster and more controlled descent than any other method (Figure 5-30). There are several mechanical rappel devices (Figures 5-31 and 5-32) that can be used for the seat-hip rappel.