If in doubt, start with four if the hitch is really sticky or difficult to move, then try three. You will generally want either three or four wraps with 6mm cord and most climbing rope thicknesses, either will work. Generally, the bigger the difference between the two, the fewer wraps you need. How many wraps do you need? It depends on the thickness of your autobloc cord as well as that of your rappel rope.

Take care to keep the cord strands untwisted and parallel as you wrap this will help your hitch move smoothly and avoid unintentional binding during use. I like to hold the knot while I do this, starting above the rappel rope and wrapping down it, toward the ground. Wrap the autobloc cord around the brake side of your rappel rope. If the autobloc does get into the rappel device, it can either jam things up so you can't move OR fail as a back-up, letting the rope run free. The length of the cord is important: it needs to be long enough to allow for the hitch with some slack, but not so long that it can get sucked up into your rappel device. If you go the girth hitch route, you'll need a longer cord than you would otherwise. Do this via a carabiner (as pictured), or by connecting the cord directly to your leg loop with a girth hitch. Attach the autobloc cord to the leg loop of your harness. Sterling makes a nice pre-assembled friction hitch cord out of heat-resistant Technora / Aramid fiber, but it's easy enough to make your own friction hitch out of 6mm accessory cord.Ģ.

A double fisherman's knot with very fairly short tails (10 - 20 millimeters) works best to connect the cord ends into a loop. I recommend 6 or 7mm accessory cord, cut to 44' long. Buy or make an friction hitch / autobloc cord.

Atc climbing rappelling instructions