We use a lot of Sterling PowerCord in our regular operations. We’ve rappelled on it with various devices but none have ever provided a comfortable ride due to the small diameter cord in your brake hand. I’ve been thinking about a new concept specifically designed for PowerCord and today I finally got around to doing a proof-of-concept sample in the shop. It gives a very smooth ride on PowerCord and is more controllable than other devices I’ve used due to the coefficient of friction between the aluminum and nylon and the degree of contact per the Capstan Equation. Total weight of the device is 3.4 ounces and it’s a little over 3” long. There are still improvements to be made but the point is the concept works and now just needs tweaking. I realize there will be those that shudder at the thought of using a 5.9mm cord to rappel or lower on and that’s fine be me. My thoughts and uses are solely my own and not suggesting anyone go outside their scope of practice or comfort zone. With that said, PowerCord is rated at 19.7 kN, so it has the potential of making a very lightweight emergency system since a lot more cord can be carried in for its weight. This is the beta model of the device. Again, there are improvements that needs to be made and once again I realize this is not for everyone.
If my office is burning (or an angry ex appears) I would be happy to slide down the wall on a shoelace ! For a lightweight system that you will have with you (like the .45 vs .32 argument) when you may need it I think it is great.
@Jeff Randall any concerns with the Sterling PowerCord rubbing against itself here? (Rope on rope friction)
This is a doubtful concern as it is never rubbing in the same spot continuously....think about a Munter hitch...same principle int that the rope is traveling over itself.
We use a Munter a LOT....usually on a wet and dirty rope....given the shape of a Munter hitch I'd say there would be more tension and high friction in the rope than on the device that Jeff designed...If anything...the actual belay device might get pretty hot on a longer rappel..I had a scar on my forearm from a ATS on a near 200' rap....quite a burn...think Jeff has one too in the same spot on his arm..