Yesterday (June 2nd) Joe, Beth and myself used AMS's drop tower to test the strength of zip-ties incorporated into the the sled hauling system for expedition/glacier travel.
We were trying to determine how many zip-ties it would require to hold the static weight of a loaded expedition sled and at what point they would fail in the event of a crevasse fall.
We used two different width zip-ties as a single and a double.
After many drop tests and static loads we determined the ideal setup would be to use two of the wider zip-ties to shorten the length of the sled haul to create a breakable link in the system to allow the weight of the sled to be transfered to rope instead of continuing to pull on the climbers pack after a crevasse fall.
This system is used by a few guide company's on the mountain, and to our knowledge, has not been tested for static and dynamic loads (only live field testing).
Getting ready to drop-test the sled haul with zip-ties.
(Photo courtesy of Joe Butler)