Slow Pull Testing 3 to 1 Haul Systems on 11mm PMI Classic Sport Max (Pit Rope)

We broke eleven 3:1 haul systems built with 11mm PMI Classic Sport Max (Pit Rope) with 8mm PMI accessory cord prusik to:
1. Identify the weakest link
2. Identify the failure mode
3. Quantify the failure strength
Results:
1. The weakest point is the prusik
2. The prusiks continuously slipped throughout the pull
3. The average highest slip value was 21.6 kN (21.6 lbs), with a standard deviation of 5.8 kN (1305 lbs), and range of 16.6 kN (3780 lbs).
4. The results were consistent for all the haul systems built with the same components, however the haul systems that were built with other rope and accessory cord combinations provided different results.
The results will be presented at the International Technical Rescue Symposium (ITRS) 2015. When the paper is finished it will be posted on the ITRS web page at:
www.itrs-online...
Or visit the SARRR research archive web page at:
sarrr.weebly.com/