Rigging Myths and other things rope
NZOIA Symposium Paper, Tihoi, October, 2014, by Grant Prattley.
At the NZOIA conference at Tihoi we had a bunch of people out for half a day breaking and load testing various components in rope systems and maybe a few myths along the way. Back in the classroom, we discussed the theoretical concept of vectors. The idea was to open up the thinking and start analysing what you have.
Testing
We set up a load cell and then various participants produced all sorts of old and new bits of gear to test. We broke the gear with a 9:1 pulley system with around 4-6 people pulling. Using a pulley system allows you to feel the real force required to break the gear. The testing was limited to software as hardware tends to have a mind of it own once broken. The serious business of breaking stuff and then the final act of breaking the load cell (accidentally).
What we tested:
- 8mm nylon accessory cord – Clove Hitch, Figure 8 on the bight.
- 6mm accessory cord on 10mm Donaghys Polyester – Prusik (Classic), Klemheist, French.
- 11mm nylon static rope – 6mm Accessory Cord VT Prusik (Canyoning), Croll (mechanical ascender).
- 10mm Beal Dynamic – Clove Hitch
- 11mm nylon static rope – Italian hitch holding power
- 20mm Webbing – Girth hitch onto a carabiner, Tape bend.
