Found an old Test Report from my Black Diamond days. Thanks to BD for the testing apparatus:
Paul so graciously tested a Sterling 8mm rope that I mangled pretty badly in Imlay canyon. In the course of 3 people rapping 35 rappels, mostly single strand, I ended up with 5 core shots. This was (thankfully) a brand new Sterling 8mm HTP Static line generously donated to the cause by Sterling Ropes.
I cut the rope around the core shots creating approx 36″ test sections with the shots in the center. I then tied each end in an overhand knot to put on the test machine. I also tested 2 segments of the same used rope with no significant sheath damage.
All test segments broke at the knot. (Guess I should have used a figure 8!)
Results:
Non-damaged: A: 1729 lbs B: 1532 lbs
Coreshots: A: 2255 lbs B: 2058 lbs C: 1750 lbs D: 1714 lbs E: 1658 lbs
Conclusions/Comments:
1. Use of a stronger knot would have made for a better test.
2. Core shot ropes showed retained strength up to 1600 lbs. (Doesn’t mean you should use them).
It should be noted in all cases that the core shots started small and spiraled down the rope via repeated rapping. In no cases was there any indication that the core itself was chewed into or damaged in any significant fashion.
It is presumed that the test results are indicative of all small diameter static ropes regardless of brand.
Tom
Sonny Lawrence
I tested my Canyon Pro which obtained a core shot on Spry a couple weeks ago. It broke at the knot (double fisherman’s)and at the pin in the machine (moving arm) at about 2200 pounds. It did not suffer more damage at the original core shot location.