Just tested some 8,5 mm dynamic half ropes to destruction on the tensile tester (because I can).
Double overhand knots both ends (uses less rope).
Breaking load was 8,0kN extension was measured at 230mm for a sample of around 250mm eye to eye.
Strain rate was 50mm / min.
Given that the double overhand de-rates the rope strength to 45-55% of the original strength then this would possibly suggest that the rope has a static strength of 14,4 - 17,8 kN.
A 10,5mm semi static EN1891 rope is required to make 22,0kN static.
Given a reduction in cross sectional area of 1,5 times, and similar core/sheath ratios I'd expect a reduction in strength proportional to the loss of cross sectional area. 22,0/1,5=14,7 kN.
I was surprised that the rope failed at 8kN I was expecting higher even with the evil overhand knots. I was impressed by the elasticity, and yes I know they are designed to stretch, Max Impact Force is quoted at 5,5kN.
My question is: Does anyone have any similar data from other ropes they can share?
Post edited at 18:32