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MariaB -> RE: dropping a bondaged person (8/6/2013 6:37:43 AM)
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just a snippet of something we are presently involved in which involves shock loading tests on 'hemp' rope and certified rock climbing carabiners. This test was to simulate what happens when small mass moves at high speed and abruptly stops (a sudden but halted drop). The tests were to find the limitations of a material, in this case 9mm hemp rope.
For the fully certified carabiner which was used in the rope anchor test, along with with a length of nylon kernmantle constructed rope, we replicated the time you fell onto it. A resulting 2ft drop of 160lbs weight, put shock loads on the bina that peaked at 1,700 pounds force, much higher than you’d expect for such a small fall. Now although this didn’t approach the gear’s load limits, these shock loads could badly injure the person being suspended ( in the case of none dynamic rope.)
The results of the hemp rope drops were more worrying. Brand new, untreated (at its strongest) 9mm hemp rope, carrying 160lbs, broke at the end of a 40 inch fall. Further testing was done with 4 anchors and four ropes suspending a weight of 160lbs, the fall was halted again at 40 inches. The shock loads were over two tons and all four ropes broke catastrophically.
Hemp rope can statically take a lot of weight but this rope is not designed for or strong enough to hold even the shortest of falls.
More to come
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