Enlengthening SpanSets more longerer


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It has to do with how the fibers move in each one and how much a bend would derate it by. In a rope when the fibers are woven together the movement of the individual fibers along the entire length of the rope are less pronounced. The weave makes the fibers work together locally, and so bending does not reduce the individual fiber strength as much. In a poly sling the fibers need to freely move along the entire "length" of the sling as they loop around to equalize the force amongst all fibers. So they are working together globally, but not locally. This means that a bend or knot will reduce the strength much more than the rope because you are halting the movement of the individual fibers.

I hope that makes sense.
Huh. First - I somehow had never noticed that a standard static line was also woven - I guess since the ends generally are melted when you cut them I had been labouring under the delusion that the strands ran parallel to each other much like in a sling - which is why I specified a kernmantle rope rather than a traditional woven rope. But of course you're right - both types have a woven core. Learn something new every day. Second: following that, the explanation seems to make sense except that it would appear to explain the opposite condition: if the strands in a sling are independently moving as a single yarn, then as force is applied - let's say as a basket over a an I-beam takes weight - all the fibres should shift to equalize the forces applied. In a rope which is woven the weaving should reduce the ability of the fibres to move which would increase the disproportionate loading as a bend is introduced. As you point out, one is is working globally and the other locally - but local distribution of force is going to make failure under load occur earlier rather than later....right? Again, what am I missing? And thanks for the reply - I'm genuinely interested in understanding this better.

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