Quote:
Originally Posted by Dan Lehman
You must have mis-typed, and mean "nylon" vice "Dacron"
--for what you cite is true only of the former, not the latter.
As for the imperviousness of HMPE to UV degradation, I've read
conflicting accounts of that, including tests of quick-draws used
by rockclimbers left on climbs showing more strength loss than
similarly exposed nylon ones (!).
--dl*
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Dan,
Thanks for the correction.
You are right that some HMPE lines can't take any uv at all, but the new crop of dyneema lines can. It is a different material, and has different characteristics than some others. Vectran for instance has limited uv stability, PBO and Zylon as well have limited uv stability.
However dyneema, specifically amsteel and it's family of lines is highly uv stable, and suitable for uncovered use outdoors. Long term uv studies are still continuing, but the current recommended replacement interval for standing rigging made from dyneema is 6-8 year, as compared to 8 years for stainless steel rigging. My lifelines are going on four years, and still look new, I haven't destruction tested them, but they are still strong enough to break the welds on my bow and sterm pulpit before the line broke.
My halyards are also four years old, and I have yet to see any noticeable degradation on them, though I am thinking of switching out one of them and doing a destruction test just to see. Sadly I don't have a load cell or testing rig strong enough to really stress the line.