Originally Posted by smurphny
These high-tech lines are light but they do stretch considerably over time. I considered it when re-rigging but did not like the idea of a sharp edge being able to slice through my standing rigging. Also, I considered abrasion resistance and sun deterioration. I did use Amsteel for lifelines which has worked out fine but they are more or less static whereas standing rigging is constantly stress-cycled.
Hmm ... "quite a bit over time" is pretty fuzzy. It may mean something different to you than to me. The engineer in me much prefers numbers and equations.
The larger the fiber the less the creep. A rigger friend says the stuff is so strong that maximum rigging loading is on the order of 10% of breaking strength even when the stuff has degraded, which is why they design for creep (i.e. stretching over time with cycling). Normally they want creep to be just a few percent over the planned 10 year lifetime of the rigging. Here's a nice paper
full of equations. Note the table on page 15. It shows creep under 1% for that particular fiber and size.
Will this stuff last 10 years? Well, it depends. Personally, I'd plan on 6 in FL, 8 - 10 in ME. As noted by others earlier, the big enemy is UV and abrasion, which is why the high strength material is used as a core around which is woven a cover that resists UV and abrasion. Regardless, it is susceptible to being sliced by a razor edge with repeated sawing, but it is harder to cut than you might think. You can tell when this stuff is getting close to replacement -- the cover becomes "fuzzy or hairy" with broken fibers sticking out.
I am no expert on these things, and certainly I'm not a rigger, but riggers frequent these boards -- anyone with some practical experience with this stuff care to comment?