Amsteel or such for offshore cruising lifelines

[Tom U]

I'm getting nervous about the rust at the swages on my vinyl covered lifelines, and wondering about using the new high strength Amsteel or Spectra materials instead. How will they hold up in this application, especially w/r/t chafe, UV, and stretch?

Our boat is 28 feet on deck with a gate on each side, so none of the lengths will be very long. Any thoughts?