I've heard or seen something somewhere about using some of the new
super low stretch rope for lifelines.
Has anyone heard about that idea?

-- Roger Long

Yup. Steve Dashew was using it for his last sailboats. 1/4" 12
strand Spectra is lots stronger than 3/16" s.s. Not as chafe/damage
resistant but actually lighter and cheaper if you buy it from the
right place. Not approved for racing sailboats generally.

Evan Gatehouse