I've used Spectra for climbing pro.

It is VERY stiff, so much so that if you bend it, it stays in that position until you bend it different.

It does tie with a double fisherman knot though. I remember it being expensive also.

: After the great discussion last week on deck rigging, I popped down to
: Mariner Kayaks and bought some 1/4" nylon line for the
: safety/perimeter line on my Arctic Tern. Nice feel to the line, thick
: enough for a cold hand to grab, one color (white) fits all, but I didn't
: buy enough. With Mariner closed on Sunday, I stopped at a West Marine
: store to buy some more line, and was amazed to see lots of other lines to
: consider -- polyester double braid; Spectra braid -- all of them with very
: low stretch, good strength and bright colors. Last night I checked Boaters
: World, and found more polyester double braids and Spectra blends. The
: latter is claimed to be not only light, but also doesn't absorb water. Now
: that's an interesting attribute for a deck line.

: A sailing friend tells me I've seen the tip of the iceberg on ropes and line.
: He advises me to disregard the strength and weight data and get a line
: that is somewhat stiff to keep it from snagging my paddle when I roll, yet
: is flexible enough to tie in knots. Sounds good to me. What experiences
: have board members had with these new lines -- particularly Spectra lines?

: Jim