typed
I'm not a whitewater boater, so take what I say with the right degree of
skepticism, but I would think that for a rescue line you want a bit of
stretch. For instance, climbing ropes always have a bit of stretch
(made out of nylon usually). The Yale and Samson lines in question are
intended for use as halyards, sheets, and control lines on a sailboat
and are intentionally made to have as little stretch as is possible.
I'm not sure that ultra low stretch is what you want in a throw line.

For my throwable lines, I just use garden variety 3/8 inch 25 cents a
foot polypro - I don't see the need for ultra low stretch or ultra high
strength in a throwable. And for docklines, you really don't want low
stretch - I've seen boats with damaged hulls because the owner recycled
his old sheets as docklines. Let the line absorb the shock, not the boat.


Since I'm one of the rescue geeks, I'll take a swing at this one.

a dynamic line like poly is fine for a throwrope to recover swimmers
since it has a bit of give when that 200 lb boater and kayak full of
water hits the end of the line, but since we normally don't have the
option to carrying two ropes, you are better of using a static line
that can double for your mechanical advantage systems. If you are
trying to pull a boat off the a rock while on a steep river bank, the
less stretch you have the better.

Just as a note, you hardly ever use dynamic lines in vertical rescues.
These type of rappelling lines have minimal stretch and very high
working loads.

BTW, I like the new Rescue Line by Bluewater, cheaper than Spectra and
with a decent working load. And it's available in a 5/16" line that
packs much better than the 3/8" and still can double as a working line
in a mechanical advantage system.