Walt wrote:

Talk to the climbers. They're even more fanatical about their lines
than we sailors. Climbing line is always a little stretchy, and the
stretchyness is not considered a sign of impending failure. That said,
a throwable rescue line doesn't need to be as stretchy as climbing
safety line, and probably shouldn't feel stretchy at all.

Different tools for different situations. A climber's line stretches to
absorb energy. After a long fall, the line is removed from service. There
isn't the option to take it out of service mid-fall. A line to a wrapped
boat can be a hazard if it breaks, throwing hardware at high velocity. If
it shows signs of hitting its limit, the line can be replaced or assisted
with a second line.

3/8" polypro line has a tensile strength of almost 3000 pounds. You're
going to heave 3000 pounds? By hand? Would your kayak stand up to 3000
pounds of force? Would your potential rescuee?

Me personally? No. 10 people using a pulley-based mechanical advantage
system? Yes. Might that much force be required for a fully submerged,
heavily loaded raft?
http://www.cacreeks.com/photos/z-blsm5.jpg
I think so.

Actually, I'd be curious as to what serious kayakers are using in the
throwable bag.

Here's what one company sells:
http://www.nrsweb.com/shop/product_list.asp?deptid=1039

I have one of the 1/4 inch polypro lines, which I concluded recently is NOT
suitable for pulling things off of rocks.

Jeremy wrote:

http://www.nrsweb.com/shop/product_list.asp?deptid=1039

I have one of the 1/4 inch polypro lines, which I concluded recently
is NOT suitable for pulling things off of rocks.

Thanks for all your poste, Jeremy.

I have a 1/4 inch Spectra line, which has almost 3x the tensile strength
of polypro, but doesn't throw or coil as easily. It feels too stiff.
Whereas the 3/8" Spectra line handles more like a real rescue rope.
But the 1/4 Spectra was able to unwrap this boat without snapping, using
the (Boy-scoutless) "Ten Boy Scouts" method:

http://cacreeks.com/photos/antelop5.jpg

The yellow line you see in the picture going from the far side of the rock
to the lower right of the picture, did snap.

(Sorry about the subject; forgot to change it)

Bill Tuthill wrote:
Jeremy wrote:

http://www.nrsweb.com/shop/product_list.asp?deptid=1039

I have one of the 1/4 inch polypro lines, which I concluded recently
is NOT suitable for pulling things off of rocks.

Thanks for all your poste, Jeremy.

I have a 1/4 inch Spectra line, which has almost 3x the tensile strength
of polypro, but doesn't throw or coil as easily. It feels too stiff.
Whereas the 3/8" Spectra line handles more like a real rescue rope.
But the 1/4 Spectra was able to unwrap this boat without snapping, using
the (Boy-scoutless) "Ten Boy Scouts" method:

That's useful feedback. I was considering replacing my polypro line with the
equivalent width spectra. The polypro started out nearly bath towel soft,
and is probably almost as strong. Have you found a better dual-use line
suitable for carrying in a kayak?

http://cacreeks.com/photos/antelop5.jpg

Our little situation wasn't nearly as submerged, but had the added benefit
of oars and frame to lock it down.

Jeremy wrote:

That's useful feedback. I was considering replacing my polypro line with the
equivalent width spectra. The polypro started out nearly bath towel soft,
and is probably almost as strong. Have you found a better dual-use line
suitable for carrying in a kayak?

Based on specs below, I am going to buy 50' of Yale Conception 6mm (1/4")
to replace the braided Polypro that came with my $27 Kayaker's Throwbag.
http://theboatpeople.com/atr_safety.html#throwbags
The 50' of braided 5/16" Polypro will become the new bowline for my raft.
I'll report back after initial use. NRS Spectra might be Blue Line.

tensile cost/ft #/100ft handling
NRS Spectra 6mm 2500# $.80 1.6# stiff and abrasive
Yale Conception 6mm 2500# $.62 1.4# soft hand?
Yale Conception 8mm 4100# $.95 2.0# soft hand?
Bluewater Polypro 8mm 1900# $.56 3.0# core, but handles well
NRS Spectra 10mm 4966# $.99 3.4# semi stiff, not bad
Yale Conception 10mm 5500# $1.32 3.5# soft hand?

What makes Yale Conception unusual (easier handling characteristics)
is that the Dyneema is braided together with Polypro. This makes it
lightweight, soft, and unitary. Blue Line(?) Spectra has an inner core
that makes it very stiff, and the Polypro sheath behaves differently,
and comes apart from, the Spectra core. This is OK in a 10mm (3/8")
line, but I just don't like it in a 6mm (1/4") line.

Bill Tuthill wrote:

Jeremy wrote:

That's useful feedback. I was considering replacing my polypro line with the
equivalent width spectra. The polypro started out nearly bath towel soft,
and is probably almost as strong. Have you found a better dual-use line
suitable for carrying in a kayak?

Based on specs below, I am going to buy 50' of Yale Conception 6mm (1/4")
to replace the braided Polypro that came with my $27 Kayaker's Throwbag.
http://theboatpeople.com/atr_safety.html#throwbags
The 50' of braided 5/16" Polypro will become the new bowline for my raft.
I'll report back after initial use. NRS Spectra might be Blue Line.

tensile cost/ft #/100ft handling
NRS Spectra 6mm 2500# $.80 1.6# stiff and abrasive
Yale Conception 6mm 2500# $.62 1.4# soft hand?
Yale Conception 8mm 4100# $.95 2.0# soft hand?
Bluewater Polypro 8mm 1900# $.56 3.0# core, but handles well
NRS Spectra 10mm 4966# $.99 3.4# semi stiff, not bad
Yale Conception 10mm 5500# $1.32 3.5# soft hand?

What makes Yale Conception unusual (easier handling characteristics)
is that the Dyneema is braided together with Polypro. This makes it
lightweight, soft, and unitary. Blue Line(?) Spectra has an inner core
that makes it very stiff, and the Polypro sheath behaves differently,
and comes apart from, the Spectra core. This is OK in a 10mm (3/8")
line, but I just don't like it in a 6mm (1/4") line.

I think you'll like the Yale Conception. It is quite soft, not at all
stiff, very lightweight and pretty grippy. I've been using it as a
mainsheet for two seasons of hard use, and it's held up pretty well.
Note that it runs a bit fat and tends to flatten out when cleated, but
that's probably not an issue for your intended usage.

I respectfully withdraw my concerns about ultra low stretch lines as
throwables, other than the increased cost. Of course, if you are ever
in a situation where it really makes a difference the extra $50 is
pretty darned irrelevant in the greater scheme of things.

//Walt