Walt wrote in rec.skiing.alpine:

Where do you get this? I've seen all-polypro rope, and Spectra with
polypro braided exterior, but not Dynema. Only 2 hits on the web for
"polypro Dynema rope", neither with substantial information.

WARNING: Boatnerd talk ahead - lubbers please avert your eyes.

I've been using Samson Ultralight, which is Polypro/Dynema SK-60 and
Yale Conception which is Polypro/Dynema SK-75. Conception is single
braid which means you can splice it, so I've been using it for
split-tail mainsheets. Ultralight is a Dynema core under a polypro
cover which makes it a PITA to splice, but it works well for anything
that doesn't need splicing. There are other choices as well.

You can get them from the usual suppliers, like APS.
http://www.apsltd.com/Tree/d3000/e846.asp

Plus they work great as thongs and string bikinis for spring [ob]skiing.

LOL. Thanks for the info Walt!

For whitewater boaters, looks like Yale Conception would make a great
throw-rope, while Samson Lite Speed would make a great rescue line.

Both are lighter than Spectra rope, and stronger than polypro rope.
The Samson Lite Speed actually has higher tensile strength than Spectra
of the same diameter.

Bill Tuthill wrote:
Walt wrote in rec.skiing.alpine:

Where do you get this? I've seen all-polypro rope, and Spectra with
polypro braided exterior, but not Dynema. Only 2 hits on the web for
"polypro Dynema rope", neither with substantial information.

WARNING: Boatnerd talk ahead - lubbers please avert your eyes.

I've been using Samson Ultralight, which is Polypro/Dynema SK-60 and
Yale Conception which is Polypro/Dynema SK-75. Conception is single
braid which means you can splice it, so I've been using it for
split-tail mainsheets. Ultralight is a Dynema core under a polypro
cover which makes it a PITA to splice, but it works well for anything
that doesn't need splicing. There are other choices as well.

You can get them from the usual suppliers, like APS.
http://www.apsltd.com/Tree/d3000/e846.asp

Plus they work great as thongs and string bikinis for spring [ob]skiing.

LOL. Thanks for the info Walt!

For whitewater boaters, looks like Yale Conception would make a great
throw-rope, while Samson Lite Speed would make a great rescue line.

Both are lighter than Spectra rope, and stronger than polypro rope.
The Samson Lite Speed actually has higher tensile strength than Spectra
of the same diameter.


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.

s/boat/rescuee

For [ob]skiing the only lines I ever use is yarn for powder cords.

//Walt

In rec.boats.paddle Walt wrote:

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.

Boating whitewater, rescue lines are usually used to pull a boat off of
rocks or other obstacles. Stretch is wasted effort, and I suppose hides signs
of an impending failure.
Sometimes it is necessary to throw the rescue line out to someone or
something midstream for an extraction, so the throwbags get used in the
same manner.

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.

Again, a difference in the whitewater environment. It might take significant
force to move a boat (or person!) pinned against a rock by the current.

Jeremy wrote:
In rec.boats.paddle Walt wrote:

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.

Boating whitewater, rescue lines are usually used to pull a boat off of
rocks or other obstacles. Stretch is wasted effort, and I suppose hides signs
of an impending failure.

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.

Sometimes it is necessary to throw the rescue line out to someone or
something midstream for an extraction, so the throwbags get used in the
same manner.

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.

Again, a difference in the whitewater environment. It might take significant
force to move a boat (or person!) pinned against a rock by the current.

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?

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

//Walt

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.

On 5-May-2006, Bill Tuthill wrote:

Both are lighter than Spectra rope, and stronger than polypro rope.
The Samson Lite Speed actually has higher tensile strength than Spectra
of the same diameter.

I'm late to this thread, but I thought I'd comment.

You do know that Spectra and Dyneema are the same thing, right? (different
trade marks).

Mike

Michael Daly wrote:
On 5-May-2006, Bill Tuthill wrote:

Both are lighter than Spectra rope, and stronger than polypro rope.
The Samson Lite Speed actually has higher tensile strength than Spectra
of the same diameter.

I'm late to this thread, but I thought I'd comment.

You do know that Spectra and Dyneema are the same thing, right? (different
trade marks).

In case anyone actually cares, Spectra is the name of product Allied
Signal manufactures in the US under licence from Hoescht-Celanese in
Germany, the manufacturer of Dyneema. They are identical fibers, though
they can be made into a variety of products that may differ widely.

In rec.skiing.alpine Brian Nystrom wrote:
Michael Daly wrote:
On 5-May-2006, Bill Tuthill wrote:

Both are lighter than Spectra rope, and stronger than polypro rope.
The Samson Lite Speed actually has higher tensile strength than Spectra
of the same diameter.

I'm late to this thread, but I thought I'd comment.

You do know that Spectra and Dyneema are the same thing, right? (different
trade marks).

In case anyone actually cares, Spectra is the name of product Allied
Signal manufactures in the US under licence from Hoescht-Celanese in
Germany, the manufacturer of Dyneema. They are identical fibers, though
they can be made into a variety of products that may differ widely.

Ultra High Molecular Weight Extended PolyEthylene if I remember
right. The carbon bonds are stretched out toward 180 degrees so it is
very stiff since you are pulling on the actual bond rather than
bending it. Once you get it warm though, those bonds go back toward
they're normal angle, making it less stiff.

-klaus

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)

In rec.boats.paddle Brian Nystrom wrote:

In case anyone actually cares, Spectra is the name of product Allied
Signal manufactures in the US under licence from Hoescht-Celanese in
Germany, the manufacturer of Dyneema. They are identical fibers, though
they can be made into a variety of products that may differ widely.

According to the Dyneema website, they are a Dutch company.

http://www.dsm.com/en_US/html/hpf/home_dyneema.htm

Spectra and Dyneema are both made of polyethylene, but is that evidence
to indicate they are really "the same thing"?

Specs indicate Dyneema-core ropes have slightly higher tensile strength
than Spectra and some marketing blurbs indicate they have a softer feel.