For the tarp end, I would use an end splice (Bitter end goes through the
grommet then through the middle of the line itself and then wraps around
and back through the middle of the better end (6" up) and then it feed
up the center. The end of a pen of a proper fid will help.

Where you tie it, I would use 4 half hitches and then wire tie the
bitter end so it can be undone

Garland Gray II wrote:

I'm sure you know that polypropelene doesn't handle uv well.
Don't know how long you expect to have this tarp erected, but maybe it's
made of the same stuff, so won't matter.

"Courtney Thomas" wrote in message
...

Thanks for the interest of all.

The immediate use is to tie a tarp down so you see my concern about it
staying tied and being easily untied, I was given 600' of 3/8" and other
than dinghy painter have no other use for it, so am going to use it to
secure the tarp.

I'll whip the ends with electrical tape but what particular knot would you
use, given my application ?

Gratefully,
Courtney

Dave wrote:
On Sun, 14 Jan 2007 15:39:48 -0500, Jeff said:

You have to tell us whether you mean Polyester, of which Dacron is a
brand name, and is used for all sorts of running rigging, or
Polypropylene which is a much weaker rope, but which floats and is
used for water toys, etc. There is a huge difference in their ability
to hold knots.

Seems to me it's fair to assume he's asking about polypropylene, since
there'd be no reason to ask about polyester lines. In fact I see no reason
to even ask your question other than to demonstrate your knowledge of
chemistry.

Sorry, I had actually composed a response assuming polyprop and then
realized the ambiguity. Part of the problem, however, is that
nowadays the newer forms of polypropylene will hold a know rather
well, so to answer the question, one must know what type it is, and
what the application is.

For holding down a tarp, I'd throw away the presumably cheap, slippery
polyprop and go to the Home Depot where you can buy a lot of line that
will hold knot and is cheap enough to just chop away in the Spring.

Dave wrote:

Possibly not a good idea. Last time I was at the yard I noted a
couple of
those jugs on other boats that had chafed through the lines and
fallen on
the ground.

Not sure I understand.

Are you saying the plastic jug handle had chafed thru or was it the
line at say a grommet?

Never had a problem myself, but then I usually checked the boat at
least once between November and April.

Lew

On 14 Jan 2007 10:54:39 -0800, wrote:

We use poly rope for stern tying up in Desolation Sound. I use the
same knots for any given application that I would use for other lines
except that I tape the bitter end off with electrical tape because poly
does have a habit for coming undone?

Yes. Leave longer tails than normal and tape them.

Look up knots for fishing line. Poly acts a lot like monofilament when
you tie it, so some of the fisherman's knots should work.

Bob wrote:
Courtney Thomas wrote:

I'll whip the ends with electrical tape but what particular knot would
you use, given my application ?

Gratefully,
Courtney


When I worked in the GOM for a diving contractor we used that
yellow/oranag poly often for attaching a bouy to a pipe.The stuff is
very slippery. The constant motion of the sea will work harder than a
raccoon to undo most any knot with great success. There are two knots
that I have used for poly in the water:

1) The Poly Knot, to make an eye with braded or three strand.
2) West Coast Dungi Crabber's Bouy Knot, to attach two bitter ends of
similar size three strand poly.

Would you like instructions?
Bob


Yes, PLEASE ...:-)

Thank you.

Jeff wrote:
Courtney Thomas wrote:
What is the best knot that not only will stay tied but is easy to
untie and where can I find an example of how to tie it, please ?

Thank you,
Courtney
You have to tell us whether you mean Polyester, of which Dacron is a
brand name, and is used for all sorts of running rigging, or
Polypropylene which is a much weaker rope, but which floats and is used
for water toys, etc. There is a huge difference in their ability to
hold knots.

While you're at it, you might tell us the application and the size and
type of line. For example, cheap polypropylene won't hold a bowline at
all, but some of the modern forms will.

Also, be careful taking advice from the traditional books, such as
Graumont or Ashley, since both types of "Poly" came into use after these
books were written.

Thank you. I'm using very cheap 3/8" polypropylene line. I have Ashley,
and that's why I'm tryin' to get experienced user's comments.

Cordially,
Courtney

Jeff wrote:
Dave wrote:
On Sun, 14 Jan 2007 15:39:48 -0500, Jeff said:

You have to tell us whether you mean Polyester, of which Dacron is a
brand name, and is used for all sorts of running rigging, or
Polypropylene which is a much weaker rope, but which floats and is
used for water toys, etc. There is a huge difference in their
ability to hold knots.

Seems to me it's fair to assume he's asking about polypropylene, since
there'd be no reason to ask about polyester lines. In fact I see no
reason
to even ask your question other than to demonstrate your knowledge of
chemistry.

Sorry, I had actually composed a response assuming polyprop and then
realized the ambiguity. Part of the problem, however, is that nowadays
the newer forms of polypropylene will hold a know rather well, so to
answer the question, one must know what type it is, and what the
application is.

For holding down a tarp, I'd throw away the presumably cheap, slippery
polyprop and go to the Home Depot where you can buy a lot of line that
will hold knot and is cheap enough to just chop away in the Spring.

Understood, but I have 600' of this stuff from Harbor Freight that was
given to me and finally have a use, hopefully, for it :-)

Just need a knot that'll hold.

Courtney

Dave wrote:
On Mon, 15 Jan 2007 03:20:28 GMT, Lew Hodgett
said:

Not sure I understand.

Are you saying the plastic jug handle had chafed thru or was it the
line at say a grommet?

Dunno. It wasn't my boat, and I didn't look closely. Just noticed the jugs
on the ground and the line ends loose.

I remember seeing the same thing at my yard - I forget where the
failure point was (I's guess the grommet), but there were several jugs
lying on the ground and I remember thinking "there's another cute
solution that didn't work." A issue with polyprop is a low melting
point, so any chafe point that causes enough friction to heat up is a
potential problem.

Courtney Thomas wrote:
Jeff wrote:
For holding down a tarp, I'd throw away the presumably cheap, slippery
polyprop and go to the Home Depot where you can buy a lot of line that
will hold knot and is cheap enough to just chop away in the Spring.

Understood, but I have 600' of this stuff from Harbor Freight that was
given to me and finally have a use, hopefully, for it :-)

Just need a knot that'll hold.


I did a quick scan of rec.crafts.knots and my newer knot books by
Budworth - they all acknowledge the problem with polyprop but offer no
easy solutions. I've always added several extra hitches, and opened
the lay to tuck a generous tail through. A wrap with electrical tape
would work, and now that I think about it, a cable tie would probably
do a great job of securing a knot.