Rusty,

Thank you. Pardon me if I push the point a bit further and ask for
clarification and amplification.

Much of the windy weather in which I dock is _dry_, so under those
circumstances the point about keeping the line wet is moot, unless I stand
there 24/7 with a garden hose. But I have never heard of lines "melting"
under those conditions.

So, I follow your theory, but i) do you have a reference and ii) do you have
any experience or knowledge of lines actually sustaining heat damage under
prolonged load/unload cycles.

I would guess that more significant advantage of leather is that it moves
with the line, whereas with hose the line moves inside the tube - still
better than rubbing against the boat (and also somewhat unsightly).

My garden hoses, OTOH, are showing no signs of wear after several seasons of
use. How long does leather last?

Thanks again.

Charles

====

Charles T. Low
www.boatdocking.com

====

"Red Cloud®" wrote in message
...

Nylon line stretches under load. In rough conditions, that line will be
stretching and unstretching constantly. As the line stretches and
contracts, the
individual fibers rub against each other, causing friction. Keeping the
line wet
lubricates and cools it so the nylon doesn't begin to melt from this
action. The
problem is not just the actual chafe point, but all along the line. If you
cover
part of the line with something that keeps it dry, you risk a melted line.

I use leather chafe protection as everyday chafe gear, and when bad storms
are
predicted, I double up on lines, and wrap bits of old towels around them
at chaf
points.

During a hurricane, there is no guarantee that anything will survive.
That's why
you add lines for storms. Leather is as good as anything. Like I said, in
really
bad conditions I augment that with towels. Once they get wet, it insures
that
the line will stay cool and wet, increasing my chances for staying put.

rusty redcloud

On Sun, 3 Jul 2005 07:55:53 -0400, "Charles T. Low"
[withoutUN] wrote:

So, I follow your theory, but i) do you have a reference and ii) do you have
any experience or knowledge of lines actually sustaining heat damage under
prolonged load/unload cycles.

Rusty has it right, but it's a little extreme.

Friction generates heat energy which transforms materials into other
states - that much is absolutely true.

Ropes have to be placed under extreme loads for internal heat to rise
enough to cause fiber melting. Under normal load/unloading cycles
you'd be hard pressed to create the heat necessary to cause fiber
degradation and melting.

For example, nylon has a critical temp point (call it transition) of
350ºF. 350ºF is the point at which the individual fibers start to
transform. It's melting point is 460ºF - it's a fairly large distance
from 350º to 460º.

Add to that factor, the strength needed for the job it's intended for.
If you are tying up a 52 foot Hatteras with 1/4' inch nylon, you can
expect those sort of stresses which would cause nylon to melt. If you
use 5/8' to 3/4' the chances of it occurring is minute.

In short, line is more likely to break from stress than melt. Now can
repeated load/unload cycles degrade line to the point where it can
"melt"? Yes, but again, the stress is more likely to break the line
than melt it.

Consider this - when was the last time, if ever, that a manila line
burst into flames from internal heat? Ever hear of one?

Manila has a critical point of 180ºF, but it's "melting" point is
350ºF - melting in this case means flames. :)

It's not a likely occupance.