[Public-List] Nylon vs. Dacron rope?

[Stephen Gwyn]

There are two ways to tell.

The first is the burn test. Buy small quantity each of polyester
(= dacron) and nylon line. Then play a lighter over an end of each and
note the smell. Do the same with the mystery ropes and you
should be able to figure it out. I am not responsible for
the effects of inhaling miscellaneous hyrdocarbons.

The second, which is has been mention by a few people already,
is to check the stretchiness. I've done this by dangling 20
or so feet of line off a balcony and attaching a handy heavy
(40 lbs) object. Hold the weight up, make a mark on the wall, let
the rope take the weight, see how much it has moved. It was
pretty easy to get a accurate measure of the stretchiness
in terms of percent elongation for a given weight. Polyester
is in general much less stretchy than nylon, at least for
rope marketed to boaters. However there is low-stretch
nylon in the rock climbing world, called "static line" which
has comparable stretch characteristics to polyester.

The jib sheet that came with my boat was nylon.

SG





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Stephen Gwyn                       | Tel: 1-250-363-3136
Canadian Astronomical Data Centre  | Fax: 1-250-363-0045
Herzberg Institute of Astrophysics | Cell: 1-250-885-6969
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