Page 15 - Mario Bigon "The Morrow Guide to Knots"

Maintenance

Because of its structure, rope is quite a sturdy product and
does not need any special attention. It is important to keep it
dry to avoid the formation of mildew and to clean off
thoroughly any grease or tar deposits. The only danger is heat
which can cause irreparable damage, especially to synthetic
fibers with low melting points. So ropes must be kept away
from direct heat sources and should not be used on small-
diameter pulleys (less than 5 or 6 times the diameter of the
rope under tension). Heat generated by friction can cause
damage similar to fire. Another point to watch out for is the
fraying of the ends due to the slipperiness of the fibers: if the
end is not backspliced properly, it will soon fray, eating up
yards and yards of rope.
Rope used in sailing should be washed at the end of the
season with a standard detergent for delicate clothing. Drying
is very important, and care should be taken to dry the rope
right through. Any tar or oil stains can be bleached away with
careful use of gasoline or trichloroethylene.

Useful points to remember

• A knot uniting two ropes reduces the strength of the unit
to about half that of the weaker rope.
• A rope that is twice the diameter of another has four times
its strength.
• Never use two ropes of different materials together, as only
the more rigid rope will work under the strain.
• It is not always true that a stronger rope is better, as
elasticity also has to be taken into consideration, and if the
rope has to take shock loads, polyester polyamides are the
best.
• Do not use ropes that float for anchorage in ports, as they
would immediately be severed by the propel lars of motor
boats.