Page 15 - Maria Constantino "The Knot Handbook"

Polyester rope is
ideal when high- shock loads: climbers use it, as it can absorb
tensile strength is the energy of a fall, and it can also be used for
required, such
as in a rescue mooring and towing lines. Nylon rope does
situation . not float and, when wet, it can lose between 5
z and 25 per cent of its strength. While nylon
0
1- rope can be bought in different colours, white
u
:::> nylon rope is, in fact, stronger. As well as
c
0 adding to the cost, colouring nylon weakens it
a::
1- by as much as 10 per cent.
z Polyester rope has 75 per cent of the
strength of nylon, but polyester ropes are
equally strong, wet or dry. Like nylon, a poly-
ester rope does not float, and 111.uch of its
The most comm.on synthetic materials are inherent elasticity can be rerns:ived by pre-
polyamide (nylon) - still one of the strongest stretching during manufacture. Consequently,
materials used to produce rope - polyester polyester ropes are used when stretch is not
and polypropylene, as well as the more required, but a high-tensile strength is needed.
recently developed aramid and HMP (high Available 111 a number of forms,
rnodulus polyethylene) . polypropylene ranks between natural fibres
Nylon was the first synthetic material to and the superior synthetics (nylon and poly-
be used for rope-111.aking. It is very elastic and ester). Polypropylene fibres make inexpensive,
under load can be stretched between 10 and all-purpose ropes that are light and that float.
40 per cent and then regain its original length This makes them very useful for short moor-
once the load is removed. Consequently, ing lines, rescue lines and for use in activities
nylon rope is most suitable for absorbing like water-skiing.

Nylon rope is preferred by climbers as it
absorbs shock and stretches.