Page 151 - Derek E. Avery - The new encyclopedia of knots

up and all up strands down – then take a second turn with the warp. This

procedure is repeated, dropping the odd strand as the taper narrows,
until the point is reached. At this juncture the ends are secured with a
whipping or a half hitch around the warp.

Alternative hitching patterns can be applied instead of the one up, one
down just described, and the whole can be finished off with a Turk’s head
(figure 98.2; see page 176).

Polyamide: widely known as nylon; this is the strongest of the man-made
synthetic fibres, with the exception of Kevlar and those which have been
reinforced. It possesses excellent ‘give’, and as such is ideal for mooring
and for anchor warps where shock loads are readily absorbed.

Contrariwise it is unsuitable for sheets and halyards.

The rope will become hard in excessive sunlight, and cannot resist acid
attack, although it stands up to alkalis; see also microfilament, polyester,
polyethylene and polypropylene.

Polyester: marketed under the trade names of Dacron and Terylene.
Polyester is another man-made fibre, which follows after Kevlar and nylon
in strength. It has a low stretch factor, is easy to handle and is thus quite
suitable for all activities aboard a boat. It comes in both plaited and

braided forms, and is also available pre-stretched. This further reduces its
elasticity, helping to maintain a constant length. Polyester is resistant to
acid attack.

Polyethylene: a cheap synthetic fibre, is difficult to knot because of its
excessive stretching. It also loses its shape and becomes very slippery; in
addition to these problems it has a tendency to retain kinks for a long
time.

Polypropylene: a soft, malleable and cheap synthetic fibre rope,
somewhat weaker than either polyester or nylon and with a poor

resistance to abrasion. It can be knotted and spliced quite easily. Being
buoyant it also makes a good heaving line. Polypropylene is resistant to
attack by most acids and alkalis.