d the
yarns are twisted together in the opposite direction from that in
which the original fibres were twisted; to form a rope the strands are
twisted in the opposite direction from the yarns of the strands, and
to form a cable each rope is twisted opposite from the twist of the
strands. In this way the natural tendency for each yarn, strand, or
rope to untwist serves to bind or hold the whole firmly together (Fig.
1).

[Illustration: FIG. 1.--Construction of rope.]

Rope is usually three-stranded and the strands turn from left to right
or "with the sun," while cable is left-handed or twisted "against the
sun" (_E_, Fig. 1). Certain ropes, such as "bolt-rope" and most
cables, are laid around a "core" (_F_, Fig. 2) or central strand and
in many cases are four-stranded (Fig. 2).

[Illustration: FIG. 2.--Bolt-rope.]

The strength of a rope depends largely upon the strength and length of
the fibres from which it is made, but the amount each yarn and strand
is twisted, as well as the method used in bleaching or preparing the
fibres, has much to do with the strength of the finished line.

Roughly, the strength of ropes may be calculated by multiplying the
circumference of the rope in inches by itself and the fifth part of
the product will be the number of tons the rope will sustain. For
example, if the rope is 5 inches in circumference, 5 X 5 = 25,
one-fifth of which is 5, the number of tons that can safely be carried
on a 5-inch rope. To ascertain the weight of ordinary "right hand"
rope, multiply the circumference in inches by itself and multiply, the
result by the length of rope in fathoms and divide the product by
3.75. For example, to find the weight of a 5-inch rope, 50 fathoms in
length: 5 X 5 = 25; 25 x 50 = 1,250; 1,250 / 3.75 = 333-1/3 lbs. These
figures apply to Manila or hemp rope, which is the kind commonly used,
but jute, sisal-flax, grass, and silk are also used considerably.
Cotton rope is seldom used save for small hand-lines, clothes-lines,
twine, etc., while wire rope is largely used nowadays for rigging
vessels, derricks, winches, etc., but as splicing wire rope is
different from the method employed in fibre rope, and as knots have no
place in wire rigging, we will not consider it.

CHAPTER II

SIMPLE KNOTS AND BENDS

For convenience in handling rope and learning the various knots, ties,
and bends, we use the terms "standing part," "bight," and "end" (Fig.
3). The _Standing Part_ is the