CHAPTER I
CORDAGE
Before taking up the matter of knots and splices in detail it may be well to give attention to cordage in general. Cordage, in its broadest sense, includes all forms and kinds of rope, string, twine, cable, etc., formed of braided or twisted strands.
In making a rope or line the fibres (A, Fig. 1) of hemp, jute, cotton, or other material are loosely twisted together to form what is technically known as a "yarn" (B, Fig. 1). When two or more yarns are twisted together they form a "strand" (C, Fig. 1). Three or more strands form a rope (D, Fig. 1), and three ropes form a cable (E, Fig. 1). To form a strand 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).
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).
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.