Both the materials used and the method by which a cable is 

 fabricated are factors in its suitability. Table 1 summarizes the 

 pertinent characteristics of several materials which are in wide 

 use in the manufacture of wire rope. It will be noted that these 

 materials vary in effectiveness , depending upon the application 

 for which they are considered. 



The method by which the cable is constructed strongly in- 

 fluences its ability to meet the rigorous demands of oceanographic 

 operations . Two common types of construction are the Warring- 

 ton and the Seale configurations , both consisting of two layers of 

 wire about a central wire: six wires in the inner layer and twelve 

 in the outer. The Warrington varies from the Seale by using large 

 and small wires alternately in the outer layer; the Seale construc- 

 tion uses the same size throughout. The Seale type yields a 

 smoother surface which reduces friction and resulting abrasion; 

 and the presence of smaller wires in its outer layer increases 

 flexibility and therefore reduces bending stresses, especially 

 when the cable is being operated over sheaves of small diameter.' 



The strength of a wire rope increases with its size and with 

 the excellence of the material (especially the core material) of 

 which it is made. The strength offered by any method of construc- 

 tion will vary with the metallic area involved and the basic strength 

 of the wire used. If a cable is made with an independent metallic 

 core or inner strand it will be somewhat stiffer than a similarly 

 constructed rope with a fiber core but, when heavy loads and high 

 radial pressures are involved, may offer greater strength and re- 

 sistance to bending fatigue. In many applications the fiber-core 

 wire rope is satisfactory or even preferable, as when it must con- 

 form to the diameter of a small sheave or drum. 



The flexibility of a wire rope is a function of its "lay," or 

 the manner in which the strands are joined or twisted, and also 

 depends upon whether or not the wire is preformed. The com- 

 monly used Lang lay produces a cable with large cover wires and 

 the same number of wires in the outside layers as in the inside 

 layer. 



If the helical angle of the wire wrap is kept tight with a 

 small angle from the normal to the cable, flexibility will decrease. 



