This stress is maximum at the top of the cable and minimum at the 

 array. For a steel cable with S=3 in"^ and L=20, 000 ft, and a 50-ton array 

 (without any buoyancy), the maximum and minimum static stresses are 103,000 

 and 33, 300 psi, respectively. For a 100-ton array these values become 130,000 

 and 66,700 psi. This cable could be a steel wire rope of the Galvanized Bridge 

 Strand type with a diameter of 2.25 inches. The ultimate tensile strength of 

 this rope is about 220,000 psi. Therefore, this rope can take the above stres- 

 ses safely. This type of rope has a ratio of ultimate tensile strength to weight 

 per unit length equal to about 62, 000 ft, which is equal to the maximum length 

 of rope that can hold itself. 



On the other hand if buoyancy is utilized, the static stresses can be 

 decreased considerably. In this respect, nylon type ropes are preferable, since 

 they are almost weightless in water while their breaking strength is just about 

 as high as that of the strongest steel ropes. 



artliur Jl.lLittlcJnt. 



8-7001-0307 



