where R is the drag per unit length of the line when the cable is normal to 

 the stream and W is the weight per unit length of the line in water . 



The following recommended values of R are based on tests made at 

 the Taylor Model Basin: 



R = 0.34V 2 d pound per foot, for wire rope [3a] 



R = Q.2QV 2 h pound per foot, for chain [3b] 



where d is the diameter of the cable in inches and h is the outside width of 

 a link of chain in inches. 



If anchor cables of different sizes were geometrically similar, W 

 would be proportional to the square of the width of a link. The data in engi- 

 neering handbooks and manufacturers' catalogues, corrected to give weight in 

 water, show a small variation. Approximately, however, 



W = 1 .40d 2 pound per foot, for wire rope [4a] 



W= 0.64/i 2 pound per foot, for chain [4b] 



From Equations [3] and [4], the expressions for n can be written as 



V = ^^2 V z = 0.24 \ for wire rope [5a] 



and 



$$fe V* = 0.31 \ for chain [5b; 



BREAKING STRENGTH AND SAFE WORKING LOAD OP CHAIN AND WIRE ROPE 



Theoretically, the breaking strength of geometrically similar cables 

 should vary as the square of the width of a link. However, data in handbooks 

 and catalogues show a small variation with size. The following approximate 

 values for the breaking strength T B are recommended: 



T B = 70,000d 2 pounds, for plow-steel wire rope 



T B = 4,000/i 2 pounds, for forged stud-link anchor chain 



Then, from Equations [4a] and [4b] 



T B 



yy = 50,000 feet for plow-steel wire rope [6a] 



and 



T 



w = 6 250 feet for forged stud-link anchor chain [6b] 



iased on a factor of safety of approximately 3> the values of the ratio of 

 tne safe working load T s to W may be taken as 



