determined by a number of experiments that the normal force, 
F, per unit length of cable is given by: 
2 
F = Rsin 9 (10) 
For the tangential force, G, we will make the same assump- 
tion as that made in Reference 1, namely that G is inde~ 
Pendent of angle and © for a reasonably smooth cable is 
approximately equal to .02. This is obviously not a completely 
valid assumption but, for a wide range of values of go it has 
been found to be of sufficient accuracy for engineering calcu- 
lations. Actually, the value of G is, in general, quite small 
compared to F for the case of a circular element, and does 
not have much influence on the calculations for values of o 
greater than about 25 degrees. For smaller angles the value 
of G is of importance in determining the tension, however, 
and this should be borne in mind in assessing the accuracy of 
these calculations. 
To further facilitate the calculation of cable configur- 
ations it is conventional to define another parameter known 
as the "critical angle" of the cable. If a completely flexi- 
ble cable is towed in a fluid and there is no force applied 
to the unsupported end, then the cable will lie in a perfectly 
straight line inclined at some angle, 9,, to the stream. 
15 
