(3s) 
Rsin?g+ Fsin o ds 
T+ dT 
of Motion ——————— 
Direction 
Figure 1/ - Coordinate System 
Figure 1/ shows the forces acting on a cable element at a point P. 
The element ds of the cable at the point P is in equilibrium under the action 
of the hydrodynamic forces and the tensions in the cable, 7 + dT and T, which 
act respectively at the forward and after ends of the element of the cable. 
By resolving forces, first tangent to and second normal to the cable, we 
arrive at the following differential equations: 
dT = Feos¢ds [1] 
Tdd = (-Rsin*¢ — Fsindg) ds [2] 
where F' is the drag per unit length of the faired cable when the cable is 
parallel to the stream, and 
Ris the form drag per unit length of the faired cable when the cable 
is normal to the stream;and 180 deg >¢> 0. 
From the geometry shown in Figure 17 
dx = cosdds ea 
