DYNAMICS AND KINEMATICS OF SUBMARINE CABLE 



Table I — Properties of Cables No. 1 and No. 2 



1137 



Cable 



Diameter (inches) 



;Wt. in water (lbs/ft.).. 



j Outer covering 



' Surface condition 



EA (twist restrained). . . 

 EA (twist unrestrained) 



No. 1 



0.75 



0.243 

 Polyethylene 

 Smooth 



No. 2 



1.25 



0.705 



Tar impregnated jute 



Rough 



4 X 108 lbs 



1.2 X 10« lbs 



as is indicated by the plotted experimental points. It is seen that (6) 

 gives a good fit to the experimental data over the entire velocity range. 



If the cable has a smooth exterior, an estimate of the drag coefficient 

 Cd can be computed from published values of resistance to flow about 

 an immersed cylinder. This computation is described in Appendix B, 

 where we have also tabulated computed ^-alues of Co • For the smooth 

 cable No. 1, the value of Cd obtained from Appendix B is 1.00 which is 

 in fair agreement with the experimentally determined value of 1.11. 



Although the drag coefficient Cd is a fundamental hydrodynamic para- 

 meter, it is not the most convenient description of the effect of the nor- 



o 



2 3 4 5 6 7 8 



TOWING VELOCITY IN KNOTS 



10 



Fig. 3 — E.xperimental and theoretical variation of critical angle with towing 

 velocity for cable No. 2. 



