to resort to an experimental determination of the coefficients of drag for the particular 

 load configuration in question, for both steady and oscillatory motions. There exists 

 little experimental data on the appropriate coefficients of drag applicable to typical 

 load shapes being lowered to the deep ocean floor. A series of experiments directed 

 toward obtaining such data thus appears justified. 



Similar arguments also apply to the values assumed for the coefficient of added 

 mass, Cj^. Summaries of information pertinent to the determination of the drag and 

 added mass coefficients are presented in Appendixes D and E respectively. 



The shape of each curve determined from Equations 7, 8, 9, and 10 differs 

 from those obtained for linear systems in that a second peak in the normalized max- 

 imum dynamic stress occurs at nondimensional frequencies on the order of 0. 10 to 0.40. 

 The significance of such a secondary peak, which is termed herein a subharmonic 

 response, is more easily discussed in relation to a specific design example. Two such 

 examples are given below following a proposed design procedure. 



PROPOSED DESIGN PROCEDURE 



The parameters required in the design procedure are those applicable to the 

 load and the cable. They may be tabulated as follows: 



Load Parameters 



M = mass of the load 



A = cross-sectional area of the load in the direction of motion (ft'^) 



C-. - coefficient of drag applicable to the load 



C = coefficient of added mass applicable to the load 

 m "^ 



Cable Parameters 



L = maximum lenath of cable (ft) 



max ^ ^ ' 



w = weight of cable per unit length (lb/ft) 



E = modulus of elasticity for the cable (lb/in. ) 



I I = ultimate tensile strength of the cable (lb/in. ) 



F = safety factor for maximum operating stress in the cable 



p = density of sea water (lb/ft>^) 



