-| — [-" i range of ship periods 



-5% accumulator (15-second resonance period) 



-2-1/2% accumulator {22-second resonance period) 



H_f 



1.6 



I (rad/sec) 



Period (sec) 



Figure 6. Response ratio for 40,000-pound load and 6,000-foot wire, showing effect of 

 accumulator size. 



/ '■3 



'C^2 



^C-Z 



7*^C'^2 



M^Z + Dj^Z + K(,Z = K(-.Z2 

 MyV ■^ DyY + KyY = -M^X - K^ (X - Zj) 



where Y = L sin 6 



M = a function of the boom mass and its 

 position along the boom length 



g-nd where the boom-tip dynamic load (Fj^) is given 

 by 



F, = Kf. (X + Y -Z,) 



A computer analysis of these equations based on 

 a Laplace transform allowed prediction of the system 

 transfer function Z/X and dynamic line tension as 

 functions of the frequency (or period) of the 

 support-platform motion X(t), type and length of lift 

 Ky = a function of the spring constant and line, spring accumulator size, and payload mass- 

 spring-boom geometry weight ratio as shown in Figures 6 through 12. 



Al, = a function of the boom mass and 

 angular inertia 



D = a function of the spring drag force 

 and spring-boom geometry 



