2. When subject to high amplitude (0.109 foot instead of 

 0.043 foot) all mooring models go slack at the lower 

 position of the slider and then snap up as the slider 

 moves to its top position. In the high amplitude ex- 

 periments, the resulting "snap" loads were observed to be 

 sensitive to bending stiffness. The relatively stiff 

 wire rope exhibited more severe snap loads than did the 

 flexible open-link chain. 



In any case, the above two conditions represent unrealistic models 

 of full-scale conditions at sea. Either the mooring is tauter or the 

 motional amplitude compared to water depth is higher than those anti- 

 cipated at sea. As a result, distorted dynamic loads were ruled out 

 from further analysis. This approach eliminated most of the data 

 gathered in high amplitude experiments. 



Distortions in the load signals also may have been influenced uy 

 uneven loading where the model lines pierce the air-water interface, 

 but these influences should not have been large enough to effect the 

 data analysis di:-;ussed below. 



DATA ANALYSIS 



The tension components contain both equilibrium and dynamic terms 

 arid may be expressed as follows: 



T x = T 0x + F x Sin <"* + *x> < 15 > 



T y * V + F y sin (wt + *y } (16) 



where 



Tq and T_ are equilibrium tension components in pounds, 



F and F are dynamic tension amplitudes in pounds, 

 x y 



t 1s time in seconds , 



<> and $ are phase angles with respect to displacement, and 

 x y 



u 1s the frequency of motion 1n radians per second. 



and 



