e n = To (10) 



KF 

 Since, by Froude scaling, equations (5) and (6) will scale according 

 to equation (3), Young's modulus and line material density are found 

 to scale by the following equations 



E m " E r/ X (11 > 



m p 



and 



o • p (12) 



M cp cm 



Now, hydrodynamic forces on the buoy which transmit into the mooring 

 line take the following form 



T - \i P U 2 A C T (13) 



where C T is a constant, force coefficient. Hence, forces scale by the 

 following 



T = T /X3 (14) 



m p 



Hence, to scale the 12,140-foot mooring depth designs shown in 

 Figures 1 and 2 or even their shallow, 3280-foot depth, counterpart 

 in the Circulating Water Channel with a depth of 9 feet would require: 



1. Kcoring lines comparable in diameter to a human hair, 



2. Input motion amplitudes of a small fraction of an inch 

 s at frequencies 20 or so times the wave frequencies 



encountered at sea , 



3. Current speeds less than one-twentieth the currents 

 encountered at sea, and 



4. Instrumentation capable of measuring in the milligram range. 



For economy and expediency, these scaling requirements were not 

 attempted. Conventional model scaling of real deep-sea moors was 

 judged to be impractical. The experiments herein were designed 

 primarily through selection of materials to provide a data base for 

 the development and validation of analytical models. If an analytical 

 model can reproduce the results of controlled experiments, even on i 



short lengths of line, then confidence in Its applicability to full- 

 scale mooring lines is increased, and the problem of linear scaling 

 of deep-moors for design data is circumvented. 



7 



