In this report the scaling problem is discussed. It should be 

 emphasized that the experimental modals do not represent a scaled model 

 of any proposed design for the Data Buoy Program. They have been 

 chosen to provide a data base having sufficient variation in key para- 

 meters to be useful in analytic node 1 validation. The report contains 

 descriptions of the models, apparatus and procedures and presents the 

 data both in the form of corrected measurements and force response ratios. 



MODELS 



With existing technology, a deep sea mooring cannot be scaled 

 in the Circulating Water Channel. However, experiments on a variety 

 of mooring line materials can provide data to validate the analytical 

 models over a limited range. Thus, in this section, scaling considera- 

 tions and descriptions of the models are given. 



SCALING CONSIDERATIONS 



Three typical mooring concepts for the National Data Buoy System 

 are shown in Figures 1 and 2. In terms of conventional buoy mooring 

 definitions, all three concepts are short, slack mooring lines with 

 various combinations of synthetic line and anchor chain. The scopes 

 of these systems are greater than one so they are slack but only a 

 fraction greater than one, so they are relatively short. Here, 

 scope is defined as the ratio of equilibrium mooring line length 

 to depth of water. 



To obtain ideal experimental data for validation of the design, 

 the mooring lines should be scaled for both geometric and elastic 

 similarity, and appropriate scaling laws should be applied to the 

 full-scale current and sea-state conditions. In Breslin's analytical 

 model, 2 , 3 the equations of motion for transverse and longitudinal waves 

 in a mooring line are properly scaled if Froude number is maintained 

 constant, where Froude number is defined as follows: 



F = u/lgi)* 1 (1) 



