ABSTRACT 



The David W. Taylor Naval Ship Research and Development 

 Center (DTNSRDC) was tasked under the National Oceanic and 

 Atmospheric Administration National Data Buoy Program to con- 

 duct an experimental program in the dynamics of mooring lines. 

 Linear scaling of deep-water moorings is impractical and 

 reliance must be made by designers on analytic models. To 

 provide a broad data base applicable to model validation, five 

 small-scale mooring line materials were selected for evaluation. 

 The horizontal and vertical components of dynamic tension 

 generated by vertical, sinusoidal motion of the upper end of 

 the mooring line were measured. The experiments were made 

 under conditions of current and no current. Data were reduced 

 to force response ratios as a function of frequency of input, 

 and observations of mooring line motions were made. These 

 response ratios were found to depend on preload, current, bend- 

 ing stiffness, and scope. 



ADMINISTRATIVE INFORMATION 



This project was established by the National Data Buoy Center, 

 National Ocean Survey, National Oceanic and Atmospheric Administration 

 through the National Aeronautics and Space Administration Defense Pur- 

 chase Request No. K-7S003A, Amendment 2 dated 9 July 1971. The work 

 was accomplished under David W. Taylor Naval Ship Research and Develop- 

 ment Center Work Unit 1-1548-007. The draft of this report was prepared 

 prior to the issuance of the directive on the use of metric units. In 

 the interest of time and economy, conversion to the metric units has 

 not been made. 



INTRODUCTION 



The National Oceanic and Atmospheric Administration (NOAA) is 

 responsible for the development of deep-ocean, moored buoy systems under 

 its National Data Buoy Program. The hydrodynamic aspect of the mooring 

 design is an important part of the moored buoy problem. In a seaway, 

 the mooring is subject to static and dynamic loading from surface and 

 subsurface currents and wave action on the surface buoy. The mooring 

 line and its behavior under current loading and dynamic wave conditions 



