INTRODUCTION 



Terminology of Table 1 



This survey presents a summary of information 

 for the analysis and design of one class of ocean 

 structure, the moored cable system. The survey is 

 divided into three broad analytical categories: (1) 

 steady-state analysis. (2) dynamic analysis, and (3) 

 cable-strumming analysis and design considerations. 

 The information is presented in a format which will 

 help the engineer select a computer program, analyti- 

 cal model, or design tool which best fits his analysis 

 or design needs. 



Three previous surveys on the analysis of cable 

 systems under hydrodynamic loading have 

 summarized steady-state and dynamic models availa- 

 ble to mid-1970 [1], summarized some of the new 

 dynamic models to early 197 3 [2] , and reviewed the 

 various mathematical techniques used in dynamic 

 analysis [3] . The present survey attempts to update 

 and complement these surveys to give a more com- 

 plete picture of the state-of-the-art of steady-state 

 and dynamic analyses and to present a summary of 

 analytical techniques and design considerations for 

 predicting and suppressing cable strumming. 



Figure 1 presents the terminology used in this 

 survey to describe the various mooring types. It is 

 particularly noted that the terms used in Figure 1 to 

 describe the moorings refer to the number of "legs" 

 involved and not the number of buoys. 



STEADY-STATE ANALYSIS 



Table 1 presents computer programs for the 

 steady-state (static) analysis of moored cable systems. 

 These programs attempt to predict the distribution of 

 stresses in the cables and the geometry of moorings 

 under the action of steady currents or other time- 

 independent forces. Information on how program 

 authors can be contacted and source reference num- 

 bers are presented to enable the reader to obtain 

 more details on the programs in which he is inter- 

 ested. 



Each of the descriptive terms used in Table 1 are 

 briefly discussed below. 



Program Dimensionality. Programs for the 

 analysis of moored cable systems may be one-, two-, 

 or three-dimensional. However, most steady-state pro- 

 grams are either two- or three-dimensional so that the 

 effects of nonaxial loadings (current forces, etc.) can 

 be accounted for. Two-dimensional programs are use- 

 ful for the analysis of single-point mooring systems in 

 coplanar force fields. Three-dimensional programs are 

 used in conjunction with multileg structures and non- 

 planar force fields. Eleven of the 27 entries in Table 1 

 are two-dimensional, 16 are three-dimensional. 



Mooring Type. The terms used to define the 

 mooring are given in Figure 1. .Most of the programs 

 in Table 1 are for the single-point mooring onI\'. The 

 program by R. A. Skop is a general one that can be 

 applied to a variety of complex mooring 

 configurations. 



Cable Material. A length of cable is compound 

 if its physical or mechanical properties (area, modu- 

 lus, etc.) vary along its length. A cable is extensible if 

 it stretches under load. Both these cable characteris- 

 tics are modeled by most of the programs in Table 1. 



Current Profile Variation With Depth. Ocean 

 currents at an)' specific point can vary in magnitude 

 and direction with depth and time. The effects of 

 current variations with time are beyond the capa- 

 bilities of the static programs unless the changes 

 occur very slowly so that the time-dependent forces 

 are very small. Gross errors can result if ocean-current 

 regimes are not properly modeled by the computer 

 program. The majority of the programs in Table 1 can 

 model variations in current magnitude with depth; 13 

 programs can model current profiles that vary in 

 magnitude and direction with depth. 



Program Validation. None of the programs pre- 

 sented in Table 1 yield exact solutions because of 



