HYDRODYNAMIC ANALYSES APPLIED TO A 



MOORING AND POSITIONING OF VEHICLES 



AND SYSTEMS IN A SEAWAY 



Paul Kaplan 

 Ooeanios 3 Inc. 

 Plainview J New York 



I. INTRODUCTION 



At present, increasing interest is being devoted to the prob- 

 lems of deep sea operations of vessels that must remain on station 

 for an extended period of time in order to accomplish their intended 

 mission. This concern was given its initial impetus by the success- 

 fully conducted preliminary operation of drilling through the ocean 

 bottom from a surface ship in the operation known as the "Mohole 

 Project," as well as the increase in oil exploration in deeper water 

 depths. On the other hand, from the point of view of military 

 operations , there is need for placing instrumentation packages and 

 other military systems on the ocean floor for various purposes of 

 National Defense. These operations require a definite degree of 

 precision, safety during the course of the operation, and the capa 

 bility of returning to a particular locale and retrieving information 

 and/or the equipment itself for further study of data or for emplace- 

 ment in another location. 



As a result of this emphasis on deep-sea operations, it is 

 necessary to determine the response of representative moored ships 

 in the open sea, and also to determine the characteristics of the 

 important parameters associated with lowering loads from such a 

 vessel to the ocean floor and returning them to the ship. The 

 parameters that are of interest to the personnel aboard the ship are 

 the forces in the mooring cables, the displacements and tensions in 

 the lowering lines , the degree of precision in placing the loads , the 

 accelerations acting on the loads , and the magnitudes of impact on 

 the ocean bottom. In order to arrive at some appropriate engineering 

 estimates of the capabilities of carrying out such operations , appli- 

 cation of available theoretical hydrodynamic studies can be made to 

 deal with problems of this nature. 



The study of motions of ships at sea is a general problem of 



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