WAVEMAKING RESISTANCE OF SHIPS 

 WITH TRANSOM STERN 



B. Yim 



Naval Ship Research and Development Center 



Washington, D,C. 



ABSTRACT 



The wave resistance of ships, having transom sterns 

 and bow bulbs, is analyzed by an indirect method. 

 The total wave resistance of a combination of singu- 

 larity distributions for such ships is minimized with 

 various parameters of the bulb and the transom stern 

 at each Froude number. The effect of free surface on 

 the body streamlines near the stern is also analyzed. 



INTRODUCTION 



There has been an increasing interest in ships having transom 

 sterns, not only for high-speed ships like destroyers but also for 

 cargo vessels, because of the advantages of more cargo room as 

 well as modern improvements in techniques of loading and unloading 

 cargoes over the stern. Recently a theoretical study was made by 

 this author [ l] , and a mathematical model was suggested in view of 

 applying a higher-order ship- wave theory [ 2] , In this paper, we shall 

 look at the problem again from a different angle, i.e. , approaching 

 the problem in a more practical manner. 



There are usually two approaches to the ship hydrodynamics 

 problems, direct and indirect. In the direct approach one starts 

 with a given ship and finds a corresponding mathematical representa- 

 tion for it, then, calculates physical quantities, and verifies the 

 results by experiments. On the other hand, one could start with a 

 mathematical model such as a singularity distribution, and calculate 

 the physical quantities of the nnodel , find the corresponding ship form, 

 check the behavior with the experimental results, and utilize the 

 knowledge in designing practical ships. This is an indirect approach. 

 Both approaches are useful In the development of ship science. In 

 Reference i by a direct approach, It was found that the transom stern 

 might be represented by a sink line along the stern, having a strength 



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