SHALLOW WAVE PROBLEMS IN SHIP 

 HYDRODYNAMICS 



E. O. Tuck and P. J. Taylor 



UniveTsity of Adelaide 

 Adelaide 3 South Australia 



ABSTRACT 



In this paper we discuss two basic problems in shallow 

 water ship hydrodynamics, ncimely the squat problem 

 and the problem of wave force due to beam seas. Squat 

 is an important phenomenon in very shallow water 

 because of the danger of scraping bottom. Apart from 

 reviewing and extending existing work on sinkage and 

 trim in canals and in a wide expanse of shallow water, 

 we indicate here how the shallow water results can 

 be obtained from a finite depth theory as the depth 

 becomes small. Unsteady problenns associated with 

 motions or of forces on a ship in beam seas are also of 

 practical importance, as for a ship standing at an ex- 

 posed mooring facility. We provide here sample com- 

 putations of the side force on a tanker hull in regular 

 beam seas. 



I. INTRODUCTION 



It must be stated at the outset that this paper is concerned 

 principally with shallow water, and not with finite depth of water, 

 except in Section 4. The distinction between these two cases is 

 important from the theoretical point of view and needs to be em- 

 phasized here since those more accustomed to dealing with water 

 of effectively infinite depth tend to refer to "shallow water" when- 

 ever the effect of the bottom is considered. 



We take the expression "finite depth" to classify a range of 

 water depths in which there are significant changes to the flow prob- 

 lems as compared with Infinite depth, and significant but not neces- 

 sarily donainant effects of the water bottom on the behavior of the 

 ship. On the other hand, the "shallow water" regime Is one In which 

 the depth is so small that the narrowing of the field of flow has a 



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