natural, since the wave resistance depends to a first approximation upon a 

 complicated function of the surface slope in the longitudinal direction, i.e., 

 on derivatives. On the other hand, the most commonly used coefficients are 

 integrals, which even when kept constant still admit of very wide variations 

 of the slopes. We realize now why the solution of the basic problem of the 

 model tanks mentioned above— to establish the resistance as a function of the 

 form— remains almost hopeless as long as the ship surfaces (or at least their 

 most important features) are not defined in a rigorous way by mathematical 

 expressions. Hence, our first task must be to find equations for the ship 

 surface, continuing the work of D.W. Taylor.*^ This phase of Taylor's re- 

 search has been more or less neglected by later investigators. 



The well known resistance phenomena are briefly reviewed herein, and 

 the formal procedures are set out by which hydrodjmamics leads to a computa- 

 tion of wave resistance.* 



The main purpose of the report is to establish simple functional re- 

 lations between resistance and form of "normal" ships, based on Michell's 

 theory and on a comparison of calculated and measured resistance values. This 

 includes a discussion of the effects of viscosity and of some proposals in- 

 tended to improve the theoretical procedure. 



It was further thought useful to mention the interaction between 

 ship and propeller and to study the effects of restricted water, especially 

 with respect to the influence of the finite dimensions of model basins, on 

 model wave resistance. 



Finally a synopsis of current knowledge regarding the wave resist- 

 ance of wholly submerged bodies is included. 



Wave resistance phenomena in a seaway have not been treated to avoid 

 making the report too long, although theory has recently made valuable contri- 

 butions to this thrilling subject. For the same reason the problem of nonuni- 

 form motion has been omitted. 



When emphasizing the importance of theoretical work, it is necessary 

 to state that the theory is based on many abstractions and that the combina- 

 tion of theoretical and experimental work is a necessary condition for reach- 

 ing useful practical results. 



*The subject of the report Is the analysis of wave resistance. Therefore for brevity "resistance" 

 is often used instead of "vave resistance;" when other "kinds" of resistance are discussed the fact will 

 be clearly stated. 



