ANALYSIS OP WAVE RESISTANCE 



by 

 Georg P. Welnblum, D.Eng. 



ABSTRACT 



The purpose of the report is to summarize the contributions made by hydro- 

 dynamics to solve problems of wave resistance of ships moving with a constant speed of 

 advance. A necessary condition for dealing with the problem is the introduction of mathe- 

 matically defined ship lines. The difficulties in determining the wave resistance experi- 

 mentally and theoretically are discussed. Endeavors are made to work out separately the 

 influence of proportions and the dimensionless shape on wave resistance; as a most im- 

 portant result, from the viewpoint of shlt>buildin|; practice, the proof is obtained that under 

 certain conditions small continuous changes of longitudinal-displacement distribution in- 

 volve large changes in wave resistance. The influence of the vertical-displacement dis- 

 tribution and of special features such as the hull are investigated. Consideration is given 

 to the propeller action and to resistance In shallow water and in canals (basins). Wholly 

 submerged bodies of revolution are dealt with. 



Appendices 1 and 2 contain a list of formulas used and Appendix 3 some remarks 

 on viscous pressure resistance. 



INTRODUCTION 



The problem of wave resistance is perhaps the most interesting if 

 not the most important problem in theoretical naval architecture. Our great 

 ship-research laboratories were founded and originally developed for the pur- 

 pose of investigating essentially this part of ship resistance, and a tre- 

 mendous amount of experimental data on models have been collected. Neverthe- 

 less, the long nourished aim to represent the resistance of a ship as a 

 function of her form, has not been solved in a general manner by such experi- 

 mental methods, although systematic model tests have been by far the most 

 Important means of improving the shape of hulls up to the present time. 



