Pien 



concept of applying ti\e wavemaking resistance theory to reduce the total resist- 

 ance of ships can be applied advantageously in the design of "practical" ships, 

 i.e., ships witli practical L B and B H ratios. 



To date, numerous attempts to utilize this theory have had disappointing 

 results. However, tliis lack of success is not necessarily due to the limitations 

 of the tlieory. It is my belief tliat, despite its defects, the existing theory can be 

 used in tlie design of practical ships with low resistance. The justification for 

 this view is fully discussed in this paper. 



In the belief that much better forms can be obtained by using this theory, I 

 have undertaken a hull form research project at the David Taylor Model Basin. 

 The first part of this project has been to program for automatic computation all 

 the numerical work involved in the application of the theory to ship design work. 

 Once this has been done, the application of the theory becomes a fruitful, enjoy- 

 able task rather tlian tasteless, tedious labor. The second part of this project 

 is devoted to the actual application of the theory to the design of ships. Models 

 will be designed according to the theory and then tested, and the model experi- 

 ment results can be applied immediately to the shipping industry. After suffi- 

 cient theoretical and experimental data have been gathered, further improve- 

 ment in the present wavemaking resistance theory can be expected. 



The first part of this project has already been accomplished. Two comput- 

 ing programs have been developed. The first is used either to compute the 

 wavemaking resistance and free-wave amplitudes of a given singularity distri- 

 bution or to optimize a singularity distribution to fulfill a ship design problem. 

 The second is used to compute tlie hull geometry from a given singularity dis- 

 tribution. 



With these two computing programs, the second part of this project becomes 

 relatively simple and easy. One model has already been designed and is under 

 construction. The theoretical results for this model are given. 



This paper is essentially a progress report of the present hull form re- 

 search project. The second part of this project has just been started. Another 

 paper will be published upon completion of this phase. 



JUSTIFICATION FOR APPLYING THE WAVEMAKING 

 RESISTANCE THEORY TO THE DESIGN OF 

 PRACTICAL SHIPS 



Two important assumptions are involved in the development of the existing 

 wavemaking resistance theory; these must be carefully considered if the theory 

 is applied to ships with practical L B and B H ratios: 



1. The free-surface disturbances created by a moving ship are small, and 

 so wave height will be small in comparison to wave length. This assumption 

 justifies linearizing the free-surface condition. 



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