Pien 



auxiliary functions arising from each term obtained by squaring the left-hand 

 side of Eq. (2) are analogous to his functions tabulated in TMB Report 886. The 

 main difference is that Eq. (2) is used to express the singularity distribution 

 which will generate the hull form rather than to express the hull form directly. 

 With this remark, I shall attempt to answer a number of points raised by him as 

 follows: 



It would indeed be erroneous to make a general statement that wavemaking 

 resistance values as computed are always larger than those obtained experimen- 

 tally. Remark 1 in the justification of application section of my paper was based 

 on the observation of Fig, 1 that if the wavemaking resistance theory is applied 

 to the forebody only, where the viscosity effect is small, the theoretical predic- 

 tion based on Professor Inui's method will be an upper limit to the possible ex- 

 perimental wavemaking resistance values. I am fully aware of the fact that 

 strong favorable interference effect may not be realized due to the viscosity 

 effect. I mentioned this fact as a source of difficulty when the wavemaking re- 

 sistance theory is applied to a whole ship. Hence the importance of minimizing 

 the forebody free- surface disturbance has been advocated. 



In the past, many comparisons have been made between the theoretical and 

 experimental wavemaking results. No consistent conclusion has been reached 

 from these comparisons. One of the main causes is due to the fact that the 

 theoretical model and the experimental model are not "exact" as explained 

 clearly by Inui in Ref. 2. Therefore it is extremely important to know whether 

 the theoretical and the experimental models are equivalent or not, when we 

 study the comparisons. To illustrate this important point, let us study the com- 

 parisons of three models made by Mr. Wigley in 1927. 



Figure A is a replot of a portion of Mr. Wigley's original comparisons. In 

 this figure, C^ versus Froude number (and v/vT) curves are plotted instead of 

 ©^ versus ©as in the original figure. Models 825, 829 and 755 are identical 

 except in beam scale. Model 825 has the smallest beam and its theoretical pre- 

 diction at high Froude number, where the viscosity effect is small, should be 

 closer to the experimental curve than in the cases of the other models. How- 

 ever, this figure does not show this fact. This apparently puzzling situation had 

 been cleared by Professor Inui thirty years later in Ref. 2. Figures B and C 

 are taken from Ref. 2. Figure B shows how the singularity distribution per unit 

 beam varies with beam instead of being constant as in the Michell's thin ship 

 theory. Figure C shows how the wavemaking resistance coefficient R^AApv^B^ 

 varies with beam rather than independent of beam as Michell's theory asserts. 

 Even though both of these figures are for the case of infinite draft, it is quite 

 obvious that the theoretical wavemaking resistance curves computed according 

 to Professor Inui's method would be higher than the experimental curves at 

 high Froude number range for all of these three models. The over estimation 

 by the theory varies depending upon the level of wavemaking resistance: the 

 higher the wavemaking resistance level, the larger the overestimation. This 

 agrees with remark 2 made in the justification of application section of the 

 paper. 



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