118 Samuel Karp, Jack Kotik, and Jerome Lurye 
No 8 
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Fig. D2. A black-and-white reproduction of a colored stereo slide 
John M. Ferguson (John Brown and Co., Glasgow) 
The authors of these two preceding papers must be admired for the ease and sureness 
of handling the complicated mathematics of this problem of minimum wave resistance. Yet 
the feeling of admiration is tempered with a little disappointment. In what way do these 
papers, as they stand, assist the practical designer in his daily work of producing the best 
form for a given set of conditions. 
A typical example is as follows: A form is designed. To this form a model is made and 
tested. The form may not come up to expectation. In what way can this model be altered to 
improve its performance? Somewhere in R. E. Froude’s published work he states that the 
quality of performance of a model depends mainly on the shape of the sectional area curve 
and the load water plane. If the mathematicians could devise some method of analyzing the 
sectional area curve so that the analysis could indicate the features of performance and 
thereby suggest the manner in which the area curve could be modified for the better, then 
their mathematics would be really worthwhile. 
The mathematician has all the time he needs. The practical designer often has to pro- 
duce the answer today, if not sooner. 
Some years ago, a young colleague of mine was interested in this problem. He devised 
a method in which a sectional area curve was analyzed by Runge’s scheme into a sine and 
cosine series. It was found that the coefficients of the sine series could be related to cer- 
tain values of the speed-length base and that the humps and hollows of the coefficients bore 
some close relationship to the humps and hollows of the typical resistance curve. If a hump 
on the resistance curve occurred at, say a trial or contract speed and there was a hump in 
the Runge coefficient at that point, it was suggested that a reduction of the hump in the re- 
sistance curve might result from a reduction in the value of the nearest Runge coefficient. 
The series would then be rearranged to give the original value of the prismatic coefficient 
