EXPERIMENT DATA FOR TWO SHIPS 

 OF "MINIMUM" RESISTANCE 



Wen -Chin Lin, J. Randolph PauUing 



and J. V. Wehausen 



University of California 



Berkely, California 



ABSTRACT 



This report presents the results of towing -tank tests carried out on two 

 of the models of minimum "total" resistance described in an earlier 

 report by Lin, Webster and Wehausen (1963). One model was sym- 

 metric fore and aft, the other asymmetric with a prescribed afterbody. 

 Each was supposed to be optimum within its class for a Froude number 

 0.316 and a Reynolds number 1.18 xlO^. Although the forms showed 

 resistance qualities near the design speed as good as the equivalent 

 forms for Taylor's Standard Series, they were not significantly better. 

 The occurrence of separation behind the stern bulb of the symmetric 

 model may have masked possible superior wave -making qualities as 

 indicated by a rather small surface disturbance. 



INTRODUCTION 



In a paper presented at the International Symposium on Theoretical Wave 

 Resistance in Ann Arbor in 1963 (Lin, Webster and Wehausen, 1964)" two dif- 

 ferent minimization problems for ship resistance were considered. In each 

 problem an estimated "total" resistance consisting of the equivalent flat-plate 

 frictional resistance plus the wave resistance as given by Michell's integral was 

 minimized for selected values of the Froude number. In one of the problems, 

 only the volumetric coefficient c^ = v/L^ and the ratio H/L were fixed. The re- 

 sulting optimum hull-form was necessarily symmetric about the midship section. 

 In the other problem, h/l and a particular afterbody were prescribed, and an op- 

 timum forebody was found. In each case the class of hull shapes within which an 

 optimum was sought was limited to a 6x6 double Fourier series: 



f(x,z) = £; 2] V ^°^ i (2'^" ^^ ^"^ ^""^ \^^^- ^^'"^• 



'References are identified by author(s) and date and collected at the end. 



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