A New Appraisal of Strip Theory 



these forms can be uniquely defined by their beam/draft ratio and area coeffi- 

 cient. Professor Grim has privately supplied to the original authors his values 

 calculated by a different program, and my work is in much closer agreement 

 with these later results. 



Model 5, however, cannot be defined by its beam/draft ratio and section 

 area coefficient alone. Therefore, calculations which define the cylinders by 

 only these two parameters will not agree with more correct predictions. This 

 is illustrated by the following figures. 



Fig. 1 - Three shipform 

 cylinders with the same 

 beam/draft ratio; Models 

 5 and 5G have the same 

 area coefficients; Model 

 5G is a Lewis form simi- 

 lar to Model 4 but slightly 

 more full 



Figure 1 shows sections of three cylinders with the same beam/draft ratio. 

 These are Model 4, Model 5, and a Model 5G which has the same area coefficient 

 as Model 5. Model 5G can be described by its beam/draft ratio alone. Model 5 

 cannot. 



Figure 2 shows values of the waveheight ratio A for these three cylinders. 

 The values attributed to Grim are taken from his values as subsequently re- 

 ported to the authors. The results of Grim and my results show only small dif- 

 ferences for Model 4. The results do not agree for Model 5; however, it is 

 clear that my results for Model 5G would agree with Grim's Model 5 to small 

 differences. The difference between my values for Models 5 and 5G is due to 

 the different vertical distribution of area. This difference is not one in theory 

 alone as shown by the results of experiments with Models 4 and 5 as reported 

 by Paulling and Porter in Ref. [44] or in Ref. [36] of the original paper. The 

 conclusion is that two parameters alone are not sufficient to define the cylinder 

 geometry. 



365 



