44 



results are Interesting. Figures 26 and 27 show that assuming rather differ- 

 ent t values optimum ship lines with a similar trend may be obtained. 



We notice that the optimum area coefficient <j> for a medium depth of 

 immersion f/L = 0.25 is much higher than for a slight immersion f/L = 0.1 25. 

 This might have been inferred from the shift of the resistance curves follow- 

 ing Figures 6, 7 and 8. 



The necessary formalism is again very simple: assuming as before 

 a curve 77 with the fixed t = t value, for example as before, rj = 1 - £ 2 , 

 t = 2, and denoting <f> = <j> + 4> x , 



n = 1 - £ 2 + 13.1250'd 2 - 2f* + | 6 ) [40] 



A n(£) = 13.125U 2 - 2£ 4 + £ 6 ) [40a] 



complies with 



^17(0) = 4^(1) = 



2. \ l A i7U)d* = 1 



94,77(1 ) 



from 



we obtain 



in = 

 5 



^ = -2| + 26.250'[£ - 4£ 3 + 3£ 5 ] 



A ' 

 *' = 26.25 A' ^ ^ 



with 



A' =m + l6ty + 9W - 8?n + 67W - 24771 

 a 11 33 55 13 is 35 



A' =1Y] -kin + 37h 



1 11 13 15 



6. RESISTANCE CURVES OF THE FAMILY (2, 4, 6; ; t) 



A systematic survey of resistance properties of ship forms can be 



obtained by a different approach, i.e. , varying the parameters of a given 



family of ship lines and plotting the corresponding resistance curves. Re- 

 stricting ourselves to a two-parameter equation 



(2, 4, 6;^; t) = 1 - £ ^ [34] 



2,4,6 



