OTIS BLAND, the required position is 1.00 percent L gp aft. The correction can be made 

 from the data given in Tables 49-53, and the resultant ehp and (?) values are shown in 

 Table D5. The parent model of 0.65 C ^ had the LCB 1.54 percent L^p aft of midships, 

 whereas the position required in the Series 60 equivalent of SCHUYLER OTIS BLAND is 

 1.00 percent L gp aft. 



The corrections given in Tables 49—53 were cross plotted to a base of LCB position 

 and the values lifted off at the desired point are shown in Table D5. Because of the erratic 

 variation of(^ with LCB position, linear interpolation is not possible. 



These values are plotted in Figures D2 and D3. The two (^ curves in Figure D2 are 

 in very good agreement, remembering that the one for the 450-ft ship should be lower than that 

 for the 400-ft ship because of the difference in skin friction coefficient. This agreement is 



R P 



of considerable interest because one (Cj curve is derived from the contours, the other 



^-^ A 



from the (^400 ft contours, and although both sets of contours are based ultimately on the 



same model experiment results, the subsequent fairing to obtain the contours was done quite 



independently. The agreement indicates that both sets represent the results very closely. 



In the course of the analysis of the Series 60 original parents, a comparison was made 

 between the model of the actual SCHUYLER OTIS BLAND and a model of the Series 60 equi- 

 valent. It is thus possible to make a direct comparison between these model results and the 

 estimates made from the Series 60 contours. The actual model results are shown in Table 

 D6 and plotted in Figures D2 and D3. They give considerable confidence in estimates made 

 from the Series 60 contours. 



For propulsion data, the wake and thrust deduction fractions and the relative rotative 

 efficiencies can be obtained from the respective contours in Figures B79 through B123, using 



R D 



the same method of interpolation as with the and {£) contours. With this information 



and suitable propeller design charts, estimates can easily be made of propulsive efficiencies 

 for different engine conditions, provided the propeller diameter is about 0.7 of the draft. For 

 any other diameter/draft ratio, corrections can be made from the data given in Chapter X of 

 this report. 



Much of the model data in the world is published in the form of (C)^qq ft using the 

 Froude 0^ and 0^ frictional coefficients in the extrapolation from model to ship. As stated 

 in the text, Gertler has given a quick method of converting ©400 ft f''°'" ^^^ Froude values 

 to the ATTC values, or vice versa,'*^ and his chart is reproduced in Figure D4. 



As an example, take the case of the Series 60 equivalent of SCHUYLER OTIS BLAND 

 at a @ value of 2.0. 



I = 20.338 ft 



m 



/400W _ ,. 



A = 14,920 tons for 450-ft ship and A = 14,920 X I 1 for 400-ft ship 



\450y 



=6.168 = 10,473 tons. 



D.9 



