The chart is drawn for 59 F and a ship correlation allowance of +0.0004 on the ATTC 

 C p values. 



Entering the chart at (^ = 2.0, going across to a displacement of 10,473 tons, up to 

 the model length of 20.338 ft and across to the scale of 5 (C), we find 5^) has a value of 

 0.017, to be subtracted from the ATTC value to obtain the Froude value. This is for a 

 standard ^^of 6.0; for the actual ^H of 6.168, the correction will be 



,-v 6.168 

 S©= T^;;^ ^ 0-017 = 0.0175 

 ^-^ 6.000 



Hence the Froude value of^^QQ f^ = 0.730 -0.017 



= 0.713 



or 2.3 percent less than the ATTC value with +0.0004 correlation allowance. One other 

 calculation may be necessary— the conversion from ATTC to ITTC correlation lines. The 

 procedure for doing this is set out in full in Appendix E, to which reference may be made 

 for details. 



The calculation for the SCHUYLER OTIS BLAND Series 60 equivalent is given below 



to illustrate the difference between the final ehp obtained by the two methods. 



V 

 At a speed defined by ■ , = 0.70, we have from Table D3 



= 1.5429 and ft o = 23,020 lbs 



A ft ' 



For the ship, VL = 14.973 x 457.6 = 6852, and entering the nomograph in Figure El with 

 this value, the corresponding value of C'p ^^^^ + 0.0004 = 0.001950 for the ITTC line. 



The model length is 20.338 ft, so that the scale is 22.5, and the model speed 

 corresponding to a ship speedof 14.973 knots is 



14.973 



= 3.16 knots 



V'22.5 



Hence for the model, VL = 3.16 x 20.338 = 64.3. Entering the same chart at this value of 

 VL gives a value for the ITTC line of C'p ^^^^^ + 0.0004 = 0.003490. 



For the same value of VL, but using the line at the extreme left of Figure El, the 

 corresponding value for the ATTC line is 



F model 



+ 0.0004 = 0.003415 



It is shown in Appendix E that the value of {C pg + 0.0004) for the ship for use with this 

 chart when making a conversion of this kind is 



D.14 



