

























' 



28 





















/ 







, 























/ 







/ 

























/ 







/ 





























r 







24 























/ 



7 























d / 





y 



J 



f 





22 



















"/ 





/ =11 





^ 





















/ 







to 























/ 





/ 



/ 



















y 





/ 







P 





18 

















/ 



/ 



























/ 



/ 





1 









16 

















i' 



/ 



y 



I 



























/ 



F 





























y^' 



Y 



- 







14 



cr 



h 



^-^ 



^- 



^-^ 











65 



6.6( 



!i 











f— =i 



t? 



^ 



^ 



r>r! 



0.70 

















f — 



f 1 



r — ' 



0.75 











f — ^ 





5.80 







OTROOST SERVICE S 



PEEDS 



10 



































.40 







50 



C 



.60 







70 



c 



80 







90 



1 



00 



D J Y 



Figure 93 - on ~p= for Series 60 Parents 



The © and ® constants were introduced by R.E. Froude, At corresponding speeds 



V r, 



for model and ship, "7=" is the same,y (volume of displacement) is proportional to L^ , and 



V ^^ 



so — -- is the same. This ratio has different values in different systems of units, and 



V r7l/3 



Froude therefore related the ship speed to the speed of a wave having a length equal to 



Wave speed = - — 

 Hence ® «hip speed 



fl/3 



„U6 jg 



wave speed 



V_ 



rl/6 



\tj 



= / , which is nondimensional. The resistance 



V 

 is expressed in terms of — which is also nondimensional in a consistent system of units. 



A 

 If this is to be presented to a base of ® , we must divide by ® 2, and Froude added 1000 



XII- 13 



