1909. ] The Wawve-making Resistance of Ships. 281 
The values of the constants in (12) have been chosen for comparison with 
an experimental curve of residuary resistance given by R. E. Froude ;* it 
was obtained from model experiments and by means of the law of 
200 
Fic 2 
150 
(0) 4 1 1 r 1 1 
10 15 20 V Knots 25 30 35 40 4s 
corresponding speeds and dimensions the results were given for a ship 
(model A) of 4090 tons displacement and 400 feet length. The actual curve 
is given in fig. 4 and is discussed more fully later; we neglect for the 
present the undulations which are known to be due to the interference of 
the bow and stern wave systems, and we consider a fairly drawn mean 
experimental curve denoted by R’. Table I shows a comparison of the 
values of R’ with those of R calculated from the formula (12). 
Table I. 
Vv. R, 
10 0-02 
14 2 
18 14 
22 38 
26 70 
30 106 
34 132 
38 157 
42 176 
46 195 
From this comparison we see that the point of inflection given by V’ 
corresponds to the point at which the slope of the mean experimental curve 
* R. E. Froude, ‘Inst. Nav. Arch. Trans.,’ vol. 22, p. 220, 1881. 
39 
