8 
2,380 at c=1°6 and 3,400 at c=1'8; but for higher values 
it increases very rapidly, and gives 15,700 at c=3 and 87,250 
at ¢=4. 
In the last column in Table I. the values of E.H.P./V3 
are given; these were obtained from the calculated total 
power in each case, and the results are graphed in Fig. 2 
on a base of V/VL. The curve is of the same type as one 
which has been deduced from the performances of high- 
speed motor boats.* 
Column 5 in Table I. gives the percentage which the 
wave horsepower is of the total horsepower. It attains 
a maximum in this case of nearly 50 per cent at about 
‘ 
¥ 
7 WE 2 3 + 
e=18. After this value the ratio diminishes, for the wave 
resistance begins to approach its limiting value while the 
frictional resistance continues increasing as V3. If we 
suppose the total power to vary as V" in the neighbourhood 
of any given value of V, we can find how the index n varies 
with the percentage (y) which the wave power is of the total 
power (EK). For we have 
py? pe 100 aye-ss 
E=F + i992 =j00= CV Si3h 
where C is some constant. 
Since » = V(dE/dV)./E, we find 
=e Vv dp 
n=2°83 + 100—p aV ‘ 
*R. E. Froude, Trans. Nav. Archi, vol. 48, p. 102 (1906). 
66 
