1909.] The Wave-making Resistance of Ships. 297 
Table VII. 
Kh. v] / (gh). L/h. m. —Bxc?. 
(eo) (0) (0) 1:0 2°53 
10 0°316 1:18 1°0 2-53 
6 0°41 1°87 1:0 2 53 
4 0°5 2°82 1-005 2°53 
2 0-69 5°42 1°077 2°43 
al 0-87 8°57 1-287 1°92 
(0) 1:0 11°3 1°5 (0) 
We consider now the experimental curve analysed in Case IV in the 
previous section, a model of 20°5 feet taken up to avalue c= 1:8. Assuming 
that the influence of finite depth was inappreciable in this range, we have for 
deep water 
R = 2e-758/9% + 82'5 {1 —0:14 cos (10°2/c?)} c= 28? (29) 
We leave out of consideration at present the first term, which is supposed 
to represent the diverging waves, and we extend the calculations for R 
(transverse) from the rest of the formula up to ¢ = 3°3 taken at intervals 
of 0-1 for ¢; we obtain thus the lowest curve given in fig. 11. With the 
help of Table VII, we calculate values of R for depths of about 5, 10, 12, 15, 
and 20 feet, taking in the formula (28) A equal to 
82'5 {1 — 0:14 cos (10°2/c?)} 
so that the results apply to the same model at different depths. An example 
of the calculations for one case may be sufficient; Table VIII shows the 
intermediate steps for h = 12°35 ft., L = 20-5. 
Table VIII. 
— Br. R/A. e—2°53/c3. 
3°73 0-024 0-024 
2-26 0-106 0-106 
1°5 0-224 0-223 
0°75 0 508 0-472 
0 °374 0-385 0 687 
0 1°5 1 
a ie [Ee eel 
The results for the five values of h are given in Table IX, and from these 
the curves in fig. 11 have been drawn. 
The general character of the effect of finite depth is clear on inspection of 
the set of curves in fig. 11. If it is required to go to high values of the 
speed-length ratio in a given tank, the ratio of the depth of water to the 
length of the model must be adjusted so that there is no appreciable effect in 
55 
