THE PROBLEM OF THE HULL AND ITS SCREW PROPELLER. 189 
Lake type but reappearing at speeds above 10 knots. With vessels of the Holland 
type, the resistance due to the influence of the diving rudders appears to reach a 
maximum at 7 knots, remaining practically constant in its effect on K until 9 knots 
is reached, when it begins to fall rapidly. 
In both types of vessels the value K at any speed appears to depend upon the 
length of boat; in the case of the Holland boats, K in the submerged condition 
becomes unity when a load-water-line length of 200 feet has been reached, while 
with the Lake type the value of unity is not reached until a load-water length of 
230 feet has been attained. 
These values of K for both types of vessels are given in the following tables:— 
VALUES OF K FOR SUBMARINES. 
Lake—Submerged. 
6 | 7 | 8 | 9 | 10 | 11 | 12 
K. 
1.35 | 1.24 | 1.14] 1.05 | 1.0] 1.1 1.4 
1.30} 1.20 | 1.12] 1.04 | 1.0] 1.09 | 1.34 
1.25 | 1.17 | 1.10} 1.04 | 1.0] 1.07 | 1.28 
1.20 | 1.13 | 1.08] 1.03 | 1.0] 1.06 | 1.22 
1.14] 1.10 | 1.06] 1.02 | 1.0} 1.04 | 1.16 
1.09 | 1.06 | 1.04 | 1.015 | 1.0 | 1.025 | 1.11 
1.05 | 1.035 | 1.02 | 1.01 | 1.0} 1.02 | 1.05 
1.00 | 1.00 | 1.00] 1.00 | 1.0} 1.0 1.0 
1 1 1 1 1 1 1 
250 | All below=unity up to 12 knots. 
260 
270 
280 
290 
300 
