Semisubmerged Ships 545 
Table 3 . 
Weight Data for Semisubmarine Series [10] 
Displacement (A) in tons 3000 1500 
Length (ZL) in feet 272 216 W715 136 
Beam (B) in feet 38.8 30.8 24.4 19.4 
SHP 130,000 70,000 40,000 25,000 
Weights in Tons 
Steel weight (0.35 A) 
Outfit weight (0.10 A) 
Salt-water ballast (0.05 A) 
Lead ballast + margin (0.10 A) 
Main propeller machinery 
Crew and all stores 
Deadweight = payload + fuel 
More Optimistic Design* 
Payload + fuel 
* All weights reduced by 20 percent. 
example, could perhaps carry a payload of about 100 tons over a range of 2500 to 4500 miles 
(including 10 hours at 45 knots). The larger ships could carry much more. 
Even better results and higher speeds might be attained with high-rpm and supercavitat- 
ing propellers. Although the design data given are only tentative, it is hoped that the sug- 
gested trends show the potentialities of unusual naval craft if the same level of technical 
effort is applied as in current hydrofoil boat designs. 
CONTROL OF NEAR-SURFACE BODIES 
The depth control of a body moving at high speed below, but close to, the water surface 
is an interesting problem. Therefore, it may be of value to summarize the theoretical work 
carried out so far for both the calm-water and following-wave cases. It is hoped that this 
will serve to clarify the problem and to specify areas that require research. 
Dynamic Stability in Calm Water 
The following analysis considers only small disturbances of equilibrium conditions, 
which the craft is assumed to have when proceeding at a constant speed (U) along a path 
