202 THE PROBLEM OF THE HULL AND ITS SCREW PROPELLER. 
The performance of this vessel’s propellers enters the overload zone to a greater 
extent than any other of which the records are available. The maximum load 
fraction attained is 1.84, while the corresponding speed fraction is 1.249. The 
ratio S. H. P.=.92 I. H. P. probably does not exactly fit this case as the main air 
pumps were driven by the main propelling engines and absorbed some of the power 
developed by those engines. 
VESSEL J. 
This vessel is a destroyer fitted with turbines connected directly to the pro- 
peller shafts. The revolutions are high with resultant high tip speeds, while 
the effective thrusts delivered at 35 knots were also very high. The blades of the 
starboard propeller had been injured by striking something and were run in this 
injured condition, with the result that the performance of this propeller was ex- 
tremely erratic. The port propeller, however, ran smoothly to the end of the trials, 
and the power data taken from this shaft were consistent. In comparing the esti- 
mated and actual performances, the actual power of the port shaft has been doubled 
for the total power, while the revolutions of that shaft have been taken as the 
normal revolutions. 
Hull. Propeller. 
Wg lbs Wiig IS See Nim Den: ee eN eee eras 2 
(Bi BOuie 18 FeYa Sip McC) Ni 2 
i OSI AGA iE ornaly ae ae einen: Standard 
B=L. L. W. L.=.99 DSL AARNE ORR ERG ta 7.8! 
Nom. B. C.=.476 Y Ee MARMION MOANA on UC Wy a teas TAZ 
H~B=.298 PAd ee TAS aie aio evia ae .648 
S. B. C. on X (corrected) =.285 PRE SE FAL oS ae HN ete Maa a 15,100 
