THE PROBLEM OF THE HULL AND ITS SCREW PROPELLER. 213 
carried as deeply as possible in the cases of deep draught vessels, propellers for 
double enders, propellers for tunnel boats, etc., have not been touched. All of 
these various problems require special study to determine the particular values of 
K and of S to use in the designs of the propellers. 
The problems involved in so recording the results and conclusions of years of 
study and experience in such a manner that all may readily make use of them have 
not been easy ones, and even in the final results as submitted there are ranges of 
indefiniteness which the author, due to lack of reliable data, has no means of clear- 
ing up. 
several of these regions of indefiniteness are the determination of the ranges 
of fineness of hulls covering the transition from hulls of type 2 to those of type 1, 
and from those of type 1 to those of type 3, also the slight range of speed fraction 
values at the curve B, Fig. 7, in which the apparent slips pass from slips of the first 
order to those of the second. 
Commander McEntee, with his hull models driven by model propellers, has 
provided a means by which some of the problems may be solved and by which, 
when propellers are designed in the safety zones, the true values of K may be 
obtained, but it is stated that this method of Commander McEntee’s is of no use 
in the cavitation ranges, although the author does not agree with this statement 
where “ Dispersal of the Thrust Column’’occurs. 
For a complete solution and accurate representation of the phenomena that 
occur, it is necessary to look to the future, trusting that it will bring with it a vast 
amount of performance data of sufficient value that it can be used with confidence, 
and the complete life history of the hull with its propeller plotted in such a manner 
as to provide an infallible guide to success in the solution of later problems. 
It is hoped that the material which has been opened up for inspection will 
thoroughly impress the student with the fact that the hull with its propeller must 
be treated in conjunction in the solution of the problem of propulsion. To treat of 
the propeller without its accompanying hull is to lose time in the ultimate complete 
solution of the problem involved. The perfect solution of the “Problem of the 
Hull and its Screw Propeller”’ rests in the hands of the shipowners, naval architects 
and marine engineers, and without their hearty and intelligent cooperation in the 
future, the problem may never be entirely solved. 
DISCUSSION. 
THE CHAIRMAN:—Paper No. 10, ““The Problem of the Hull and Its Screw Pro- 
peller,”’ by Rear Admiral Dyson, is open for discussion. Will Commander McEntee 
discuss this paper? 
CoMMANDER WILLIAM McENTEE, Member:—There are two general methods of 
