AERONAUTICS IN RELATION TO NAVAL ARCHITECTURE. 
By Nava Constructor H. C. RicHarpson, U. S. N., Member. 
[Read at the twenty-fourth general meeting of the Society of Naval Architects and Marine Engineers, held in 
New York, November 16 and 17, 1916.] 
The most intimate point of contact between aeronautics and naval architecture 
exists in the design of floats for aeroplanes, and I shall confine this paper to that 
subject although the question of stream line forms and the pressure and flow of air 
on such forms and on flat and cambered surfaces is also closely related to naval ar- 
chitecture. 
Early in 1911 work was started at the model basin at the Washington Navy 
Yard, with a view to the development of floats for aeroplanes. This work has been 
constantly followed up by making tests of model floats of all descriptions, and par- 
ticularly with models of floats actually furnished, or proposed, for use with naval 
aeroplanes. In addition to this, series of models embodying variations of particular 
features were tried from time to time, covering a wide range of possible useful fea- 
tures, and, where such models showed sufficient merit, full-size construction has been 
carried on, and the full-size floats have been given tests in actual service. A de- 
tailed account of the complete series of tests would be too voluminous for reproduc- 
tion, and would cover many defective types, so that I shall enter only into a general 
discussion of types and the requirements for floats for naval aeroplanes. 
It appears well to point out at once the differences existing between the condi- 
tions of use of aeroplane floats, and those met in the use of ordinary displacement 
vessels, or vessels of the hydroplane type. The principal differences arise from the 
fact that, as the square of the speed increases, the lifting power of the wings becomes 
more and more important, and the load carried by the aeroplane float constantly 
diminishes until at the get-away speed no load is any longer carried by the float. 
At the higher speeds near the get-away conditions, the form of the bottom of the float 
becomes unusually important, due to a prominent suction effect which is present if 
any downwardly bowed lines of flow are presented. 
It might readily be imagined at first thought that what proves the best type 
for hydroplane hulls would naturally be the best type for aeroplane floats, but the 
reason just mentioned may operate seriously against certain types of hydroplanes for 
aeroplane use, for the hydroplanes themselves constantly carry the same load, 
whereas aeroplane floats carry a diminishing load, are consequently less deeply im- 
mersed, and, therefore, present in general a different set of lines to the flow of the 
water than is the case with hydroplanes. Besides this, a hydroplane is never pro- 
jected suddenly at high velocity into the water with any lateral velocity. This, how- 
ever, is frequently the case with aeroplane floats, which must be able to make skid- 
ding landings, or get-aways, across the wind without danger. 
