TAYLOR MODEL BASIN—HOWARD 247 
This division also carries out full-scale special tests aboard ships of 
the fleet, usually at the time of their trials, such as turning trials to 
determine the track of a ship under different conditions of speed and 
rudder. 
The structural mechanics division is concerned with all questions of 
the strength of ships’ structure, vibration, and related subjects. 
The work in structural mechanics at the model basin had its incep- 
tion a number of years ago in the thought that if the performance of 
full-sized ships could be accurately forecast through experimental 
work with models in a model basin, it should equally well be possible 
to forecast the performance of the structure of ships by the use of 
accurately constructed models, with proper technique in carrying out 
the tests. This would permit gaining knowledge as to the performance 
of such structures long before a ship itself was finished. 
This work was started with elementary models of the hulls of ships, 
and sectional models of the hulls of submarines. Proving successful, 
it has been continued to the present time, until it now includes deck 
and bottom structures, turrets and their foundations, and similar 
projects. 
The next problem undertaken in this field was the resistance of the 
structure of ships to underwater explosions. It was soon found that, 
for this work to be effective, fundamental knowledge must be gained 
as to the nature of the underwater explosions themselves. With the 
construction of the new Taylor Model Basin an extensive research 
program was taken in hand to investigate the effect of the explosion of 
small charges against simple diaphragms, and also to study the explo- 
sions of charges themselves, by the use of extremely high-speed under- 
water motion photography. From this research, information is being 
gained as to the nature of explosions themselves, and their effect upon 
the structure of ships. 
A third most important work of this division is that of investigating 
vibration of ships’ hulls and structural foundations, including support 
of instruments and other equipment aboard ship. Some of this work 
is done at the model basin but a large part of it is carried out aboard 
newly commissioned ships of the fleet when undergoing their first 
high-speed runs and gun-firing trials. 
The work of the aeromechanics division, including the operation of 
the two new wind tunnels, is concerned principally with wind-tunnel 
tests of models of new designs of airplanes for the Bureau of Aero- 
nautics of the Navy Department, and with tests to determine the effects 
of modifications to improve the performance of existing designs. 
Wind-tunnel tests are also made for the Bureau of Ordnance, and 
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