Evening star., 1938-01-02
MARYLAND SH1P>TEST1NG BASIN BE WORLDS GREATEST
David W. Taylor Plant Is
Provided With Latest
Cavitation Tunnel.

old in facilities for efficient testing
In the shallow" basin of this new
plant will be tested the shallow-water
ships, such as steamers, barges and
similar craft. At one end of the basin
building will be turning" basin, and
In this section models will be tested
on the turn, or when backing up," or
in reverse positions and speeds.
During every experiment photo
graphs Of each step in the test will be
taken by means Of the cameras ad-
justed overhead that will photograph
regularly the progress of the model
through the water. Several exposures
will be taken on the same plate, so
that when the film is developed q
complete pictorial story will have been
recorded, comparatively, by means OF
the superimposed exposures.
While there are wind tunnels"
for testing aircraft in the present
basin at the navy yards, there will
be no facilities for aircraft tests at
the Carderock plant. Congress having
considered that facilities for such
work were ample at Langley field, half
a million dollars was struck from the
appropriation that would have gone
toward construction of some such
facilities.
There will, however, be a very COM
plete and modern "cavitation tunnel"
in the laboratory Of the new plant.
This tunnel will be the only one of its
kind in this country. although there
is a similar one in England and
another in Germany.
TO UNDERSTAND how vitally i'm
portant will be the work con-
Quoted in this laboratory, one must
understand what cavitation is. Gen.
orally speaking, and without getting
too technical. cavitation is the condi-
ton obtaining when a propeller is
driven faster than can be accommo-
dated by the water in its vicinity.
Propellers can be driven so fast, in
other words. that they create vacuum
behind the blades which is not filled
with water fast enough to furnish
that thrust which comparatively in
compressible water would furnish if it
remained at the blades of the pro-
peller.
Cavitation means much to the naval
designer who seeks the maximum in
speed from his power plant and the
propellers which push a vessel through
the water. II United States vessels,
for example. are a knot or two slower
than foreign cruisers, it may mean
losing naval battle. This disparity
in speed is likely to be caused by cavi-
tation.
Because of this phenomenon of
cavitation, it was necessary for the
Normandie to alter its propellers
after two trips across the Atlantic,
while the Bremen had to make SINH
lar adjustments after one trip. So
damaged had the propellers of this
latter vessel become, through cavita-
tion, that it was necessary for some
of the wheel" to be cut away to cor
rect the condition. In fact, accord
ing to naval authorities, this same
phenomenon of cavitation-or the
vacuum behind the propeller-causes
bubbles to arise in the wake of the
propeller which can eat into the metal
of the wheel" as sharply as the
pockmarks of acid, and may. during
the course Of one ocean voyage, COM
pletely destroy propeller. Thus the
cavitation laboratory will be one Of
the most important sections of the
new David w. Taylor Model Basin.
The officer in whose honor the new
basin IS to be named is enjoying the
distinction during his lifetime. First
ofncer in charge Of the present basin,
when it was placed in commission in
1900, he remained in that capacity
until 1915. In that year he was made
chief constructor Of the Navy and
served during the World War and
until 1922. He is an eminent naval
architect.
While the name of the commander
Of the new basin has not as yet bean
announced, 1t will be in the charge of
an odicer from the Bureau of Con-
struction and Repair Of the Navy De-
partment, under which the David w.
Taylor Basin will be operated upon
compilation. 4