Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-11-27


heaviest OF our future ships may be deter
| mined to nicely. %
The last regular session of Congress COM
pleted total provision Of 100000 for the
construction Of this. experimental plant
and by Industrious work the establishment
has already been fastened half way to
completion. Easily within a year the place
Will be ready for practical application.
For years such a plant has been recog-
nized by the principal European naval pow
ers as necessity, and the praiseworthy
performance of our ships reflects all the
more credit upon our designers, handicap
ped as they have been by the lack of such
practical facilities Much as mathematical
science has done in other directions, it still
Is unequal to the solutions of all the diff
fcult questions involved in the motion of q
body in water; and it is only by practical
experiments that the forces at work can
be rightly measured and divided among the
clements of wave motion, surface friction
| and mechanical propulsion.
Based upon the Investigations of the late
Doctor William Froude of England. it is
| known that the performance of a model
bears a mathematical ratio to the perform
ance Of full-sized ship; and, by multiply
| ing the known functions of the miniature
| by its ratio to the proposed craft, the posi-
| ed vessel are predetermined beyond ques-
! ton. What this may mean when peculiar
forms of hull or exceptional speeds are in
volved Is easily grasped even by the lay
man, and the discovery of what must be
expected of a ship built upon those lines
may mean the success or ruin of a vast
| enterprise. The application of the model
tank applies as well to merchant craft as
| to naval vessels, and 1t is the purpose of
the Navy Department to place the estab-
| lishment at the disposal of civilian and
commercial undertakings.
Ahead of All Others.
The present tank may truly be said to be
the result of the persistent efforts of Chief
Constructor Hichborn, and. following out
his direction, the plant will be at once upon
a scale and of q character considerably In
advance of anything now extant abroad.
The completed structure will consist pri-
| marily of a concrete-lined basin, surround
| ed by one-story brick building. which is
! surmounted by a steel-trussed roof of an
| approved pattern.
| The building is 500 feet long and 80 feet
wide. with two small extensions for the
installation of the ventflating, heating.
pumping. filtering and power plants BY
| this means the main body of the structure
| is left unhampercd for the experimental
| work.
The main basin is $40 feet long and AZ
| feet wide. and will have a uniform depth
| of IA feet. At either end there will be
narrow. shoal extension. one 20 feet long
! and feet wide, from which the trial runs
| will be started, and the other 81 feet long
and feet wide. into which the models will
| be carried upon the completion OF the
runs. The latter extension will have no
| special features; but at the starting end
there will be pit on each side and at the
rear for the purpose Of providing conven-
| lent means for measuring the models as
they float in the basin preparatory to the
| trials. There, too. will be a standard
VI OIL ,,of}r
standardizing the dynamometer. which
measures the resistance OF the models or
the correlative. the power required to tow
them at their several speeds
On the inner lip. soto speak, Of the main
/ foundation of concrete. will rest the tracks
upon which the carriage will travel during
the runs These tracks. of which there are
two on each side of the basin, extend from
heaviest railroad type. and are so fastened
10 the foundations as 70 make them as near
| ~ rigid as possible. The object of this is to
OBTAIN surface over which the carriage
which spans the basin and tows the models
may be run at high speeds and with the
| least amount OF, jarfr This is essential to
| cate instruments. that register and record
| accul ately the various elements OF the
trials.
| The Towing Carriage.
The towing carriage is also rigidly con-
structed, and is driven by electric motors
run on the trolley system. There are four
OF these motors. Two will be needed for
runs at speeds from to IL knots, while
| all four will be required from that up to
the maximum of 20 knots. 1t may be
stated here that 20-knot run on the part
OF model is the correlative of speed Of
| perhaps 40 knots or more in the contem-
plated craft.
The dynamometer for measuring the re-
| sistance of the models, the apparatus for
| recording the results and the necessary fix
| lures and electrical arrangements required
are grouped on platform at the center of
the carriage. This platform can be raised
| or lowered to suit the various models.
In addition to these more simple expert
| ments. arrangements will be provided for
| testing the functions or qualities of the
models; the effects Of propellers Of various