The morning times. [volume] (Washington, D.C.) 1895-1897, 1896-08-20
BABY FLEET OF CRUISERS
Testing Ship Models in Tanks
at the Navy Yard.
CHILD'S PLAY FOR SCIENCE
Tiny Craft Are FIoated In Order to
Figure ON Disbursements, Ascertain
Lines and Other necessary Data.
Idea Wars borrower rom Europe.
Naval Officers Experiments.

or all the wonders that the Washinsto on
Navy Yard has brought forth, the ship
| model testing tank. which is 10 be placed III
! operation shortly, is by Tar the most in
! teresting nd useful.
An experimental tank, in which carefully
conducted experiments can be made with
models in such way as to anticipate the
performance of the completed vessel, has
come o be necessity
| Several foreign governments have al
ready preceded us in this direction u nd have
caused elaborate experimental stations
! to Dr. constructed. tie British admiralty
| taking the lead. There are three or four
| officials from the construction department.
constantly on duty the admiralty expert
mental tauSs ut Haslar, and there is plenty
| OF evidence obtainabie which goes To prove
| the inestirnabie value OF the data derived
from the experiments there conducted.
RESISTANCE OF SHIPS.
| Many OF the most valuable Contributions
| to our knowledge OF the resistance Of
ships" WIRE made by the tate Mr. William
| FroId-. who was the originator and Ill
| rector OF the first Admiralty exp.rim entail
! tank
| for models is TO determine to a nicely,
| scarcely understood by the unscientIfic
mind, the resistance Of the hulls Of cruis-
ers not yet built, the effect Of disturbing
/ currents on bulls OF different shapes, and
the revealing OF errors too minute to he dis
| tingu.shed except 10y working mode! an
! der proper conditions of water pressure.
With the employment OF the new tank Is
| each contemplated cruiser These are to
lie constructed OF parafin wax, and must
| for the complete success of the idea. IL.
masterpieces OF workmanship and ahso ute
| fac-s,miles of the enorn ou> cruisers In
length these little WAX cruisers vary from
ten to thirty feet. As rule. they arr
made as large as possible. that their
performances may be on a corresponding
scale with less likelihood OF minor errors
being disguised, which Will naturally lie
correspondingiy multiplied in the finished
vessels.
WHAT THE TANK is.
The tank in reality is 10 tank at all, LUIS
Il good sized water course, Icing Two hun
drcd feet in length, forty fcet M width, ard
having depth OF twelve feet IL is to lie
built substantially, with u solid bottom and
SIDES uf stone. Above this waterway there
extends what At first glance very much re-
seinhies a regular trolley wirc. with IA
Observation-Disclosures oncend. Atcither
side OF the water tank Their. is Il little
car traCk On which u machine runs that -
callct carriage Its only Resemblance
10 Il carriage - ats wheels Beyond that
1t is Il complicated affair. which shows
on a fiat surface half Il dozen dials Of
various sizes with little hands. seine Of
which rush over the numbers OF the hal
ut lightning speed, while others creep with
Il snail pace
wire running from the overhaneiHs
trolley connects with this carriage, ami
from the connecting point branches off
into Il net work OF Wits, To the dialS.
Again from the main trolley wire above
the water, the connecting carriage VIE
extends 10 the model OF WAX in tie water.
II is from this that wonders are worked
on the carriage. BY talf Il hCndItd dtI-
cate CuD;rivInccs on board the miniature
cruiser, current Is SIM through tie cuI-
netting wires to the dial bands 10 mark
the distance Travelled in each fraction Of
a second, 10 register tie slightest sGggrs-
ton of Il disturbing draugEt OF current OF
water. or To show tie exact resistance
in the propclling
As The wax model moves through tie
water, at any desired rate OF speed, the ex-
pert naval officers watch the tia / plates
To make iDnumerable calculations. The
moment TIE figures slow that some varia-
ton of The hull Is rec Uir6d the current Is
switched off. Then one II he Icasons for
the use of parafiD wax becomes evident,
for 1t can be easily cut ard readily m. di-
fed 10 suit the alterations suggested 10y
experiments. These alterations are but
iDfinitcsmal scrapinCS fIt iii lie outer she'll,
but each spot tie size OF IN head taken
from the model meaDs Il Plate section from
the completed cruiser. Another reason for
the Use OF Ills type Of WAX, is That 1T does
not change its weight by absorbing water,
thus permitting of absolute calculations
being made.
Is ABSULUTELY ACCURATE
When the naval officers and shipbuil.t
erS are in possession Of the ciicately oh
tained results of the ship oGel testing
iank, it can be known to a certainty just
what is to be done by th. cruiser before
she is launched. OF all the problems about
a warShip, the only one at the present
moment incapable of being solved by
ordinary methods in extreme cases is
that of speed and power. M ability and
NO training will enable even the most
skillful naval architect to overcome the
want of an experimental tank in coping
with these questions The csta biisiment Of
an experimental tank will not only benefit
the naval service, but will greatly promote
the shipbuilding interests Of the country
as to the future performance Of new types
OF commercial vessels that will aid Ameri-
can shipbuilders to compete on more equal
terms with foreign yards in which similar
information is already available.
In 1889 a similar apparatus was con-
structed by the Italian government at
Spezzia. which is practically a duplicate
OF the British plant ut Hasiar. except
that tie tank is five hundred feet long
and twenty-five feet wide. The latest
appara tus constructed is ttat OF the Rus
sian government at st. Petersburg, built
in 1892.
In conducting model experiments tho
models are tested at various speeds he
tween certain fixed limits. and also at
varying draughts Of water and condition
of trim. The results, after being correct
ed. are plated and curves drawn. giving