Evening star., 1898-08-06

thought desirable. BY constant expert
ment the very best forms for hulls will be
secured, SO that when a vessel is built the
speed it should develop will be accurately
known. What is now to a large extent
guess work viii then be certainty.
Illinois to BE the First.
model of the Illinois, now under con-
struction at the Newport News ship yard,
is being built at the navy yard and as soon
as all the arrangements for operating the
tank have been completed this model will
be tested to see exactly what speed the ILL.,
nois can attain. If that vessel is found by
the experiments to be lacking in any re-
srect efforts will be made to correct short
comings. Not only do these tests indicate
the best forms of hull, but they demon
strate the influence on speed of various ar
rangements of armor plate, draft of water,
etc.
Not only will this experimental plant be
of use in the designing of naval vessels, but
1t will be used by shipbuilders in determin-
ing designs of merchantmen, Congress hav-
ing provided that private ShipbuilderS
might use the tank for experiments by pay
ing the cost of operating the plant when so
used.
The experimental tank, while new in this
country has long been in successful opera
ton abroad. and Chief Constructor Hich-
born of the navy has for many years en-
deavored to secure an appropriation from
Congress for the purpose of building such a
tank here. The credit for demonstrating
the utility of experimental tanks belongs
to England.
Experiments to determine the resistance
OF ships in advance of construction by tow
ing models of the proposed ships were COM
menced by the late DR.. VIM. Froude in
lSf2 in a tank built by him at Torquay g.
This tank was 2S0 feet long, 30 feet wide
and 10 feet deep, and in it experiments Were
carried on for the admiralty and in con-
nection with the towing experiments with
the greyhound certain laws and deductions
were established beyond question.
Since the death of Dr.. Froude in 1879.
the work mas been carried on by his son.
MT X. T.. troude. and many useful and val
uahie results have been obtained the de-
sihghs OF many proposed ships having been
altered after model trials, notably In the
case OF the Polyphemus and the Medway
class of Sunboats. the deductions being
afterward verified by the performance of
the vessels.
In 1889 tank of about the same dfuen-
sions and with practically identical appli-
ances was constructed by Denny Rrothers
OF Dnnoarton, in which many thousands of
engineering and commercial success IN
tank having enabled them, as case ir
point, to successfully construct high
spted vessel for he Belgian government u1-
ger conditions so rigid that under ordinary
circumstances surety of fulfilling them
would have been impossible.
British Admiralty Approved,
The British admiralty considered the re-
suits obtained SO valuable that, in 1856. p
new tank was constructed at Haslar. near
Portsmouth, and the apparatus at Tor
quay was removed to that place and ir-
stalled there with many improvements and
additions under the charge of Mr. r. z
Froude. The new tank is 400 feet long, 20
feet wide and feet deep and commodious
Offices are attached with a view of enter
ing extensively upon the work of expert
mental investigation. In 1889 an apparatus
was constructed by the italian government
at Spezzia, which is practically a duplicate
of the British plant at Has1ar. except that
the tank is 800 feet long and p feet wide
The latest apparatus constructed Is that
installed by the Russian government at ST
Petersburg in 1892. To duplicate such a
plant, including cost of all apparatus and
the necessary buildings, but exclusive Of
ground, would cost $4,000. The primary