Virginian-pilot. (Norfolk, Va.) 1898-1911, 1899-02-12


large cruisers. vessaIs capable under
first-class conditions of making twenty
knots Per hour. were reduced in speed
full four knots under the maximum az
tainments. It is n matter OF record
that the cruiser Philadelphia. a shin
with speed showing to her credit Of
some twenty knots per hour, entered
San Francisco harbor, after long
stay at Honolulu. able to make nor
much more than eight knots per hour.
The instances are innumerable OF high
speed ships having their powers
crippled by marine growth on the
underwater hull.
PRESENT ATTEMPTS AND RE Is
SUITS.
''To obviate the trouble, recourse has
been had to various patented paints.
1t has been claimed for nearly all un-
der-water paints that they possess anti
fculng properties. So far, however, tina
paint has yet to be produced that will
guarantee immunity from marine
growth.
In the British navy the practice OF
late has been to sheathe the bottoms Of
the warships. This is done by secur-
ing wooden strips to the skin OF the
vessel. and counter-sinking the bolts
used in fastening the planking to the
plates. The heads of the bolts are
covered with plugs. leaving absolutely
no metal surface to come in contact
with the copper. With the plauking Sc
cured firmly to the ship, the copper
plates are next fastened to 1t, the man
ner OF securing being the same as in
the case OF q wooden ship.
OBJECTION TO SHEATHING.
The objection to sheathed yes
that not only is the vessels dispiace-
ment increased, but that on given
morse power the speed is less. The cost
OF sheathing is estimator roughly at
80 per square foot. 1t is said that the
be carried on for about SO per square
foot. For q vessel $50 feet long about
twenty tons OF copper are required by
the electro-fusing process. The same
vessel If sheathed would have an added
weight OF about one hundred tons 1t IS
not generally known that q copper bot
tom adds TO the speed OF vessel 1t is
Il fact. however, that the frictional
contact OF water against copper is over
5la per cent. less than against iron. a
painted surface can never be made as
smooth as FURNISHED copper surface.
An iron vessel with a speed OF twenty
knots per hour. If coated with copper.
VIII have speed power Of twenty-one
Knots. -
TRIUMPH OF AMERICAN BRAINS.
The success of the experiment with
the Assistance is u distinct triumph for
American inventive ingenuity and
American perseverance. The world
over governments, and individuals act
ing ON their accounts. have strlven to
obtain substance that would prevent
the fouling of ships hulls. 1t would
seem that the credit is to be claimed
wholly by American engineers
The question of covering ships bot
toms was never more pertinent IN the
history of the American service. a
number of battleships are now in pro-
cess of building. and provision will
have To be made for them. 1t is under
stood that the plan had in mind by the
government officials was TO sheathe
these vessels. The Board OF Con-
struction after examining the Assist
ance. may recommend otherwise, but it
is extremely doubtful If such a radi-
cal departure will be taken prior to a
test on n small government vessel"
The Assistance was built in Camden
n. j.. i'll 1883. for the Standard OH
Company: was electro coppered in 1895
as an experiment; sold in 1891 to p
Dempsey. Son Il Co., it being thought
the coppering was q failure. This is
now thought to be n mistake.