The Red Cloud chief., 1897-03-12

PLATING SHIPS HULLS.
Ison ships to lie Placed In an Eiectr,
Bath.

bnth.
a new departure In the sheathing OF
vessels is to be undertaken In this
country. and the future cruisers and
battleships made for the United States
navy will probably be copper-sheathed,
according to the new process of olec-
tro-plating. Experiments have been
going on for many years TO electro
plate with copper the hulls OF iron or
steam vessels, and the results oh
tanned now justify the general adop-
ton OF u process of protection that can
he called purely American. An cleo
trio plant has been established at Jer-
sey City by the Ship Copper-Plating
Company, and the scagoing tug Assist
ance was treated to the new process as
an experiment. She has stood the test
u well that, after a year, she has a
hull nearly as free from all defects
caused by corrosion and sea animals
as when first launched.
Copper sheathing has been adopted
by ship-builders Of all the leading
countries for years, and Il has always
proved the best protection to the hulls
that could be devised. but rust and cor
rosion find Its way between the cop
per plates in time, and starts up open
ings that eventually destroy the ships
bottom or necessitates the costly work
Of resbeathing It.
The old way was to plate the bottom
OF the ship carefully from stem to stern
| with stout wood, and then coat this
| with sheath copper, but the new meth
cd Is to place the vessel In a bath OF
copper sulphate, into which IN electric
current Is passed. Liquid-tight COM
partments are made to fit firmly upon
| the sides and bottom Of the hull, and
when filled with a solution OF the cop
per the four anodes are placed through
an opening In the top. These .consti-
tute the positive pole, and the iron
hull acts as the negative. A Aim or
copper without seams or breaks gradu-
ally forms on the bottom OF the ship.
and In forty-eight hours this air-tight
sheathing il one-sixteenth of an Inch
thick. The sheathing fits 10 tightly
to the hull that 1t cannot be removed
without cutting into It with sharp In
struments, and even then 1t has be-
come so welded to the iron that tho
two cannot always be separated.
The value Of this unbroken surface
Of copper plating can be readily under
stood when some of the injuries to tho
bottom of iron vessels are examined.
The old method Of copper sheathing
added so much to the weight of the
vessels that the naval advisory board
in 1882 refused to have the hulls OF
the Chicago. Boston, Atlanta and Dol
phin sheathed. In the ease OF the CHI
cago II was estimated that 255 tons
would be added to the weight OF the
vessel, and 100 tons would be added ia
both the Boston aud Atlanta. Pur-
suing this same policy Of keeping ths
vessels light and buoyant on the water,
and thereby gaining additional speed,
the department refused to have any oil
the subsequent wal vessels copper
sheatEcd. AS a resr.t none OF our wal
vessels are sheathed. although a good
percentage of the ships Of the English
French. German and Russian navie'
, have their bottoms protected In THU
way. BY the new process OF electro.
plating the weight added to the yes
sells amounts only to 2.S5 pounds to TIKI
square foot.-Philadclphia Times.