The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1896-04-06
ELECTRoPLaTING.
New Process of Protecting Vessels
HuIIs Against BarnacIes.

Hul1s Against Barnacies.
The iron tug Assistance, which was re-
Gently launched from Jersey City dry
dock, had been copper-shathed by novel
process. Copper was deposited on her
bottom by electro-plating, just as spoon
or knife is electroplated with silver. The
invention is intended to solve the vexed
problem of protecting the hulls of vessels
! against barnacles. Until this invention
no means had been discovered by which
| copper could be successfully attached to
an IRON bottom. If the copper plates are
| bolted on, galvanic action sets up as soon
as the metals come in contact with the
salt water, and the iron is rapidly eaten
away.
Moreover, the barnacles attach them
selves TO the joints, though not in such
numbers as when the iron is unprotected
! The British men-of-war and many liners
have their iron bottoms covered with a
| two-inch oak planking, fastened with iron
bolts, then another two-inch teak plank
! ing, fastened with copper bolts TO which
! last the copper sheathing is attached.
! This method. though effectual, is tremen-
dously expensive, and repairs are difficult
to make. BY the new electroplating pro-
cess, equal protection can be secured at
far less cost. Our own men-of-war have
no copper sheathing at all, the only pro-
lection being coating of copper paint,
which is practically useless. When ves-
sci like the New York is locked after a
| cruise in southern waters, twenty tons of
| barnacles are often taken Off The bar
nacles fasten on to the bottom of the
ship, from which they extend out to a
distance Of six or seven inches. In adj
| dition to their own resistance to the ship S
progress, they catch up all kinds Of sea-
weed and floating debris, which makes
matters much worse. Every time big
man-ofwar is dry-docked and cleaned it
costs the country about $4,000. The
greater amount of coal necessary to main
a UiVnn onnaI adj ysAt n a
| bill. AS a vessel unprotected by copper
sheathing should be cleaned at least twice
a year, the Importance of some protection
TO the hull is apparent.
In the new process the copper skin is
deposited by means of large baths about
/ five feet square and eighteen inches deep,
which are shaped to tit the curvature of
! the ships bottom. The baths have to be
applied three times, each time containing
different solutions. First of all, strong
acid solution is put in them, and they are
shored up against the sides of the vessel
and plugged with oakum until Watertight.
After twenty-four hours' application, the
acid thoroughly cleans the iron and leaves
a good surface for the copper deposit.
baths containing a solution of cyanide
of copper are then placed in position and
allowed to remain twenty-four hours. The
cyanide aids in cleaning the surface of
the iron, and also acts as a sort of flux
TO hasten the process of electroplating. a
ACCOMPLISHMENTS, current of electric
ity at a voltage of six is kept playing
through the cyanide bath. The last bath
! is one of a solution containing sulphate
of copper in which are placed some large
copper plates. To the plates are attached
the positive pole of a dynamo, the mega
tive pole being connected with the side Of
the ship. A current of 800 amperes is still
kept going through the bath, but the volt
age is reduced to three. This last bath re-
mains on for four days or longer, accord
ing to the thickness of deposit required.
1 When removed, the iron hull is covered
| by copper skin from one-sixteenth to
one-eighth inch in thickness, which can
not be detached except with a cold chisei
joints, and insures complete protection
against barnacles Each bath is so placed
as to just overlap the other, which does
away with any joints. There can be no
Ealvanic action, because the iron and
copper are practically one nor can the
iron rust.
If the copper skin should be torn off
by scraping against rock or otherwise,
ample time would be given to reach port
before any galvanic action could set up.
Nearly all modern ships are provided with
! electric lights, and they could replace the
/ injured part while at sea. Every sailor
can make a Golfer dam, and by the help O..
this and few pounds of copper salts, the
! dynamos on board could replace the hull
where the skin had been scrape1 off This
would obviate all danger of any galvanic
! action-that bug-bear of iron shpbuilders
setting in. Under the influence of gall
Nanic action, iron melts away like sugar,
and copper and iron cannot be placed to-
gether in salt water. When the salt
new process, there is no such danger. The
| attention of the government has been
called to the eleCtroplating process as
protection to warships.