The morning news. [volume] (Savannah, Ga.) 1887-1900, 1895-11-08
ELEcTRoPLATING FOR SHIPS.
A METHOD TO PREVENT CORROSION
AND TO KEEP OFF BARNACLEs.
Copper Il Deposited Directly ON the
Iron HILLS by EIectrOiySiS-GaIva
lie Action Is Thus Guarded Against.
The Savings Effected.
ne Savings EHecteu'

copper the iron hull Of a large ocean
going tug is being carried out In a Jersey
| City dry dock. When the plating is fin
! ished the inventor will be prepared TO
show that the vessels bottom is per-
fectly protected from barnaces and COW
cred with a homogeneous coating Of cop
| per. which is practically indestructable.
The attention Of the government has been
called TO the invention and it is being
closely watched by the agents Of foreign
countries.
This invention. it is hoped. Will solve
the great problem which confronts all
the builders Of iron ships-h0w TO protect
the hull from barnacles and corrosion.
The hull of a wooden ship can easily be
protected by simply mailing on sheets of
| copper, but this method cannot be used
| in the case Of an iron vessel. II the sheets
| of copper are bolted directly to the iron,
/ galvanic action is set up by the. salt
water and the iron plates are rapidly
eaten away. In the British navy a thick
/ wooden plankng is first bolted 10 the iron
| hull and then the sheets of copper are
nailed to the wood. This method is ef-
fectual so far as protection from barna-
/ cles is concerned, but IL is enormously
| expensive and adds considerably to the
weight of the vessel The hulls of Amer
| lean warships are not copper sheathed
at all. being merely coated with copper
/ paint. which soon becomes useless. The
ship requires dry docking and cleaning
twice a year to keep the bottom in any
thing like condition. To dock a warship
and clean the hull costs about $4,000, be-
sides the risk of straining the vessel and
| the time wasted while she is in dry dock.
| The value OF a copper sheathing which
can be applied to the iron In such a way
as to become perfectly homogeneous with
| thus evident. Where there is such close
| contact the water cannot get between
| the iron and copper and consequently no
| galVanic action sets in, while the vessel
| never requires taking out OF the water,
inasmuch as the copper skin is almost in
destructible. No barnaeles can adhere TO
The process Of electroplatng the hun OF
| a ship consists in depOsitng a layer of
copper upon the iron BY means of baths
| or tanks filled with solution of copper
| and subjected to the action of an electric
| battery. These baths which are about
I three feet square and six inches in depth,
| are laid fiat against the side Of the yes
| sci. They are shaped so as to fit the
| curvature of the side of the vessel ana
rendered thoroughly water-tight. by be-
| ing damned up against the iron hull anc
| then packed with oakum round the edges.
| Three sets of baths are used in the pro-
| cess and the entire operation takes about
| two weeks, though In a large vessel the
| time would be longer.
The first bath is one of suphurlc acid,
which cleans the iron eplates thoroughly
and prepares them for the deposit of cop
per. About twelve hours is sufficient for
| the cleansing process, when the baths are
are removed, cleaned and replaced on the
hull. They are then filed with a solution
| of cyanide Of copper, which, by means of
pipes and a pump. Is kept in constant cir
tive pole of a powerful battery is then
connected with two copper plates placed
in each bath and the negative pole to the
eopper 9 u soon od t9e S nm i9geF OF
cred by the bath, which istcalled the stTdk-
ing coat and serves as foothold for
bath. After the cyanide has been re-
moved from the baths, solution of sui
phate of copper is introduced, which acts
in the same way as the cyanide solution
The action of the electric current which
passes through the baths subtracts the
metal from the copper plates in the bath
and deposits it upon the striking coat OBJ
| tanned by the cyanide bath. When about
| three-sixteenths of an inch has been de-
| posted the baths aTe..Tem0ved and..the
| coat of copper is thoroughly Furnished
1t Is then In almost perfect unison with
| the iron plates and cannot 'be removed ex-
cept with a cold chisel Heavy blows
with a hammer do not produce any i'm
| of the iron.
With big ships much Iargep baths would
| be employed and the inventor declares
that the process is much cheaper than The
| present costly plan OF first covering the
| iron with a plank sheathing. The iron
plates could even be coated before the
| ship was built and the joints gone over
with the baths after the new vessel was
constructed and before she was off the
| ways. On account of the great expense
involved in the present plan of first plank
ing, and then copper sheathing the iron
hull, few vessels have their bottoms pro-
tected with copper. All the British war
| ships are so treated, and so are some OF
| the fastest liners. Besides the danger of
| COrrOGiOn UNPROTECTED ha
| heavy demonstrations of barnacles consti-
tute an impediment which seriously affects
| the barnacles catch hold Of everything
| floating in the water which comes In con-
tact with them, and when the New York
| was docked not long ago her bottom was
| covered with seaweed and debris caught
up by the shells and mollusks. Such an
incubus under water as masses of sea-
weed, yards in length, trailing along
makes big difference in the amount OF
coal required to produce a given speed.
ton, is a formidable addition to the al
ready large enough bill for drydocking,
so that the expense Of coppering a vessel
bottom is soon made up In dFydocks and
In case a ship whose hull was electro
! plated with copper should Craze a rock
| and grind off any of the deposit, the sim
! pie remedy of applying a bath to the in
! jured plate would be all that would be
necessary to repair the damage. No gal
| Vanic action of any consequence can go
on while the ship IS making for drydock
as it requires months for the sea water
! to make any tangible impression upon
the iron. The tug which was electro
plated last winter, the first time the ex-
pertinent was tried, had one or two plates
/ imperfectly coated owing to the freezing
/ of the solution. and though she was in
the water over six months, there was
! no appreciable damage done by reason of
/ the galvanic action set up. This same tug
4 is the one now being electroplated, but
| the process is being carried out more thor
/ oughly, three-sixteenths of an inch of
1 copper being deposited instead of one thir-
| ty-second of an inch, as was the case in
| the first instance.
The process is an interesting one, and
| the ships side represents all stages of
/ the operation, first the rusty iron, then the
| clean iron the dull red coating of cop
per and lastly the FURNISHED copper which
/ shines like gold. When the process is
/ finished there is not a seam or Joint in
/ the copper from stem TO stern, each bath
being moved so as just to overlap the
/ coating deposited by the next one This
is TO prevent any corrosion or galvanic
action by reason of the sea water, which
would gradually eat into the iron
wherever there was a joint.
A GREAT NERVE TONIC.