IMPROVEMENTS IN MEANS OR APPARATUS FOR PREVENTING THE CORROSION AND FOULING OF THE METAL SHEATHING OF WOODEN SHIPS "
Year: 1883

page_text: LETTERS PATENT to James Ballantyne Hannay of Glasgow in the County of
Lanark, North Britain, Chemist, for an Invention of "IMPROVEMENTS IN
MEANS OR APPARATUS FOR PREVENTING THE CORROSION AND FOULING OF
THE METAL SHEATHING OF WOODEN SHIPS
"
PROVISIONAL SPECIFICATION left by the said James Ballantyne Hannay
at the Office of the Commissioners of Patents on the 20th April 1883.
JAMES BALLANTYNE HANNAY, of 'Glasgow, in the County of Lanark, North
Britain, Chemist, " IMPROVEMENTS IN MEANS OR APPARATUS FOR PREVENTING
THE CORROSION AND FOULING OF THE METAL SHEATHING OF WOODEN SHIPS
"
This Invention has for its object to prevent the corrosion and fouling of the
metal sheathing of wooden ships; and whilst it is applicable to sheathing of
copper or Muntz's metal it has the important advantage of allowing of the satis-
factory use for sheathing wooden ships of thin sheet iron or steel, and generally of
a thinner metal of any kind than what has hitherto been considered necessary.
In carrying out the Invention care is taken to put all the sheets forming the
metal sheathing of a wooden ship in metallic connection with each other by rivets
or by the application of solder at suitable points; and the sheathing is (externally)
kept clean or uncoated with any paint or composition and is rendered electro-
negative. For this purpose an electric current is made to pass from a galvanic
battery or a dynamo-electric machine or other suitable source to one or, more
positive electrodes in contact with the sea or external water, thence through the
water to the external surface of the sheathing and finally through one or more
suitable conductors from the sheathing back to the battery or other source.
Rods
of carbon may be used for the positive electrodes, and they are by preference
made to project through stuffing boxes at the stern or any other convenient part
of the ship below water. The electrodes are connected by a suitable conductor
to the battery or source of the electric current but are carefully insulated where
they pass through the skin of the ship. Any suitable metal or material may
be used instead of carbon for the positive electrode and it may be held in the water
in any convenient way.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Ballantyne Hannay in the Great Seal Patent Office on
the 16th October 1883.
coic of over zot
94 TO DO
JAMES BALLANTYNE HANNAY of Glasgow, in the County of Lanark, North
Britain, Chemist "IMPROVEMENTS IN MEANS OR APPARATUS FOR PREVENTING
THE CORROSION AND FOULING OF THE METAL SHEATHING OF WOODEN SHIPS
"
My said Invention has for its object to prevent the corrosion and fouling of the
metal sheathing of wooden ships; and whilst it is applicable to sheathing of
"copper or Muntz's metal, it has the important, advantage off allowing of the
satisfactory, use for sheathing wooden ships of thin sheet iron or steel, and,
'been considered
generally, of a thinner metal of any kind, t THAT A
than what has hitherto b
necessary.
"
C
J
17
In carrying out my Invention care" is taken to put all the sheets forming the
metal sheathing of a wooden ship in metallic connection with each other, by rivets,
or, as I prefer, by the application of solder at suitable points; and the sheathing is
(externally) kept clean or uncoated with any paint or composition, and is rendered
electro-negative. For this purpose an electric current is made to pass from a
galvanic battery or a dynamo-electric machine or other suitable source, on board of
the ship, to one or more positive" électrodes in contact with the sea or external
water, thence through the water to the external surface of the sheathing, and
finally through one or, more suitable conductors from the sheathing back to the
battery, or other source. Rods of carbon may be used for the positive electrodes;
and they are by preference made to project through stuffing boxes at the stern or
any other convenient part of the ship below water. The electrodes are connected
'by a suitable conductor to the battery or source of the electric current, but are
carefully insulated where they pass through the skin of the ship. A sheath of
rubber may be conveniently used to insulate and protect each electrode where it
passes through the stuffing box, the external projecting end of the electrode being
of course left uncovered. Any suitable, electrode which can by the electric current
be rendered electro-positive to the metal sheathing of the ship may be used instead
of a carbon electrode; and the electrode or electrodes may be held in the water in
any convenient way.
T
"In practically applying my Invention the strength and quantity of electric
current required will vary in different cases, and will depend upon the nature or
quality of the metal forming the sheathing of the ship, and upon various conditions
and circumstances. As a guide I may state that for a copper-sheathed ship having
about 18000 square feet of wetted surface, one or more galvanic batteries or
dynamo-electric machines yielding an aggregate current of 1200 amperes of an
electro-motive force of 7 volt will secure the object in view. For the same ship
there should be two carbon electrodes consisting each of a round rod 1 inches in
diameter and made to project about inch. These two electrodes may be placed
one at each side of the stern of the ship; or there may be more of the carbon
electrodes and they may be placed at various parts of the ship's bottom.
:
1
Having thus particularly described my said Invention and the manner of
performing the same I have to state that I do not restrict myself to the precise
details herein described, but that what I believe to be novel and original and claim
as the Invention secured to me by and in terms of the herein before in part recited
Letters Patent is:
Dumating the corrosion and fouling of the metal sheathing of wooden ships

page_text: by keeping its outer surface uncoated with paint or composition and rendering it
electro-negative by means of an electric current applied substantially in the manner
hereinbefore described.
In Witness whereof I, the said James Ballantyne Hannay, have hereunto set
my hand and seal this fifteenth day of October, in the year of our Lord One
thousand eight hundred and eighty-three.