Improved Method of and Means for the Application of Anti-fouling Coating for Metallic Submerged Structures
Year: 1899

page_text: Date of Application, 7th July, 1899-Accepted, 2nd Sept., 1899
Improved Method of and Means for the Application of Anti-fouling
Coating for Metallic Submerged Structures,
A communication from abroad by GEORGE DENSMORE COLEMAN, of Boston, State
of Massachusetts, United States of America, Engineer.
I, REGINALD WILLIAM JAMES, of the Firm of Foll and James, of 1, Queen
Victoria Street, in the City of London, Chartered Patent Agent, do hereby
declare the nature of this invention and in what manner the same is to be
performed to be particularly described and ascertained in and by the following.
statement: -
The present invention relates to an improved antifouling coating for metal
structures intended to be submerged in water and more particularly in sea water,
such for example as the bottoms of iron or steel vessels, iron or steel work in
bridges, piers, docks, caissons, light houses or other structures, the whole or
parts of which are intended to be submerged in water.
The object of the present invention is to prevent deterioration and corrosion
of such metal structures and the accumulation of marine growths thereon.
I am aware that it has been proposed in the prior art to apply to the bottoms
of iron or steel vessels or other submerged structures a coating containing finely
divided copper, such copper being commonly mixed with some kind of paint
and applied directly to the bottom of a vessel or other structure. I am also
aware that it has been proposed first to cover the portion of the vessel or other
structure to be protected with a coating of paint and then while such coating
is still moist to apply to its surface pulverized copper, the particles of which
are scattered upon the adhesive surface and thereafter to press the copper into
the coating of paint by rollers or other suitable instrumentalities.
So far however as I am advised, the methods of using pulverized or finely
divided copper as above suggested have been found objectionable for the reasons
that when mixed with any form of paint and applied directly to the bottom of
a vessel, the copper with the iron or steel sets up electrolytic action which pits
and corrodes the latter, or when applied to the moist surface of the paint and
thereafter rolled into the same some particles of the copper will be forced into
contact with the iron or steel with the same resulting corrosion. It will be
further noted that when mixed with a paint or rolled into the same that most
of the copper will be enveloped by the paint and but little exposed to the action
of the sea-water, so that a coating formed in this way is not effective as a pre-
ventative of marine growth. It is to be further noted that when pulverized
or granulated copper is used in the manner above suggested, flotsam by striking
against the structure will scale or chip off the coating leaving the iron or steel
bare and liable to the accumulation of marine growths thereon.
The object of the present invention is to provide an antifouling coating for
metal structures, the active ingredient of which shall be pulverized, granulated
or comminuted copper, which shall be tough and durable and in which the

page_text: copper is so effectively separated from the iron or steel that danger of electro-
lytic action is greatly reduced.
To the above end the present invention consists of an antifouling coating as
hereinafter described in this specification and defined in the claims.
The annexed drawing illustrates diagrammatically the preferred form of my
improved antifouling coating Figures 1, 2, 3 and 4 being enlarged diagramatic
sections illustrating the successive steps in process of applying my improved
antifouling coating.
Figure 5 being a similar diagramatic section on a still larger scale illustrating
the completed coating.
Figure 1 illustrates the first step in the process of applying my improved
antifouling coating to surfaces which it is desired to protect from the action
of water.
I indicates the metal which is to receive the protective coating and 2 indi-
cates a layer of paint such as red lead mixed with a binder as oil and a
drier such as turpentine which after the surface of the metal I has been
thoroughly cleaned by scraping and washing is applied to the same with a
brush, or if the paint be of a stiffer consistency it may be applied with a trowel
or the like. This layer of paint which is shown very much exaggerated in
thickness in this figure having been applied to the surface of the metal is
allowed to dry until it becomes tacky and then as shown in Figure 2, I apply
to this tacky surface of paint by means of a blower or any other suitable means,
granulated or comminuted lead 3 or other soft metal, such as tin or zinc. Then
the paint first applied is allowed to dry with the layer of granulated lead
adhering to its surface. I next apply to the layer of granulated lead a thin
coating of paint 4, as shown in Figure 3, which may be the same kind of paint
as that first applied to the metal, to which coating 4 is then applied by means
of a blower, or any other suitable means, a layer of comminuted copper 5, as
shown in Figure 4, which adheres to the freshly applied coating of paint 4.
This layer of comminuted copper 5 will now be rolled or hammered or pressed
into the coating of paint 4 and the layer of granulated lead 3, as shown in
Figure 5, which latter will effectually prevent any of the comminuted copper
from coming in contact with the metal to be coated, thereby preventing electro-
lytic action between the two metals which would result in corroding the metal 1.
If desired before rolling the layer of comminuted copper into the coating of
paiut 4 and the layer of lead thereunder, I muy first apply by a blast or other
suitable means still more finely divided comminuted copper 6 which will enter
the interstices between the larger particles of comminuted copper 5 previously
applied, and then the surface may be finished in the same manner as above
described.
Thus it is seen that my improved antifouling coating for metal structures
which are submerged in or exposed to the action of water consists of a coating of
which one layer is composed of soft metal which adequately prevents any acci-
dental contact of the copper with the surface of the iron or steel, besides which
being built up in the manner above described it is a strong, tough, wear-resisting
coating which presents on its outer surface particles of copper exposed to the
action of the water which gradually reduces the exposed portions thereof by
chemical action into poisonous salts which effectively cover the entire surface
and prevent the accumulation of marine growth thereon.
The layer of soft metal 3 constitutes an important ingredient of any coating
not only for the reasons above set forth but for the further reasons that it
serves as a spongy body into which the harder, angular granules of commi-
nuted copper can be forced, without bringing them into contact with the metal
to be covered, and which at the same time serves as a strong supporting body
to hold and retain the copper in place; again its soft and yielding qualities
enable the surface of the coating to be made smooth and uniform; and being
inelastic, wlieu the coating is subjected to the action of flotsam or materials

page_text: accidentally brought into contact with it, it bends and does not chip or flake
off as would a more brittle coating.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. An antifouling coating composed of a layer of paint, a layer of commi-
nuted soft metal, a second layer of paint, and a layer of comminuted copper,
substantially as described.
2. An antifouling coating composed of a layer of paint, a layer of soft metal
ombedded' in but not penetrating the layer of paint, and a layer of comminuted
copper embedded in the layer of soft metal, substantially as described.
3. An antifouling coating composed of a relatively thick layer of paint, a
layer of comminuted soft metal, adhesively attached to the surface of the said
layer of paint, a second relatively thin layer of paint, and a layer of commi-
nuted copper driven into the last named layer of paint, presenting a smooth
surface closely studded with bare particles of copper, substantially as described.
Dated thin 7+1 f T. 1. 1000
FELL & JAMES,
Agents for the Applicant.