AN IMPROVED METHOD OF PRO- TECTING THE SURFACES OF SHIPS AND OTHER SUBMERGED BODIES FROM INCRUSTATION OR ADHERENCE OF ORGANIC MATTERS, AND FROM CORROSION
Year: 1876

page_text: LETTERS PATENT to Frederic Pelham Warren, of Southsea, in the County of
Hants, Captain in the Royal Navy, and Edward Field, of the Firin of Field,
Field, and Cotton, of Chandos Chambers, Adelphi, in the County of Middlesex,
Consulting Engineer, for the Invention of "AN IMPROVED METHOD OF PRO-
TECTING THE SURFACES OF SHIPS AND OTHER SUBMERGED BODIES FROM
INCRUSTATION OR ADHERENCE OF ORGANIC MATTERS, AND FROM CORROSION.”
Sealed the 30th September 1876, and dated the 3rd August 1876.
PROVISIONAL SPECIFICATION left by the said Frederic Pelham Warren
and Edward Field at the Office of the Commissioners of Patents on the 3rd
August 1876.
FREDERIC PELHAM WARREN, of Southsea, in the County of Hants, Captain in the
Royal Navy, and EDWARD FIELD, of the Firm of Field, Field, and Cotton, of
Chaudos Chambers, Adelphi, in the County of Middlesex, Consulting Engineer.
"AN IMPROVED METHOD OF PROTECTING THE SURFACES OF SHIPS AND OTHER SUB-
MERGED BODIES FROM INCRUSTATION OR ADHERENCE OF ORGANIC MATTERS, AND
FROM CORROSION."
This Invention has for its object an improved method of protecting the surfaces
of ships and other submerged bodies from incrustation or adherence of organic
matters, and from corrosion.
For this purpose we coat the surface to be protected with a layer or layers of
cement, upon which we superpose a layer of paper, which paper in the case of a
submerged vessel or body constitutes the sheathing or external covering in direct
contact with the water in which such vessel or body is immersed.
We have found that the following constitutes an efficient method of covering
the surface of a submerged iron structure to protect that surface from marine growth
and organic incrustation (fouling) :-The surface to be protected is coated with a
layer of cement composed of ground quick (or unslacked) stone lime, intimately
mixed with Stockholm tar, and over the layer of cement, which is applied in a cold
state to the surface to be protected, is laid a layer of thick brown paper. The
proportions of lime and Stockholm tar to be used in making the cement will depend
upon circumstances; if the cement be required to harden quickly a larger pro-
portion of lime must be used than in the case of the cement, being required to be of
a tough nature.

page_text: The intimate admixture of the ground line with the Stockholm tar may be
effected in a mixing mill just before the cement is to be used. We have found by
experiment that cement composed of a mixture of ground quick (unslacked) stone
lime and Stockholm tar, as described, will adhere firmly to wet iron, and that thick
brown paper laid upon such a coating of cement will adhere immediately, and in
the course of a few hours becomes sufficiently hard to resist the heat of tropical
climates.
We desire it to be understood that the application of our Invention is not limited
to the protection of vessels or bodies composed of iron; also that we do not intend
to contine ourselves to the precise composition of the cement above described, nor
to the use of paper.
In lieu of paper we may, in some cases, use a sheathing composed of loosely felted
material, which will effect the same purpose of preveting the adherence of organic
bodies to the coated surface, so long as the cohesiveness of the particles of material
composing the sheathing employed be such as will not prevent the exfoliation or
detachment from the main layer of sheathing of any outer part or portion thereof to
which an organic body may have become securely attached.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederic Pelhaun Warren and Edward Field in the Great Seal Patent
Office on the 3rd February 1877.
FREDERIC PELHAM WARREN, of Southsen, in the County of Hants, Captain in the
Royal Navy, and EDWARD FIELD, of the Firm of Field, Field, and Cotton, of
Chandos Chambers, Adelphi, in the County of Middlesex, Consulting Engineer.
AN IMPROVED METHOD OF PROTECTING THE SURFACES OF SHIPS AND OTHER SUB-
MERGED BODIES FROM INCRUSTATION OR ADHERENCE OF ORGANIC MATTERS, AND
FROM CORROSION."
This Invention has for its object an improved method of protecting the surfaces
of ships and other submerged bodies from incrustation or adherence of organic
matters, and from corrosion.
For this purpose we coat the surface to be protected with a layer or layers of
cement, upon which we superpose a layer of paper, which paper in the case of the
submerged part of a vessel or body constitutes the sheathing or external covering
in direct contact with the water in which such vessel or body is immersed.
We have found that the following constitutes an efficient method of covering
the external surface of an iron structure intended for use in sea water to protect that
surface from marine growth, organic incrustation (fouling), and corrosion. The
surface to be protected is scraped clean, and must be free from grease or oil. The
angles or recesses formed by overlapping plate edges should be filled in with coment,
such as is herein-after described, so as to present a surface free from sharp angles.
The surface to be protected is then coated with a layer of cement composed of sifted
stone lime, quick or slaked (the latter is preferable), intimately mixed with good
Stockholni tar.
We find it advantageous to add about one-tenth part by weight of gas tar, but
such mixture of lime with vegetable tar and mineral tar is not claimed as of our
present luvention, being mentioned in the Provisional Specification of one of us
(the said Frederic Pelham Warren), filed with his application for Letters Patent,
No. 4621, dated 29th November 1876.
The proportions by weight, which we consider to be the best, are one part of lime
to from three and a half to four and a half parts of tar, or of the tar mixture.
In cold weather the tar may be warmed to about from 60° to 70° Faht. to liquify
it sufficiently for mixing.

page_text: In slaking the lime, we have obtained the best results by using one part of
water to from four to four and a half parts of stone lime by weight.
After slaking the lime it is sifted, and in the sifting operation we usually add
for coloring purposes about half an ounce of crocus to the pound of lime.
The cement, when well mixed, should be laid on quickly by a plasterer, and the
paper should be immediately placed upon the cement. Thus, where a large area
has to be coated, it is not entirely covered with cement at one operation; only so
much is coated with cement as corresponds to the size of the sheet of paper about
to be put on.
We consider it preferable to coat that surface of the paper which is intended
to be laid against the cement with waterproof substance, such as marine glue,
according to the Invention of Walter Field, forming the subject of his application
for Letters Patent, No. 435, dated 1st February 1877.
The said glue hardens before the glued surface of the paper is placed on the
cement. The coating with waterproof substance is necessary when sheathing or
covering on our plan surfaces of ships or vessels intended for use wholly or partially
in contact with fresh water as distinguished from sea water only.
Care should be taken to ensure good contact of the paper with the cement, for
which purpose a mallet with an india-rubber or other resilient face may be used to
hammer the paper all over against the surface to be protected. Sometimes, and
especially when covering surfaces difficult of access, instead of spreading the cement
directly over the surface of the vessel to be protected, it may be spread over the
waterproof substance with which the paper has been covered, and the paper thus
doubly coated must be laid with its cemented face on to the vessel before the cement
hardens; thus the cement will adhere to the surface to be protected, and will
securely hold the paper in place.
The paper we prefer to uso is generally known as sheathing paper. A good
paper for the purpose is comparatively soft and porous. The paper we have used
is of the same description as that used by the British Admiralty to form inter-
mediate layers between the hulls and the outer sheathing of sea-going vessels built
of wood, and sheathed with metal.
If the cement be required to harden quickly a larger proportion of lime must
be used than in the case of the cement being required to be of a tough nature.
The composition of the cement may be otherwise varied, as, for instance, by
substituting Archangel tar for the Stockholm tar.
Our Invention may be applied to the interiors of iron ships and vessels, such as
pontoons, to preserve them from the corrosive action of water, such as bilge water
or the water of condensation which ordinarily accumulates on the iron walls of
the interior of a ship or iron vessel, and is known as "sweating," and which in a
short time seriously oxydises the metal, and thus exercises a destructive influence
upon the vessel.
In applying our Invention for this purpose, we first lay on where needful cement
in one or more layers, so as to produce a comparative smooth (though it may be
undulating) surface, thus burying in the cement the rivet heads, plate edges, and
other similar inequalities to which the paper would not readily accommodate itself.
This having been done, and the cement having set firmly, we proceed, as already
described with reference to the outsides of vessels, commencing with a layer of
cement to cover the entire surface, including the surface of the cement already
laid on, as and for the purpose just above specified.
"
We desire it to be understood that the application of our Invention is not limited
to the protection of ships or vessels composed of iron; it may be used for protecting
the subinerged portions of other structures, such as metallic piers, and may also be
applied to wooden vessels to prevent fouling.
And having now described the nature of our said Invention, and in what manner
the same is to be performed or carried into practical effect, we hereby declare that
what we consider to be novel and original, and therefore claim as the Invention
secured to us by the heroin-before in part recited Letters Patent is, the method of

page_text: protecting from incrustation or adherence of organic matters and from corrosion
the surfaces of ships, and the immersed surfaces of other bodies, by the application
and use of cement in conjunction with an external covering of paper, substantially
as herein-before described.
In witness whereof, I, the said Edward Field, have hereunto set my hand
aud seal, this Second day of February, in the year of our Lord One
thousand eight hundred and seventy-seven.
EDWARD FIELD. (1.S.)