IMPROVEMENTS IN PRESERVING SHIPS' BOTTOMS AND OTHER EXPOSED SUR- FACES PROM FOULING AND INJURY OR DECAY
Year: 1858

page_text: LETTERS PATENT to Daniel McCrae, of Greenock, in the County of
Renfrew, North Britain, Grease Manufacturer, for the Invention of
"IMPROVEMENTS IN PRESERVING SHIPS' BOTTOMS AND OTHER EXPOSED SUR-
FACES PROM FOULING AND INJURY OR DECAY."
".
Sealed the 4th June 1858, and dated the 10th April 1858.
PROVISIONAL SPECIFICATION left by the said Daniel McCrae at the
Office of the Commissioners of Patents, with his Petition, on the 10th
April 1858.
I, DANIEL MCCRAE, of Greenock, in the County of Renfrew, North Britain,
Grease Manufacturer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN PRESERVING SHIPS' BOTTOMS AND OTHER EXPOSED SURFACES
FROM FOULING AND INJURY OR DECAY," to be as follows, that is to say:-
The
This Invention relates to the adaptation and use of a greasy substance as a
preservative coating for ships' bottoms and other exposed surfaces.
grease employed for this purpose is of a peculiar character.
What is known as "bone grease" is preferred for the purpose, that is
to say,, the species of fibrine grease obtained from the cells of bones by.
boiling; other greases or greasy matters may, however, be employed, such as
that obtainable from "kitchen stuff;" but oils and tallows or lard are not
available. This peculiar grease may have "blue stone" or sulphate of copper.

page_text: mixed with it, or it may have various poisonous matters incorporated; but the
essence of the Invention is, the use of this peculiar grease as a protective
varnish.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Daniel McCrae in the Great Seal Patent Office on the
9th October 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DANIEL
MCCRAE, of Greenock, in the County of Renfrew, North Britain, Grease
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of April, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Daniel McCrae, Her special license that I, the said Daniel McCrae,
my executors, administrators, and assignis, or such others as I, the said Daniel
McCrae, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
PRESERVING SHIPS' BOTTOMS AND OTHER EXPOSED SURFACES FROM FOULING AND
INJURY OR DECAY," upon the condition (amongst others) that I, the said
Daniel McCrae, by an instrument in writing under my hand and seal,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Daniel McCrae, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the follow-
ing statement, that is to say :-
My said Invention relates to the adaptation and use of a greasy substance
as a preservative coating for ships' bottoms and other exposed surfaces. The
grease employed for this purpose is of a peculiar character.
What is known as "bone grease" is preferred for the purpose, that is to
say, the species of fibrine grease obtained from the cells of bones by boiling;

page_text: other greases or greasy matters may, however, be employed, such as that
obtainable from "kitchen stuff;" but oils and tallows or lard are not
available. This peculiar grease may have "blue stone" or sulphate of copper
mixed with it, or it may have various poisonous matters incorporated; but
the essence of the Invention is the use of the peculiar grease as a protective
varnish.
And in order that my said Invention of "Improvements in Preserving Ships'
Bottoms and other Exposed Surfaces from Fouling and Injury or Decay" may
be properly understood, I shall now proceed to describe certain modifications
under which my improvements may be judiciously carried out in practice.
In preparing this preservative material according to one modification of my
Invention, the several ingredients are melted together in a copper or other
vessel, such as is ordinarily used for similar purposes. One ingredient in this
preservative material is what is technically known as "bone grease;" this
material is the greasy matter that lines or fills the cells of bones in their
natural state or condition, and is obtained therefrom by boiling the bones
in water and afterwards separating the grease from the liquid.
In order to prepare one ton of the preservative coating or material, I take
five hundredweight of the bone grease, and place it in the copper or boiling
vessel. To the bone grease is to be added a like quantity, that is to say, five
hundredweight of butter, which must be previously deprived of salt, if any has
been mixed therewith. The commonest kinds of butter, or that which has
become rancid, may be made available for the purpose of manufacturing this
preservative material. To the ingredients herein-before named is added five
hundredweight of what is technically known as "skin grease," that is to say,.
the fatty matters which line or form a coating upon the inner side of the skins.
of sheep.
The fourth ingredient in the preservative material is "dripping," or refuse
kitchen stuff, of which a corresponding quantity, namely, five hundred--
weight, is added to the other materials. Thus, whatever may be the quantity.
of the preservative coating to be manufactured, the four ingredients herein-
before named are to be mixed in equal proportions, that is to say, a fourth.
part by weight of each is taken, and the whole are blended together by heat..
The greasy matters are boiled together in the copper or boiling vessel.
until they assume the proper consistency, the time necessary to obtain this.
degree of solidity will vary with the natural or atmospheric temperature:
Thus, in cold weather the materials or ingredients will require less boiling
than when the natural heat is greater; but as a general rule it may be stated,
that the boiling may be continued for one hour or one hour and a half to

page_text: obtain the requisite degree of solidity. The consistency I prefer for this
preservative material is somewhat softer than the ordinary state of butter at
the medium atmospheric temperature; the object being to make it of such
consistency that it will not peel or break off from the ship's bottom or other
surface when applied thereto, and this will be the case if the preservative
coating is made too hard. On the other hand, if the material approaches too
near to the liquid condition, it will be washed off by the friction of the water
on the vessel's sides; or if applied to an exposed but not submerged surface, it
.will be too readily acted upon by the heat of the sun's rays or variations in
the atmospheric temperature. In order to impart a darker colour to the
preservative material, which is in most cases desirable, I mix with the
ingredients, either prior to or during the boiling operation, a small quantity of
Archangel tar sufficient to give the entire bulk the desired tint. After
completing the boiling of the preservative material, it is removed from the
copper or boiling vessel, and packed in cakes or other vessels ready for use.
Previous to applying the preservative material to the surface to be coated, it
is reduced by heat to the fluid state, and is then laid upon the iron, wood, or
other surface by means of a brush, in the same manner as paint is ordinarily
applied. In applying the coating to iron ships, it has been found in practice
that the grease sinks into the pores of the metal, and preserves it from
oxidation far more effectively than the coating of red lead paint ordinarily
applied to the plates. In new vessels the preservative material may therefore
be applied to the natural surface of the metal without its requiring any
previous preparation. The preservative material may in like manner be
applied to coating or covering the submerged or the exposed parts of the hulls
of wooden vessels. The smooth unctious surface thus imparted to the
submerged portion of the hulls of iron and wooden vessels tends to repel the
water and greatly facilitates the passage of the vessel through the sea; thus,
in addition to preserving the hull of the vessel, its sailing qualities are also
improved. The most important object, however, is to prevent the adhesion of
barnacles, algae, and other marine animal and vegetable substances to the
submerged surface of the vessel, which, as is well known, not only retard the
-vessel's progress, but rapidly destroy the hull itself. This object is effectively
obtained by means of the preservative coating, the unctious nature of which
affords no hold for the adhesion of either animal or vegetable substances, the
surface of the grease remaining perfectly clear and free from any parasitic
matters; hence this preservative coating is a valuable agent for coating the
surfaces of copper-bottomed vessels, as well as those which are plated with
zinc, or what is known as "patent sheathing." For in all these cases tlie

page_text: surface of the metal speedily becomes roughened by the chemical action of the
sea water, and at once affords a hold for the adhesion of zoophytes and algae.
The coating of the preservative material thus not only prevents the adhesion
of animal and vegetable life, but it preserves the metal also from the chemical
action of the water at a cost which is merely nominal compared with that of
the metal. It will be obvious that this preservative material may be advan-
tageously applied in a variety of cases to the surfaces of wood or iron, where
such surfaces are exposed to the action of water or weather.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe in conclusion that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my Invention; but what I
consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is,―
First, the system or mode of preparing or manufacturing a preservative
material for coating ships' bottoms and other exposed surfaces from the
ingredients and in the manner herein-before described, or any mere equivalent
therefor.
Second, the use and application of the ingredients or materials herein-
before named to the purpose of preparing therefrom a preservative material
for coating vessels and other exposed surfaces, as herein-before described.
In witness whereof, I, the said Daniel McCrae, have hereunto set my
hand and seal, this Seventh day of October, One thousand eight
hundred and fifty-eight.
D. MCRAE. (L.B.)