IMPROVEMENTS IN SHEATHING SHIPS' BOTTOMS AND OTHER SURFACES EXPOSED TO THE ACTION OF SEA. WATER.
Year: 1868

page_text: LETTERS PATENT to John Scoffern, of 21, New North Street,
Finsbury, in the County of Middlesex, M.B., for the Invention of
"IMPROVEMENTS IN SHEATHING SHIPS' BOTTOMS AND OTHER SURFACES
EXPOSED TO THE ACTION OF SEA. WATER.!".
Sealed the 17th October 1868,, and dated the 27th April 1868.
PROVISIONAL SPECIFICATION left by the said John Scoffern. at the
Office of the Commissioners of Patents, with his Petition, on the
27th April 1868.
I, JOHN SCOFFERN,. of 21, New North Street, Finsbury, in the County.
of Middlesex, M.B., do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SHEATHING SHIPS' BOTTOMS. AND OTHER SURFACES EXPOSED
TO THE ACTION OF SEA WATER," to be as follows:--
This Invention has for its object improvements in sheathing ships'
bottoms and other surfaces exposed to the action of sea water. For this
purpose I prepare a solution of copperised ammonia by exposing copper.
to the action of ammonia; then having painted the ship's bottom or:

page_text: other surface by preference with a paint herein-after described, I take
sheets of paper, or it may be of felt or woven fabric or similar material,
and dip them into the solution of copperised ammonia and at once
apply them to the ship's bottom or other surface to be sheathed. The
sheets rapidly harden and adhere firmly. Over the first sheathing
another coating of paint may be applied and a second layer of sheets.
If desired the process may be again repeated.
The paint which I prefer to employ is prepared by mixing copperised
ammonia, boiled oil, marine glue, and india-rubber; these materials are
boiled together and compounded with suitable pigments.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Scoffern in the Great Seal Patent Office on
the 27th October 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
SCOFFERN, of No. 21, New North Street, Finsbury, in the County of
Middlesex, M.B., send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of April, in the
year of our Lord One thousand eight hundred and sixty-eight, in the
thirty-first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Scoffern, Her special licence
that I, the said John Scoffern, my executors, administrators, and assigns,
or such others as I, the said John Scoffern, my executors, adminis-
trators, and 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
SHEATHING SHIPS' BOTTOMS AND OTHER SURFACES EXPOSED TO THE ACTION OF
SEA WATER," upon the condition (amongst others) that I, the said g
John Scoffern, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,

page_text: 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 John Scoffern, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
My process consists in the application to ships' bottoms and sides,
and to other surfaces exposed to the action of sea water of certain
materials, herein-after to be specified, by way of sheathing, whereby
corrosion and other disintegration may be prevented, lessened, or
controlled.
It will conduce to the better understanding of my process if pointed
attention be called to the fact that each and all of the semi-fluid matters
commonly used for the protection of ships and other surfaces are
popularly known as "paints." For present purposes I desire to limit
the term paint, as herein-before stated, to be a semi-fluid holding a
true oil as an integral component.
E
In my Provisional Specification I have described what I call a
preferential paint," by which is to be understood a paint that I
consider answers better than any other for my subsequent operations,
inasmuch as this paint holds copperized ammonia, or rather a product
of the evaporation of copperized ammonia as an integral part. I will
begin by describing this copperized ammonia, notwithstanding that this
body is already known, and the manufacture of which I do not in
this Specification claim to have been discovered by me.
Copperized ammonia, or (as some have denominated it, though not
I believe in accordance with chemistry) "copperate of ammonia," is the
blue result occurring when liquor of ammonia has been brought into
contact with copper surfaces in the presence of atmospheric air, and
allowed to remain in contact for a considerable time. By preference
I use ammonia of 880, and any amount of copper, provided it be in
excess of the ammonias solvent power. The time of steeping or
exposure varies with circumstances, but I consider six weeks to be an
average time, whether more or less is of no consequence provided the
result be efficient, and this may be known by testing. The best test

page_text: I know of depends upon appreciation of the remarkable fact that
copperized ammonia in good order rapidly dissolves woody matter, and
still more rapidly silk. Supposing then I desire to know whether a
specimen of copperized ammonia be in good order for the preparation
of either my preferential paint or certain semi-fluid sheathing bodies
herein-after to be described and not coming within the category of
paints, or the final laying on of paper or textile sheathing surfaces.
I adopt the following test:-Having poured a convenient quantity of
copperized ammonia (say half a pint) into a wide-mouthed stopper
bottle of at least one pint capacity, I add thereto a test quantity of
one quarter of a yard of thin white Persian silk. If on agitation the
silk wholly and absolutely dissolves within one minute, I conclude
the copperized ammonia is adapted to all my purposes. If more than
one minute be required I conclude it not to be perfected, and that
longer steeping of copper in contact with ammonia in access with
atmospheric air is needed. This is the best test of efficiency I know of
Specific gravity for present purposes I consider fallacious; the fact is,
however, that prolonged experience with copperized ammonia will place
"an intelligent operator beyond the need of using any test, appearances
not possible to describe affording a sufficient guide.
Having described this copperate of ammonia, I will now explain its
application in the manner which I prefer to the manufacture of my
preferential paint. The materials employed are linseed oil, india-
rubber, and copperized ammonia. To be precise I will assume that
one imperial gallon of linseed oil is to be operated on. Having turned
this quantity of oil into a capacious boiler of iron or copper (it must
not be of zinc) I add thereto one pound avoirdupois of india-rubber,
and boil until the latter is wholly dissolved; I then add one imperial
pint of copperized ammonia little by little; the commotion is very
violent, and the addition must be made with care; I then boil until
the last traces of ammonia, as indicated by the smell, have escaped;
I then allow the whole to cool, and use it as a vehicle for holding any
such body color as a painter may desire.
Having described the process of manufacturing this my preferential
paint, I will next describe the mode of preparing certain adhesive semi-
fluid sheathing materials necessary wholly or in part to my process.
These said adhesive semi-fluid sheathing materials I do not call paint, or
the operation of laying them on painting, inasmuch as no oil proper or

page_text: available time whereby the sheathing or painting operator is hurried;
again, the duration and direction of a voyage will have to be consulted.
A ship destined for Calcutta will need less protection, for example,
than one destined for Bombay. Assuming an iron ship to be perfectly
new, I first lay on two coats of my preferential paint or rather paint
vehicle mingled with any convenient body colour, I prefer red lead.
A prejudice lies against this material because of a prejudicial chemical
action sometimes set up, there can be no chemical action however so
long as the paint is dry, and my subsequent processes of sheathing keep
it dry. As soon as the second coat of paint has firmly set, I lay upon
it sheets of paper, linen, or calico, either of which has been steeped in
copperized ammonia in good condition for about one minute a time
sufficient to have promoted surface solution of the materials steeped,
and to bring about adhesion when the applied sheet has been rubbed
down by a pad of linen, calico, or caoutchouc. This vegetable sheathing
will dry hard and adhere firmly. Upon convex and plain surfaces it
always sticks tightly. From concave surfaces it may separate by the
shrinkage of drying if not slit at intervals more or less frequent,
according to the abruptness of the concavity; but what I prefer is
to treat concave surfaces by a special modification of my process, which
is the following:-Upon the painted surface I smear one coat of either
of my adhesive sheathing semi-liquids, by preference No. 2, and allow
it to dry; when dry I smear another layer of the same, and to this
whilst wet and ammoniacal smelling I apply by pressure and rubbing
sheets of paper, calico, or linen that have already been steeped for about
a minute in copperized ammonia, withdrawn and allowed to dry, they
will adhere perfectly. Sheets of paper or woven vegetable material
will desquamate under the action of sea water just as copper des-
quamates. For the majority of voyages they need no reduplication or
covering; I usually recommend, however, a finish of one of the sheathing
semi-liquids numbered from 1 to 8. A brush not of bristles but of
vegetable fibre is best adapted for laying on these sheathing glazes.
I have here to repeat that my preferential paint though best adapted
to my sheathing process is not indispensible. Any ordinary paint I
can operate upon, provided it really be paint, that is to say, a compound
made up of body colour and a true drying vehicle, such as a real oil,
with or without turpentine. Many, I may state most, of the so-called
marine paints are chemically regarded, and according to the scientific
chemical limitation no paints at all, they are merely greasy, permanently

page_text: moist smears. Upon surfaces such as these I cannot lay either my
sheathing semi-fluid adhesive bodies or my sheet sheathing successfully.
Upon a dry coating of any ordinary paint I can operate as follows:-
Although sheets of paper or woven vegetable material that have been
immersed in copperized ammonia for the time specified and withdrawn
will not stick with any practical efficiency to ordinary paint, they will stick
with efficiency to a surface of any one of my sheathing adhesive semi-
liquids laid on dry ordinary paint; herein lies the solution of the problem.
It remains to be observed that either of my sheathing adhesive semi-
liquids from 1 to 8 may be laid on a metal or wooden surface directly,
if such surface be neither acid nor greasy, understanding by grease,
fatty or oily matter not having the quality of drying.
Although I have hitherto treated only of the application of my process
to iron ships, yet it is applicable to wooden ships, it is also applicable
to the covering of other surfaces, for example, iron, copper, or yellow
metal of iron bridge work, in short, the portion of my sheathing process
which has reference to the laying on of either of my sheathing adhesive
fluids can be applied to any surface however irregular and even. The
portion which relates to the laying on of paper or woven sheets can be
applied to surfaces having considerable irregularity of outline.
I would observe that the fullest developement of my sheathing process
is made up of the following stages:-
1
(1.) Painting either by my preferential paint or else some true paint,
as already defined.
(2.) The laying on of one or more of my copperized ammonia
sheathing semi-fluids if the paint used have not been my preferential
paint.
(3.) The laying on of paper or woven tissue sheets by one of the
two processes already described.
(4.) The sheathing not to be confounded with painting with one of
my specified sheathing copperized semi-fluids. Nevertheless the opera-
tion may be stopped at any stage according to the amount of protection
desired..
Having stated how my process is conducted, and described how the
materials used in this process are to be manufactured, it is to be under-
stood that considerable variations may be permitted in the proportions
of ingredients used. I have stated the proportions which I consider best,

page_text: not limiting myself thereto, but claiming the general application of
copperized ammonia to the purpose of sheathing ships' bottoms and
other surfaces exposed to the action of water.
In witness whereof, I, the said John Scoffern, have hereunto set
my hand and seal, this Twenty-fourth day of October, in the
year of our Lord One thousand eight hundred and sixty-eight.