IM- PROVEMENTS IN THE PROPULSION OF SHIPS
Year: 1872

page_text: LETTERS PATENT to John Buchanan, of Greenock, in the County of
Renfrew, North Britain, Gentleman, for the Invention of "IM-
PROVEMENTS IN THE PROPULSION OF SHIPS."
Sealed the 21st January 1873, and dated the 8th October 1872.

page_text: rendered water-tight on either side with bulkheads, beams, knees, and
stays being introduced to maintain the strength of the hull at the part
where the opening is made. In the opening referred to the propeller is
situated, it consisting of revolving screw blades whose radius is equal or
nearly equal to the half width of the opening, and by reason of the
position of the screw propeller at the place named the portions of it
operating in the act of propulsion are always immersed in the water, so
that the "racing" of the engines by the screw being out of the water
when passing through the trough of a wave, which obtains when the
screw propeller is placed at the stern, is prevented.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Buchanan in the Great Seal Patent Office on
the 7th April 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BUCHANAN, of Greenock, in the County of Renfrew, North Britain,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of October, in the year of our Lord
One thousand eight hundred and seventy-two, in the 36th year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said John Buchanan, Her special license that I, the said
John Buchanan, my executors, administrators, and assigns, or such
others as I, the said John Buchanan, 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 THE PROPULSION
OF SHIPS," upon the condition (amongst others) that I, the said John
Buchanan, 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 noxt and
immediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said John Buchanan, do hereby declare
he nature of my said Invention, and in what manner the same is to be
erformed, to be particularly described and ascertained in and by the
ollowing statement, reference being had to the accompanying Drawings
nd to the letters and figures marked thereon, that is to say :-
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
following statement, reference being had to the accompanying Drawings
and to the letters and figures marked thereon, that is to say :—
-
My said Invention relates to improvements in the propulsion of
ships.
In carrying out the Invention an open space is formed in the hull
transversely with the length of the ship, and this is rendered water-
tight on either side by bulkheads. In the opening referred to the pro-
peller is situated.
And in order that my said Invention may be properly understood, I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, that is to say :-
On the Sheet of Drawings hereunto appended Figure 1 is a longi-
tudinal section of a steam ship or vessel illustrating my improved
system of propulsion adapted thereto; Figure 2 is a part horizontal
section and part deck plan thereof; whilst Figure 3 is a transverse section
of the same on the line a, b, Figure 1.
As shown by these Figures a space A is constructed in the hull
transversely with the length of the ship or vessel, and which is rendered
water-tight with bulkheads B. The lower part of the space A is open
to the water, and on each side of the opening a bilge keel C is formed,
as shewn at the transverse section, Figure 3, in order to maintain the
strength of the ship or vessel at that part. The ordinary keel D proper
to the ship or vessel is continued across the lower part of the space A,
and further strength is imparted to the hull at that part where the
space is formed by introducing beams, knees, and stays into the hull
in the manner ordinarily practised for strengthening any weak portion
in an iron or steel structure, such as a ship or vessel. In the space A
the propeller E is situate, and which is by preference constructed of a
disc a formed with a broad or flanched periphery or rim to which the
propeller blades 6 are attached; but in lieu of such a propeller as that
shewn one of any of the well-known types of screw propellers may be
employed.

page_text: In addition to the opening at the bottom of the space A pipes or
channels may or may not be provided, leading to and from the space A
to assist the influx and efflux of the water as it is acted upon by the
propeller E. Such pipes or channels marked F arc shewn on the
Drawings, and more particularly at Figure 2 thereof, and if desired,
when a ship or vessel provided with the pipes or channels F is pro-
ceeding forwards," the outer extremities of the "forward" pipes or
channels may be closed by valves, and similarly the outer extremities
of the "aft" pipes or channels may be closed when the vessel is pro-
ceeding "aft."
"
By placing the propeller E in the position shewn on the Drawings,
the portions of it operating in the act of propulsion are always immersed
in the water, so that the "racing" of the engines G consequent on the
propeller being out of the water when passing through the trough of a
wave, as obtains in ordinary arrangements where the propeller is situate
at the stern of the vessel is prevented.
Another advantage accruing from placing the propeller in the position
shewn in ships or vessels, which are sometimes propelled by steam and
sometimes by the action of the wind upon sails is, that in the said
position the propeller, when the ship or vessel is sailing under canvas,
can be stopped in such a position that the greater portion or the whole
of its blades bare within the space A and not projecting beyond the
surface of the ship, thereby in a great measure preventing obstruction
or resistance to the forward course of the ship or vessel.
It is to be here understood that I do not confine myself to construct
the space A and to place the propeller E in the position shewn on the
Drawings, that is, towards the stern of the ship or vessel, as the said
space and propeller may with equal advantage be placed towards the
bow of the ship or vessel, or directly amidships and in front of the
engines.
Having now described and particularly ascertained the nature of my
said Invention, and the system, mode, or manner in or under which
the same is or may be used or practically carried into effect, I would
observe in conclusion that 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, propelling ships or vessels by means of a
propeller placed in a space formed between water-tight bulkheads in the

page_text: hull of the ship or vessel, as herein-before described and shewn on the
appended Sheet of Drawings, or any mere modification thereof.
In witness whereof, I, the said John Buchanan, have hereunto set
my hand and seal, this Third day of April One thousand eight
hundred and seventy-three.