IMPROVEMENTS IN PROPELLING VESSELS
Year: 1856

page_text: LETTERS PATENT to John Buchanan, of Katrine, in the County of Ayr,
North Britain, Gentleman, for the Invention of "IMPROVEMENTS IN
PROPELLING VESSELS."
Sealed the 27th January 1857, and dated the 13th September 1856.
PROVISIONAL SPECIFICATION left by the said John Buchanan at the
Office of the Commissioners of Patents, with his Petition, on the
13th September 1856.
I, JOHN BUCHANAN, of Katrine, in the County of Ayr, North Britain,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PROPELLING VESSELS," to be as follows, that is to say :-
This Invention relates to an improved arrangement and construction of
ships or vessels, and a new disposition of their propelling apparatus, designed
with the view of obtaining an increased speed with a given expenditure of
power, together with other practical advantages.
In carrying the Invention into effect, according to one modification, the
Ivessel is made with a curved recess or channel in or near the centre of her
bottom. This channel only extends a certain portion of the ship's length, that
is to say, the two ends are exactly like ordinary vessels in cross section, and
the channel gradually rises from the longitudinal bottom line of the vessel,
reaching its greatest height at or near the centre of the vessel, whence it

page_text: gradually re-descends to the bottom line. The sides of the vessel remain the
same or nearly the same as in ordinary vessels throughout their entire length,
the channel or recess only occupying the middle of the vessel as taken trans-
versely. The keel may either be continued unbroken from end to end along the
centre line of the ship, forming in this case a diaphragm dividing the channel
or recess; or it may be interrupted at the channel, and at that part it may be
substituted by two keels placed one on each side of the channel. In the
channel or recess obtained in this way is placed the propeller, which may be
of any suitable kind. If a screw or other propeller which is worked by means
of a longitudinal shaft is used, this shaft is supported either in the keel in the
usual way, if the keel is continued through the channel; or if the keel is not
thus carried through the channel, in a ridge or feather projecting down into
the channel. The shaft may either be continued through to the part of the
vessel beyond the channel, or the ridge or feather supporting the shaft may be
made sufficiently wide for the connecting rods of the propelling engines to
be coupled to cranks on the shaft immediately behind the propeller, in which
case a very short length of the shafting will suffice. It is intended in
vessels of light draught to exhaust the air from the channel, so that the
water will fill this channel, notwithstanding that it may rise above the
general level of the water outside. When the channel is below the water
level any air in it will be allowed to escape, and in this manner the propeller
will always have a sufficient body of water to act upon, whilst it will be
protected from injury.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Buchanan in the Great Seal Patent Office on the
11th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BUCHANAN, of Catrine, in the County of Ayr, North Britain, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of September, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth 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 9

page_text: 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 PROPELLING
VESSELS," 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 next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said John Buchanan, 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 following statement
in writing, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is say:-
My said Invention relates to an improved arrangement and construction of
ships or vessels, and a new disposition of their propelling apparatus, designed
with a view of obtaining an increased speed with a given expenditure of power,
together with other practical advantages.
In carrying the Invention into effect, according to one modification, the
vessel is made with a curved recess or channel in or near the centre of her
bottom. This channel only extends a certain portion of the ship's length, that
is to say, the two ends are exactly like ordinary vessels in cross section, and
the channel gradually rises from the longitudinal bottom line of the vessel,
reaching its greatest height at or near the centre of the vessel, whence it
gradually re-descends to the bottom line. The sides of the vessel remain the
same or nearly the same as in ordinary vessels throughout their entire length,
the channel or recess only occupying the middle of the vessel as taken trans-
versely. The keel may either be continued unbroken from end to end along the
centre line of the ship, forming in this case a diaphragm dividing the channel
or recess; or it may be interrupted at the channel, and at that part it may be
substituted by two keels placed one on each side of the channel. In the
channel or recess obtained in this way is placed the propeller, which may be
of any suitable kind. If a screw or other propeller which is worked by means
of a longitudinal shaft is used, this shaft is supported either in the keel in the
usual way, if the keel is continued through the channel; or if the keel is not
thus carried through the channel, the shaft may be supported by a ridge or
feather projecting down into the channel. The shaft may either be continued

page_text: through to the part of the vessel beyond the channel, or the ridge or reather
supporting the shaft may be made sufficiently wide for the connecting rods of
the propelling engines to be coupled to cranks on the shaft immediately
behind the propeller, in which case a very short length of shafting will suffice.
It is intended in vessels of light draught to exhaust the air from the channel,
so that the water will fill this channel, although the latter may rise above the
When the channel is below the water
general level of the water outside.
level any air in it will be allowed to escape, and in this manner the propeller
will always have a sufficient body of water to act upon, whilst it will be
protected from injury.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the several illustrative Figures on the explanatory Sheet
of Drawings which I have hereunto appended, for the purpose of showing
certain modifications under which my improvements may be judiciously carried
out in practice.
Figure 1 on my Sheet of Drawings is a longitudinal elevation, partially in
section, of a ship's hull, constructed according to one modification of my
improvements, and as fitted with a single-bladed propeller. Figure 2 is a
tranverse section, corresponding to Figure 1, as taken at a part immediately
behind the propeller. Figure 3 is a bottom view, or reversed plan of a hull, as
fitted with a single-bladed screw propeller corresponding to the longitudinal
view, Figure 1. Figure 4 is a transverse section of a hull, showing a double-
bladed propeller as fitted thereto. Figure 5 is a longitudinal section of the
central portion of a vessel, showing another form of channel or trough, as well
as a different diposition of the engines, boilers, and propeller. Figure 6 is a
transverse section of the hull, corresponding to Figure 5, this section being
taken at the most elevated part of the channel's roof. Figure 7 is a reversed
plan view of the same hull, corresponding with the sectional view, Figure 5.
Figure 8 is a transverse section of a steamer hull as formed with a double
channel or trough, or with a channel divided longitudinally down the middle,
so as to accommodate two screw propellers, one in each section of the channel;
or the central partition may be supposed to be omitted, leaving the channel
quite open. Figure 9 is a longitudinal section of another form of steamer's
hull as formed with a central channel of another shape, and propelled by a
central paddle wheel.
In the arrangement delineated in Figures 1, 2, and 3 the propeller works
in a channel or trough formed in the lower part of the hull, and at
or near the centre of the vessel. This channel or recess A has a transverse
sertion of a semicircular form at its upper part, as shown at Figure 2

page_text: and is carried upwards at an angle, the apex of which is over the part
where the propeller is fitted. From this part the roof of the channel is
carried gradually downwards until it meets the keel. From the forward end
of the channel or trough A a strong bearer or kelson B is carried upwards at
an angle and then horizontally terminating in a stern post C which is carried
up to the deck timbers and secured thereto. The beam or kelson B forms a
continuation of the keel D, and the whole is strongly secured together in order
to form a firm support for the engines. Upon the beam or kelson B a sole
plate E is fitted, on which are placed a pair of direct action engines; these are
placed on the forward portion of the channel's roof, which is suitably recessed
for the purpose. The engines F consist in this instance of a pair of parallel
horizontal cylinders driving an inclined screw propeller shaft G, which runs aft
and passes through a tube H fitted in the stern post C. To the inner end of
the tube H is fitted a stuffing box I, through which the propeller shaft G
works; the screw or propeller blade is keyed to the end of the shaft outside
the tube in the ordinary manner. This arrangement of the stuffing box I at
the end of the tube H brings it into a position where it may be readily got at
for inspection or repair. The boilers K of the engines are placed on the
opposite sides of the apex of the channel; or this space may be occupied by
the coal bunkers, the boilers being disposed over the highest part of the
channel. The keel D terminates at the fore and after ends of the channel A,
along each side of which a bilge keel L is made. With this arrangement, the
vessel when aground rests at the stem and stern upon the ordinary keel, and
amidships upon the bilge keels L, which will keep the vessel always in an
upright position.
corre-
Another modification of my improvements is shown by Figures 5, 6,
and 7, in which arrangement the longitudinal section of the channel or
trough A is not of an angular form, as in Figure 1, but curves gradually
upwards from the fore part of the vessel, and descends in a
sponding or nearly corresponding manner towards the stern of the vessel.
The cross section of the roof of the channel may be either flat in its form, as
shown at Figure 4, or arched, as shown at Figure 6. The screw propeller M
is fitted in the central part of the channel or trough in a trunk N, which is
carried up to the deck to afford facilities for raising the propeller out of the
water when required. The propeller shaft O is carried through a casing P,
recessed in the channel A, as shown in the reversed plan view, Figure 7. The
cranks on the end of the propeller shaft O are coupled by connecting rods with
a pair of direct action engines of that class in which the pair of cylinders are
inverted and placed at some distance above the shaft.

page_text: In the arrangement delineated in Figures 5 and 6 the keel D is carried from
the stem to stern of the vessel in the usual manner.
Another of my improvements consists in exhausting the air from the
channel or trough A by means of certain mechanical arrangements which
I shall now describe. The object of this improvement is to fill the channel
with water, so that the propeller may be completely immersed therein. At
the highest part of the channel A a cover Qis bolted to the channel's
roof, to which a pipe R, furnished with a stop-cock or valve, is connected;
the other end of this pipe is connected to the air pump of the engine,
or with a hand pump. As the air is exhausted from the channel, the water
rises within it until it is filled, and it will remain so, owing to the atmospheric
pressure on the surrounding water. It will be obvious that the exhausting of the
air will only be required when the draught of the vessel is below the channel's
roof.
Another modification of my improvements is shown in the transverse
section, Figure 8. In this arrangement the channel A is made sufficiently
wide to admit of a pair of screws S being fitted therein, and a partition or
diaphragm T is fitted between the screws in a longitudinal direction, to divide
the channel into two. The diaphragm T is carried down sufficiently low to
form a keel along the central portion of the channel; or the diaphragm may
be dispensed with, and the water allowed an uninterrupted passage across
and through the channel.
Another modification of my improvements is shown at Figure 9, in
which the propeller is a single paddle wheel, fitted in a suitable recess
made in the centre of the ship. The channel A is in this arrangement of
a different form to the foregoing modifications; it is carried upwards from
fore-and-aft in a very gradual rise, until it meets the circular recess in which
the paddle wheel is fitted. The propelling portion of the paddle wheel U
projects below the channel A, and as the backwater from the wheel passes
away through the channel and under the bottom it lifts the hull, and tends to
assist the progress of the vessel through the water. In all cases of vessels
constructed as herein-before described with a channel or trough beneath, it is
intended to fit them with suitable valves or stop-cocks, to allow the air contained
within the channel to escape, and the water to rise therein, that the propeller
may have a sufficient body of water to work in. A few revolutions of the S
propeller is sufficient to drive out the air from the channel or trough.
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

page_text: 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 arranging and constructing ships or vessels
with a central recess, channel, or trough, for the purposes herein-before
described.
Second, the system or mode of propelling ships by means of a screw or other
propeller disposed in a submerged or partially submerged recessed channel or
trough, as herein-before described.
Third, the system or mode of securing efficient means of propulsion for ships
of comparatively light or shallow draught, by causing the propeller to work in
a submerged or partially submerged central recess or channel.
Fourth, the system or mode of obtaining a body of water for the propeller
to work upon, by exhausting the air from the propeller, recess, or channel.
Fifth, the system or mode of propelling ships wherein the backwater of a
central propeller is made to impinge against bottom inclined surfaces, for the
purpose herein-before described.
In witness whereof, I, the said John Buchanan, have hereunto set my
hand and seal, this Ninth day of March, One thousand eight hundred
and fifty-seven.
JOHN BUCHANAN. (L.S.)