A NEW OR IMPROVED METHOD OR METHODS 07 PROPELLING VESSELS THRO' OR ON THE WATER BY THE AID OF STEAM OR OTHER MECHANICAL FORCE
Year: 1828

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
NAIRN, of Davic Street, Edinburgh, in the County of Mid-Lothean, Mason,
send greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fifth day of February, in the ninth year of His reign, did, for
Himself, His heirs and successors, give and grant unto me, the said William
Nairn, His especial licence that I, the said William Nairn, my exors, adiňors,
and assigns, or such others as I, the said William Nairn, my exors, adiñors,
and assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies and
Plantations abroad, my Invention of "A NEW OR IMPROVED METHOD OR METHODS
07 PROPELLING VESSELS THRO' OR ON THE WATER BY THE AID OF STEAM OR OTHER
MECHANICAL FORCE;" in which said Letters Patent there is contained a proviso
obliging me, the said William Nairn, by an instrument in writing under
hand
and scal, particularly to describe and ascertain the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same to
be enrolled in His Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at
large appear.
my
NOW KNOW YE, that in obedience to the said Letters Patent, and in
compliance with the said proviso therein contained, I, the said William Nairn,

page_text: do hereby describe and ascertain the nature of my said Invention, and the manner
in which the same is to be performed, in manner following, that is to say:―
My said Invention consists in making and suspending from rocking shafts
or moveable joints two, four, or more levers or arms over the sides or thro'
an aperture or apertures of the vessel to be propelled, and so connected with the
engine or first mover as to have a reciprocal motion, the same as or similar to that
of a common pendulum, either parallel or at a small angle to the line of the vessel's
motion. (But I do not claim the manner of connecting these with the engine or
first mover as any part of my Invention, such connections, altho' for different
purposes, having been used before.) The under ends of these levers or arms
reach considerably under the surface of the water, and the part which works in
the water is made of such a shape as to permit the said levers or arms to move
thro' it with as little resistance as possible; that is, sharp at both edges, and
swelled in the middle, thus
They are so placed on the vessel as
full stroke without striking each
to allow them to take their
other. In vessels that take the ground they may be placed so low as their
lower ends shall just clear the ground when the vessel rests; but on vessel's
that never take the ground they can be placed lower if requisite. On the lower
ends of these levers or arms are placed articles which, for the sake of distinction,
I shall afterwards call fins. These fins are plates or flat bodies, two of which are
hinged or jointed on the lower end of each of the said levers or arms in such a
manner as, when moving in the same direction as the vessel, they shut, and
consequently that part of the said lever to which they are attached passes thro'
the water with nearly as little resistance as if no fin were attached to it, but
when moving in a contrary direction they open, and present to the water a
large surface. On the levers or arms are fixed stops or snugs to prevent
the fins from opening too far or shutting too close. Or the same end
may be accomplished by bows or arches on which the fins work in a
manner similar to a pair of compasses, with an arch of degrees, only in the
compasses the arch is fixed in one leg, and moves thro' the other, but here
the arches are fixed to stops or snugs projecting from the lever, and work freely
thro' both fins. Or the same end may be accomplished by small pieces of chains
fixed to the stops or snugs at the one end, and to the fins at the other, which
chains are tight when the fins are open, and hang slack between them when
they are shut. Or the same end may be accomplished by means of jointed stays
moving in the same or in a similar manner to the jointed parallel frame of the
conical pendulum or common governor of a steam engine, or there may only
be one fin or flat body hinged or jointed on a rod placed at right angles to the
lever or arm, which fin, when moving in the same direction with the vessel, is

page_text: drawn thro' the water by the edge, but when moving in a contrary direction
folds against the lever or arm, and presents a flat surface. But altho' any of the
foresaid methods will answer the purpose, so far as I have been able to ascer
tain, the two plates or flat bodies which I have called fins, hinged or jointed on
cach lever or arm, with the bows or archs, or the stops or snugs projecting
from the levers or arms, and so constructed as to permit the fins to open to an
angle of from one hundred and forty to one hundred and sixty degrees, and to
shut till the two leaves of the fins become nearly parallel to each other, are the
best; only any particular angle is not indispensable, altho' I would recommend the
above. Altho' it is not absolutely necessary, it is best either to make the leaves
of the fins of such a shape, or to line them with any suitable substance till they
become of such a shape, as when shut, and, as before stated, forming nearly a
parallelogram on the outside, they shall form a considerable angle on the
inside, thus
which adaptation makes them
more ready
.
to open when passing thro' the
water. When only two of these levers or arms with fins are used, except the
one is placed before the other in a line with the centre of the vessel, that is,
the keel, or between the vessels where twin boats are employed, they will have
a positive and negative effect alternately, the same as when a boat is pulled or
rowed with two oars; but when four are used two are moving in the same
direction as the vessel, while the other two are moving in a contrary direction,
and thus exert a constant force to propel the vessel; where six are used two
may be made to take an intermediate stroke, and where eight are used they
may be made to pull four and four alternately, that is, two on each side of the
vessel at a time, and so on in the same manner whatever may be the number
employed. But altho' any number may be used to pull at once or otherwise,
so far as I have been able to ascertain, four, that is, two on each side, made to
exert a constant force as above stated, will be found most advantageous, only it
may be adviseable on very large vessels to have four on each side, in order that
the fins might not require to be so large. If it is intended to have the vessel
fitted so as she can be put astern or turned round by means of the machinery,
the levers or arms are suspended from the rocking shafts or moveable joints by
passing thro' apertures or ruffs in the same, to which they are fitted in such a
manner as permits them to turn, and consequently to alter the position of the
fins, so as when moving towards the prow of the vessel they open and push her
back, and if only the fins on one side are turned, the vessel will be put back on
that side while she goes forward on the other, and consequently turned on a
space. The levers or arms are turned by having a pinion or small
toothed wheel fixed on each of them, which pinions or wheels are operated
very
small

page_text: upon by an endless screw, and this screw is turned by a rod which comes to
any convenient place of the vessel, and thereby brings the command of all the
fins within the power of the engineer; or this rod may be connected with
moving gear from the engine, which may be thrown out or into gear when
necessary; or in place of the screw a wheel or segment of a wheel, or a rack,
may turn the lever or arm by working in the pinion; or in place of the pinions
a small lever on each lever or arm may be used, and simply turned by the hand.
But altho' any of these methods will answer the purpose, so far as I have been
able to ascertain, in vessels that require often to be put astern the screw and
pinion is the most convenient; and in vessels that require but seldom to be put
astern the small levers on each lever or arm will answer the purpose, and will
be both less expensive and less apt to get out of order. A considerable way
down the levers or arms are fixed to the vessel guides parallel to each other,
between which the levers move. Or there may only be one guide to each lever;
and a clutch or bush thrown around the lever, and also round the guide, in such
a manner as it may move along the guide freely. These guides serve to keep
the levers steady. But altho' one guide to each lever or arm will answer the
purpose, I would in all cases recommend two. The levers or arms and fins may
be made of copper or iron, or any other metal or compound suitable for tho
purpose; and to prevent corrosion advantage may be taken of the well-known
discovery of Sir Humphrey Davy for preserving the coppering of vessels,
namely, a small piece of zinc may be attached to any convenient part under water.
Altho, as before stated, I do not claim any particular arrangement or
modification of the engine, or any particular manner of connecting it with the
propelling apparatus, as any part of my Invention, yet I would strongly recom-
mend to connect it in one of the two following manners, and particularly the
last; 1st, lot two shafts cross the vessel, with a lever on each of them, to receive
the motion from the steam piston rod, which levers, if properly connected, may
form a parallel motion; on cach end of these cross shafts let another crank, arm,
or lever be fixed, and consequently when the steam piston moves up and down
the cranks or levers on the end of the cross shafts will move back and
forward, and by connecting the arms or levers on which the fins are jointed
with these cranks the motion required will be produced; or, 2d, let only one
shaft cross the vessel, and let it be made to revolve by the steam engine, and
on each end of it have a double crank or eccentric, and let cach arm or
lever be connected with one of these cranks or eccentrics, so when the shaft
revolves the arms and fins will have the motion required; and in this
manner my propelling apparatus may be used on vessels which are
already fitted up with paddle wheels, without making any alteration on the

page_text: engine, for the wheels may be taken off, and double cranks or eccentrics put
n their place.
In witness whereof, I, the said William Nairn, have hereunto set my
hand and seal, this Thirty-first day of July, in the ninth year of the
reign of our Sovereign Lord George the Fourth, by the Grace of God of
the United Kingdom of Great Britain and Ireland King, Defender of the
Faith, and in the year of our Lord Eighteen hundred and twenty-eight.
J. P. for the City of Edinburgh.
AND BE IT REMEMBERED, that on the oath of James Aitken the
Specification aforesaid was inrolled, word for word, as above written. And also
the Specification aforesaid was stamped according to the tenor of the Statuto
made for that purpose.
Inrolled the Fourth day of August, in the year of our Lord One
thousand eight hundred and twenty-eight.