IMPROVEMENTS IN PROPELLING VESSELS
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MELVILLE, of Upper Harley Street, in the County of Middlesex, Esquire, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-first day of January, in the eighth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said John
Melville, Her especial licence, full power, sole privilege and authority, that I,
the said John Melville, my exors, adiñors, and assigns, or such others as I, the
said John Melville, my exors, adors, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter 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
in the Islands of Jersey, Guernsey, Alderney, Sark, and Man, and also in all
Her said Majesty's Colonies and Plantations abroad, my Invention of
"IMPROVEMENTS IN PROPELLING VESSELS;" in which said Letters Patent is
contained a proviso, that I, the said John Melville, shall cause a particular
description of the nature of my said Invention, and in what manner the
same is to be performed, to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that, in compliance with the said proviso, I, the said
John Melville, have ascertained and set forth the nature of my Invention, and
the manner in which the same is to be carried into effect, in and by the
following description thereof, reference being had to the Drawings hereunto
annexed:-
My Invention consists in certain arrangements for causing the floats or
paddles to enter the water at a favorable angle, or to "feather," as it is commonly
termed, with the view to avoid the evils of oblique action and backwater; and
also in certain arrangements for raising or lowering paddle wheels or propellers
to accommodate them to variations in the vessel's draught of water.
Figure 1 is an elevation of my improved propellers; a, a, are a series of
floats attached to horizontal spindles ; the surfaces above and below the
spindle being equal or nearly so; these spindles turn in the ends of the arms
C, C, C. On one end (or on both ends if thought desirable) of each of these
spindles is fixed a crank d, d, standing parallel to the plane of the float,
and these cranks are connected together so as to stand parallel to each other
by means of chains or rods e, e, the length of each rod being equal to the
distance. between the centres of two contiguous spindles. By this means it
will be seen that the centrifugal effort of the floats as they successively enter
the water is counterbalanced by that of the continuous floats, and that the
floats at all times preserve or nearly so their parallelism. Figure 2 shows
another arrangement for producing the same effect; a, a, are the floats
attached to the horizontal spindles b, b, which revolve in the ends of the arms
C. C, C. On the ends of these spindles are fixed cranks d, d, all of equal length,
and these cranks are connected by rods or links e, e, (all equal lengths) to a
ring or hoop through which the shaft or axis of the wheel passes. The
internal diameter of the ring must not be less than the diameter of the shaft
which passes through it, added to twice the radius of the cranks, and the rods
must be of such length that the distance from the centre of the ring to
the centre of the crank pin shall be equal to the distance between the centre
of the shaft and the centre of the spindles of the floats. Figure 3 represents
the principle of my arrangement applied to a pair of propelling levers,
intended principally as an auxiliary mover for sailing vessels; the cranks are
connected by a bar f, having an aperture in the center for the shaft of the
propeller to pass through, which aperture must not be less than the diameter
of the shaft, added to twice the length of the cranks, and the distance between
the centers of crank pins must be equal to the distance between the centers
of the spindles. I would observe that the object of the arrangements herein

page_text: described is solely to overcome the effects of the centrifugal force upon the
floats when about to enter the water, and therefore the cranks and connecting
links do not require to be of great strength and nicety of workmanship; also
that the lower portion of the paddles may be made slightly heavier than the
upper portion. The propellers above described being applicable, with equal
advantage, to wheels or levers of large or small radius, they may be worked at
the stern of the vessel so as to avoid the necessity of paddle boxes; and
Figures 4 and are Diagrains of two arrangements for raising or depressing
the shaft of the paddle wheel or propelling lever to adapt it to the varying
draft of the vessel. In Figure 4, a represents the engine shaft, having two
cranks at right angles, which are connected by connecting rods to two cranks
similarly arranged on the shaft of the paddle wheel b. The bearings of
this latter shaft are moveable in a circular are, of which the engine shaft is the
center, and the radius of which is equal to the length of the connecting rod;
it will be obvious therefore that in every position of the paddle shaft in the
circular are, that the cranks on the engine shaft will always stand parallel to
those on the paddle shaft, and that the two shafts will consequently always
revolve together. In Figure 5, a represents the engine beam, and the
paddle shaft, which is supposed to be moveable in a straight line. at right
angles to the engine beam when.at the middle of the stroke, and to enable the
wheel to work at different heights it is merely requisite to adjust suitably the
length of the connecting rods.
Having thus set forth the nature of my Invention, and the manner of
carrying the same into effect, I would have it understood that I claim as my
Invention,
First, the arrangement of cranks and connecting links or chains, herein-
before described, for the purpose of counteracting the effects of the centri-
fugal force upon propelling floats or paddles attached to revolving-spindles
or axles.
Secondly, claim the arrangements described for raising or depressing
the shafts of paddle wheels or propellers to suit a vessel's varying draft
of water.
In witness whereof, I, the said John Melville, have hereunto set my
hand and seal, this Eighteenth day of July, in the year of our Lord
One thousand eight hundred and forty-five.
JOHN (L.8.) MELVILLE.

page_text: AND BE IT REMEMBERED, that, on the Eighteenth day of July, in the
year of our Lord 1845, the aforesaid John Melville came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and everything therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Nineteenth day of July, in the year of our Lord One
thousand eight hundred and forty-five.
Enrolled the Nineteenth day of July, in the year of our Lord One
thousand eight hundred and forty-five.