CERTAIN IMPROVEMENTS IN MACHINERY FOR ACQUIRING POWER IN RIVERS AND CURRENTS
Year: 1833

page_text: MCCURDY'S SPECIFICATION.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MCCURDY, of Southampton Row, in the County of Middlesex, Esquire, send
greeting..
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Royal Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Twenty-second day of January, in the third year of
His reign, did, for Himself, His heirs and successors, give and grant unto me,
the said John McCurdy, his especial licence, sole privilege and authority, that
I, the said John McCurdy, my exors, admors, and assigns, or such others as I,
the said John McCurdy, my exors, adññiors, or 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, the Invention of
"CERTAIN IMPROVEMENTS IN MACHINERY FOR ACQUIRING POWER IN RIVERS AND
CURRENTS," partly communicated by a certain foreigner residing abroad; in which
said Letters Patent is contained a proviso that I, the said John M'Curdy, 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 His 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.
" "
NOW KNOW YE, that in compliance with the said proviso, I, the said
John M'Curdy, do hereby declare that the nature of the said Invention, and
in what manner the same is to be performed, are particularly described and
ascertained in and by the following description thereof, reference being had to

page_text: the Drawing hereunto annexed, and to the figures and letters marked thereon
(that is to say):-
I fix a horizontal shaft, with two or more cranks upon it of any given throw;
this shaft is supported upon a frame at the ends, the cranks being placed upon
different angles of the shaft. Above this shaft, at any required distance, so as to
permit the cranks in revolving to clear the shafts, I place a second shaft with
similar cranks upon it. The upper shaft may be exactly perpendicular over
the lower, or vary, but parallel with each other. The cranks upon the two
shafts being then brought into a relative position as regards each other, I attach
or connect them together (with arms or rods of wood or iron, of any given
length) at the gudgeons, turned upon the elbows of the cranks, opposite to each
other upon the two shafts, by means of plummer blocks fixed upon the rods or
arms, permitting the gudgeons of the cranks to revolve in them. The paddle
or propeller of any required shape is then attached to the lower end of the
arms or rods thus connected. By giving a rotary motion to the shafts, the
arms describe parallel lines with each other, the paddles describe a circle of
the same sweep as the throw of the cranks, are kept vertical in every part of
their revolution, alternately dipping in and raising out of the water.
The Drawing annexed represents two shafts, with four cranks upon each,
one placed upon each square of the shaft, with four arms and four paddles,
which are represented of the shape of the South Sea paddle. A, A, represents
the main shafts, similar to each other, one placed over the other; B, B, repre-
sents the rods or arms which are connected to the cranks by the plummer
blocks; C, C, are the cranks, with a gudgeon or bearing on each at the point
F; D, D, represents the paddles at the lower ends of the arms or rods; E, E,
represents the timber frame; F, F, represents the plummer blocks which attach
the arms to the cranks; G is a wheel at the point of the lower shaft, where
the machine is geared to the engine or machinery in the vessel; H, H, repre-
sents the flanges, with bolts that unite the cranks, should they be cast or made
separate.
I simply claim as original the combination, attachment, and connection of
the arms or rods to the double cranks, acting together with the paddle attached
to the lower end of them, by this principle of motion producing a more perfect
propeller than heretofore known. This machine, when attached to the sides of
a vessel, can be used either as a means of acquiring power by being acted upon
by the force of the stream or current, for the purpose of driving machinery in
the interior of the vessel when at rest, or may be driven by the force of steam
or other means, for the purpose of acquiring power for propelling the vessel
forward. In the latter case the objections to the common water wheel are

page_text: materially obviated. From the vertical position of the paddle there is no con-
cussion or vibration on entering or back water on leaving the water. Its expense
is much less, and its simplicity is such that it is not so liable to derangement, and,
in case of damage, can be soon repaired. By means of gearing any velocity may
be given to the paddles required. In case of a storm at sea, by detaching the
rods or arms from the upper shaft, the paddles may be entirely raised from the
water by laying the rods horizontal. I prefer the cranks to be cast or made
separately, and united together by means of flanges and bolts; an extra hearing,
if necessary, may be placed betwen each two cranks. As the whole action of
these paddles is applied in a horizontal direction, smaller engines than those
now in use will probably produce as great an effect, and consequent saving of
expence in engines and fuel thereby effected, by adopting them in lieu of the
wheel. This machine occupies but a small space, and can be fixed in any
part of the vessel.
In witness whereof, I, the said John M'Curdy, have hereunto set my
hand and seal, this Twenty-second day of July, in the year of our
Lord One thousand eight hundred and thirty-three.

page_text: one placed above the other.
Represents the Rods or Arms which are connected
to the cranks by plummer blocks.
Are the cranks with a bearing on each at the point 1
Represents the Paddle (of the South Sea form) at
the lower end of the Rods.
Represents the timber upon which the Shafts rest at
the ends upon plummer blocks.
Represents the plummer blocks which attach the
arms to the cranks.
Is a wheel at the point of the Lower Shaft, where
the Machine is geared to the Engine or Machinery
in the Vessel.
Represents the Flanges with bolts that unites the
Cranks should they be made single...