CERTAIN IMPROVEMENTS IN PADDLE WHEELS POR PROPELLING VESSELS
Year: 1835

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ELIJAH
GALLOWAY, of Wellington Terrace, Waterloo Road, in the County of Surrey,
Engineer, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Eighteenth day of August, in the sixth year of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the said
Elijah Galloway, His especial licence, full power, sole privilege and authority,
that I, the said Elijah Galloway, my exors, admors, and assigns, or such
others as I, the said Elijah Galloway, my exors, admors, 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, my Invention of "CERTAIN IMPROVEMENTS IN PADDLE
WHEELS POR PROPELLING VESSELS;" in which said Letters Patent is con-
tained a proviso, that I, the said Elijah Galloway, 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 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
Elijah Galloway, do hereby declare the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following description thereof, reference being had
to the Drawings hereunto annexed, and to the figures and letters marked
thereon, that is to say :-
My Invention relates to the methods of affixing the floats or paddles of
paddle wheels, whereby I am enabled more advantageously to apply the power
of the engines, and at the same time in a great measure prevent concussions
from the floats or paddles in entering, and avoiding lifting so much water on
leaving it, by which means the swell, heretofore so prejudicial, is in a great
degree avoided. But in order that my Invention may be most fully described,
and readily applied to the varied circumstances of different vessels, I will first
explain the Diagram, Figure 1; having, however, first stated that in construct-
ing wheels to new vessels it will be necessary to make the calculations precisely
in the same way as if ordinary fixed radial floats or paddles were to be used,
in order to ascertain the quantity of surface for the floats or paddles with refer-
ence to the number of strokes of the engines, its power, and the desired velocity
to be obtained to the vessel; but in place of having the whole depth of the
float of one unbroken area, the floats as used by me are in divided portions,
and it is the method of arranging such divided floats according to the principle
hereafter described which constitutes the Invention secured by the present
Letters Patent.
Figure 1 represents a Diagram of two circles a, a, and b, 6; the circle a, a,
being the circle or course of the outer edges of the floats, and the circle b, b,
that of the inner edges of the floats; d, e, is a radial line, which, according to
the most general method of affixing floats, would represent one of the floats of
a paddle wheel. Now, when a paddle wheel is propelling a vessel at any given
velocity an imaginary circle may be drawn (say b, b,), the circumference of
which, multiplied by the number of revolutions in a given time, will exactly
coincide in measurement with the distance through which the vessel has
moved in the same given time; and I prefer that such line should coincide
with the circle which the inner edges of the floats traverse. This circle b, b,
may, therefore, when the vessel is in motion, be conceived to roll along the
imaginary horizontal line c, c. Such being the case, any point in the whole
area contained within the circle a, a, will describe in its passage through space
a cycloidal curve; but the curve described by the point d will be a true
cycloid; and conceiving the line c, c, to be the water line at which the vessel
floats, and the point d to be at first in contact with the point f, and then the

page_text: circle or disc b, b, to be rolled along c, c, till it reaches its present potition, the
segment of a cycloid d, f, would thereby be generated. Now, if a bar or curved
plate were affixed to the circles a, b, of the form of the curve d, f, such body
or curved plate would, in causing the wheel a, a, and b, b, to revolve in the
direction of the arrow, enter the water and be completely immersed, every part
passing through the point f on the line c, or surface of the water.
Having thus explained the principle of generating the curve d, f, I will now
proceed to describe the manner of affixing the float boards according to my
Invention.
Figure 2 represents a side elevation, and Figure 3 a perspective view, of a
paddle wheel having my Invention applied thereto. 9, 9, 9, 9, 9, 9, are a series
of portions of floats which radiate from the common centre of the paddle
wheel. These portions of floats are set on a curved line approximating to the
line d, f, Figure 1; but the Drawing, Figures 1 and 2, having been made from
a paddle wheel actually constructed, is not exactly of the same curvature as
d, f, but will sufficiently explain the principle of this Invention, by assuming
the bars, as in Figure 1, to be arranged on the curve d, f, and the bars consti-
tuting a float board to touch the curve d, f, at their outer edges, as shewn at
9.9.9.9.9.9, Fig. 1. These portions of float boards are securely affixed to
the paddle wheel by screw bolts and nuts, or by other well-known means.
Now, it will be obvious that if the paddle wheel be supposed to be revolving
in the direction of the arrow, Fig. 2, and the vessel going at such speed as
that her velocity is equal to the inner circle b, b, then the bars constituting one
paddle would enter the water at the point f, or nearly so, and displace a very
little more water than that disturbed by the lowest bar. Thus the waste of
power attendant on the entrance of a common radial float board is obviated,
and the concussion produced thereby almost entirely avoided. When the
paddle arrives at the point of deepest immersion the resistance reaches its
maximum, thence gradually diminishing until it quits the water at j, and the
water falls more easily through the open spaces between the bars than from
the common paddle.
cycloidal curve,
cause the series
have described,
I wish it to be understood, that although only the true
generated as I have shewn in Figure 1, is best adapted to
of bars forming a paddle to enter the water in the way I
yet there is a limit beyond which the true cycloidal curve ceases to be the
most efficient arrangement; this is when the retrograde motion of the paddle
through the water is much greater than I have assumed in Figure 1; for
it is obvious that if the circle coinciding with the vessel's velocity were only
half the diameter of a, a, Fig. 1, then a cycloidal curve, generated under

page_text: such circumstances, passing through d, would reach at its outer extremity to the.
point (Figure 1). In that case, if the bars 9, 9, 9, 9, J,g, were arranged upon:
such curve, they would be considerably wider apart than is shown in Figure 2
and 3. And I have ascertained that it is essential, in order to obtain the.
maximum of propelling resistance in paddles of this description, that the space
between any two of the bars 9, 9, 9, 9, 9, g, should not be too great, and thereby,
lose the property of acting in combination or conjunction, thereby entailing
a loss of propelling resistance; and I would therefore have it understood that
when the cycloidal curve is of such a form as that a straight line drawn
from the bisecting point in the arm, as d, to the bisecting. point in the rim,
as f, forms a very considerable angle to the radius d, e, (say, d, l,) then I do not
confine myself to the cycloidal curve, but place the bars in such positions that
they will be nearer to each other than if placed in the direction from d to l.
I do not therefore coufine myself to the necessity of the cycloidal curve d, f,
(though such curve, under the precise circumstances therein set forth, is the
most efficient arrangement of the bars); for I am aware that if the bars
9, 9, 9, 9, 9, 9, were placed upon a curve or line (forming even a straight line) at
a less angle than d, f, to d, e, they would have a superior effect, to the common
paddle; or supposing the cycloidal curve to extend from d to 1, then if
9.9.9.9.9.9, were placed upon any line which formed a less angle to d, e, than
d, l, such an arrangement would be within the limits of my claim.
It should be remarked, that since the sealing of my said Letters Patent
I have been informed that Joshua Field, Esquire, Engineer, of Lambeth,
some years before the date of my said Patent, made an experiment of a
paddle wheel on a small vessel belonging to him or his partners, called the
"Endeavour," the floats of which were divided into portions, but they are not
fixed according to the principle the application of which constitutes the
object of my Invention; and which experiment I have been informed, and,
from the nature of the construction of the wheel, I verily believe was declared
by him to be a failure. And I have only thus noticed this experiment in
order to state that I do not claim the exclusive use of divided floats or paddles
unless they be applied and affixed to paddle wheels according to the principle
herein described. And in order to point out more accurately the difference of
a wheel constructed according to my Invention and that experimented on
by the said Joshua Field, I have annexed a Drawing of a portion of the said
wheel so used in the "Endeavour" sufficient to show the principle thereof;
but on inspecting the same Drawing at Fig. 4, it will be evident that the
portions of the floats are not affixed according to the method described and
claimed by me.

page_text: I would, in conclusion, wish it to be understood that I lay no claim to the
various parts of paddle wheels herein described, and generally well known, when
the same are not combined according to the method of affixing the portions of
floats as herein explained; and I do declare that my Invention consists in
affixing the portions of floats or paddles 9, 9, 9, 9, according to the arrangements
herein described.
In witness whereof, I, the said Elijah Galloway, have hereunto set my
hand and seal, this Eighteenth day of February, in the year of our Lord
One thousand eight hundred and thirty-six.