CERTAIN IMPROVEMENTS IN PADDLE WHEELS OR PROPELLERS OF STEAM SHIPS
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by Wiliam Henry Aldridge at the
Office of the Commissioners of Patents, with his Petition, on the 2nd
December 1859.
I, WILLIAM HENRY ALDRIDGE, of Kingsdown, in the City of Bristol, Iron
Merchant, do hereby declare the nature of my said Invention for "CERTAIN
IMPROVEMENTS IN PADDLE WHEELS OR PROPELLERS OF STEAM SHIPS," to be as
follows (that is to say) :—
My Invention consists in a combination of two compound cranked bars
forged of suitable square or round bar iron, either in one piece or suitably
connected as convenient, each being cranked forward and backward at each
end in the parts that carries the paddles, the cranks being on each side in the
same plane, and that portion of the bars that is amidship, or extending from
side to side on the interior, is cranked in opposite directions at right angles to
the plane of the end cranks. The two compound beams or cranks are con-
nected together with strong suitable connecting rods so as to work in unison,.
and according to the distance they are placed asunder, so the greater or less.
number of paddles I am enabled to use, and which paddles are by this arrange-.
ment always maintained in a vertical position. When the end cranks are in a
horizontal position the paddles are entirely out of the water, offering no resist-
ance, leaving a ship fitted with them in trim for taking full advantage of any
favourable wind that may suit her course. But when the paddles are in use,
the one set on each side are fully immersed, while the other set are passing.

page_text: over their highest point out of the water; or, in other words, when one set are
finishing their stroke, the other set are ready to commence..
This system of propulsion may be covered up with paddle boxes in the
ordinary way, which will prevent or reduce the resistance offered to the
advancing paddles by the atmosphere or current of air. But instead of
the paddle box being of a semicircular form, as with the ordinary paddle
wheels, it will be of a semi-elliptical form, the poles of the ellipse being
increased or diminished according to the distance the compound cranks or bars
are set apart, and the number of paddles desired to be used. But instead of
using permanent paddle boxes, I prefer covering the paddles with suitably con-
structed inverted boats, as their form will best assimilate with the elliptical
motion of my paddles. I am not compelled with this system of propulsion to
apply the paddles on the outside of the ship or vessel to which they may be
applied, as it is equally applicable to vessels constructed for a series of paddles
to work each side of the keel, say at midship, in which case they would not
effect the outward appearance of the ship, and be in a position where they
may be perfectly protected from harm, and be out of the water when not
required for propelling. This is an important feature, and renders my mode
of propulsion applicable for war steamers, as under no circumstances are the
paddles liable to fouling, and may at all times be repaired with great ease and
facility. Nor do I require any particular construction of steam engine for working
my paddles, as the ordinary oscillating marine engine will do, which may be
worked in single or double pairs, the piston rods being connected directly with
the midship cranks before described.