IMPROVE- MENTS IN MACHINERY OR APPARATUS FOR PROPELLING VESSELS, SHIPS, AND BOATS
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by James Holmes at the Office of
the Commissioners of Patents, with his Petition, on the 24th February
1859.
I, JAMES HOLMES, of Glasgow, in the County of Lanark, North Britain,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN MACHINERY OR APPARATUS FOR PROPELLING VESSELS, SHIPS, AND BOATS,"
to be as follows, that is to say :-
This Invention relates to the arrangement and construction of machinery or
apparatus to be used for effecting the propulsion of vessels, ships, and boats,
so as to secure a more effective propulsive action than is obtainable according
to any of the plans hitherto in use. Under one modification of the details of
this Invention a pair of parallel horizontal steam cylinders are fitted up in the
stern of the vessel beneath the level of the water line, one on each side of and
parallel with the keel. Each piston rod is connected in any convenient way
with a horizontal propelling rod, the axes of the two rods being in one and
the same line. The propelling rod works out astern through a stuffing box
in the ship, and its outer end is connected directly to a vertical transverse stan-
dard piece, formed with slide pieces at the top and bottom to fit in between the
upper and lower parallel longitudinal guide bars. The propelling rod is passed
through the centre of this standard or central bar, and it has upon its extreme
end two transverse stop bars set across or at right angles to each other, and
keyed firmly on. The central bar or standard has hinged to it on each side a
propelling float board or flap of metal or wood, each float having a top and

page_text: bottom vertical hinge like a gate. Provision is made for turning the propelling
shaft as required, so as to set either of the transverse stop bars horizontal at
pleasure. When the forward or inner stop bar is horizontal, the after or
external bar being vertical, the propeller is adjusted for going a-head, for as
the piston reciprocates, the standard going with it causes the propelling floats
to open out transversely against the forward stop bar during the outward
traverse of the apparatus, whilst on the inner or return stroke, the water
causes the two floats to close upon their hinges. They thus lay parallel to
each other, and oppose but a trifling resistance to the water. In this way the
vessel receives a powerful propelling motion ahead by the simple reciprocatory
action of the pair of steam pistons as when open the floats expose their full
propelling surface to the water, and thus secure the necessary resistance for
causing the vessel to move. When the ship is to go astern the shaft or
propelling rod is turned round so as to bring the after stop bar into a horizontal
position, when the action of the floats is just the reverse of what has been
described, as they open on the inward movement of the rod, and close as the
rod goes out. The steam cylinder valves are worked by suitable stop catches,
so set as to reverse the motion of the pistons at the proper intervals. To
deaden or relieve the concussion on the stop bars, the latter may be lined with
caoutchouc or other elastic substance. And further to enable the vessel to
turn easily, the propellers may be set to operate in reverse directions, one
working ahead and the other astern.