IMPROVEMENTS IN PROPELLING VESSELS, SHIPS, AND BOATS
Year: 1858

page_text: LETTERS PATENT to John Buchanan, of Greenock, in the County of
Renfrew, North Britain, Gentleman, for the Invention of "IMPROVEMENTS
IN PROPELLING VESSELS, SHIPS, AND BOATS."
Sealed the 25th February 1859, and dated the 10th November 1858.
PROVISIONAL SPECIFICATION left by the said John Buchanan at the
Office of the Commissioners of Patents, with his Petition, on the 10th
November 1858.
I, JOHN BUCHANAN, of Greenock, in the County of Renfrew, North Britain,
Gentleman, do hereby declare the nature of the said Invention for" IMPROVEMENTS
IN PROPELLING VESSELS, SHIPS, AND BOATS," to be as follows, that is to say :-
This Invention relates to the propulsion of vessels, ships, and boats, by the
agency of machinery or apparatus operating on the general principle of the
feathering oar. Where one such propeller is used it is disposed in the contre
or keel line of the vessel, being attached to a long vertical transversely
vibrating arm long enough to reach from the deck level low down in the boat;
this arm is made to vibrate by an upper crank or other movement driven by a
steam engine, or by any other convenient agency. To the lower portion of
this vibrating arm there is fitted a rectangular float or propelling board capable
of sliding up or down the arm, as may be required, and working through an

page_text: aperture in the bottom of the boat down into the water. The float or propeller
is central at its upper end to the sliding apparatus on the arm, so as to be
capable of turning upon a stud, this sliding apparatus consisting of a rotatory
spindle turning in bearings on the main arm; it is also connected at its two
upper corners with the lower ends of a pair of chains or other connections,
which pass upwards to a winch or other operating movement on deck. When
set to work, one of the side chains attached to the corners of the float is
hauled up so that the float takes a diagonal position, and hence, as the arm
vibrates across the vessel, the float propels the vessel in the manner of a
feathering oar, that is to say, that at each traverse the float takes up an
inclined position like the blade of a screw propeller, and thus propels the
vessel, the proper incline being determined by a stop on the float spindle
pressing against the main arm. On the return traverse movement the float
feathers by the action of the water, and reverses its position so as to take up
an inclined position exactly corresponding to that first taken up. When the
vessel is under sail and the propeller not required, it takes up a position in line
with the keel so as to oppose little or no resistance to the vessel's motion.
When the float is to be raised up, both side chains are hauled so as to draw
up the float by its two corners to any desired elevation. When two propellers
are employed, one is disposed on each side of the keel, which is thus left
unbroken, the whole apparatus being boxed in by suitable bulkheads, or
otherwise. Any required number of such pairs of propellers may be used in
a vessel. In backing, the reverse chain attached to the float's corner is hauled
up, and this gives the float the necessary reverse incline for going astern.