IMPROVEMENTS IN MACHINERY OR APPARATUS FOR PROPELLING SHIPS OR VESSELS
Year: 1857

page_text: (This Invention received Provisional Protection, but notice to proceed with the,
application for Letters Patent was not given within the time prescribed.
by the Act.)
PROVISIONAL SPECIFICATION left by William Thomson at the Office
of the Commissioners of Patents, with his Petition, on the 2nd December
1857.
I, WILLIAM THOMSON, of Dalkeith Park Gardens, in the County of Mid-
Lothian, North Britain, Gardener, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR PROPELLING
SHIPS OR VESSELS," 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 ships or vessels, so as to
secure a more effective propulsive action than is obtainable according to any of
the plans hitherto in use. This system of propelling is carried out in practico
by fitting in the stern of the ship or vessel an arrangement of folding or hinged
propellers or reciprocatory floats. These propellers may be arranged in various
ways, but it is preferred to make each of them in the form of a pair of semi-
circular discs, hinged in each instance one on each side of a longitudinally
reciprocatory bar which works out into the water through the stern or quarter
of the ship. This bar is caused to reciprocate longitudinally, either by the
direct action of the piston of a horizontal steam cylinder, or by a crank or
other mechanical mover; and the portion which actually works in the water
has upon it two or more of the divided propellers, so fitted with stops that
when the bar is traversed in a direction opposite to the ship's notion the

page_text: divided propellers stand firmly at right angles to the axis of the bar, and thus
present efficient propelling surfaces to the water; whilst on the return stroke,
in the same direction as that of the ship's motion, the hinged portions of the
propellers fold over and present the least possible resistance to the water, but
again opening when the bar returns sternwards. These hinged propellers may
be in more than two pieces; for example, each section may be again sub-
divided, just as may be found convenient.
Any convenient number of these propelling bars may be used in concert,
and either one above the other or alongside each other in a horizontal line.
When set in a horizontal line the arrangement enables the captain to direct
his ship with peculiar ease, as one or other of the bars may be disconnected
from the motive power at pleasure, so as to allow the propelling power still
left at work to act in directing the ship's head. The propeller bars may either
work direct out in a straight line through a stuffing box in the ship's stern, or
they may be cranked downwards so as to pass through the ship's side above
the water line and still enter the water, as required. Provision is also made
for lifting the propellers clear of the water when the ship is to sail under
canvas, this being effected by jointing the bars, so that the outer ends can be
hauled up by proper tackling as high as is required. The joint action of
the propeller boards, is so arranged with elastic bearing surfaces that as the
sections work serious concussion is avoided.