IMPROVEMENTS IN PROPELLING MACHINERY FOR CANAL BOATS AND OTHER VESSELS
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
16th July 1869.-A communication from abroad by Frederick
R. Pike, of the City and State of New York, United States of
America.
I, WILLIAM ROBERT LAKE, of the "International Patent Office,"
No. 8, Southampton Buildings, London, Consulting Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN PROPELLING
MACHINERY FOR CANAL BOATS AND OTHER VESSELS," a communication, to be
as follows:-
The nature of my Invention consists in the peculiar combination of the
dynamic lever with a pair of piston propellers, whereby I am enabled to
apply the power so as to overcome the resistance of a vessel's immersed
cross section without overcoming the resistance of the water at the pro-
pellers, and by so doing reduce the "slip" to a fraction of 1%; hence its
great economy for the loss from "slip" in the present system of screw
and paddles averages 30%. The dynamic lever is provided with long
and short arms extending from the axis which swings in two bearings,

page_text: A. static lever has also long and short arms attached to its axis, the
reank or short arm of the static lever is attached to and acts upon the
crank or short arm of the dynamic lever. A double piston is made use
of in the cylinders of the propellers, and by proper connecting links
is attached to the long arm of the dynamic lever, and acts upon the
piston through a piston rod. A link motion is attached to the piston rod
of the steam engine, and acts on the long arm of the static lever.
The foregoing parts may be made of any suitable substance, and may
be arranged vertically, horizontally, or set at any angle. The piston,
propellers, and cylinders may be made of varying shape and dimensions,
or elongated pistons of various shapes may be constructed and arranged
so as to act on the water by passing through proper ports duly fitted
with stuffing boxes, so as to impinge against the water at one end only,
but the form already described will be found the best. Instead of using
a piston working in a cylinder I sometimes use a propeller consisting of
a pair of leaves or plates hinged together, so as to open when acting
against the water, and to close when drawn in the opposite direction.
The static lever may be dispensed with and the power applied directly
to the crank of the dynamic lever, but I prefer to employ the static lever
because by this means engines at present in use of any ordinary length
of stroke may be adapted to this apparatus. The crank of the dynamic
lever must never exceed in length (or distance from the centre or axis)
one-twelfth of the length (or distance from the centre or axis) of the
long arm, it will be found that the shorter the crank and the longer the
said arm the greater the economy of power. Two or more of the pro-
pellers may be used and may easily be arranged to work simultaneously
or alternately; four is a convenient number to be used, two facing the
stern ports for going ahead, and two facing the bow ports for backing.
Ropes are attached to the links which connect the propeller rods to the
dynamic lever for the purpose of connecting and disconnecting the same.
To find the area of propellors required add 20% to area of immersed
cross section, divided by the leverage used and by two, the result is the
required area of piston. Power being applied to the engine the static
lever oscillates in the arc of a circle, and acts upon the crank of the
dynamic lever, this again acts on the piston propellors which impinge
against the water, the resistance of the small area of water at the
propellors being by means of the dynamic lever made virtually greater
than that of the larger area of immersed cross section, it is evident from

page_text: the known law that power applied to overcome two unequal resistances
of necessity overcomes the least; that the water forming the resistance
to the boat's motion will give way before the water at the propellors, the
former offering practically the smallest resistance, consequently that the
boat can be propelled by this means without "slip."
The propellor cylinders are duly provided with stuffing boxes, their
pistons having the water on one side and a vacuum on the other, so that
little, if any, steam will be required to bring them back, the pressure of
water alone being generally sufficient for that purpose. The series of
toothed wlieels may be made use of or not at will in combination with
this propelling apparatus to apply power directly at the crank or to any
other point of the static lever.