IMPROVEMENTS IN APPARATUS FOR PRO- PELLING SHIPS AND OTHER VESSELS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
23rd May 1872.-A communication from abroad by Lewis Budd
Bruen, of the City and State of New York, United States of
America.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR PRO-
PELLING SHIPS AND OTHER VESSELS," a communication, to be as follows:-
66
The said Invention relates to the propulsion of vessels by apparatus
to which for convenience I will give the name of a 'tube propeller."
In practising my said Invention I arrange a conduit or passage, or two
or more of the same, in the stern of the vessel. For this purpose I
prefer to use cylinders whose bore is perfectly smooth and true, the
length and diameter varying according to the size and character of the
vessel and the number of propellers used. These cylinders may be either
closed or open at their inner ends, but the other ends which project
through the hull of the vessel are open. A perfectly true and water-
tight plunger is fitted to cach cylinder and attached rigidly to a piston

page_text: rod, by means of which a reciprocating motion is communicated to
the said plunger from the cylinder of a steam engine. In its outward
motion the plunger forces the water out of the tube, and the resistance
encountered by the water expelled from the tube constitutes the pro-
pelling force. The motion being then reversed the plunger is moved
inward, being forced forward by the pressure of the water which rushes
in to fill the tube. The extreme forward point being reached the motion
of the engine is again reversed, the plunger being driven back and the
water expelled as before. By this simple operation the power is applied
direct from the cylinder of the steam engine in the line of motion
without producing any resistance to the forward motion of the vessel
during the return of the plunger, and I dispense with the contrivance
used in the production or transmission of rotary motion.
In practice it is necessary to use the aforesaid tube propellers in pairs,
as if only one propeller is used it must be placed over the keel line,
that is to say, in the exact centre of the vessel, so that the propelling
force shall not be exerted unequally on the two sides of the vessel. And
in order that the time occupied in the return stroke of the plungers
may not be lost so far as propulsive force is concerned and the acquired
velocity diminished and the vessel have an unsteady or intermittent
motion, I use two pairs of propellers, the inward stroke of one taking
place during the outward stroke of the other.
But a single pair of propellers may be used in vessels of small
dimension; they should be applied at the extreme stern and placed
one above the other, so that their centres may exactly coincide with the
line of motion or keel line. In most cases however it will be advan-
tageous to use two pairs arranged horizontally and equidistant from the
line of motion or the keel line, and they should project through the
hull just below the line of the centre of gravity. This arrangement
secures perfect equipoise of motion.
Between the piston rods of each pair of plungers I place heavy fly
wheels. These wheels are intended to be made of such weight as will
give steadiness to the motion of the plungers with which they are
connected through cranks. The latter are so attached to the piston
rods and fly wheel that the alternate motion of the pistons will com-
municate to the fly wheel a regular and continuous rotary motion, and
they will regulate and equalize the movements of the plungers. These
wheels are to be made double, support being given to their axes between

page_text: their two parts. When one of the plungers has been driven outward to
its extreme point, the steam pressure being removed from the inner
side of the pluuger, the external pressure of the water thereon which
equals the area of the plunger's surface multiplied by the depth of
immersion below the surface of the water immediately drives in the
plunger. The natural water pressure from without thus affords all the
power necessary for the return or inward stroke, and any spare power
may be controlled to assist the outward stroke of the alternate pistons.
By this plan of using the power only for the outward stroke and the
water pressure for the return stroke a great saving is effected.
But if desired the steam engine may be double acting. It is obvious
that so soon as condensation takes place in the steam cylinder a vacuum
more or less complete is formed; to fill this vacuum the water pressing
against the exterior face of the plunger will drive it in with great force,
and if unrestrained with considerable violence. When one plunger
reaches its outward limit of motion and the condensation of steam takes
place in the cylinder newly admitted steam begins to force out the
other plunger. The pressure of the steam being greater than that of
the external water it follows that the first plunger is driven out with
greater force than the second plunger is driven in. The aforesaid cranks
being connected to the two pistons and also at diametrically opposite
points of the fly wheel at a distance apart equal to the length of the
stroke and equidistant from the centre of the said fly wheel, it follows
that the returning piston cannot move faster than the acting piston,
thus the motion of the outwardly moving piston controls that of the
inwardly moving piston and secures perfect equilibrium of motion.
The propulsive power of these propellers will obviously depend on
the area of the plungers and depth of immersion below the surface of
the water in which the vessel floats. When greater propulsive power is
required than can be secured by stern propellers without making them
of inconvenient size, an additional pair may be used, one propeller being
placed on each side of the vessel, or in extreme cases an additional pair
may be placed on each side.
Two of my propellers must be placed in the vessel forward of the
mid-ship section for backing or reversing the vessel. These reversing
propellers may be provided with water-tight caps or covers for the outer
openings of the tubes, which caps are constructed to be easily removed
from or placed over the openings as occasion may require. It may also

page_text: be found advantageous to provide the stern and side tubes with similar
caps to be used in case of accident at sea or if any part of the machinery
should need repair.
When the propelling tubes are left open at the inner ends it will be
necessary to provide a tank or cistern in which the leakage from the
said tubes shall be collected to be pumped therefrom by a steam pump.
If the ends are closed an opening of proper diameter should be made in
the inner end of the tubes or the caps, and a pipe should lead therefrom
to the side of the vessel above the water. The plunger in its return
stoke will then act as a pump and relieve the propelling tube from any
air or water that might be admitted by leakage.