IMPROVEMENTS IN MACHINERY FOR PROPELLING VESSELS
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents, with his Petition, on the
8th June 1869.-A communication from abroad by Frederic Lesnard,
Engineer, of Marseilles (Bouches du Rhone) France.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MACHINERY FOR PROPELLING VESSELS," to be
as follows:-
This Invention relating to improvements in the propulsion of vessels
is illustrated in the accompanying Drawings, Figure 1 of which represents
a partial horizontal section of a vessel with the propeller and principal
parts of the apparatus. The broken lines indicate the form of the hull
from the stern in a forward direction, the space between being available
for placing the propelling apparatus up to and above the water line.
Figure 2 shows a longitudinal section of the vessel and side view of the
propelling apparatus; Figure 3, a transverse section of a vessel taken
near the stern post with a front view of the propelling apparatus;
Figure 4-shows a front view of the propellers, properly so called, with the
principal parts for operating the same; Figure 5 shows a side view of

page_text: the propellers with some of the parts detached; Figure 6, a section of a
.vessel at the part where the propelling apparatus placed. Figures 4,
5, and 6 represent a vessel intended for river and canal navigation. The
same letters apply to all the Figures.
A, horizontal shaft on which are fixed the port side propeller and
balance lever for operating the same; A', similar shaft placed on the
starboard side of the vessel; L, balance lever of shaft A; L', balance
lever fixed on shaft A¹; P, P, bearings of shafts A, A; B, B, connecting
rods of balance levers L, L', attached to the piston rods of cylinders
C, C; B, B', connecting rods placed at the opposite ends of the balance
levers and operating the crank shafts A³, A³, for regulating the motion
of the pistons; C³, horizontal auxiliary engine the cranks of which are
placed at right angles to those of shafts A, A, to assist their action
when on the dead point; L, L, double balance levers set in motion by
connecting rods attached to the ends of the cross heads of pistons C for
ensuring a unity of action of the two engines. On shafts A³, A³, are
mounted eccentrics E, E, one for each slide valve and two for each
propeller. Other accessory parts in ordinary use are omitted in the
Drawings for the sake of clearness. R, double oscillating lever fixed on
shaft A; n, part of spade form mounted on an axis at the lower end of
levers R, and to which part are rivetted the plates or pallets S, forming
the propelling surface; 9, 9, two jointed catches placed between levers R
above part n to which are connected the rods y, y, in a mortise made in
the head of part n, see Figures 4 and 5; d, lever placed between levers Ry
below shaft A to which lever are attached the ends of rods y, y, set in
motion by means of balance levers b, b, and connecting rods t, t, through
the medium of hand lever f, which has a pin at its upper part held in
position by a toothed part h. The parts g, g, and .their accessories serve
as an abutment for part n. When lever fis in the position shown the
parts g, g, will admit of the forward motion of the vessel, and in order to
reverse the motion the lever fis brought to the centre of part / to allow
of the eccentrics changing the position of the pallets, after which the
stud on hand lever fis placed in the first notoh of h. The two propellers
are both similarly arranged and therefore do not require separate
description; d, lever similar to d placed at back of R and carrying the
rod a before mentioned as mounted on part n. This lever d¹ is set in
motion at the completion of each stroke of the piston by the eccentric E
by means of rod k, balance levers b', 6', and rods f, t. On the eccentric

page_text: rod k is mounted a rod i supported by a lever j serving to raise or lower
rod when the direction of motion is to be changed. In order to move
the vessel in one direction or the other it is simply necessary to change
the position of propellers 8, 8¹³, by means of the two eccentrics of each
propeller, one of which is used for the forward and the other for the
backward motion. This mode of reversing is much more easily and
promptly effected than by reversing the engines of the propellers. Thus
the engines continue to work during short stoppages, as in order to stop
the motion of the vessel it is simply necessary to throw the pallets 8, 81,
out of action. u, u, indicate the space in which the propellers work
between the walls 2, 3.
In vessels used for maritime navigation, see Figures 1, 2, and 3, the
propellers are placed on each side of the keel and within the hull; but
when used for navigating canals and rivers the propellers would be
placed in the centre near the stern of the vessel, as indicated in Figure 4.
In this case the propellers have the same arrangement as before. The
engines C, C, are placed horizontally and their pistons have double rods,
one of which sets lever L in motion, while the other is connected with
crank shaft As for regulating the stroke of the piston and propeller.
This shaft A carries the eccentrics E and is provided with a fly wheel V,
as seen. 1, 1, levers and rods by means of which the eccentrics com-
municate motion to parts 6' acting on levers d', d, for changing the
position of the propellers on the completion of each stroke of the piston
as shown, b, d, f, h, parts similar to those before described for acting on
parts g, g, Figures 4 and 5. The balance levers L, L', before referred to
as fixed on shafts A, A¹, are set in motion by the levers L³, L³, fixed on
shafts A2, A3, by means of double connecting rods B, B, B', B¹. u, u,
Indicate the enclosed spaces in which the propellers act. The bearings
of shafts A, A, are placed on the deck of the vessel, while the propellers
and balance levers L, L, are contained within the vessel,
It will be readily understood that when the piston of port cylinder O
descends the piston of the starboard engine rises so as to apply the power
simultaneously on balance lever L for moving the vessel forwards by
projecting the propeller R, and also on balance lever L' for bringing
back the propeller R' previously projected. In this manner the vessel
is moved forward at each stroke of the piston nearly in a straight line
without requiring to transmit the motion by intermediate parts, and all
the effective power is thus utilized for propulsion. The propeller R

page_text: acts on the water which rushes from the stern in a forward direction
to replace that displaced by the vessel in its motion. The water thus
forms a fulcrum for the propeller almost equal to that of a solid body,
there is consequently but little loss of power, and the speed of the vessel
will almost equal that of the propeller. This is the more so in conse-
quence of the propelling surface 8 acting at a great depth under the side
of the vessel at a speed of nearly twenty feet per stroke of the piston.
Further, the pallet being feathered and at right angles to its former
acting position) meets with but little resistance in its backward motion
in the water flowing with the vessel. When the wind is favorable the
pallets is placed in the position of 8', and in this manner neither will
offer any resistance to the sailing of the vessel, and thereby fuel is
economized by dispensing with the engine power, or both may be used
together if desired. I should observe that the pistons, connecting and
other rods, and cross heads suspended from the port side balance lever
are made to equally balance the same parts on the starboard side by the
aid of levers L, L. The same is also the case with the propellers R, R',
and the rods B', B'. In this manner the friction of the shafts in their
bearings will be considerably diminished as they are subjected to but
slight oscillation (from 18 to 20 degrees only).
The improved form given to the vessel, shown in Figures 4, 5, and 6,
from the stern to the extreme forward limit of the propelling apparatus
is of great advantage in river navigation where the current is rapid, as
the water following in the wake of the vessel forms a counter current
in the space in which the propellers act, which gives them a firm hold on
the water to enable them to more easily stem the current. There is also
this further advantage, that the propellers are protected from all external
injury while the objectionable agitation of the water in canals is also
prevented.
This improved propelling apparatus is based on the principles of the
laws of locomotion, consisting of fins to be adapted to vessels of con-
siderable length and driven by motive power at a high speed.