IMPROVEMENTS IN THE CONSTRUCTION OF SCREW PROPELLERS, AND IN THE MODE OF MOUNTING AND WORKING THE SAME
Year: 1881

page_text: LETTERS PATENT to Nicholas Demetrius Spartali, of Liverpool, in the County
of Lancaster, Steam Ship Agent, for an Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF SCREW PROPELLERS, AND IN THE MODE OF MOUNTING
AND WORKING THE SAME."
PROVISIONAL SPECIFICATION left by the said Nicholas Demetrius Spartali
at the Office of the Commissioners of Patents on the 26th March 1881.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool, in the County of Lancaster,
Steam Ship Agent. "IMPROVEMENTS IN THE CONSTRUCTION OF SCREW
PROPELLERS, AND IN THE MODE OF MOUNTING AND WORKING THE SAME.
"
This Invention relates to improvements in the construction of the screw
propellers described in the Specifications of the Patents granted to me and bearing
date the 10th September, 1875, No. 3180, the 15th July, 1876, No. 2906, and
29th April, 1879, No. 1670.
In constructing the blades and placing them round the whole length of the shaft
in such a manner as to increase their diameter and the length of their pitch, and in
bringing their greatest displacement in the immediate periphery of the shaft in
addition to the upper surface of the blades in connecting the one blade to the other
round the whole circumference of the shaft by suitable gradually sloping surfaces
somewhat in the shape of channels for the free flow of the water from between
each intervening space, the whole forming a free working of a series of blades
longitudinally in the line of the shaft in the form of an archimedean screw,
avoiding the obstructions caused by too bulky masses of dead metal, and of cramming
together of a number of blades close to each other, the arc in the way of the other
as heretofore, and which has been the chief obstacle in the success of similar helical
propellers so far.
In constructing the blades, the centre of which may be taken as a line drawn
vertically to the shaft, I extend the one half of same on a gently inclined line
forward in a cross line to the shaft, and a similar inclined line extending abaft the
shaft also on a similar cross line, or equivalent short links or arms forming the

page_text: extreme bearings or seats of the same blades, these two extreme points fore and
aft forming a long diagonal line in two distinct sections, the internal ample recessed
area forming the lower and most effective part of the blade, the above links or
arms being placed at opposite angles to each other diagonally at an incline of
between 40° and 50° from the line of the shaft to those extended arms or links. I
set the frame of the blades also on an opposite incline fore and aft vertically to
the lower supporting arms, the whole of each blade forming a spacious hollowed out
diagonal square, the half projecting to the rear and the other half to the fore part
of the line of the shaft, and the counter blade. opposite to the same is similarly
constructed, the base of which is placed at half the diameter to the back of the
former blade on similar projecting inclined lines opposite to each other as
described.
▷ My Invention relates, secondly, to an improved method of applying my propeller
to steam ships. This I propose to effect in the following manner:-I lengthen the
space abaft the stern post of the ship in which the propeller revolves, and I mount
my improved propeller on the shaft which protrudes through the stern post as
usual; in rear of this shaft, and in a direct axial line with it, is mounted a second
short shaft which carries a second propeller; this short shaft is mounted at its
rear end in the rudder post, and at its opposite end in a bearing suitably fixed in
or near the centre of the space between the stern post or rudder post of the vessel,
and receives motion from the first shaft by suitably arranged gearing which will
cause it to rotate in a contrary direction to the shaft from which it receives motion.
Thus it will be seen that by mounting a right handed propeller on the main shaft
and a left handed one on the shorter or auxiliary shaft, these propellers will be
caused to rotate in opposite directions, and always exert a forward thrust on the
ship, the rearmost one working in the broken water of the forward one, and thus
as it were utilizing every available particle of water for the propulsion of the vessel.
It will be understood that the blades being of gradually decreasing diameter
towards the rear end the water will be allowed to flow freely from them aſt,
thereby carrying no dead water as is now so often the case.
The shaft may be circular or of any other form, or made into partly furrowed
and partly projecting spaces, or made in one with the socket arms and frames,
suitable for the form of the blades and connections as described, or in separate
distinct lengths connected together.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Nicholas Demetrius Spartali in the Great Seal Patent Office on the
26th September 1881.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool, in the County of Lancaster,
Steam Ship Agent. "IMPROVEMENTS IN THE CONSTRUCTION OF SCREW
PROPELLERS, AND IN THE MODE OF MOUNTING AND WORKING THE SAME."
The Invention relates to improvements in the construction of the screw propellers
described in the Specifications of the Patents granted to me and bearing date the
tenth September, One thousand eighty hundred and seventy five, No. 3180, the
fiftoenth July, One thousand eighty hundred and seventy six, No. 2006, and the
twenty ninth April, One thousand eight hundred and seventy nine, No. 1670; and
the Invention consists in constructing the blades and placing them round the
whole length of the shaft in such a manner as to increase their diameter and the
length of their pitch, and in bringing their greatest displacement in the immediate
periphery of the shaft, in addition to the upper surface of the blades, in connecting
the one blade to the other round the whole circumference of the shaft by suitable
gradually sloping surfaces somewhat in the shape of channels, for the free flow of
the water from between each intervening space, the whole forming a free working
of a series of blades longitudinally in the line of the shaft, in the form of an
archimedean screw, thus avoiding the obstructions caused by two bulky masses of
dead metal, and of cramming together of a number of blades close to each other,
the one in the way of the other as heretofore, and which has been the chief obstacle
to the success of similar helical propellers so far.
In constructing the blades, the centre of which may be taken as a line drawn
vertically to the shaft, I extend the one half of same on a gently inclined line
forward in a cross line to the shaft, and a similar inclined line extending abaft the
shaft also on a similar cross line or equivalent shoot links or arms forming the
extreme bearings or seats of the same blades, these two extreme points fore and
aft forming a long diagonal line in two distinct sections, the internal amply recessed
area forming the lower and most effective part of the blade, the links or arms
being placed at opposite angles to each other diagonally at an incline of between
forty and and fifty degrees from the line of the shaft. To these extended arms or links
I set the frame of the blades also on an opposite incline fore and aft vertically to
the lower supporting arms, the whole of each blade forming a spacious hollowed
out diagonal square, one half projecting to the rear and the other half to the fore part
of the line of the shaft. The counter blade opposite to the same is similarly con-
structed, the base being placed at the back of the former blade on similar projecting
inclined lines opposite to each other as described.
Although the forms of blades hereafter to be described greatly resemble those
described in the Specifications above referred to, there is a material addition to the
breadth of the blades as well as to the pitch and to the connection of each two
blades one to the other, and also in utilizing the curvilinier lines of the two centre
halves forming the foundation of the blades, and in the connection to the centre
and shaft which has the effect of an additional propelling surface, doing the service
almost of a third blade; also in the formation of a diagonally triangular recess or
chamber in which a great mass of water is contained and bodily displaced, the
length of the blades being formed as it were in two and even three sections, united
in their breadth to each other diagonally in their thickness. By this combination
I gain considerably in extending the outward end of the front of the blades quite
fully up to the line of the front of the boss and considerably beyond it, which edge
I gently round somewhat, and I obtain a great breadth of sloping surface at about
an angle of forty-five degrees in relation to the centre shaft. The travel of the

page_text: blades round the shaft I always- maintain at an angle of from about twenty to
twenty five degrees.
The principle of the new propeller is to construct the lower part of the blades
more or less triangular, and place every two blades at opposite angles diagonally
across the shaft, their front base forming two long curvilinear seats at a long angle
from the front of the shaft, and at opposite equal angles and distance. At the end
of each of these angular points the inside of a knee is formed, whence the upper
part of the blade or the blade proper is carried upwards in a more or less tapering
breadth from the lower base, thus maintaining the diagonal triangular form. The
above mentioned seats form a slightly sloping recess from the knee point to the
front of shaft supported underneath, or at back by a good thickness of metal from
the end of the opposite blade. The other limb or end of long triangular base of
the blade is carried in long line far to the back of the boss, ending at the knee
point of the other blade and forming a continuation of the slope of the blade in a
line with the back of the boss or centre. The shaft intersects the two huge
triangular chambers or seats at long diagonal angles. The inside of each main
blade forms by the position of the blades to the centre, which can be described as
riding across a curvilinear cross rod across the shaft, a slightly hollowed triangular
space in the centre part of its length at the end of the sloping seat, forming the
principal base or the point of the knee.
The imaginary or real cross rod can be made more or less curvilinear or even in
a straight line, the long diagonal triangular base of the blade being equally
práctical. The blades I either connect close to each other or at long curves, as will
be seen on reference to the Drawings. The power of the blades is very great to
the water, besides cutting the water as they travel round displace a mass of water
bodily and release it at about the front of the boss, returning. to the upper part of
the circle at the smallest possible exposure of surface and least resistance to the
water. For large ships I make the blades shorter and broader. For smaller ships
and yachts I make the blades longer and narrower.
Any set of two blades shewn in the Drawings can be used for the propeller on
the archimedean principle. They can be placed in series of two pairs on the line
of shaft in the same line and angle to each other or at opposite intervening angles,
and they can be constructed with holes in the front of their frames for interlocking
or bolting one to the other. They can also be arranged two blades to the right
and two blades to the left hand, or in pairs, one half to act as right hand, and the
other half as left handed.
My Invention relates, secondly, to an improved method of applying my propeller
to steam ships. This I propose to effect in the following manner:--I mount one
of my improved propellers on the main shaft which protrudes through the stern
post as usual. In front of this shaft and in a direct axial line with it is mounted
a sleeve shaft carrying a second propeller. This sleeve shaft is supported at its
rear end in the stern post, and its opposite end in a bearing suitably fixed inside
the vessel. This sleeve shaft receives motion from the main shaft by suitably
arranged gearing situate inside the vessel, and which will cause it to rotate in a
contrary direction to the main shaft from which it receives motion. Thus it will
be seen that by mounting a right handed propeller on the main shaft and a left
handed one on the sleeve shaft, these propellers will be caused to rotate in opposite
directions, and always exert a forward thrust on the ship, the rear most one
working in the broken water of the forward one, and thus as it were utilizing
évery available particle of water for the propulsion of the vessel.
It will be understood that the blades being of gradually decreasing diameter
towards the rear end the water will be allowed to flow freely from them aft,
thereby carrying no dead water as is now so often the case.
The shafts may be circular or of any other form, or made into partly furrowed
and partly projecting spaces, or made in one with the sockets, arms, and frames
suitable for the form of the blades, and connecting as described, or in separate
distinct lengths connected together.

page_text: The gearing consists of five wheels altogether worked from the one attached to
the main shaft, and connected to the intervening small wheel again working the
two sets of wheel on the sleeve shaft, and again working the larger wheel on the
main shaft.
The main shaft receives motion from the ships engines direct, whilst the cog
wheel arrangement is actuating the sleeve shaft supporting the forward set of
propellers, and rotating in the opposite way to the set on the main shaft. The cog
wheels may be placed outside the vessel. In this case the sleeve shaft into which
the counter cog wheels take may be made to work from the bottom at about the
lino of the keel. Any of the two bladed propellers above referred to may be
applied to the series of archimedean screws, and I may place them in a series of
one pair to the rear of the other quite close together or at different angles.
The propellers may be cast in one or forged of iron, steel, or phosphor bronze, or
any other hard and ductile metal best suited; the blades may be made either
shorter and wider or longer and thinner, and have sharp edges for cutting the
water.
In the accompanying Drawings I have shewn in Sheets I., II., III., various forms
of propellers, and in Sheet IV., the mode of mounting the propellers according to
the second head of the Invention.
Figures 1 show a front and back view of a two-bladed propeller with centre and
shaft. a is the main slope of blade at about forty five degrees to shaft; b is the
slope to the rear of shaft, the parts between the two slopes being slightly rounded;
c, recessed seat forming a diagonal triangle; d, centre; e, the ridge of the joint of
the supposed two parts of the blades forming the diagonally triangular portions
of the blade, the shaded part sloping to the inside of the shaft. Figures 2, 2",
represent respectively the front and back views of another form of propeller.
Fig. 2 is large bladed with flange of the enlarged recess carried forward of front of
the shaft, and the boss with a larger centre than Fig. 1, and with recesses made.
The two longitudinal sections of the blades form two distinct diagonal triangles
sloping at a considerable angle from the centre boss outwards, and from about
centre of blade inwards to the back of the boss.
Fig. 2° represents the back of the blades showing two distinct ridges or angles
where the portions of the blades are supposed to be joined diagonally to each
other, the shaded portion forming a slight sloping in front of centre line of back
of shaft.
Fig. 3 is a front view of a moderate sized bladed propeller working more
immediately to its own centre, the two blades working as one.
Fig. 3 is a back view of the same shewing the centre. The diagonally crossed
large plate in the centre represents the counterpart belonging to the shaft, forming
ono body. The plate is screwed on. the four points with bolts to the body of the
propeller, but not through and through. This piece of metal, shown also detached,
will give the shaft additional leverage power on the body of the propeller.
This mode of combining the main shaft to the body of the propellers applies
generally to all my forms of propeller when it can be applied.
Fig. 4 is a two bladed propeller still nearer and in a line of its own centre, acting
with propelling power backwards and forwards of the blades and centre as one
continuous and endless blade vertically.
Figures 5, 5ª, show in front and back view another form of propeller having
longer blades and extended centre and area of travel of blades, and cutting the
water in two half curvilinear semi-circles from a long angle to front of boss at f, to
a long counter angle to the extreme point g, or sloped back end of other blade.
The long curved line shows the long continuous propelling power of the front of the
one blade to the extended and sloped back of the other blade.
Figures 6, 6, shew front and back view of another form. In this form main
blades are shorter, but the curvilinear line of the two halves is considerably longer,
centreing in the axial portion forming the boss, the inside sloping ridge h of one
blade continuing to the end of the other blade, which can be made longer or shorter,

page_text: as desired. The triangular chamber or recess formed by the curved and diagonally
formed blades is shown at i.
Fig. 7 is a front view of a long bladed propeller, the recesses of which are longer
and more diagonal to the centre. In this form and construction the same principle
is used as in the other forms.
Fig. 8 shews a longer curve of the centre part, which enables the two blades to
act nearly as threo.
Figs. 9, 9, shew a propeller having a very neat front and particularly a back
centre junction, and enables the back of the blade to be seen more clearly..
Figures 10, 10%, another form in front and back view, in which the blades are in
a more direct line to the centre, and there is less curve to the recessed triangle.
Fig. 11 is a side view of a two bladed medium sized propeller, showing internal
-portion of recess and the form of the back of the blade, j being the forward blade,
and the receding blade.
Fig. 12 is a full bladed propeller with considerably elongated and more gently
sloped recessed portion of the blades, which gives considerable propelling blade
space to the back of the other blade. A long more concentric propeller shewing
centre and back and portion of the interior of the back of blade.
Fig. 13 shews a four-bladed propeller constructed according to the principle
above enunciated. Fig. 13a is a side view of portion of propeller shewing back of
one of the blades and the centre.
It will be understood that a six-bladed propeller may also be constructed on the
same principles.
Fig. 14 shews two two bladed propellers on the same shaft, one in rear of the
other. Each series of two blades crosses the other and propels the water in two
distinct circles intermediately.
In this Figure k, k, is the second series of blades which are placed quite close
to the front row, and shewn in the receding position with the inside curved
lines of the lower part of the blade; is the forward blade, and l' the receding
blade.
Fig. 15 shews the mode of mounting and working screw propellers, as before.
referred to.
Having now described the nature of my Invention of "Improvements in the
Construction of Screw Propellers, and in the Mode of Mounting and Working tho
same," and explained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent, I claim,-
First. Constructing screw propellers as herein described and shewn in the
Drawings, whereby, owing to the peculiar connection.of the blades with the centre,
great additional propelling power and pitch are obtained.
Second. The mode, substantially as herein shewn and described, of mounting and
working screw propellers.
In witness whereof, I, the said Nicholas Demetrius Spartali, have hereunto
set my hand and seal, the Twenty-sixth day of September, in the year of
our Lord One thousand eight hundred and eighty one.