IMPROVEMENTS IN PROPELLING SHIPS OR VESSELS
Year: 1876

page_text: LETTERS PATENT to Nicholas Demetrius Spartali, of Liverpool, in the County
of Lancaster, Steam Ship Agent, for the Invention of "IMPROVEMENTS IN
PROPELLING SHIPS OR VESSELS."
led the 12th January 1877, and dated the 15th July 1876.
PROVISIONAL SPECIFICATION left by the said Nicholas Demetrius Spartali
at the Office of the Commissioners of Patents on the 15th July 1876.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool, in the County of Lancaster, Steam
Ship Agent. "IMPROVEMENTS IN PROPELLING SHIPS OR VESSELS."
The present Invention relates to various improvements upon an Invention for
which I obtained Letters Patent, dated 10th September 1875, No. 3180.
In carrying out the present Invention all the propelling blades are made of a
curved form, starting from the boss, and with their faces set at a slight angle to the
boss at the root of the blade, but gradually increasing the angle towards the outer
end. The blades may either consist of a simple curve or of a compound curve, that
is, two or more curves set one upon another, but with their propelling faces at
different angles.
The main blades may have branches fixed on them, and set diagonally (that is, at
an angle) to the face of the main blades, and I sometimes attach to the branch
blades sub-branch blades, which are also set diagonally on the branch blades.
All the blades, whether main blades, branch blades, or sub-branch blades, are
made in curved sections, with their faces set diagonally to each other. The curved
faces may be either flat or slightly concave at their inner ends, and with an
increasing pitch outwards, so as to lay hold of the water.
I find it advantageous to arrange the blades in two sets on opposite sides of the
boss, leaving a considerable space between the two sets of blades, so that each set
may act in solid or undisturbed water.
The boss of the propellor is mounted excentrically on the propellor shaft, and if
twin propellors are used the shafts may be set at a slight angle to the keel or longi-
tudinal axis of the vessel, so that the propellors will not work in the same plane.
I sometimes construct side wheel propellors on the same principle, except that the
paddles or floats are not set at such a sharp angle. The boss to which the paddles
or floats are attached is mounted excentrically on the propellor shaft, as in the other
instance. I find that I obtain a good propelling effect with a less number of floats

page_text: or paddles than heretofore; moreover, side wheel propellors of this kind may, if
desired, be entirely submerged.
In order to increase the depth of the column of displacement I sometimes arrange
two or three propellors, one behind the other, on the same shaft, but all the main
and branch blades must be arranged to work free of each other, and all must work
in free water.
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
15th January 1877.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool, in the County of Lancaster, Steam
Ship Agent. "IMPROVEMENTS IN PROPELLING SHIPS OR VESSELS."
The present Invention relates to various improvements upon an Invention for
which I obtained Letters Patent, dated Tenth September One thousand eight
hundred and seventy-five, No. 3180, and consists in an improved mode of con-
structing the blades and bosses or centres of propellers, whether used as stern or side
wheel propellers.
In carrying out the present Invention all the propelling blades are made of a
curved form, starting from the boss, and with their faces set at a slight angle to the
boss at the root of the blade, but gradually increasing the angle towards the outer
end. The blades may either consist of a simple curve or of a compound curve, that
is to say, two or more curves set one upon another, but with their propelling faces
at different angles.
The main blades may have branches fixed on them, and set diagonally (that
is to say, at an angle) to the face of the main blades, and I sometimes attach to
the branch blades sub-branch blades, which are also set diagonally on the branch
blades.
All the blades, whether main blades, branch blades, or sub-branch blades, are
made in curved sections, with their faces set diagonally to each other. The curved
faces may be either flat or slightly concave at their inner ends, and with an
increasing pitch outwards, so as to lay hold of the water.
I find it advantageous to arrange the blades in two sets on opposite sides of the
boss, having a considerable space between the two sets of blades, so that each set
may act in solid or undisturbed water.
The boss of the propellor is mounted excentrically on the propellor shaft, and if
twin propellors are used the shafts may be set at a slight angle to the keel or longi-
tudinal axis of the vessel, so that the propellors will not work in the same plane.
I sometimes construct side wheel propellors on the same principle, except that the
paddles or floats are not set at such a sharp angle. The boss to which the paddles
or floats are attached is mounted excentrically on the propellor shaft, as in the other
instance. I find that I obtain a good propelling effect with a less number of floats
or paddles than heretofore; moreover, side wheel propellors of this kind may, if
desired, be entirely submerged.
In order to increase the depth of the column of displacement I sometimes arrange
two or three propellors, one behind the other on the same shaft, but all the main
and branch blades must be arranged to work free of each other, and all must work
in free water.
In the accompanying Drawings I have shown various forms of propellors con-
structed according to my present improvements.
Fig. 1 is a front view of a four-bladed double branch propellor.
Fig. 2 is a front view of a propellor with four simple blades, and with what I call
a full centre."
Figures 3 and 4 arc front views of two more four-bladed propellors, the blades of

page_text: Fig. 3 being formed of simple curves from a compact centre, and set at an angle;
the blades of Fig. 4 are constructed with an elbow, the inner part of the blade, or
that nearest the centre, being nearly straight, but at an angle, while the outer part
is formed in a curve, but also set at an angle.
Fig. 5 is a front view of a propellor with four compound blades, that is to say,
with branch blades, the main blades being attached to a full sloped centre.
Fig. 6 is a front view of another four-bladed propellor with branch blades, the
main blades being attached to an enlarged centre.
Fig. 7 represents a somewhat similar propellor, but with the branch blades set
lower down the back of the main blades.
Fig. 8 is another form of four-bladed propellor, but with larger branch blades and
short main blades.
Fig. 9 is a front view of a four-bladed propellor with two branch blades on each
rudimentary main blade.
Figures 10 and 10 are front and edge views of a two-bladed propellor with a
peculiar form of blade.
Fig. 11 represents another two-bladed propellor having blades with a double pitch
at a small angle.
Fig. 12 is another two-bladed propellor with blades at a small angle.
Figures 13 and 13ª are front and edge views of another form of two-bladed
propellor.
Fig. 14 is an end elevation, and Fig. 14ª a perspective view of a two-bladed pro-
pellor with fully developed blades.
Fig. 15 is a perspective view of a propellor with a series of screw blades working
in a line to the depth of the vessel's stern, the blades being constructed very much
in the form shewn at Fig. 14ª.
Fig. 16 is an elevation of a multi-bladed propellor with an excentric centre or
boss.
Fig. 17 is a front view of a two-bladed propellor, and Fig. 17a is a perspective
back view of the same, shewing the junction of the blades with the shaft; Fig. 17b
is another view of the same, shewing the back centre shaft.
Figures 18 and 18° are views of another two-bladed propellor, the latter Figure
showing the junction of the blades with the centre shaft.
Figures 19 and 19ª are front and side views of another two-bladed propellor, the
blades being of full pitch and set at a small angle diagonal to the centre.
Fig. 20 is an end view of a two-bladed propellor in which the rudimentary part
of the blade is curved and carried back to the rear of the rudimentary part of the
other blade.
Fig. 21 is a two-bladed propellor in which the rudimentary part of the blade is
carried in a diagonal direction to the back of the other blade.
Figures 22 and 22a represent a two-bladed propellor with elongated central part,
one half of the blade being carried round to the rear of the other, the upper part of
the blades being concave.
Fig. 23 is a two-bladed propellor with concave blades, and in which one half of
the centre of the propellor works diagonally to the back of the other half.
Fig. 24 is a two-bladed propellor with an elongated centre, the centre forming
part of the blade, the curve being continued to the concave upper part of the blade.
Fig. 24ª is another two-bladed propellor with concave blades and an elongated
centre, one half of which is carried to the back of the other half in a long diagonal
line; Fig. 24b is a back view of the same, showing the junction of the blades with
the shaft.
Fig. 25 is a front view, and Fig. 25 a back perspective view of a double-bladed
propellor with branches all starting from one centre.
Fig. 26 represents a two-bladed propellor with double branches.
Fig. 27 is a four-bladed propellor, the rudimentary or lower part of the blades
having a large slope and being wider than the upper, and having concave upper
blades with or without branch blades,

page_text: Fig. 28 is a front view of a multi-bladed propellor having a large excentrical
centre.
Fig. 29 is a four-bladed propellor with enlarged diagonal centre, short main blades,
and long concave branch blades.
Fig. 30 is a front view of a massive four-bladed propellor with large diagonal
centre and large concave branch blades.
Fig. 31 is a front view of a simple four-bladed propellor with enlarged disunited
centre, and showing full balanced curved blades; this propellor may be used either
with or without branches.
Fig. 32 represents a four-bladed propellor with an ordinary spherical boss, the
blades being at the same angle as the diagonal centres, and being provided with
branch blades, and showing how the latter can be adapted to ordinary propellors.
Fig. 33 represents a propellor which can be used either as a stern or side pro-
pellor, and consists of a series of rudimentary blades on an excentric centre.
Figures 34 and 35 represent multi-bladed propellors mounted on excentric centres,
and having concave blades and branch blades.
Fig. 36 is a front view of a two-bladed propellor with a diagonal centre or
boss.
Fig. 37 is a perspective view of a four-bladed propellor divided into two parts
in a diagonal direction across; by constructing the propellor in this manner I
obtain an uniform angle of pitch of blades.
Figures 38 and 38a are back and front views of a blade constructed with parts
at different angles but continuous pitch.
Fig. 39 is similar in character to Fig. 38, but with wider blades and fuller pitch.
Fig. 40 represents a double pitched single blade of greater width and fuller pitch; 2
it may be used either with or without branch blades.
Fig. 41 is a similar view to Fig. 40, but it has a smaller lower blade and larger
upper full pitched concave blade.
Fig. 42 represents a three pitched blade with double branch blades.
Fig. 43 is a view of a two-bladed propellor with much fuller and deeper pitched 3
blades; it is much deeper, stronger, and more effective than some of the other
propellors.
Fig. 44 is a modification of Fig. 42, and is a preferable form of propellor.
Fig. 45 is a two-bladed propellor with a long centre and crescent-shaped blades.
Fig. 46 is a modification of the same with a long centre, but with a finer pitch of 3
blade.
In these my latest propellors I still maintain the principle of obtaining my centre
by placing the blades across each other at the edge of their breadth at the base for
each two-bladed propellor, but at a more or less inclination of angle, according to
the greater or less pitch that I intend to give to the blades, a very slight difference 4
in the angle of the base which forms the centre causing a much more rapid increase
or diminution of the inclination of the blades or their pitch to similar centres. I
also obtain (by two sections or picces of metal similarly placed to each other) a boss
or centre for the blades, or for forming their rudimentary blades.
The propellor may be either forged or cast, and the centre between the two blades 4
more or less clongated, in some cases forming a long neck between them divided
into two equal parts, and with the shaft running to the immediate back of their
junction, where the metal is thickest, as shewn in Figures 17, 18, and 24.
The centre of the new four-bladed propellor is formed by similarly placing two
pairs of blades to each other (such as the two-bladed propellor) at more or less angle 5
at the diagonal connection of their respective base, or pieces, or sections of metal,
forming twoseparate pairs of triangles more or less thick, which are cut in their
centre diagonally and connected or joined to each other, the one pair crossing the
other diagonally, and the one half diagonal section forming exactly the counterpart
of the other half, by which combination I obtain a more distended or elongated 5
centre or rudiments for the blades, as shewn at Figures 37 and 31, in which the
blades are made much wider at the lower than the upper parts, but gradually

page_text: tapering. By such combination of centres I also obtain an uniform and very gradual
inclination of the blades to the centre, reducing their pitch to as low as from five
degrees to ten degrees at the base, and increasing gradually to forty degrees or
forty-five degrees at their maximum position during their revolution round the axis
diagonally across, such blades and centres also working more or less excentrically
round the axis, more so in the case of the multi-bladed propellors, Figures 16, 28,
33, 34, and 35, increasing or reducing the pitch according to the connecting angles
of their base at the centre.
I construct my blades either straight or more or less curved, and more or less
concave, or wider or narrower, as shewn in the Drawings, according to the power
required or the form of the vessel, and according to the more or less speed and
power of the propelling engine.
The propellors cut and displace the water as from extreme left to extreme right
in long oval slices, the half of the centre acting exactly and at sharp opposite
curves to each other (as shewn at Figures 1 to 9), and still more so in the case of
the multi-bladed propellors previously referred to.
The branch blades which are added to the main blades are constructed longer or
shorter, wider or narrower, straight or more or less curved, and more or less concave,
as may be found necessary.
In some cases the lower blades are made shorter and the branch blades longer, or
vice versa; or a second series of branch blades are added to the first, or to the back,
or to the front of the main blades, or to their lower or upper part, these being
always placed diagonally across the edge of the main blades, and similarly the sub-
branches to the main branches. The construction and strength of these parts are
seen in Figures 30, 9, 8, 7, 6, 42, 25, 25ª, and 20.
.
I also sometimes construct the blade in such a manner as to represent two, three,
or more sections, each section of the blade beginning at the back corner of the one
below vertically and diagonally, so that where the pitch of one section ends, that of
the other begins, each blade thus forming a continuous pitch, and displacing the
water in a mass continuously and without resistance. Such sections of blade at
different angles form a kind of continuous negative pitch compared to full bladed
propeller, presenting its broadside to the water at an angle of forty-five degrees, as
per sectional view, Fig. 37.
The blades as a rule are constructed narrower and longer than the present pro-
pellors in use, and together with their branch connections and their long excentrical
travel to the back and the side of the axis, and by their large sub-divided spread of
propelling surface and gradually developing pitch at a minimum resistance to the
water, their work becomes equivalent to that of large blades, less their mass and
friction. The mass of water displaced by them being increased considerably
relatively to the mass of revolving metal in the same area, causes a free expulsion
of the water from the ship's stern and from between the propelling blades, and
reduces to a minimum the drag caused by the massiveness of the present propellors.
Fig. 15b represents a propellor with branches working to the length of the vessel's
stern in a series of two or more bladed propellors, with or without branches suc-
ceeding each other, and working in a line to the rear of the vessel's stern. The
shaft continues its connection lengthways, the shaft itself forming the boss, or in
connection with a cylindrical boss or passing through it, the blades always being
placed diagonally to each other and in such a line that one set of blades catches the
water which is uncovered by the other. This propellor is otherwise constructed on
the general principles described in this Specification, and shewn at Figures 15 and
15b, but in the style of an archimedean screw.
In fact, any of my various propellors (represented in the Drawings) if placed onc
to the rear of the other, but at such distances apart and in such curves as to allow
a clear run for the water to the rear without the one fouling the water of the other,
may serve for the same purpose.
I also make use of the same principles of centre and position of blades in respect
to centre, such as ny four or more bladed propellors, for the construction of side

page_text: wheels of vessels, such propellors being made to work either under water or
partially submerged as ordinary paddle wheels constructed after the manner of
Figure 35.
It will be seen from the foregoing explanation of my various improvements in
propelling ships or vessels that the essential points of novelty are,-
The enlargement of the centres of the propellors and spreading out and sub-
dividing the propelling surface by reason of the position of the blades in regard to
the centre.
There is also a more gradual and imperceptible increasing pitch on the travel of
the blade, which pitch is reduced to as low as from five to ten degrees at their base
towards the centres.
An important point is also the better arrangement and construction of the branch
blades and their mode of adaptation to the main blades at different positions.
Moreover, by the peculiar construction of the blades in the manner described a
continuous pitch in the blade is obtained.
It will also be seen that a considerable increase of water area in relation to the
propelling surface is obtained, and also a considerable reduction of the mass of metal
revolving in the same area, as compared with the propellors now in use.
The resistance and friction of the revolving blades and branches to the water is
reduced to a minimum.
The heavy drag caused hitherto by the massive propellors now in use is also
reduced.
A considerable reduction of the engine power required to drive my improved pro-
pellors is also effected, as compared to the amount of effective work of propulsion
obtained from them.
Lightness of construction combined with strength and efficiency is also obtained
by means of my improvements.
From the nature and construction of my improved propellors they are eminently
suited for being used as side wheels, and may be worked under water or partially
submerged like ordinary paddle wheels. For the same reasons the improved pro-
pellers are capable of being used and adopted as propellors in the style of an
archimedean screw.
I would observe in conclusion that my improved propellors are also and above all
peculiarly adapted for and intended to be used as twin screws, one on each side of
the stern and keel, and they are to be placed in such a manner and at such a
distance from each other as is found requisite for the discharge of the aggregato
diagonal displacement of the water from each side of the ship's stern, it being
important that this displacement should be effected in as combined, collective, and
central a column as possible, so that a rapid and constant flow of such displaced
column of water to the rear of the ship should be obtained. To effect this object
properly the two twin propellors must be brought nearer to the centre of the stern
than is usually the case with the present twin screws now in use.
Having now described my Invention of "Improvements in Propelling Ships or
Vessels," and having explained the manner of carrying the same into effect, I would
observe in conclusion that what I claim as the Invention secured to me by Letters
Patent is, constructing propellers for propelling ships or vessels in the manner
above set forth, so that the blades will act more effectively on the water, as above
described.
In witness whereof, I, the said Nicholas Demetrius Spartali, have hereunto set
my hand and seal, the Tenth day of January, in the year of our Lord One
thousand eight hundred and coventry cavon