IMPROVEMENTS IN THE CONSTRUCTION OF PROPELLERS FOR NAVIGABLE VESSELS AND IN THE MODE OF MOUNTING AND WORKING THE SAME
Year: 1883

page_text: LETTERS PATENT to Nicholas Demetrius Spartali of Liverpool, in the County
of Lancaster for an Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
PROPELLERS FOR NAVIGABLE VESSELS 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 May 1883.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool in the County of Lancaster
"IMPROVEMENTS IN THE CONSTRUCTION OF PROPELLO[E] RS FOR NAVIGABLE VESSELS
AND IN THE MODE OF MOUNTING AND WORKING THE SAME
"
My present Invention relates to a further developement of and improvements in
the construction of the propellers described in the Specifications of former Letters
Patent granted to me, namely, N° 3180 A.D. 1875; N° 2906 A.D. 1876; N° 1670
A.D. 1879; N° 1359 A.D. 1881.-In N° 1359 A.D. 1881 in Figures 1, 7 and 8 I
have described, as will be seen on reference, a novel form of propeller apparently
having two blades but forming with the centre web three propelling sections, the
curvilinear centre plate, or section forming the stand, or base of the two arms
forming the blades on each side of the centre plate, or section all being cast in one
solid piece, the centre section being set on a gently increasing angle, or curve to
the centre. The form of the rear end view of the propeller is that of a figure.
It will be seen that the centre section connecting the two arms or blades will
present a surface of a gradual incline to the water in its rotation, acting as a
powerful propeller in the centre water, which part is in common screw propellors
taken up by the boss and propeller shaft. I also mention in the specification of
Patent No 1359 A.D. 1881. that I propose to construct propellors of double, treble,
or multiple form by connecting two, or more propellers described as above together,
either by joining the second portion of the multiple propeller ou to the rear end
Prine 1021

page_text: of the first portion and so on, or by connecting the portions diagonally. Thus the
former forms a multiple propeller round the whole circumference of the shaft
whilst the latter forms a inultiple propeller of diagonally consecutively arranged
portions. When constructed following each other round the whole circumference
of the shaft, the ends of the centre section plates were flanged up and connected
one to the other by bolts, or rivets a similar device being used for connecting the
propellers when set diagonally one across the other.
Now in carrying out the construction of propellers as above described and the
mode of connecting the one to the other I find that the arrangement is inexpedient
for such narrow sections and that by lengthening the supporting centre plate
section and by widening the blades on the same principle, namely by adding to
the centre section in gradually increasing curvilinear lines both to its length and
breadth and by correspondingly adding to the breadth of the blades in similar
long curvilinear lines and by continuing the lengthening and widening, the outer
diameter of the centre plate developes into a fish-tail shape and its diameter at
this point is double, or treble to that of the leading end and the lines of this
gradually extended breadth of the centre plate and blades appear to cross each
other By this mode of construction a great mass and weight of metal which
would have to be added in joining narrow widths as before described is avoided,
whilst I add considerably to the useful propelling surface all round, the enlarged
propeller representing four, or more blades as if the two set of blades forming the
four crossed bladed ordinary screw propeller where by a fine combination of
curvilinear lines made to meet the lines of the other two and to act as two blades
instead of four covering the twin spaces with their finely developed curved lines.
One such enlarged section would act as a powerful propeller of small diameter, but
with an enormous displacement of water. I further add one, or more such lengths
in sections similarly constructed to each other either in similar consecutive con-
struction as in one solid structure, or casting, or I join such enlarged sections one
to the other in the manner proposed for the single narrow widths, or by dovetailing
the one to the other horizontally, or diagonally. Thus by this mode of construction
of continuous, or cross line of connection and with continuous varying pitch all
round the propeller, the length and breadth of a propeller becomes practically
unlimited and a matter of convenience to suit the relative power of the engines.
Thus my present Invention consists in the developement and enlargement of the
principle of construction of the types of screw propellers as above mentioned,
namely propellers constructed of three sections thus
section in plan
I form the centre
thus the surface being curvilinear, or set with a pitch with
the horizontal axis, the leading end of the central section being narrow and the
section expanding out as it extends aft in the form of a fish tail, this extension
being considerably greater than shown in my former specifications
The blades, namely the outer sections, are two in number and spring one upwards
and the other downwards from the edges of the centre section each blade is a
simple plate having a parabolic diagonal curve more, or less. Thus these parabolic
plate blades make a continuously increasing angle with the centre section, or plate
by reason of the centre section, or plate having a varying pitch, or twist on its
horizontal axis and thus a front section of the propeller will be
the rear, or aft section will be
4 shaped and
shaped. By this construction the
centre section is itself a propeller and with the outer sections, or blades forms a
powerful propeller of small diameter with maximum surface

page_text: To construct the propeller of double, treble, or multiple form I prolong the
centre sections, or plate, continuing its pitch, or twist and gradually enlarging its
diameter into a gentle developing gradually increasing ogivel shaped surface in
such a manner that such slight increase in the width of the surface of the centre
section adds to the slope of the succeeding centre section, or plate which is
connected to it either by ribs, or as a plain continuation, the blades maintaining
their individual parabolic curve and joining at their front, or leading edge to the
rear, or aft edge of each preceding blade, or the blades and centre section are set
slightly apart so as to leave a waterway between them.
The whole propeller may be formed in one piece and forms a continuous multiple
propeller having an uninterrupted continuation of the diagonal curves of the
centre section. By this construction the objections to the obstructive connections
and weight on my former methods of forming the multiple propeller are obviated
and by thus constructing the propellers in multiple each has a lead on the pitch
of the other and at each point where one propeller developes into the next there
are formed gentle sloping waved recesses or set backs. The blades towards the
rear, or aft end diminish in length as the diameter of the centre section increases
so forming semi hollow gently sloping recesses, it is in this line of curvilinear
recesses and increasing outward spread of the blades the water is caught and
carried. Thus in continuing the centre section if it is carried out far enough the
diameter at the leading and narrow end will be crossed by the diameter of the
rear, or broad ends.
For large size propellers the diameter of the centre plate can be widened
rapidly so as to obtain readily large spans and longer blades, or so to speak a
rapidly increasing propelling area. In the case of small propellers starting with a
width of centre section of two to three inches at the shaft end I obtain a length of
propellor from four to six inches long with five to six inches of diameter of rear
end of centre section with a very large propelling space and a long line of
propelling surface working in free centre water, I also obtain from a five, or six
inch width of centre section at the shaft, or front end and a diameter of ten to
twelve inches at the rear, or aft end of centre section a line of blades fifteen to
eighteen inches long capable of displacing an enormous volume of water.
The leading end of the propeller next to the stern of the ship where the diameter
of the centre section is the smallest is made of a greatly increased thickness of
metal in proportion to the other part of its length and forins the boss for the shaft
and fills up the inside hollow space the blades and the centre plate. This thickness
is carried for a length of a third, or fourth of the centre section and forms the
strongest part of the whole structure. The thickness is mostly concealed in the
inward part of the propeller, but is partially continued on the outside of the
propeller & the whole length of the propeller is made sufficiently thick in
proportion The surface of the blades and of the whole propeller is inade quite
smooth and the edges fine to cut through the water and the back of the blades
and of the centre section and of the whole propeller is likewise made smooth and
the blade and centre sections are slightly rimmed internally and much more so
externally for strength and for gripping the water; the propelling action con-
tinuing to a great extent to the back as well as to the internal part of of each
half section diagonally to the axis The Bulk and thickness of the whole propeller
will be reduced to the greatest extent the casting or castings being made of the
finest metal capable of a tensile strain of fifteen or twenty tons to the square inch
or more if required. The back of the propeller being so smooth it will be quite as
effective in the reversing or backward movements of the ship as almost in its
forward action.
The propeller is constructed as if it were made in two parts joined along the
centre of the centre section plate and the joint lapped diagonally, so that the
thickness merges gradually into each side of the centre section plate this lap forms
the boss for the shaft and is made partly hollow in its thickest and widest part
that is at its leading end

page_text: The outside width of the front of the propeller in the centre for the boss and
shaft for a propeller of twelve or fourteen inches centre and ten to twelve inch
blades is only about five to six inches, in fact viewed from this point it only
presents a thin edge to the water and if viewed from the rear end this edge is
further reduced to a very thin line and therefore the immense drag of the common
four bladed propeller is done away with I form the end of the shaft either of
square or round section and onto the end of the shaft I fit a boss corresponding in
form to the end of the propeller
The shaft is composed of two parts One part is formed square or cone shaped of
corresponding thickness to the internal hollow space formed by the boss and centre
of centre section and is firmly inserted and bolted into it and to the back of the
boss by a corresponding slab of metal of sufficient thickness and breadth to cover
the whole breadth of the said back and corresponding in shape and of sufficient
length to secure a firm hold in its whole diameter This covering piece is formed
in one with the part inserted into the internal hollow space, or tunnel and forms a
counterpart of the back of the boss and centre section and is firmly bolted into
Baid back on its four sides corresponding to the outward shape of the back of
the propeller close to the ships stern Onto said outward back and in direct line
with the part internally bolted is formed a tube of sufficient thickness and diameter
for the insertion of the main shaft in connection with the engines the form of
which may be diagonal or partly square and partly round or set at an angle at its
base to the centre As a modification of the method described for fitting the shaft
I dispense entirely with the internal tube or tunnel and fit the same externally
to the back of the solid boss and form the described externally bolted counter boss
as part of the base of the shaft itself the hollow space being formed partly onto
the thickness of the boss internally and partly onto the outward back and insert
this thick square or diagonal (oblique) base of the shaft into this reduced hollow
space and continue the line of the shaft in a gradual taper to the bearing or to
the stern bush thus avoiding weight and bulk of metal
The space at present available in Steamships between the stern post and the
rudder post is ample for a propeller of my construction and can be made of
sufficient size and width ample propelling surface to displace an enormous volume of
free centre water in the immediate wake of the ships stern in the space of the
shaft and the large boss and unprofitable portion of the blades of present four
bladed propellers but for great length of propeller sections this tunnelled space can
be made longer and a portion of it carried more into the space of the under part of
the stern in a line with the keel and between the keel and the ends of the speed
lines and that part of the upper stern made a little wider or less tapering so as to
offer ample floor space in between the upper tween decks above the water line to
work the engines in a line with the propeller shaft when fitted outside the ships
stern, with the shafting supported on substantial bearings fixed to the outside under
part of the stern or onto the vessels run lines and a counter bearing fixed onto the
stern post made to support a short length of shaft fitted into the outward end of
the propeller which is necessary for such long propellers in all cases for support and
steadiness of working
This latter plan of working moderate size propellers of this construction under
the ships run within an open tunneled space on the line of the keel and worked in
bearings outside the ships stern and by engines from above in a line with the stern
deck I deem particularly adapted for sailing vessels using the same as auxilliary
power in cases of becalmed weather or contrary winds and particularly useful to
enable sailing vessels to navigate the Red Sea through the Suez Canal

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 24th November 1883.
NICHOLAS DEMETRIUS SPARTALI, of Liverpool, in the County of Lancaster
"IMPROVEMENTS IN THE CONSTRUCTION OF PROPELLERS FOR NAVIGABLE VESSELS
AND IN THE MODE OF MOUNTING AND WORKING THE SAME
"
My present Invention relates to a further development of and improvements in
the construction of the propellers described in the Specifications of former Letters
Patent granted to me, namely N° 3180 A.D 1875.-N° 2906 A.D. 1876 N° 1670
A.D. 1879 N° 1359 A.D. 1881. In N° 1359 A.D 1881 in Figures 1. 7 and 8, I
have described, as will be seen on reference a novel form of propeller apparently
having two blades, but forming with the centre web three propelling sections, the
curvilinear centre plate, or section forming the stand, or base of the two arms
forming the blades on each side of the centre plate, or section, all being cast in one
solid piece, the centre section being set on a gently increasing angle, or curve to the
centre. The form of the rear end view of the propeller is that of a
S
figure
It will be seen that the centre section connecting the two sets of arms, or blades
will present a surface of a gradual incline to the water in its rotation, acting as a
powerful propeller in the centre water, which part is in common propellers taken
up by the boss and propeller shaft. I also mention in the Specification of Patent
N° 1359 A.D 1881 that I propose to construct propellers of double, treble, or
multiple form by connecting two, or more propellers described as above together,
either by joining the second portion of the multiple propeller onto the rear end of
the first portion and so on, or by connecting the portions diagonally. Thus the
former forms a multiple propeller round the whole circumference of the shaft,
whilst the latter forms a multiple propeller of diagonally consecutively arranged
portions. When constructed following each other round the whole circumference
of the shaft, the ends of the centre section plates were flanged up and connected
one to the other by bolts, or rivets, a similar device being used for connecting the
propellers when set diagonally one across the other.
The following is a description of the improvements in the construction of
propellers for navigable vessels and in the mode of mounting and working the
same, which constitute this my present Invention, reference being had to the
accompanying sheets of Drawings and to the letters and figures of reference
marked thereon, like letters and figures being used to denote the same, or
corresponding parts throughout the various figures of the Drawings.

page_text: Figure 10 shows another method of attaching the propeller to the propeller
shaft
Figure 11 shows the after end of a ship with a propeller according to my
Invention fitted thereto
Now in carrying out the construction of propellers as above described and the
mode of connecting the one to the other, I find that the arrangement is inexpedient
for such narrow sections and that by lengthening the supporting centre plate
section and by widening the blades on the same principle, namely by adding to
the centre section in gradually increasing curvilinear lines both to its length and
breadth and by correspondingly adding to the breadth of the blades in similar
long curvilinear lines and by continuing the lengthening and widening until the
outer diameter of the centre plate developes into a fish tail shape and its diameter,
which at this point is double, or treble to that of the leading end, that is the lines
of this gradually extended breadth of the centre plate and blades appear to cross
each other. By this mode of construction a great mass and weight of metal,
which would have to be added in joining narrow widths as before described is
avoided whilst I add considerably to the useful propelling surface all round, the
enlarged propeller representing an equivalent to four, or more blades as if the two
sets of blades forming the four crossed bladed ordinary propeller where by a fine
combination of curvilinear lines and cross lines made to meet the lines of the other
two, and to act as two blades instead of four covering the twin spaces with their
finely developed curved lines. One such enlarged section would act as a powerful
propeller of small diameter but with an enormous displacement of water.
further add one, or more such lengths in sections similarly constructed to each
other either in similar consecutive construction as in one solid structure, or casting,
or I join such enlarged sections one to the other in the manner proposed for the
single narrow widths, or by dovetailing the one to the other horizontally, or
diagonally. Thus by this mode of construction of continuous or cross line of
connection and with continuous varying pitch all round the propeller the lengtlı
and breadth of the propeller becomes practically unlimited and a matter of
convenience to suit the relative power of the engines. Thus my present Invention
consists in the development and enlargement of the principle of construction of the
types of screw propellers as above mentioned, namely propellers constructed of
three sections thus
S.
I form the centre section in plan
I
the surface being
curvilinear, or set with a pitch with the horizontal axis, the leading end of the
central section being narrow and the section expanding out as it extends aft in
the form of a fish tail, this extension being considerably greater than shown in my
former Specifications.
The form of the propeller will be understood upon reference to Figures 1 to 5
inclusive, the blades A namely the outer sections are two in number and spring
one upwards and the other downwards. from the edges of the centre section C.
Each blade A is a simple plate having a parabolic diagonal curve more, or less
where it joins the centre plate C Thus these plate blades A make a continuously
increasing angle with the centre section, or plate C by reason of the centre section,
or plate C having a varying pitch, or twist on its horizontal axis.
By this
construction the centre section is itself a propeller and with the outer sections,
or blades A forms a powerful propeller of small diameter with maximum surface.
To construct the propeller of double, treble, or multiple form I prolong the centre
section, or plate C continuing its pitch, or twist and gradually enlarging its
diameter (by adding the sections C₁ C³) into a gentle developing gradually
increasing curved surface in such a manner that the increase in the width of the
centre section C adds to the slope of the succeeding centre section C¹ which is
connected to it either by ribs or as a plain continuation. The blades A are also
continued by adding the blades A¹ A³ to join onto the sections C¹ C and maintain

page_text: their individual parabolic curve and joining at their front, or leading edge to the
rear, or aft edge of each preceding blade. If desired the blades A A' A' may be
set slightly apart so as to leave a waterway between them.
The whole propeller may be formed in one piece and forms a continuous multiple
propeller having an uninterrupted continuation of the diagonal curves of the centre
section. By this construction, the objections to the obstructive connections and
weight on my former methods of forming the multiple propeller are obviated and
by thus constructing the propellers in multiple each has a lead on the pitch of the
other and at each point where one propeller A developes into the next, there are
formed gentle sloping curved recesses, or set backs. The blades twoards the rear,
or aft end diminish in length as the diameter of the centre section increases so
forming semi hollow gently sloping recesses, it is in this line of curvilinear recesses
and increasing outward spread of the blades the water is caught and carried in a
mass. Thus in continuing the centre section if it is carried out far enough the
diameter at the leading and narrow end will be crossed by the diameter of the
rear, or broad end.
For large size propellers the diameter of the centre plate can be widened rapidly
so as to obtain readily large spans and longer blades, or so as to speak a rapidly
increasing propelling area. In the case of a small propeller starting with a width
of centre section of two to three inches at the shaft end, I obtain a length of
propeller from four to six inches long, with five to six inches of diameter of rear
end of centre section with a very large propelling space and a long line of propelling
surface working in free centre water I also obtain from a five, or six inch width
of centre section at the shaft or front end and a diameter of ten to twelve inches
at the rear, or aft end of centre section a line of blades fifteen to eighteen inches
long capable of displacing an enormous volume of water.
The leading end of the propeller next to the stern of the ship where the diameter
of the centre section C is the smallest is made of a greatly increased thickness of
metal in proportion to the other part of its length and forms the boss for the shaft.
This thickness is carried for a length of a third, or fourth of the centre section and.
forms the strongest part of the whole structure. The thickness is mostly concealed
in the inward part of the propeller but is partly continued on the back of the
propeller and the whole length of the propeller is made sufficiently thick in pro-
potion. The surface of the blades A and of the whole propeller is made quite
smooth and the edges fine to cut through the water, and the back of the blades
and of the centre section and of the whole propeller is likewise made smooth and
the blades and centre section are slightly rimmed internally and much more so
externally for strength and for gripping the water, the propelling action continuing
to a great extent to the back, as well as to the internal part of each half section
diagonally to the axis. The bulk and thickness of the whole propeller will be
reduced to the greatest extent, the casting, or castings being made of the finest gun
metal capable of a tensile strain of fifteen, or twenty tons to the square inch, or
more if required. The back of the propeller being so smooth, it will be quite as
effective in the reversing, or backward movements of the ship as almost in its
forward action.
The propeller is constructed as if it were made in two parts joined along the
centre of the centre section plate and the joint lapped diagonally so that the
thickness merges gradually into each side of the centre section plate; this lap
forms the boss for the shaft and is made partly hollow in its thickest and widest
part, that is at its leading end.
The outside width of the front of the propeller in the centre for the boss and
sbaft for a propeller of twelve, or fifteen inches centre and ten to twelve inch blade,
is only about five to six inches, in fact viewed from this point it only presents a
thin edge to the water and if viewed from the rear end, this edge is further reduced
to a very thin line and therefore the immense drag of the common four bladed
propeller is done away with. I form the end of the shaft D either of square, or
round section and onto the end of the shaft D I fit a boss corresponding in form

page_text: to the end of the propeller and bolted to the end of the propeller as shown in
Figure 6. 6ª
Reference to Figures 7 and 8. In this case the shaft is composed of two parts
D D', the part D' is cone shaped and ships into the internal hollow space formed in
the boss and centre of the centre section C and is firmly inserted into the centre
section and the shaft is bolted to the propeller by the collar D2 and bolts as shown.
This collar, or slab of metal D³ may be of sufficient size to cover the whole breadth
of the back of the propeller at the boss and centre section to which it is firmly
bolted.
As a modification of the method shown at Figures 7 and 8 for fitting the shaft,
I dispense entirely with the coned part D' as shown at Figures 9 and 10, and I
bolt the shaft D to the back of the propeller by the collar, or slab D' and I continue
the boss to the end of the centre section C and I add a length of shaft to the
propeller at D³ on the same line as the shaft. This projecting part D³ takes into
an outer bearing on the outer stern post and helps to support the weight of the
propeller.
As another means of connecting the propeller to the shaft D I form the shaft D
with a central slot so that it embraces the propeller in the manner shown at
Figure 10. The centre section C of the propeller coming in the slot in the shaft
and being bolted to the propeller as shown.
The space at present available in steam ships between the stern post and the
rudder post is ample for a propeller constructed according to my Invention and
allows for the propeller being of sufficient size and with ample propelling surface
and able to displace an enormous volume of water in the immediate wake of the
ship, and in the space now occupied by the large boss and unprofitable portion of
the blades of propellers as at present constructed. For great length of propeller
sections the screw aperture of the ship can be made longer (as shown at Figure 11)
and carried more into the under part of the stern in a line with the keel and
between the keel and the end of the run of the ship and the upper portion of the
ships stern can be made a little wider above the water line so that the propeller
can be worked by engines from the deck of the ship by connecting rods F which
work onto the propeller shaft D which is carried on substantial bearings in the
screw aperture, there being a bearing on the stern post and on the rudder post as
shown at Figure 11.
This latter plan of working moderate size propellers of this construction under
the ships run within an open aperture on the line of the keel and worked in
bearings outside the ships stern and by engines from above in a line with the stern
deck, I deem particularly adapted for the use of sailing vessels, or as an auxiliary
power in cases of becalmed weather, or contrary winds and particularly useful to
enable sailing vessels to navigate the Red Sea through the Suez Canal.
Having now described the nature of my Invention of Improvements in the
construction of Propellers for Navigable vessels and in the mode of mounting and
working the same, and explained the manner of carrying the same into effect I
would have it understood that the Drawings Figures 1. 2. 3. 4 and 5 (in which
Figure 1 is an end view and Figure 2 a bird's eye view of a three sectioned
propeller. Figure 3 a birds eye view of a one sectioned small propeller and
Figure 4 an end view of Figure 3 and Figure 5 an end view of a three sectioned
propeller) merely show examples to illustrate the form of my propeller and such
form is capable of extension in its essential parts, namely the angle of the blades A
to the centre section, the pitch and varying width of the centre section and the
number, or extension of the blades A A A and the centre sections C C C as these
can be continued in length to any desired extent.
What I claim under the in part recited Letters Patent is
First Constructing screw propellers as herein described and shown in the
Drawings hereto annexed, whereby owing to the multiple construction of the
propeller great additional propelling power and pitch are obtained, and also any
desired length of propeller in one structure,

page_text: Second Constructing screw propellers as herein described and shown in the
Drawings, whereby owing to the peculiar connection of the blades with the centre
great additional propelling power and pitch are obtained.
Third The mode substantially as herein shown and described of mounting and
working screw propellers.
In Witness whereof, I, the said Nicholas Demetrius Spartali, have hereunto set
my hand and seal this twenty third day of November in the year of our Lord
one thousand eight hundred and eighty three.
NICHOLAS D, SPARTALI (L.S.)