IMPROVEMENTS IN THE CONSTRUCTION OF PROPELLERS
Year: 1855

page_text: LETTERS PATENT to William Soelman, of 3, Bennett Street, Fitzroy
Square, in the County of Middlesex, for the Invention of "IMPROVEMENTS
IN THE CONSTRUCTION OF PROPELLERS."
Sealed the 8th February 1856, and dated the 20th August 1855.
PROVISIONAL SPECIFICATION left by the said William Soelman at
the Office of the Commissioners of Patents, with his Petition, on the
20th August 1855.
I, WILLIAM SOELMAN, of 3, Bennett Street, Fitzroy Square, in the County
of Middlesex, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN THE CONSTRUCTION OF PROPELLORS" to be as follows:-
In the construction of my propellers I use two or more blades. I use
principal blades and dwarf blades. A principal blade of my Invention may
be described as having a broad base adjoining the nave, and as having one
or more portions of the other part comparatively narrow. The lateral edges of
the latter part may be either divergent, parallel, or convergent, as in Figures 1
and 2, or they may partake of a combination of two or all three of these forms.
A dwarf blade has also a broad base, but has less height than a principal
blade, as Figure 3. The edges of both principal blades and dwarf blades
may be either curved or straight, or partly curved and partly straight. Two

page_text: blades may be used, but I prefer to use more than two, and these may be
all principal blades, or principal blades combined with dwarf blades.
Figure 4 represents, in perspective, a combination of principal blades and
dwarf blades.
Figure 5 shows, in perspective, a combination of dwarf blades with
blades of a different form. In this Figure the real and apparent dimensions
are shewn.
I prefer that the height of dwarf blades be at least equal to the width of a
superficial ring, the area of which is equal to that of the circle contained within
the periphery of the nave; they may, however, in most cases be made higher
than this. Dwarf blades are applicable to be used in combination with other
blades than those invented by me. The thickness of the nave at the circum-
ference may be about equal to the depth of the blades at the base, or it may
be less than this, as in Figure 6, so as to bring a portion of the blade partly
down the face of the nave.
Figure 7 represents such a blade together with a different modification of
form. Figure 8 represents, in perspective, a propeller with such a nave.
For full power vessels requiring a greater amount of resistance, I apply to
the faces of the blades inclined planes, which may be either fixed or moveable.
In Figures 9, 10, and 11, m, n, indicate examples of such planes. I do not
bind myself strictly to the different forms, proportions, and combinations
described and delineated, as they will admit of modifications, provided that my
intentions therein be not departed from.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Soelman in the Great Seal Patent Office on the 2
20th February 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SOELMAN, of 3, Bennett Street, Fitzroy Square, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 3
Patent, bearing date the Twentieth day of August, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Soelman, Her special licence that I, the said William
Soelman, my executors, administrators, and assigns, or such others as I, the 3

page_text: said William Soelman, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might make,
úse, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN THE CONSTRUCTION OF PROPELLERS," upon the condition (amongst
others) that I, the said William Soelman, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Soelman, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, that is to say:-
In my improvements in the construction of propellers, my object is to save
power by employing a combination of forces, namely, the centripetal force and
the modiolic force. By the latter term I mean the force of the water dis-
placed by the progressive motion of the nave. Either of these may be made
the primary force.
In employing the modiolic as the primary force I prefer a nave of large
diameter, as Figure 3, and A, B, Figure 5. I use principal blades, as Figure 1 ;
and dwarf blades, as Figure 2.
Figure 4 represents on a flat surface the arrangement of the blades at
the base.
Figure 5 represents a combination of principal blades (Figure 1), and
dwarf blades (Figure 2).
When the blades are set at a small angle, as in Figure 5, I increase the
angle of resistance by deflecting a, a, the upper angles of the principal blades,
as in Figure 6. When the blades are set at a large angle a smaller nave may
be substituted. The centripetal then becomes the primary force. With such
nave I use blades either of the form Figure 7, or of that represented in
Figure 9. I make the height of the base of each blade proportionate to the
height of the centripetal current.
Figure 8 represents a combination of four blades of the form Figure 7, set
at an angle of forty-five degrees. They may be set at other angles. Blades
of the form Figure 9 may be employed in the same manner.

page_text: Having now described the nature of my improvements, and in what manner
the same is to be performed, I hereby declare that I claim as my Invention,
propellers constructed and arranged as above described, and illustrated by
reference to the accompanying Drawings.
In witness whereof, I, the said William Soelman, have hereunto set my
hand and seal, this Twentieth day of February, in the year of our Lord
One thousand eight hundred and fifty-six.
WILLIAM SOELMAN. (L.S.)