IMPROVEMENTS IN APPARatus FOR PROPELLING SHIPS AND OTHER VESSELS
Year: 1861

page_text: LETTERS PATENT to Thomas Seaville Truss, of No. 53, Gracechurch
Street, in the City of London, and of Grove Terrace, Plaistow, in the
County of Essex, Civil Engineer, for the Invention of "IMPROVEMENTS IN
Sealed the 7th June 1861, and dated the 22nd March 1861.
PROVISIONAL SPECIFICATION left by the said Thomas Seaville Truss at
the Office of the Commissioners of Patents, with his Petition, on the
22nd March 1861.
I, THOMAS SEAVILLE TRUSS, of No. 53, Gracechurch Street, in the City of
London, and of Grove Terrace, Plaistow, in the County of Essex, Civil
Engineer, declare the nature of my Invention of "IMPROVEMENTS IN APPARatus
FOR PROPELLING SHIPS AND OTHER VESSELS," to be as follows:-
My said Invention consists of improvements in constructing the blades of
propellers for propelling ships and other vessels, and one of such improvements
consists in constructing the blade of such a propeller so that it shall increase
in pitch or curvature from the fore part of the place at which it is attached
to a boss or shaft to or towards the point or rear end of it, and shall also have
a diametrical curvature, the blade being mounted upon a rotating shaft or axle
(by means of a boss or otherwise), so that the concave face or surface of it
shall act against the water behind a vessel for the purpose of propelling it.
I place these blades upon a shaft or axle at an angle varying from a radial
line drawn from the centre of rotation, so that a line drawn across the concave

page_text: face or surface of cach blade to or towards the centre of rotation of the pro-
peller shall be considerably less than ninety degrees, about forty-five degrees
being, I believe, the best angle.
And another of my said improvements consists in making the blade of a
propeller so that it shall vary in curvature from the fore part of it to the
point or rear, firstly in one direction, and then in an opposite direction, in
what may be called an O. G. line, one part of the face at the fore part being
made convex, and the other part concave. This blade I attach to a shaft or
axle in like manner as the blade firstly above described. Two or more of
either of theso blades may be combined in order to form a propeller, for the
purpose of obtaining increased power or propulsion.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Seaville Truss in the Great Seal Patent Office on
the 21st September 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SEAVILLE TRUSS, of No. 53, Gracechurch Street, in the City of London, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of March, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fourth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Thomas Seaville Truss, Her special licence that I, the
said Thomas Seavillo Truss, my executors, administrators, and assigns, or
such others as I, the said Thomas Seaville Truss, my executors, adminis-
trators, 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, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN APPARATUS POR PROPELLING SHIPS
AND OTHER VESSELS," upon the condition (amongst others) that I, the said
Thomas Seaville Truss, 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 Invention, 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.

page_text: NOW KNOW YE, that I, the said Thomas Seaville Truss, 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 :-
My said Invention consists of improvements in constructing the blades of
propellers for propelling ships and other vessels intended to be used in lieu
of ordinary screw propellers, and one part of such improvement consists,
firstly, in constructing the blade of such a propeller so that it shall increase
in pitch or curvature from the fore part of the place at which it is fixed upon
the boss, shaft, or axle of the propeller to or towards the point or rear end of
it; secondly, in constructing the blade so that it shall have a curvature in a
diametrical direction or across the face of it, and the blade is mounted upon
the shaft or axle of the propeller (by means of a boss or otherwise), so that the
concave or hollow face or surface of it shall act against the water behind the
vessel in which the propeller is mounted for the purpose of propelling it;
and, thirdly, in fixing such a blade or blades upon the shaft or axle of a
propeller at an angle varying from that of a radial line drawn from the centre
of rotation, that is to say, so that a line drawn across or along the concave
face or surface of each blade to or towards the centre of rotation of the pro-
peller shall form an angle with the central line of the axle, which shall be
considerably less than 90 degrees, about 45 degrees being, I believe, the best
angle.
The second part of my said improvements consists in making the blade of
such a propeller as herein-before mentioned so that it shall vary in curvature
from the fore part of it to the point or rear (firstly in one direction, and then
in an opposite direction) in what may be called an O. G. line, one part of the
face at the fore part (the end which is attached to the axle or boss) being
made convex, and the other part concave. This blade I attach to a propeller
shaft or axle in like manner as the blade firstly above described. Two or
more of either of these blades may be combined or fixed on the same shaft
or axlo in order to form a propeller for the purpose of obtaining increased
power or propulsion.
By constructing a propeller according to my Invention I am enabled to
place the greater part or a considerable part of each of the propelling blades
behind the boss upon which it is fixed, for the purpose of increasing the power
of the propeller.
I have in the said Drawings shewn how propeller blades may be constructed
and fixed according to my Invention.
Figure 1 is a perspective view of the boss of a propeller having two blades

page_text: constructed and fixed thereon according to the first part of my Invention.
The boss e has an orifice iu it, so as to be fixed upon a shaft or axle in the
usual way. Each of the blades A increases in pitch or curvature from the
fore part d to the point or rear end f, and also has a diametrical curvature
across the face of it from g to h, the inner surfaces of the blades which act
against the water for the purpose of propelling the vessel forward being
consequently more or less hollow or concave according to the amount of pitch
and curvature. Each of the blades A is fixed upon the bosse at such an
inclination or in such a position that when placed upon the axle or shaft of
the propeller the rear ends project backwards behind the boss and behind a
radial line y, z, drawn from the centre of the axle, and so that a line drawn
across or along the face of the blade from k to or towards a line i, m, along
the centre of rotation forms an angle with a portion of the central line of the
axle, which is considerably less than an angle of 90 degrees.
Figure 2 is a section of Figure 1 taken in the dotted line a, a, shewing the
curvature at o, and Figure 3 is a section of Figure 1, taken in the dotted line
b, b, and shewing the curvature at p.
Propellers made according to my Invention may be considerably varied
in form, each form retaining the properties or modes of construction herein-
before described.
By way of illustration I have shewn varieties in the forms of my propeller
in Figures 4 and 7. Figures 5 and 6 are sections of Figure 4, and Figures 8
and 9 are sections of Figure 7 respectively, taken in like manner as the sections
of Figures 2 and 3. Each of the Figures from 4 to 12 inclusive are marked
with the like letters of reference as Figures 1, 2, and 3, which will render
further description unnecessary.
Figure 10 is a perspective view of the boss of a propeller, having fixed
thereon two blades constructed according to the second part of my Invention.
The boss is similar to that herein-before mentioned. Each of the blades A, B,
is made with a double or O. G. curvature, in lieu of the curvature of blades
made according to the first part of my Invention, the blade being in other
respects constructed and fixed in like manner as the blades of propellers con-
structed according to the first part of my Invention. In each of these blades
the part marked A is curved outwards, and the part marked B is curved
inwards, and the inclination at which each of the blades is fixed upon the
boss is shewn by the lines k, and i, m, and y, z, in like manner as in
Figure 1.
Figure 11 is a section of Figure 10 taken in the dotted line a, a, and
Figure 12 is a section taken in the dotted line b, b, those sections showing

page_text: the curvatures of those parts of the blades respectively through which the
sections are taken.
The propellers which I have described may be made of any suitable
material.
Having now described the nature of my Invention, and in what manner
the same is to be performed, I declare that I claim as of my said
Invention,
First, the construction of rotary propellers with blades increasing in pitch,
and curved and fixed in manner herein-before described.
Secondly, the construction of rotary propellers with double curved blades
increasing in pitch and fixed in manner herein-before described.
In witness whereof, I, the said Thomas Seaville Truss, have hereunto
set my hand and seal, the Twenty-first day of September, in the
year of our Lord One thousand eight hundred and sixty-one.
THOMAS SEAVILLE TRUSS. (L.S.)