AN IMPROVED CONSTRUCTION OF PROPELLER
Year: 1862

page_text: LETTERS PATENT to James Lowe, of Claremont Place, Old Kent Road,
in the County of Surrey, Machinist, and Josiah Harris, of Ess Hill
House, Newton Abbott, in the County of Devon, Gentleman, for the
PROVISIONAL SPECIFICATION left by the said James Lowe and Josiah
Harris at the Office of the Commissioners of Patents, with their
Petition, on the 10th October 1862.
We, JAMES LOWE, of Claremont Place, Old Kent Road, in the County of
Surrey, Machinist, and JOSIAH HARRIS, of Ess Hill House, Newton Abbott,
in the County of Devon, Gentleman, do hereby declare the nature of the
said Invention for "AN IMPROVED CONSTRUCTION OF PROPELLER," to be as
follows:-
The object of this Invention is to economise the power required in driving
propellers. This we propose to effect by so modifying the form of the blades
of that class of propellers known as screw propellers, as to prevent the
churning of the water near the centre of motion. In carrying out our Inven-
tion we shape the blades so that when viewed in edge view and in cross
section instead of forming portions of the thread of a screw they will present a
curved line curling in opposite directions from the centre to the edges. The

page_text: blades may be set at any desired angle; and for convenience we propose to
cast them with the boss, which by preference we make spherical. The pro-
peller may be constructed with two or more blades, and these blades may
taper either to or from the boss.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Lowe and Josiah Harris in the Great Seal Patent
Office on the 10th April 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
Lowe, of Claremont Place, Old Kent Road, in the County of Surrey,
Machinist, and JOSIAH HARRIS, of Ess Hill House, Newton Abbott, in the
County of Devon, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent bearing date the Tenth day of October, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said James Lowe and Josiah Harris, Her special license that we,
the said James Lowe and Josiah Harris, our executors, administrators,
and assigns, or such others as we, the said James Lowe and Josiah
Harris, our 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, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED CON-
STRUCTION OF PROPELLER," upon the condition (amongst others) that we, the
said James Lowe and Josiah Harris, by an instrument in writing under our
hands and seals, or under the hand and seal of one of us, 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.
NOW KNOW YE, that we, the said James Lowe and Josiah Harris, do
hereby declare the nature of our said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Drawing here-
unto annexed, and to the letters and figures marked thereon (that is to
say):-

page_text: The object of this Invention is to economize the power applied to the
driving of ships' propellers. This result we obtain by so modifying the form of
the blades of that class of propellers known as screw propellers, in contra-
distinction to paddle wheel propellers, as to prevent the churning of the water
near the centre of motion, and at the same time to effect a reduction of the
"slip" of the propeller and of the vibration of the propeller shaft. In carrying
.out our Invention we use two, three, or more radial blades, and these blades
we shape so that when viewed edgewise or endwise instead of forming portions
of the thread of a screw they will present a curved line curling in opposite
directions from the centre to the edges of the blade.
In the accompanying Drawing Fig. 1 shews in side elevation, and Fig. 2 in
plan view, a two-bladed propeller constructed according to our Invention.
The blades a, a, are cast in one with the boss b which is solid, and by
preference of a spherical form. The blades in this instance taper laterally
outwards from the boss, and in thickness they also have a slight taper to
ensure sufficient strength to the blades at their root. Fig. 3 shews the
improved construction of propeller applied to a steam ship. The amount and
character of convexity which we give to the opposite faces of the blades will
be clearly seen by inspecting Figures 1 and 2.
The manner in which we obtain the right curvature for blades of different
sizes and proportions is the following:-Taking the extreme breadth of blade
required we divide that measurement into four, and use the measurement thus
obtained for forming four cubes of wood of a length equal or somewhat
superior to the length of the blade required. These long cubes we string on
to a rod, as shewn in the perspective view Fig. 4, and we then set them side
by side, so that the free end of the leading cube will be in advance of the
adjoining cube to the extent of one half its width, and so on throughout the
series (see the plan view Fig. 4*). Having secured the cubes in this position
we cut away the projecting angles, trimming down the cubes until an even
surface is obtained, as shewn at Fig. 5. We then hollow out the opposite
faces of the blade, as shewn at Fig. 5*, and thus produce the curved transverse
line curling in opposite directions, as shewn in the propeller blades, Figures 1
and 2.
The Invention is equally applicable to propeller blades tapering inwards
from the boss towards their extremities, the root of the blade being in this
case, as in the former example, the straight part of the blade looking at it in
end view. The opposite edges of the blade will in this as in the first-
described blade have a corresponding curl (in transverse section), as shewn
at Fig. 8.

page_text: Fig. 9 shews a three-bladed propeller, and Fig. 10 a four-bladed propeller,
formed according to our Invention and cast with a spherical boss.
Figures 12 and 13 shew in elevation and sectional plan view a mode of
adapting our improved propeller blades to bosses, so as to allow of their angle
being altered to suit different speeds. In this example it will be seen that the
boss 6 is cast with flanges c, to which the blades a are attached by screws with
countersunk heads. Between the blades and the flanges we insert wedge-
shaped plates, as shewn at Figs. 14, which interposed plates according to the
angle of their inclined faces will determine the angle of inclination or set of
the blades.
The tendency of submerged propellers constructed with blades of the form
above described will be to work smoothly in the water, and to drive the water
outwards or away from the boss instead of churning it up, as is frequently the
case with submerged propellers. Our improved propeller it will be readily
seen will work indifferently in opposite directions.
Having now set forth the nature of our Invention of "An Improved Con-
struction of Propeller," and explained the manner of carrying the same into
effect, we wish it to be understood that under the above in part recited Letters
Patent we claim, shaping propeller blades in the manner and for the purpose
above set forth.
In witness whereof, we, the said James Lowe and Josiah Harris, have
hereunto set our hands and seals, the Twenty-seventh day of March,
in the year of our Lord One thousand eight hundred and sixty-three.
JAMES LOUZD
JAMES LOWE
(L.S.)
JOSIAH HARRIS. (L.S.)