IMPROVEMENTS IN PROPELLERS a
Year: 1859

page_text: LETTERS PATENT to Charles O'Hara, of Toronto, Canada West, but now
residing at No. 4, Upper Seymour Street, Hyde Park, in the County of
Middlesex, Esquire, for the Invention of "IMPROVEMENTS IN PROPELLERS
a
PROVISIONAL. SPECIFICATION left by the said Charles O'Hara at the
Office of the Commissioners of Patents, with his Petition, on the 21st
January 1859.
I, CHARLES O'HARA, of Toronto, Canada West, but now residing at
No. 4, Upper Seymour Street, Hyde Park, in the County of Middlesex,
Esquire, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PROPELLERS FOR PROPELLING STEAMBOATS, SHIPS AND VESSELS," to be
as follows:-
This Invention consists of a new mode of propelling, steam vessels by means
of a propeller constructed in the form of half a right cylinder, having four
surfaces, two semicircular plane surfaces, one semicircular curved surface,
and the impinging surface which strikes the water..
This propeller is placed in a semicircular recess at the. stern of the vessel
in a horizontal position, and is caused to vibrate or move to and fro on a
vertical axis placed at the centre of the impinging surface, and at right angles
to the two semicircular plane surfaces. By this movement each. half of the
impinging surface strikes the water alternately, each half being furnished with
an indentation of an hemispherical form, one half striking the water while the
other half returns to its initial or starting point, the curved semicircular
surface preventing, any reaction.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles O'Hara in the Great Seal Patent Office on the
13th July 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
O'HARA, of Toronto, Canada West; but now residing at No. 4, Upper Seymour
Street, Hyde Park, in the County of Middlesex, Esquire, send greeting.
WHEREAS. Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of January, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Charles O'Hara, Her special licence that I, the said Charles O'Hara,
my executors, administrators, and assigns, or such others as I, the said Charles
O'Hara, 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, 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
PROPELLERS FOR PROPELLING STEAMBOATS, SHIPS, AND VESSELS," upon the con-
dition (amongst others) that I, the said Charles O'Hara, 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.
NOW KNOW YE, that I, the said Charles O'Hara, 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 thereof, reference being had to the accompanying
Drawings, and to the figures and letters marked thereou (that is to say):-
Figure 7 of the Drawings is a perspective view of my propeller, the
external form of which is that of a short solid seini-cylinder, having four
surfaces, viz., two semicircular plane surfaces A and B, a semi-cylindrical
surface C," and a rectangular surface D, 'the latter being made somewhat
concave as shown.::.
:
Figures 8, 9, and 10 show perspective views of the propeller slightly
modified in form; at Figure 8 the back E of the propeller forms an acute
angle; at Figure 9 the area of the top and bottom F and G somewhat

page_text: exceed that of a semicircle; and at Figure 10 those surfaces marked H and
J have a diminished area.
The mode of applying my propeller will be fully understood by referring to
Figures 1, 2, and 3, which are respectively the stern, side elevation, and plan
views of a flat-bottomed vessel suitable for the navigation of canals and very
shallow waters; and I would here remark, it is to vessels for such purposes
that my propeller is more particularly adapted. K is the propeller placed in
a horizontal position, and L is the vertical shaft on which it moves. The pro-
pelling action is as follows:-On motion being given to the propeller, its
rectangular or propelling surface impinges on the water by moving alternately
to and fro on the shaft to the extent shown by the red lines a, b, c, and d, at
Figure 3.
Backward motion may be obtained by reversing the position of the propeller,
so that its propelling surface shall face the stern.
Another mode of application is shown at Figures 4, 5, and 6, which are
respectively stern, side elevation, and plan views of a vessel, showing the
propeller applied in a vertical position working on a horizontal shaft. M is
the propeller; N, the horizontal shaft on which it works. When the propeller
is placed in this position, only one-half of its rectangular surface is submerged,
the necessity for keeping the other above water will be at once apparent. The
red lines f and 9, at Figure 6, show the extent of stroke.
Having thus described the nature of my said Invention, and the manner
of carrying the same into practical effect, I would have it understood that
what I claim is,―
First, the form of propeller for ships or vessels as herein described and
shown at Figure 7 of the Drawings.
Second, the several modifications thereof herein described and shown at
Figures 8, 9, and 10 of the Drawings.
In witness whereof, I, the said Charles O'Hara, have hereunto set my
hand and seal, this Twelfth day of July, in the year of our Lord One
thousand eight hundred and fifty-nine.
CHARLES O'HARA. (L.S.)