IMPROVED APPARATUS TO BE EMPLOYED IN PLACE OF PADDLE WHEELS OR ORDINARY STERN PROPELLORS FOR PROPELLING VESSELS
Year: 1855

page_text: LETTERS PATENT to James Lowe, of East Greenwich, in the County of
Kent, Machinist, for the Invention of "IMPROVED APPARATUS TO BE
EMPLOYED IN PLACE OF PADDLE WHEELS OR ORDINARY STERN PROPELLORS FOR
PROPELLING VESSELS."
Sealed the 1st April 1856, by Order of the Lord Chancellor, and dated the
16th June 1855
PROVISIONAL SPECIFICATION left by the said James Lowe at the Office
of the Commissioners of Patents, with his Petition, on the 16th June
1855.
I, JAMES LOWE, of East Greenwich, in the County of Kent, Machinist, do
hereby declare the nature of the said Invention for "IMPROVED APPARATUS TO
BE EMPLOYED IN PLACE OF PADDLE WHEELS OR ORDINARY STERN PROPELLORS FOR
PROPELLING VESSELS" to be as follows:-
My Invention of improvements in propelling vessels relates to improve-*
ments upon
that description of propeller commonly known as screw propellers,
and which are usually placed at or near the stern of the vessel. These pro-
pellers usually consist of two or more wide vanes or blades, mounted on or
attached to a boss, which is keyed on to the propeller shaft. I have discovered,
however, that a considerable portion of the surface of these propellors does
not act properly and effectively on the water, and consequently there is a con-
siderable waste of power.

page_text: The first improvement of the present Invention consists in dividing the
blade or vane of screw propellors. into two or more parts, and placing them in
pairs or sets in or near a line which passes, diagonally across the boss. By
thus dividing the propellor into parts, the second half of the propellor is made
to act more effectually than heretofore, and the choking action incidental to
ordinary stern propellors is obviated, as a portion of the water that has been
acted on by the first section of the propellor is allowed to escape between the
first and second sections, and the latter will then be able to act with greater
effect on the water.
propellors I propose to
When pairs of blades,
My next improvement relates to the form of the
use in carrying out the first part of the Invention.
that is, sets of two blades, are used, the first one of the pair is made slightly
convexed, or bowed, with the edges rounded off, so that they may enter the
water more quietly than if left square. The second blade is, on the contrary,
made slightly concave, so that when the water slips from the first blade on to
the second, the latter will act more effectually than if it were straight or flat,
or made convex like its fellow.
Although I have spoken of pairs of blades, I sometimes propose to have
three or more in a set, and two, three, or four sets may be adapted in a proper
manner to the same boss, which, by preference, I propose to make of an
elliptical shape.
SPECIFICATION filed in pursuance of the conditions of the Letters Patent
and of an Order of the Lord Chancellor, by the said James Lowe in the
Great Seal Patent Office on the 7th April 1856.
AL-
TO ALL TO WHOM THESE PRESENTS. SHALL COME, I, JAMES
Lowe, of East Greenwich, in the County of Kent, Machinist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of June, 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
James Lowe, Her special license that I, the said James Lowe, my exécutors,
administrators, and assigns, or such others as I, the said. James Lowe, 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

page_text: Islands, and Isle of Man, an Invention for "IMPROVED APPARATUS TO BE
EMPLOYED IN PLACE OF PADDLE WHEELS OR. ORDINARY STERN PROPELLORS FOR
PROPELLING VESSELS;" upon the condition (amongst others) that I, the said
James Lowe, by an instrument in writing under my hand and seal; 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 on or before the Eighth day of April, One
thousand eight hundred and fifty-six..
1
NOW KNOW YE, that I, the said James Lowe, .do. hereby declare .the
nature of my said Invention, and in what manner the same. is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed, and. to
the letters and figures marked thereon (that is to say) :-
My Invention of "Improved Apparatus.to be employed in place of Paddle
Wheels or ordinary Stern Propellors for Propelling Vessels" relates to im-
provements upon that description of propellor commonly known as screw
propellors, and which are usually placed at or near the stern of the vessel.
These propellors, usually consist of two or more wide.vanes or blades, mounted
on or attached to a boss, which is keyed on to the propellor.shaft. I have dis-
covered, however, that a considerable portion of the. surface.of. these propellors,
as usually, constructed, does not act: properly and effectively on the water, and
consequently there is, considerable slip: or: waste of power.
The first feature of novelty in my improved apparatus, which constitutes
the present Invention, consists in dividing the blade, or vane of screw propellors
into two or more parts, and placing them in pairs or sets in or near a line
which passes diagonally across the boss. By thus dividing the propellor into
parts,, the second half. of the propelloŕ is made to act more effectually,than
heretofore, and the choking action incidentaluto:ordinary.stern propellors is
obviated, as a portion of the water that has been acted. on by the. first section
of the propellor; is allowed to escape between..the first and second sections,
and, the, lätter will then be able to act:with greater effect on the water. . . .
My next improvement, relates to the form. of the propellor, or rather of the
blade, or vane, which I propose to, use in carrying-out.iny Invention. When
pairs of blades (that is, sets, of two:blades).are used; the first one of the pair
is to be made slightly convex, or bowed, with the front edges chamfered off, so
that it may enter the water more quickly than if left.square.. The second blade
is, on the contrary, made.slightly concave in the direction of its length,.so that
when the water slips from the first blade of a pair on to the second, the latter
will act more effectually. than if it were straight or flat, or made convex like its

page_text: fellow. Although I have spoken of pairs of blades, I sometimes propose to
have three or more in a set, and two, three, or four sets may be adapted in a
proper manner to the same boss, which I intend to make of an elliptical shape.
In order to construct the blades of my propellor so as to give it-the desired
configuration, I proceed in the following manner:-I take a piece of iron,
wood, or other material (see Figs. 1, 2, 3, and 4,) of a size (say, for example;
four inches thick and six feet long,) depending upon the diameter of propellor
required to be made. I begin by first drawing a line x, x, all around the
middle of the edge of the intended blade, as indicated.in the edge views, Figs.
2, 3, and 4. This line forms a guide or gauge of distance up to which the
several cuttings hereafter mentioned are to be carried. Having thus marked
out this line upon the blade, I take a cutting in the direction of the line
11, Fig. 2, and chamfer off the piece marked z, z, up to the centre
line xx, from edge to edge of the blade, and in the direction from left to
right, gradually cutting off a portion of the thickness of the edge of the blade,
Figs. 1 and 4. I then take a cutting in the direction of the line 2. 2;
Fig: 3, (which makes a bevil in the opposite direction to the. last,) that is,
from right to left, and chamfer off the piece y, y, on the same side of the blade
and up to the centre line x, x. After having thus chamfered away the face of
one side of the blade, I turn it over and proceed in like manner upon its other
side in the direction of the lines 3 3, and 4. 4, of Figs. 2 and 3,
the chamfering being as before in opposite directions, thus making the two
faces exactly alike, and with a 'kind of twist on the face. When this has been
done, the back angle of each side or edge of the blade will coincide with the
line 5...
5; I then slightly round off the front edges of the blade; so that
it may enter the water more easily. It will now be seen, on applying a
straight edge" to the face of the blade on the line 6. . . 6 of Fig. 1, that
it's surface is concave; and, on the contrary, when the "straight edge" is.
applied on the line 7. 7 of the same Figure, its surface in that direction
will be convex, forming a curve inwards between the extremes of the lines
6. . . 6, and a curve outwards between the extremes of the line 7 7
By constructing a blade in this manner the angle on the face of the blade is
made to vary gradually between the outer edges and periphery. Fig. 5
represents, in perspective, this mode of constructing the blades.
66
Having described the manner of forming the blades of the propellor, I will
now explain how I place them upon their boss, and also shew the position in.
which they stand with respect to each other when fixed, so as to produce the.
greatest amount of useful effect when in operation.
Fig. 6 is a plan of a propellor having two pairs of blades; Fig: 7 is, a side

page_text: .
elevation, shewing a propellor of this construction applied to the stern of a
boat; and Fig. 8 is an end view of the same. In proceeding to fix these
propellors upon their boss, I first draw a line a, b, diagonally upon the surface
of the boss 'c at an angle of about thirty-three degrees with the axis of the
propellor shaft d. Upon this line a, b, at a suitable distance on either side of a
centre cross line e, f, I mark upon the boss the positions where the respective
blades 9, h, are to be placed, the centre line of the plane of the base of each
blade coinciding with the diagonal line a, b, as shewn at Fig. 6. Having thus
defined the positions of the blades g and h, I turn the boss half a revolution,
and proceed in like manner for determining the position of the other pair of
blades i and k. When three pairs of blades are used, as shewn at Fig. 9,
I of course draw three diagonal lines upon the boss, and proceed. to determine
the positions of the blades in a manner analogous to that above explained.
In Eigs. 10 and 11, I have shewn a propellor wherein the above arrange-
ment of the blades and also the formation of the same are somewhat modified:
In this arrangement I use a curved twisted blade, as shewn; and instead of
fixing them on the diagonal line a, b, as before described, I place them out of
the line, one blade being on one side and its fellow blade on the other side
of such line, as shewn at Fig. 10; the side of each base or root of each pair.
of blades (as shewn in the last-mentioned Fig. 10), instead of the centre of
the plane of the base, as above mentioned with reference to Figs. 6, 7, 8, and
9, being made to coincide with the said diagonal line. By the peculiar con-
figuration given to these blades by reason of their twisted form, an opening
between the blades constituting each pair is formed, through which any sub-
stance likely to obstruct the action of the propellor when in operation can
readily pass; I also chamfer or bevil each side of the edges of the blades, so
that should the vessel be engaged in deadly combat with the enemy, any
broken masts, sailcloth, &c. coming within range of the propellor may be
chopped, cut, or divided by the same, by reason of its sharp or bevilled edges,
and thus be prevented from obstructing its action.
Having now described my Invention of "Improved Apparatus to be em-
ployed in place of Paddle Wheels or ordinary Stern Propellors for Propelling
Vessels," and the manner of carrying the same into effect, I would observe, that
although I have mentioned thirty-three degrees as the angle at which I prefer
to mount the propellors or blade on the boss in reference to the axis of the
shaft, yet I do not intend to confine myself to that particular angle, as it may
doubtless be varied and yet produce a satisfactory effect. The parts which I¸
consider to be new in this improved apparatus, and therefore wish to claim
as the Invention secured to me by Letters Patent, as aforesaid, are,

page_text: First, dividing, the blade or vane of screw propellors into two or more parts,
and placing them in pairs or sets in or near a diagonal line drawn across the
boss, as above described.
.Second, I claim the method above described,.,with reference to Figs. 1 to 5,
whereby the proper formation is given to the propellor blade.
Third, I claim the employment of an elliptical propellor boss in place of the
ordinary bosses now used..
Fourth, I claim constructing and mounting the blades of the propellor in
the manner shewn in Figs. 10 and 11, or any mere modification thereof for
effecting the desired purpose..
In witness whereof, I, the said James Lowe, have hereunto set my hand
and seal, the Seventh day of April, in the year of our Lord One
thousand eight,hundred and fifty-six.
Witness;
شدو
*J. W. MOFFATT,
$66, Chancery Lane..
JAMES LOWE. (L.S.)