IMPROVEMENTS IN MARINE PROPELLERS.
Year: 1858

page_text: LETTERS PATENT to James Greenwood, of South Audley Street, Gentle-
man, for the Invention of "IMPROVEMENTS IN MARINE PROPELLERS.
Sealed the 24th December 1858, and dated the 5th July 1858.
PROVISIONAL SPECIFICATION left by the said James Greenwood at
the Office of the Commissioners of Patents, with his Petition, on the
5th July 1858.
I, JAMES GREENWOOD, of South Audley Street, Gentleman, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN MARINE PRO-
PELLERS," to be as follows:-
This Invention relates to the construction and arrangement of floats or float
boards either disposed around a circular wheel of the ordinary form commonly
employed for propelling vessels, or the said floats or float boards may be
applied as propelling surfaces upon arms, or as vanes radiating from a central
axis or shaft, which may be placed in any convenient position in the vessel,
either horizontally at a right angle with the keel line as in the ordinary paddle
wheel on each side of the ship, or in the same manner applied or placed in
the center of the vessel in a suitable well-hole prepared to receive it, or the
axis or shaft may be placed longitudinally in a line with the keel as in the
screw propeller, or transversely at a right angle with the keel line, and at any
suitable incline or angle. The said floats may be constructed of a parellogram
shape upon the face or any other suitable form, and may be constructed of
wood or any other suitable material, and are mounted upon a central axis
upon which or with which they revolve.

page_text: Instead of the two sides or ends being formed square with the back and
front face, considerable bevil is given to them, so that a horizontal section of
the float or float board would present wedge-like terminations, the area of the
surface of the back face being considerably greater than that of the front face,
the bevils being deducted therefrom.
When each float, mounted as described, enters the water, it presents its edge
only, and upon meeting with the resistance the bevilled surface or edge causes
the float to turn or rotate upon its axis, and present the full surface to the
action of the water, whilst as the float is withdrawn it is caused to turn the
fourth of a circle upon its axis, and is thus feathered and presents its edge
again to the line of rotation. This feathering action is ensured by means
of an inclined or curved surface or director, against which some part or
portion of the float or float board, or the axis on which it turns, or of an arm
or othe projection thereupon, is made to come in contact therewith, and is
acted upon thereby.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Greenwood in the Great Seal Patent Office on the
3rd January 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
GREENWOOD, of South Audley Street, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of July, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Greenwood, Her special licence that I, the said James Green-
wood, my executors, administrators, and assigns, or such others as I, the said
James Greenwood, executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times there-
after 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
MARINE PROPELLERS," upon the condition (amongst others) that I, the said
James Greenwood, 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

page_text: to be filed in the Great Seal Patent Office within six calendar months iext
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Greenwood, 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 :-
This Invention relates to the construction and arrangement floats or
float boards, either disposed around a circular wheel of the ordinary form
commonly employed for propelling vessels, or the said floats or float boards may
be applied as propelling surfaces upon arms, or as vanes radiating from a
central axis or shaft, which may be placed in any convenient position in the
vessel, either horizontally at a right angle with the keel line as in the ordinary
paddle on each side of the ship, or in the same manner applied or placed in
the centre of the vessel in a suitable well-hole prepared to receive it, or the
axis or shaft may be placed longitudinally in a line with the keel as in the
screw propeller, or transversely at a right angle with the keel line, and at any
suitable incline or angle. The said floats may be constructed of a parallelo-
gram shape upon the face, or any other suitable form, and may be constructed
of wood or any other suitable material, and are mounted upon a central axis,
upon which or with which they revolve.
Instead of the two sides or ends being formed square with the back and
front face, considerable bevil is given to them, so that a horizontal section of
the float or float board would present wedge-like terminations, the area of
the surface of the back face being considerably greater than that of the front
face (the bevils being deducted therefrom).
When each float mounted as described enters the water, it presents its edge
only, and upon meeting with the resistance, the bevilled surface or edge
causes the float to turn or rotate upon its axis, and present the full surface to
the action of the water, whilst as the float is withdrawn it is caused to turn
the fourth of a circle upon its axis, and is thus feathered, and presents its
edge again to the line of rotation. This feathering action is ensured by
means of an incline or curved surface or director, against which some part or
portion of the float, or float board, or the axis on which it turns, or of an arm
or other projection thereupon, is made to come in contact therewith, and is
acted upon thereby.
I may either substitute a series of the floats as herein described, mounted
upon seperate shafts or spindles radiating from a common centre, and in
number according to the circumference of the wheel, or the circular frame in
which they may be-mounted, as a substitute for the ordinary paddle wheels

page_text: applied in the midship portion of the steam ship; or, I may apply a single
wheel or propeller of the construction herein described, in any convenient
position along the line of the keel, or I may apply more than one such pro-
peller in the length of a vessel. In either case an opening of suitable width and
length to permit of the free revolution of the wheel of the propeller within it
must be provided, and a trunk or well-hole formed within the vessel to a line
above the load-water line; free ingress and egress for the water must be
insured by so shaping or forming the entrance and exit of the chamber or
opening in which the propeller works.
Propellers constructed according to this Invention and applied as last described,
may work or operate as submerge propellers, but where they can be applied
in the place of or in substitution for paddle wheels on each side of the mid-
ship portion of a steam ship, then a considerably reduced width of paddle box.
will suffice, as the floats in ascending and descending above the line of immer-
sion assume a position at right angles to the central or main axis or propeller
shaft, and so present their thickness only, instead of the length of the float-
boards, parallel to and as revolving around the propeller shaft as in the ordi-
nary form of paddle wheel; the internal width of the paddle box is determined
by the length of the floats, and the clearance space required at each end
thereof, whereas with propellers according to this Invention, when applied as
substitutes for the ordinary paddle wheels, the paddle boxes need only be of a
width on the top side or above the centre line of the propeller shaft, of a width
sufficient to allow of the floats or paddles revolving therein end way on, and for
the requisite thickness of the radial arms or spindles, and their framing and
fittings for carrying the paddles or floats.
When applied as a single wheel at the stern of a ship, and either revolving
in a trunk suitably formed for its working as a submerged propeller, or when.
applied as an overhung or overhanging propeller mounted in a frame projecting
over the stern of the ship, (in which latter case the diameter may be greatly
increased if the propeller be not used as an entirely submerged propelling
power,) in each case the propeller revolves in the direction of the length of the.
keel; but I do not intend to confine myself to apply this form of propeller to
work or rotate upon a paddle shaft or axis, fixed at right angles with the keel
line, as the same form of floats or paddles may be applied and mounted upon.
spindles or arms radiating from a central axis, which central axis or propelling
shaft, like the screw propeller shaft, may run fore and aft of the ship parallel
with or at an angle with, and singly above, or when two are employed one on.
each side of the ship's keel, in accordance with the requirements of the vessel,
its form, construction, or the mode of applying the power. In such an applica-

page_text: tion as the last described, I regulate the angle at which the paddles or floats
may work with the central shaft, around which they are fitted, so as to ensure
the best propelling effect being obtained; but I do not confine myself to placing
the central axis or shaft either at right angles to or parallel with the line of
the keel, or the line of motion of the vessel, as other intermediate angles
or positions may in some cases be found more advantageous for propellers
constructed according to my Invention.
I have described my Invention, and some of the various modes of applying
and working the same which I prefer to employ, and I have described in the
early part hereof the form of float board or paddle as being in shape a paral-
lelogram on the face, whilst the one face or side is of greater length than the
other, which is due to the bevil or chamfer given at each end, which may prac-
tically be limited or governed in its extent by the thickness of the float, and
such floats may be formed of wood shod or framed together with iron; or
they may be hollow metallic cases of the required thickness, so as to enable
the extent of bevil. to be given at the ends or sides, but I do not propose
to limit myself in the form of float board or propeller to the parallelogram
form of face or shape of float board, as that also may be varied without
departing from the novel and peculiar feature of my Invention, which consists
in mounting a series of float boards or propellers of suitable form, and in con--
struction as herein described, each mounted centrally or excentrically upon a
shaft, spindle, or bar radiating from a common centre, and such float boards or
propellers may be so fitted upon the radial shaft, spindle, or bar, as to turn
freely thereon, (in which case the shaft, spindle, or bar would be fitted nearer
to one end, or out of the centre of the length,) or each float may be securely
fixed upon its radial shaft, spindle, or bar, which latter being mounted in
suitable bearings is free to turn therein, so as to enable the float board to
present its face to the water at a right angle with the direction of the ship's
motion, whilst it is submerged and effective as a propeller, but upon its
immerging from the water it will be caused to present its edge, and so retain
that position during the remaining part of the revolution, when it re-enters
the water, or when by the angular and bevil form given to the end, it is
caused to assume its proper position. When the float boards or propellers
are secured upon their respective radial arms for the purpose of constructing a
vertical outside or central propeller, the feathering action or changing of the
position of the float boards may be effected by forming a bent level or tappet-
like termination to the inner ends of the radial bars, or those nearest to the
main axis or paddle shaft, and these cranked ends being turned toward the
side of the vessel, or to one side of the propeller, so that they may alternately

page_text: be acted upon by an inclined curved or cam surface fixed to the side of the
vessel, or on one side of the trunk or elsewhere, thus causing the float boards
and the shafts upon which they are fittted to turn to the proper extent and at
the proper time during the rotation of the propeller shaft and the float boards
or propellers surrounding it; but when the float boards or propellers are
mounted. loosely upon the radial shafts, spindles, or bars, their changes of
direction, and the regulation of the time at which each change shall be effected
may be governed or operated by means of a suitably curved strake rail or
surface guide applied to the side of the ship, or fitted or fixed in the trunk or
other space in which the series of propellers constructed and mounted as
'described are intended to rotate, or wherever else it may best operate.
Having now described my Invention, and illustrated it by describing several
modes of applying the same under various circumstances and conditions, I
claim, the mode of constructing, mounting, or fitting, and working propellers
in manner and for the purposes as herein described.
In witness whereof, I, the said James Greenwood, have hereunto set
my hand and seal, this Thirtieth day of December, in the year of
our Lord One thousand eight hundred and fifty-eight.
Witness,
GEORGE CHURCHILL,
18, Salisbury Street, Strand.
JAMES GREENWOOD. (L.S.)