AN IMPROVED SHIP'S PROPELLER
Year: 1885

page_text: I, ROBERT JAMES RAE of 85 Gracechurch Street, London, Engineer, do hereby
declare the nature of my invention for AN IMPROVED SHIP'S PROPELLER, to be
as follows:-
This Invention consists of improvements in the construction of propellers, and
means of altering their immersion as circumstances require.
The propeller when only partially immersed exerts great propelling powers, and
is therefore well adapted for light draft purposes in lieu of Stern Paddle wheels,
and as it generally revolves at a much higher velocity than the latter, engines of
smaller size are capable of transmitting the motive power direct to the axle of the
propeller without the aid of intermediate gearing.
Another important feature is that on account of its compact form, this propeller
can be used on vessels navigating rivers or canals where low or narrow arches and
tunnels exist.
The Invention is intended to be carried out in the following manner,
The propeller is made of a cylindrical form and works in a horizontal position
similar to ordinary paddle wheels. The immersed portion consists usually of a
number of thin circular plates or rings which are secured to the axle, and revolve
edgways in the water.
a
The sides of these plates or rings are shaped or bent in and out in a radial
direction so that the edges acquire corrugated or other like form, and are fixed
in such positions that the corrugations or projecting portions of one plate stand
opposite the corresponding projections of the adjoining plates, a space being left
between the plates, or they may be placed so as to touch each other and thereby
form in the rim or periphery of the propeller a regular network of spaces or
apertures.
When revolved, the propeller obtains a continual grip or hold of the water and
thereby drives the vessel forward, imparting little if any vibration to the hull or
machinery, & without causing the disturbance or wash of water that generally
occurs,
The circumferential area or surface of the propeller may be constructed in
various other ways, as for instance by adopting a combined arrangement of
properly shaped castings and plates fixed edgways thereto in such a manner as to
rD 077

page_text: produce the beforementioned or other like formation in the rim, Or if desirable
the entire propeller may be made in a single piece or casting, while in some
cases, with a view to afford means for readily repairing the propeller, its external
or other parts may be made in sections or segments of convenient form and size,
provided with proper means of attachment.
The immersion of the propeller is made adjustable in the following manner,
Instead of being fixed to the vessel in the usual way, the bearings of the propeller
axle are fitted and fixed to the after end of a horizontal rocking frame or beam
secured to the stern of the vessel in such a manner, that by means of levers or other
mecanism, the after part is raised or lowered to vary the immersion of the propeller 1
to the degree required, Or the axle may fit in bearings secured to a frame made
to slide in upright grooves or guides formed on the vessel, the vertical position of
the frame being controlled by eccentrics levers or other suitable contrivances.
In some cases the adjustment may be accomplished by means of eccentrics fitted
and working in straps or recesses provided on the vessel, the bearings of the 1
propeller axle being formed in or upon the bodies of the eccentrics, Levers or
other means are applied to turn the eccentrics, and so alter the position of the
propeller.
Whenever the propeller is made to be adjustable, it is requisite that the engines
driving it should either be attached to the beam or frame supporting the propeller,
or be made to move in guides on the vessel or otherwise, so as to ensure the
relative position of the engines and propeller axle being always properly
maintained.
It is obvious that this Invention admits of various modifications in its details,
and for this reason it is needful to point out, that although this Specification 2
describes generally the nature of the improvements, I do not propose to confine
myself entirely to the precise form of all the detailed parts therein mentioned, or to
the description of the materials employed in their construction.
DIL_ TA
1

page_text: I, ROBERT JAMES RAE of 85 Gracechurch Street London, Engineer do hereby
declare the nature of my invention for AN IMPROVED SHIPS PROPELLER, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This Invention consists of Improvements in the construction of ships propellers
capable of exerting great propelling power when only partially immersed, and on
that account well adapted for light draft steamers in lieu of Stern Paddle wheels,
and for other like purposes.
This propeller can be driven at a high velocity and being of a very compact
form, its immersion may be altered or adjusted by various means, the details of
which it is unnecessary to describe herein, as I do not purpose making any claim
in respect thereto.
The propeller is made of a cylindrical form and works in a horizontal position
athwartships, the immersed portion consisting usually of a number of thin circular
plates or rings secured to the axle, and revolving edgways in the water, the sides
of the said plates or rings being shaped or bent, in and out, in a radial direction, so
that the edges acquire a corrugated or other like form, The plates or rings are
fixed in such order or position, as to cause the corrugations or projecting portions
of each plate to stand opposite the corresponding projections of the adjoining
plates, and it is preferable to leave a space between the plates, but they may be
placed so as to touch each other, and thereby form in the rim or periphery of the
propeller a regular network of spaces or apertures.
The circumferential area or surface of the propeller may be constructed in various
other ways, as for instance, by adopting a combined arrangement of properly
shaped castings and plates, the latter being fixed edgways to the castings in such
a manner as to produce the before mentioned or other like formation in the rim or
immersed portion, Or if desirable the rim may be made in a single piece, or it
may consist of a number of sections or segments of convenient form and size
provided with suitable means of attachment, so that any portion may be readily
removed and replaced.
The annexed drawing shews a propeller of a twin type in its position on the
stern of a vessel, the engine axle being placed in the centre, Fig. 1. shews an end
elevation of the propeller, Fig. 2. is a plan of same A. A. are the corrugated
plates or blades.
The Invention obviously admits of modifications both as to the details of its
various parts, and the description of materials employed in their construction.

page_text: Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is,
Constructing a ships propeller with the periphery, or immersed portion, composed
of a number of plates or rings, having edges of a corrugated or other like form, as
shewn in the annexed drawing, or constructed otherwise, substantially as herein-
before described.