improvements on Screw Propelling Apparatus for Steam Vessels.
Year: 1885

page_text: improvements on Screw Propelling Apparatus for Steam Vessels.
I, HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents, of
52 Chancery Lane, London, in the County of Middlesex, do hereby declare the
nature of my invention for "IMPROVEMENTS ON SCREW PROPELLING APPARATUS
FOR STEAM VESSELS," which invention has been communicated to me from abroad
by Edward H. Hall, residing at the City of Brooklyn, County of Kings, State of
New York, United States of America, Gentleman, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the following
statement:
My invention relates first to a steam vessel the hull of which has, longitudinally
thereof, and below the unloaded water line, the hereinafter described laterally
projected guards or floats, and a propelling screw located one on each side of the
hull, at or about the waist line, in the recesses in the said guards or floats as
hereinafter set forth, together with two propelling screws at the stern, as herein-
after specified, and my invention further relates to the form of the propeller screws
employed, as hereinafter particularly shown and described.
Figure 1 is a horizontal section of the hull of a steam vessel, on line xx figure 2,
(which may be regarded as also the water line) showing also the side and end
screw propellers according to my invention.
Figure 2 is a side elevation of the same.
Figure 3 is a bow elevation.
Figure 4 is a side elevation of my improved propeller screw, and
Figure 5 is a face elevation of the same.
A. is the hull of a ship or boat which may be constructed of
any desired proper
form and dimensions, I prefer the comparatively flat bottom, and the water line
shown in the drawings.
B. and B are guards on each side of the hull placed on the bull below its
unloaded water line and secured fimly thereto.
These guards are triangular in cross section as appears plainly in figures 2 and 3,
the wall of the hull forming one side of the triangle the upper and lower plane
[Price 8d1

page_text: sides of the guard forming the other sides of the triangle, their outer edge meeting
to form an acute angle. They extend longitudinally of the hull and their bow
ends curve inward and disappear a little abaft the stem of the hull. They are made
hoilow of heavy sheets or plates of iron, riveted together and secured to the sides of
the hull, with watertight joints, thus constituting them both guards and floats.
These floats must of course be well supported and stayed in the hull.
To this end I construct the hull with cross-beams represented by broken lines
at a in Fig. 1 placed at suitable intervals throughout the hull and framed therein
with their ends projecting on either side of the hull to which ends the walls of the
guard-float may be bolted.
C. C are two screw propellers, one on either side of the ship, about centrally in
the ship's waist. At this place a section is cut or left out of each guard leaving a
clear space between the opposite ends of the guard (as shown in Figures 1 and 2)
in which the propeller is located with its axis parallel to the ship's keel; journal
boxes b for its shaft are supported on and secured to the ends of the cross-beams
before mentioned.
The described guards along the ship's waist are of a width corresponding to the
diameter of the screw on the outer side of it, and those portions within which the
bearings of the screw shaft are located, are made of rectangular cross sections thus
presenting on their outer surface, a place surface as wide vertically as the diameter
of the screws. Thus constructed and arranged, the screw is completely protected
by the said guards against all liability to injury from coming [in contact with any
object which the ship may encounter.
D. D¹ represent two stern screw propellers which may be of the usual con-
struction, the propeller shafts c. c. pass through the interior of the stern end of the
described guard, in which they are supported, journaled in suitable journal boxes,
the said shafts extending forward within the hull to their connection with the
motive power.
I do not deem it necessary to describe or represent in the drawings the steam
engines that furnish the motive power for actuating the propeller, nor the
mechanism through which the power is communicated from the engines to the
propeller shafts, these may be of any desired suitable construction.
I do not claim broadly, the employment of side propellers being aware that the
same are common.
In the screw propeller shown in Figures 4 and 5 the blade is composed of a
body and two wings, and extends entirely once around the shaft on which it is
mounted, and adapted and intended to be wholly submerged, and having an
elliptical opening in the body of the blade in the portion thereof immediately
adjacent to the shaft, said opening being concentric in curve to the shaft and the
outer rim of the blade body and extending into the wings of the blade on each side
to about 'one-third the length of the wings from the axial line of the shaft to the
edge or extremity of the wings, as hereinafter described' and claimed.
G is the shaft and C. is the propeller screw, composed of the body E, and
wings F shown, and forming a continuous blade, extending once entirely around
the shaft with the appropriate pitch. The said screw is formed on or attached
directly to the shaft.
In the body of the blade is formed the opening E, the said opening being
elliptical in form or outline, and having a curve longitudinally which is coincident
to the circle or curve of the shaft and that of the rim of the blade. The opening E
is furthermore located in that portion of the blade which is immediately adjacent
to the shaft, but having a portion of the blade continuous around and in contact
with the shaft. The said opening E, extends into each wing of the blade to about
one-third of the length of the wing, measuring from the axial line of the shaft to
the rim or extremity of the wing, as shown in Figure 5.
The screw propeller thus constructed is adapted and intended to be wholly
submerged when it is operated as a propeller, and the full advantages of its
peculiar construction are only obtained when it thus submerged.

page_text: I am
aware that screw propellers have been heretofore constructed with
openings in their blades, and hence I do not claim such form and construction
broadly,
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
(1.) In a steam-vessel the combination with the hull A of the guards or floats B
and B, longitudinally of the hull below the water line, triangular in cross-section
from the bow and stern respectively to near the vessel's waist, and rectangular in
cross-section at the vessel's waist and there constituting the spaces or recesses B³,
together with the screw propellers C and C, located one on each side in said
recesses B³, and the screw propellers D and D¹ at the stern of the vessels, as
described.
(2.) A screw propeller, adapted to be wholly submerged in operation, consisting
of an axial shaft G and a blade C extending helically entirely once around the said
shaft, and having the elliptical opening E in that portion of the body of the blade
which is immediately adjacent to the shaft, and extending, in a curve which is
concentric to that of the shaft and the blade-rim, into each wing F1 of the blade
about one-third of the distance from the axial line of the shaft to the extremity of
the wing, as and for the purpose specified.
D
1
D
100-