Improvements in and relating to Screw Propellers for use on Steamboats.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Screw Propellers for use on
Steamboats.
I, GEORGE ROOKE, a citizen of the United States, residing at Emporia, County
of Lyon, and State of Kansas, United States of America, Mechanic, do hereby
declare the nature of this invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
The object of my invention is to improve the bow of a ship so that its speed may
be materially increased.
My invention consists in forming the bow in two separate parts, one normally
above and the other below the water line; and in providing a revolving conical
beak (or extension of that part of the bow which is under water) having blades
that tend to draw the ship through the water, and having peculiar spiral projections
back of the blades that diminish the pressure of water upon the bow, and thus tend
to increase the speed of the ship.
My invention is designed to be employed chiefly upon steam ships (but may be
used elsewhere) and the blades are designed to supplement the action of a screw
propeller or paddles, while the spiral projections diminish the resistance to motion
of the ship through the water.
In the accompanying drawings,
Fig. 1 is a side elevation of so much of the forward part of the hull of a boat as
necessary to illustrate my invention;
Fig. 2 is a section on the line 2, 2, of Fig. 1 ; and
Fig. 3 is a section on the line 3, 3, of Fig. 1.
Fig. 4 is an elevation showing the guard in section.
Referring to the letters on the drawings, A indicates the hull of a boat, which is
provided at its bow with a separate deck part A', and between the keel and the
water line with a conically tapered part B, which may be built into the boat, or
may be provided in one already built by removing a part of the hull and rebuilding
that portion of it. Any kind of boat, whether old or new, may thus be adapted to
use my improvements.
C indicates a conical beak, whose base is of the same diameter as the part B,
where the beak joins it, and whose sides form a continuation of the taper of that
part. It is mounted, by means of the shaft D, on suitable bearings E in the
interior of the vessel, and in the forward part of the keel F, respectively, and is
adapted to be rapidly revolved by any suitable mechanism, not shown in the
drawings. Upon the forward end of the beak are provided blades G, so arranged
thereon as to tend to draw the boat through the water when the beak is revolved.
S indicates an encircling shield or guard around the beak. It may be fixed or
rotary.
Near the largest part of the beak, and behind the blades on the beak, are pro-
vided spirals H that preferably consist of ribs arranged obliquely and parallel to
each other. They should be so constructed (substantially as shown in section in
Figs. 1 and 2, & 3 for example) as to throw the water away from the bow of the
boat, thereby diminishing the resistance against its onward movement, and at the
same time so as to cause in themselves the minimum resistance to rotation and to
forward motion. The form illustrated in the drawings I regard as preferable for
the spirals, but it may be varied.
In this form, as shown in section Fig. 1, the beak being rotated in the direction
of the arrow, it will be seen that the incline K will tend to throw the water away
from the submerged part B of the bow, and as it were open a cavity for the passage
of the bow,

page_text: The front ends of the spiral ribs are tapered at L so as to wedge their way into
the water as the boat advances, and also tend, like the inclined sides K, to throw
the water away from the submerged part of the bow.
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. A boat provided at its bow with a separate deck part A', a conically tapered
part B, and a revoluble beak provided with blades and forming a pointed forward
extension of the part B, substantially as described.
2. In a boat the combination with a separate tapered part B, of a revoluble
conical beak C provided with blades and with spirals H in rear thereof, sub-
stantially as set forth.
3. A revoluble conical beak C, provided with blades and spirals H in rear
thereof, each spiral having the incline K upon one side and the front incline L,
substantially as set forth.
4. A revoluble conical beak C, provided with blades and spirals H in rear
thereof, in combination with the guard or shield S, substantially as set forth.
Dated this 5th day of November 1891.
GEORGE ROOKE.