Improvements in Water-jet Propulsion for Steam-ships.
Year: 1887

page_text: Date of Application, 4th Feb., 1887
Complete Left, 4th Nov., 1887
Complete Accepted, 3rd Feb., 1888
PROVISIONAL SPECIFICATION.
Improvements in Water-jet Propulsion for Steam-ships.
I, FREDERIC WILLIAM RICHARDSON, of Strathmore House, West Hartlepool, in the
County of Durham, Land Agent do hereby declare the nature of my invention to be
as follows:-
In constructing an apparatus for carrying my Invention into effect I place two
circular chambers amidships upon the floor of the vessel, one at either side, the
extremities of which extending outwards to the skin of the ship, form openings of
uniform size, one the inlet pointing forward, and the other the output pointing aft.
At the centre of each chamber, an ordinary two or three-bladed screw is worked by
independent engines, which revolving, draws in a continuous stream from the intake,
and discharges it at the output, the recoil of which propels the boat.
Assuming that the vessel were drawing fifteen feet, with the screw in motion, the
water passing through the intake aperture would flow unimpeded, at a velocity due
to the fifteen feet head, any increase in the number of the screw's revolutions, is
accompanied by the formation of a partial vacuum at the intake side of the screw,
which accelerates the velocity of the stream, at the same time reducing the pressure
at the intake aperture, from six and a half pounds per square inch (viz. that due to
the fifteen feet head) to below the atmospheric pressure, according to the partial
vacuum. This volume of water having passed through the screw's disc, is discharged
at the output, at the same velocity as it passed through the intake, thus giving
a pressure at the discharge aperture, due to the fifteen feet head of water, to the velocity
at which the jet is moving, and to the difference in the atmospheric pressure, or in
other words, the thrust available for propulsion is the difference in pressure per square
inch, between the intake and the output sides of the screw multiplied by the sectional
area of the discharge jets.
By reversing one or both of the engines, the boat is instantly turned on her centre,
or driven astern.
1
Th 1
1007

page_text: COMPLETE SPECIFICATION.
Improvements in Water-jet Propulsion for Steam Ships.
I, FREDERIC WILLIAM RICHARDSON, of Strathmore House, West Hartlepool, in the
County of Durham, 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 :-
My Invention which relates to an improved method of applying a propelling power
to ships, has for its object to obtain such power by the employment of hydraulic or
water-jet pressure applied about amidships from water channels provided in the inside
bottom of the vessel, and may be applied as an auxiliary force to the propelling power
derived from paddle wheels or screws, but principally in substitution of these modes
of propulsion.
The advantages derived from my invention are a steady propelling force which may
be relied on in all states of the water and with vessels of light draught and which is
capable of propelling the vessel straight ahead or straight astern with equal facility,
or of manoeuvring or even turning the vessel round on its centre. If my improved
mode of propulsion be employed independently of paddle wheels or ordinary screws,
a reduction and simplification of the internal machinery of the vessel is effected, all
liability of the engines racing is obviated, and much of the vibration and side wash
inseperable from the action of screws and paddle wheels is avoided.
In carrying out my invention for obtaining the hydraulic or water-jet pressure, one
or more chambers forining water channels are provided about amidships on the inside
bottom of the vessel forming water channels communicating at either end with the
water in which the ship floats; for manoeuvring purposes two such water channels
are provided, one on each side of the keel and preferably as far from the keel as
possible to obtain greater manoeuvring power, their positions being parallel to each
other and to the keel, each water channel is curved or inclined so that each end dips
down through the skin of the ship and communicates with the sea or water supporting
the vessel, and the centre rises high enough up into the inside bottom of the ship to
form a chamber in which a two or three bladed screw propeller can be rotated by a
shaft extending to one of the engines of the ship; each screw propeller, where more
than one is provided, is preferably driven independently, so as to be under separate
control for manoeuvring purposes.
And in order that my invention may be fully understood and readily carried into
effect I will now proceed to describe the same with reference to the annexed drawings,
in which Fig. 1. llustrates a transverse section of a vessel taken about amidships;
Fig. 2. is a sectional view taken on line X X of Fig. 1. a a are chambers forming
the water channels and are preferably cylindrical, in each chamber a is provided a
screw propeller b rotated by means of a shaft c extending through to the engines of
the ship.
The propelling power is obtained as follows:-the action of the screw propeller b
rotating in the chamber a expels the water therefrom through what may be termed

page_text: the outlet end, the influx of water into the chamber or water channel a is maintained
at a velocity due to the difference of level between the surface of the water and the
position of the screw propeller plus the velocity due to the suction of the screw when
revolving at a sufficiently high speed to cause a partial vacuum in the chamber a on
the intake side of the screw, the thrust available for propulsion being the difference
of pressure between one side of the screw and the other multiplied by the sectional
area of the jet.
The number of screw propellers provided in chambers forming water channels
through the inside bottom of the vessel as herein before described may be varied to
correspond with the general design and requirements of the vessel, but where two
screws are provided one on each side of the keel as illustrated in the drawings and
worked from separate engines by reversing one or both of the screw propellers or by
altering their relative speed the ship can be turned round on its centre or may be
otherwise manoeuvred much more effectually than is possible by any means at present
in use.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is carried into effect, what I claim is :-
The means employed for propelling ships by providing one or more chambers
forining water channels in the bottom of the ship from each of which chambers water
is discharged at pressure by the action of a screw propeller, substantially as
hereinbefore described with reference to the accompanying drawings.
Dated this 3rd day of November 1887.
G. J. CLARKSON,
Agent for the Applicant.