IMPROVEMENTS IN THE MEANS OF PROPELLING AND STEERING STEAMSHIPS OR ANALOGOUS VESSELS
Year: 1883

page_text: LETTERS PATENT to Joseph Stewart of Blackwall in the County of Middlesex
for an Invention of "IMPROVEMENTS IN THE MEANS OF PROPELLING AND
STEERING STEAMSHIPS OR ANALOGOUS VESSELS
"
PROVISIONAL SPECIFICATION left by the said Joseph Stewart at the Office
of the Commissioners of Patents on the 28th June 1883.
JOSEPH STEWART of Blackwall in the County of Middlesex
"IMPROVEMENTS
ANALOGOUS
IN THE MEANS OF PROPELLING AND STEERING STEAMSHIPS OR
VESSELS
73
This invention relates to the means employed for propelling and steering steam-
ships or analogous vessels in which motion is imparted by means of what aro
commonly known as propellors The invention consists of the improvements
hereinafter set forth According to my invention I propose to have one propellor
and one rudder in the middle of the stern of the vessel as at present generally in
use and in addition thereto I add a smaller propellor and smaller rudder on each
side of the main one, but placed lower down and further forward The power of
the two side propellors combined to be to the power of the main one about
as 2 is to 3, for instance if a ship has 1000 HP nominal, the main propellor engine
would be 600 HP and the two side propellor engines about 200 HP each The
two side propellors to be each about half the diameter of the main one and placed
well forward under each quarter of the ship The tip of the side blades is preferably
about level in heighth with the centre of the main or middle shaft I further
propose to have three keels the centre keel to extend the whole length of the ship
as is now customary and the two side keels to commence from the midship section,
running aft There will be a stern post and rudder abaft each propellor, the centra
rudder may be much smaller in proportion than those now generally in use while
the two side ones should be of suitable size All three rudder-heads to be connected
by the same wheel-chain or other suitable apparatus, so that when the helm is
put to port or starboard, all three rudders will move in unison. Some of the

page_text: advantages of this form of construction being that, when encountering a heavy
head sea, the side propellors being well down will always work steadily in solid
water and the main one can be eased if considered necessary, letting the side ones
do the work, and the loss of power consequent on the engines racing will thus in
a great measure at least be saved. Further advantages will be found in the
facility with which a vessel so constructed may be manoeuvred or turned in narroW
channels, in docking and undocking while in case of the breaking of a propellor,
a shaft, or one of the engines the vessel could still be worked by the other engines
and propellors and thus the ordinary yards and square sails would not be required,
while in ordinary circumstances, if the three propellors are in operation at the
same time, an increased speed over vessels of the usual construction will be
attained coupled with the advantages of a more oven distribution of power and
greater stability.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Joseph Stewart in the Great Seal Patent Office on the 26th December
1883.
JOSEPH STEWART of Blackwall-in the County of Middlesex
"IMPROVEMENTS,
IN THE MEANS OF PROPELLING AND STEERING STEAM SHIPS OR ANALOGOUS
VESSELS
17
This invention relates to the means employed for propelling and steering steam
ships or analogous vessels in which motion is imparted by means of what aro
commonly known as propellors The invention consists of the improvements
hereinafter set forth. reference being made to the accompanying drawings in which
Fig 1 represents a side elevation of the stern of a vessel Fig 2 a plan view of half
the bottom of said stern and Fig 3 a sectional elevation, like letters of reference
referring to corresponding parts
According to my invention I propose to have one propellor A and one rudder B
in the middle of the stern of the vessel as at present generally in use and in
addition thereto I add a smaller propellor C and a smaller rudder D on each side
of the main one, but placed lower down and further forward
The power of the two side propellors C combined to be to the power of the main
one A about as 2 is to 3 for instance if a ship has 1000 PP nominal the main
propellor engine would be 600 HP and the two side propellor engines about 200 HP
cach, although I do not confine myself to these exact proportions The two side
propellors C to be cach about half the diameter of the main one A and placed well
forward of the latter under each quarter of the ship The tip of the side blades or
propellors C is preferably about level in heighth with the centre of the main or
middle shaft of propellor A I further propose to have three keels E and F, F.,
the centre keel E to extend the whole length of the ship as is now customary and
the two side keels F to commence from the midship section, running aft There
will be the usual stern post and rudder abaft cach propellor the centre rudder B
may be much smaller in proportion than those now generally in use while the two
side ones D should be of suitable size. All these rudder heads may be connected
by the same wheel chains or other suitable apparatus, so that when the helm is
put to port or starboard all three rudders will move in unison Some of the
advantages of this form of construction being that, when encountering a heavy
head sea, the side propellors C being well down will always work steadily in solid
water, and the main one A can be eased if considered necessary, letting the side
ones do the work, and, the loss of power consequent on the engines racing will
thus in a great measure at least be saved Further advantages will be found in
the facility with which a vessel so constructed may be manoeuvred or turned in
narrow channels, in docking and undocking while in case of the breaking of a
propellor a shaft or one of the engines, the vessel could still be worked by the
other engines and propellors, and thus the ordinary yards and squaro sails would
not be required, while in ordinary circumstances, if the three propellors are in
operation at the same time, an increased speed over vessels of the usual construction
will be attained, coupled with the advantages of a more even distribution of power
and greater stability
Having thus described my invention and how the same may be employed I
would have it understood that I am aware that it has been proposed to provide
vessels with more than one propellor and even with more than one keel, and as an
instance of the latter what are known as "twin ships" may be quoted, but no ono

page_text: so far as I am aware has heretofore proposed the arrangements and combination
as above set forth and what I therefore claim and desire to secure by Letters
Patent is
The improvement in the means of propelling and steering steamships or
analogous vessels substantially as described.
In Witness whereof I the said Joseph Stewart have hereunto set my hand and
seal this sixteenth day of December in the year of Our Lord one thousand eight
hundred and eighty threo