IMPROVEMENTS IN APPARATUS FOR PROPELLING AND STEERING SHIPS OR VESSELS
Year: 1883

page_text: .
LETTERS PATENT to Benjamin Dickinson of Bourne End in the County of
Bucks for an Invention of IMPROVEMENTS IN APPARATUS FOR PROPELLING
AND STEERING SHIPS OR VESSELS,
44
PROVISIONAL SPECIFICATION left by the said Benjamin Dickinson at the
Office of the Commissioners of Patents on the 26th November 1883.
.
BENJAMIN DICKINSON, of Bourne End, in the County of Bucks, "IMPROVE-
MENTS IN APPARATUS FOR PROPELLING AND STEERING SHIPS OR VESSELS
"
My invention has reference to an improved screw propeller and to means for
utilizing the force of water thrown off laterally by the rotation of screw propellers,
by directing the course of such water so that it shall assist in propelling the
vessel.
A propeller according to my invention is formed with a quick pitch and of
considerably greater length in proportion to the diameter than is usual in ordinary
screw propellers-The root of each blade is cut away or removed for a part (say
about one half, more or less) of the radius, the blades being carried by arms which
support them away from the shaft and allow water to pass between the blades and
the shaft. To utilize the force of water thrown off laterally by the propeller or
propellers I provide louvre gratings having the bars or slats set at such an angle as
to give a rearward action to any water that may be driven between them.
I prefer to use a pair, or "twin" screws and to make the pitch of one right-handed
and that of the other left-handed, driving them in opposite directions so that when
the vessel is going ahead the motion of the adjoining peripheries will be upward
and will have a tendency to throw the water upward through an upper louvre
grating in conjunction with which side louvre gratings are or may be used. To aid
in steering the vessel these side louvre gratings can be made to turn on hinges or
joints at their forward ends so that either of such gratings may by means of
suitable operating gear worked from the deck, be turned outward from the
propeller so as to offer less resistance to the trajected water,—thus the stern of the
vessel will be driven over towards that side at which the grating is in the closed
position, near the propeller.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Dickinson in the Patent Office on the 24th May 1884.
BENJAMIN DICKINSON, of Bourne End in the County of Bucks. IMPROVEMENTS
IN APPARATUS FOR PROPELLING AND STEERING SHIPS OR - VESSELS
My invention has for its object improvements in apparatus for propelling and
steering ships or vessels.
Referring to the accompanying drawings Fig 1 is a side elevation of the stern
portion of a twin screw ship or vessel or boat showing partly in section my
improved propelling and steering apparatus as applied thereto and Fig 2 is an end
view.
J
A. A¹ are the propellers of equal diameter each formed with a quick i.e. coarse
or long pitch and of considerably greater length in proportion to the diameter than
is usual in ordinary screw propellers.
The two propellers A. A having each two or more blades are formed respectively
with right and left handed pitches and are driven concurrently in opposite
directions as shewn by the arrows (Fig 2) so that when the vessel is going ahead
the motion of the adjoining peripheries will be upward. The intended effect of
such concurrent motion of the propellers is that as the corresponding blades of the
respective screws descend below the level of their axes or shafts and approach each
other in the lower portion of their spheres they should press with equal power upon
the water for the time being within their influence and thereby reciprocally create
an increased resistance to their own rotation. This reciprocal resistance I call
grip" and inasmuch as the water thus gripped cannot escape laterally and only to
a limited degree upward it must of necessity as the blades close on it find its
escape rearward at a downward angle in a line governed by the pitch of the blades
pressing upon it. This would be the result till the respectively corresponding
blades begin to rise which they do immediately after passing under the line
perpendicular to their axes or shafts when their action would be to carry upwards
at a rearward angle the water contained between them.
се
"
The blades as here shewn are carried by bosses B which support them away from
the shaft C and allow, water to pass between the blades and the shaft at D the
object of cutting away the roots of the blades being to allow a portion of the
gripped" water to pass through the openings into the spaces between the blades
which for the time being are not exercising "grip" and by the greater pressure of
such water to destroy gyration and allow thereby the screws to exercise greater
beneficial power throughout that portion of their spheres which lies above the level
of their shafts.
E is an upper louvre grating through the slats of which the water carried
upwards by the blades of the propellers as they rise to the upper portion of their
spheres is more or less forceably discharged and by pressing in its passage against
the lower side of the grating bars assists to propel the vessel. In order to utilise
the force of the water thrown off laterally by the propellers side louvre gratings F. F¹
are shewn. These side louvre gratings F. F' are in the example illustrated made to
turn respectively on hinges or joints G. G¹ at their forward ends so that either of
such gratings may by means of suitable operating gear worked from the deck or
other part of the vessel be turned outward from the propeller as shewn at F¹
(Fig 2) so as to offer less resistance to the trajected water but that resistance
will be established to the outer currents through which the vessel is passing, thus
the stern of the vessel will be driven over towards that side at which the grating F
is situated,

page_text: Although I prefer to use "twin "
screws of substantially the form illustrated yet
other forms of screws with quick or coarse pitch may be used so long as the two
screws are arranged near together with their axes parallel, the pitch of one being
right handed and that of the other left handed and the two being driven in opposite
directions so as to grip the water as above described. Likewise I would remark
that in some cases it may be found convenient to dispense with all the gratings or
to dispense with the side gratings retaining only the upper one or to dispense with
the upper grating and use only side gratings
In lieu of making the whole of each side grating to turn on a hinge or joint
a portion thereof may be fixed and the remainder be movable and the hinge or
joint may be arranged in any suitable position according to the requirements of
particular applications.
There may be cases in which it will be found convenient to make the bars or
slats of the louvres adjustable but I consider it will usually be advantageous not
to do so as such an arrangement will involve a certain amount of complexity in
construction which it will usually be desirable to avoid.
There may be cases where for constructive convenience it would be desirable to
use quick or coarse pitch twin propellers arranged as above described of a length
somewhat less than their diameter.
Having described the nature of my said invention and the manner of performing
it, I claim
1. The use for propelling a ship or vessel of two screw propellers having blades
of quick or coarse pitch the one being right handed and the other left handed these
two screw propellers being arranged side by side with their axes parallel and being
caused to rotate in unison but in opposite directions in such a manner that by the
reciprocal and simultaneous pressure of their respectively corresponding blades upon
the water for the time being within their influence resistance of the nature herein-
above explained is created to the rotation of the propellers substantially as
described for the purpose set forth.
2. The use for propelling a ship or vessel of two screw propellers having blades
of quick or coarse pitch arranged with their axes parallel and driven in unison but
in opposite directions in conjunction with a louvre grating arranged above them
substantially as described for the purpose set forth.
3. The use in combination for propelling and steering a ship or vessel of two
screw propellers having blades of quick or coarse pitch arranged with their axes
parallel and driven in unison but in opposite directions and side louvre gratings
having their bars or slats arranged at such an angle as to give a rearward action
to water thrown against them by the propellers such side louvre gratings or
portions thereof being made to turn on hinges or joints so that either of such
gratings may by means of suitable operating gear be turned outward from the
propeller next to it thus offering less resistance to the trajected water and greater
resistance to the outside current substantially as described for the purpose set
forth.
4. The improved apparatus for propelling and steering a ship or vessel comprising
the two propellers A. A¹, means for driving them in unison but in opposite
directions, the upper louvre grating E and side louvre gratings F, F' all constructed
arranged and operating as hereinabove described and illustrated.
In Witness whereof I the said Benjamin Dickinson have hereunto set my hand
and seal this twentieth day of May in the year of Our Lord one thousand eight
hundred and eighty-four.
BENJAMIN DICKINSON
(L.S.)