Improvements in Propelling Mechanism for Vessels.
Year: 1893

page_text: Date of Application, 14th Oct., 1893
Complete Specification Left, 12th Dec., 1893-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Propelling Mechanism for Vessels.
I, FRANK TAFF of 7th Avenue and 7th Street, Whitestone, Long Island, in
the County of Queens and State of New York, United States of America, Builder,
do hereby declare the nature of this invention to be as follows :-
:-
My invention relates to that class of propellers for vessels which, following the
analogy of a fish's tail, seeks to accomplish the same result by an oscillating blade
or fin which is made flexible or elastic in its length so as to bend laterally when
oscillated about a centre. The difficulty has been that any such blade or fin which
is mounted to oscillate about a vertical axis involves a backward drag on the vessel
just in proportion to the radial swing of the blade which, in departing from a
straight longitudinal line, must necessarily also move forward involving a backward
drag and this backward drag so largely nullifies or neutralizes the sculling effect
of the rear edge as to give this form of propeller but little practical value.
My invention avoids this backward drag by doing away altogether with the
pivoted or oscillating movement of the flexible fin or blade and arranging it to
move bodily or integrally, so that the front part of the fin or blade moves laterally
just as far as the rear part does and with a reciprocating motion at right angles to
its plane. This avoids the backward drag incidental to the radial swing and causes
the reactionary effect to be resolved wholly into a forward movement, as will be
fully described hereafter.
In carrying out the invention, the propeller consists of a blade or fin constructed
of steel, or other elastic material, of such thickness that it will flex sidewise, the
shape of the blade being approximately that of a fish-tail or the blade of an oar.
Two propelling blades are employed provided with hubs at their ends secured in
any suitable manner to the outer extremities of two independent shafts so that the
blades shall extend rearwardly in the direction of the stern parallel with the keel.
The shafts are located in the bottom of the hull of the vessel and extend outwardly
through suitably packed openings in the sides of the hull. The two shafts are
arranged end to end and have end movement. The one shaft is provided at its
inner end with a socket or bore into which the inner end of the other shaft enters
and slides, the said inner end being reduced in diameter and made to conform to
the cross-sectional shape of the socket of the first-mentioned shaft. Thus one
shaft serves in a measure to guide the other and by thus coupling the shafts they
are kept in proper alignment. As a further guide for the shafts each one is
provided with a shoe located near its inner end and travelling upon a track or slide-
way, or its equivalent, located transversely in the bottom of the hull across the
keel. The shafts are adapted to move simultaneously outward and inward and any
approved form of driving mechanism may be employed for that purpose, such for
example by means of two gear wheels meshing with each other, one of which
wheels is keyed to a driving shaft, each gear wheel being connected likewise with
each shaft by means of a connecting-rod.
When the shaft is forced outwardly the flexible blade or fin curves during this
stroke and at the end of the stroke straightens out, by its elasticity, to the right
angular position and during both the outward integral movement of the blade
and its reactionary spring movement in straightening, the resultant line of
pressure is forward. Then when the shaft is drawn in the blade from its normal
straight position assumes a curved position and then straightens out again and
in both this inwardly integral movement and the reactionary spring movement in

page_text: straightening, the resultant line of pressure is still in a forward direction. In
both strokes then it will be perceived that the curving and deflection of the blade,
or its departure from the right angular position, only takes place within the limits
of the two positions which are parallel to the longitudinal axis of the vessel, so
that the entire effect of the blade is expended in a forward direction without any
such backward drag as a pivotal and oscillating swing would involve. By causing
the two blades on opposite sides of the vessel to move oppositely by reason of the
gear wheels, their lateral thrust on the vessel is neutralized and all jarring or
trembling of the vessel is avoided.
It will be understood that the improved propelling mechanism may be used of
itself to propel a vessel, or it may be employed as an auxiliary to the usual screw-
propeller or propellers and the peculiar movement of the blades serves to force a
vessel through the water steadily and speedily. As the side propellers are placed
near the bottom of the hull they will not disturb the surface of the water when
they are in action.
Dated this 14th day of October 1893.
COMPLETE SPECIFICATION.
Improvements in Propelling Mechanism for Vessels.
I FRANK TAFF, of 7th Avenue and 7th Street, Whitestone, Long Island in the
County of Queens and State of New York, United States of America, Builder 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 relates to that class of propellers for vessels which following the
analogy of a fish's tail, seeks to accomplish the same result by an oscillating blade
or fin, which is made flexible or elastic in its length so as to bend laterally when
oscillating about a centre. The difficulty has been that any such blade or fin,
which is mounted to oscillate about a vertical axis, involves a backward drag on
the vessel just in proportion to the radial swing of the blade, which in departing
from a straight longitudinal line must necessarily also move forward, involving a
backward drag, and this backward drag so largely nullifies or neutralizes the
sculling effect of the rear edge as to give this form of propeller but little practical
value.
My invention avoids this backward drag by doing away altogether with the
pivoted or oscillating movement of the flexible fin or blade, and arranging it to
move bodily or integrally, so that the front part of the fin or blade moves laterally
just as far as the rear part does, and with a reciprocating motion at right angles
to its plane. This avoids the backward drag incidental to the radial swing, and
causes the reactionary effect to be resolved wholly into a forward movement, as
will be hereinafter fully described.
Reference is to be had to the accompanying drawings forming a part of this
Specification, in which similar figures and letters of reference indicate corresponding
parts in all the views.
Figure 1 is a side elevation of the stern of a vessel, illustrating the application
of the improved propeller;
Figure 2 is a transverse section through the hull, illustrating the propellers in
rear elevation and the mechanism for driving them; and

page_text: Figure 3 is a plan view of one of the propellers, the said view also illustrating
the action thereof.
In carrying out the invention the propeller consists of a blade A, constructed of
steel or other elastic material, the blade being made of such thickness that it will
flex sidewise. The shape of the blade is approximately that of a fish tail, or that
of the blade of an oar, and the end of the blade adapted for connection with the
vessel is provided with a hub 10. Two blades are employed each mounted upon an
independent shaft; the shafts being designated respectively as 11 and 12.
The shafts are located in the hull of the vessel, and extend outwardly through
suitably packed openings in the sides of the hull. The two shafts are arranged
end to end and have end movement. The shaft 12, is provided at its inner end
with a socket or bore 13, into which the inner end of the shaft 11 enters and slides,
the said inner en1 of the shaft 11 being reduced in diameter and made to conform to
the cross sectional shape of the socket of the shaft 12. The reduced portion of the
shaft 11, is designated in the drawings as 11. Thus one shaft serves in a measure
to guide the other, and in thus coupling the shafts they are kept in proper alignment.
As a further guide for the shafts each one is provided with a shoe 14, located near its
inner end, and the said shoes travel upon a track or slide-way 15, or the equivalent
thereof, located transversely in the bottom of the hull across the keel. The propelling
blades A, are secured at their hubs to the outer extremities of the shafts 11 and 12,
the blades extending rearward in direction of the stern, substantially parallel with
the keel.
The shafts are adapted to move simultaneously outward and inward, and any
approved form of driving mechanism may be employed for that purpose.
In the
drawings the mechanism used consists of two toothed wheels 16 and 17 geared
together, one of which is keyed upon a driving shaft, each gear wheel being
connected by a crank pin and connecting rod 18 with its corresponding shaft.
Referring now to Figure 3, when the shaft is forced outwardly, as shown in
dotted lines, the flexible blade or fan A curves during its stroke to the position A',
and at the end of the stroke straightens out by its elasticity to the right angular
position A2, and during both the outward integral movement of the blade, and its
reactionary spring movement in straightening, the resultant line of pressure is
forward, as shown by the arrow S. Thus when the shaft is drawn in, the blade
from its normal straight position A' comes to the position A³ and then straightens
out to the position A again, and in both this inwarilly integral movement, and the
reactionary spring movement in straightening, the resultant line of pressure is still
in a forward direction, as shown by the arrow S. In both strokes then it will be
perceived that the curving or deflection of the blade, or its departure from the
right angular position only takes place within the limits of the two positions A
and A2, which are parallel to the longitudinal axis of the vessel, so that the entire
effect of the blade is expended in a forward direction without any such backward
drag as a pivotal and oscillating swing would involve.
By causing the two blades on opposite sides of the vessel to move oppositely by
reason of the gears 16 and 17, their lateral thrust on the vessel is neutralized, and
all jar or trembling of the vessel is avoided.
It will be understood that the improved propelling mechanism may be used of
itself to propel a vessel, or it may be employed as an auxiliary to the usual screw
propeller or propellers, and the peculiar movement of the blades serves to force a
vessel through the water steadily and speedily. As the side propellers are placed
near the bottom of the hull they will not disturb the surface of the water when
they are in action.
It will be understood that the driving shafts may be reversed by any suitable
mechanism in order that the free ends of the fius may point in the direction of the
bow in order to back the vessel, or the fins may be given any upward or downward
inclination. To enable this reversal or adjustment to be effected the connecting
rods 18 would be jointed to collars held between shoulders on the shafts 11, 12, so

page_text: as whilst the shafts are reciprocated longitudinally as above described the are fre
to be rotated about their own longitudinal axis by suitable gear.
Having now particularly described and ascertained the nature of my said inver
tion, and in what manner the same is to be performed, I declare tha what
claim is,
1. A propeller for vessels, substantially as herein shown and described.
2. A propeller for vessels, consisting of a blade or fin made flexible an
in its length, combined with and rigidly attached to a shaft or support, and
and actuating devices for moving the fin bodily at right angles to it
substantially as and for the purpose described.
3. A propeller for vessels, consisting of a blade or fin made flexible and
in its length, combined with and attached to a shaft or support at right an
guiding and actuating devices for reciprocating the fin bodily in a plane
angles to the blade, substantially as and for the purpose described.
[This Drawin
4. A propeller for vessels, consisting of two elastic blades or fins arı
substantially parallel to the longitudinal axis of the vessel at opposite sides
same, two corresponding shafts rigidly attached to the blades and arranged
versely to the vessel to reciprocate through the sides of the same, and means fo
imparting an opposite or reverse movement to the shafts to cause the lateral thrus
of one blade to neutralize the lateral thrust of the other to relieve the vessel of th
tendency to tremble, substantially as and for the purpose described.
5. A propeller for vessels consisting of two elastic blades or fins arr. nge
substantially parallel to the longitudinal axis of the vessel on opposite sides o
same, two reciprocating shafts rigidly attached to the blades, arranged transversei
in the sides of the vessel and having a sliding connection with each other at thei
inner ends, and gear wheels and connecting rods arranged to impart a revers
reciprocating motion to the two shafts and blades, substantially as shown an
described.
Dated this 12th day of December 1893.
By A. M. & Wm. Clark.
F. TAFF,
53, Chancery Lane, London, Chartered Patent Agents.