IMPROVE- MENTS IN PROPELLING VESSELS, AND IN THE ARRANGEMENT AND CONSTRUC
Year: 1868

page_text: LETTERS PATENT to Robert Griffiths, of Rhual Issa, near Mold, in
the County of Flint, Engineer, for the Invention of "IMPROVE-
MENTS IN PROPELLING VESSELS, AND IN THE ARRANGEMENT AND CONSTRUC-
Scaled the 22nd June 1869, and dated the 31st December 1868.
PROVISIONAL SPECIFICATION left by the said Robert Griffiths at the
Office of the Commissioners of Patents, with his Petition, on the
31st December 1868.
I, ROBERT GRIFFITHS, of Rhual Issa, near Mold, in the County of
Flint, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PROPELLING VESSELS, AND IN THE ARRANGEMENT AND CON-
STRUCTION OF SCREW PROPELLERS AND APPARATUS CONNECTED THEREWITH," to
be as follows:-
One part of my Invention relates to improvements by means of which
the blades of screw propellers may be caused to assume such a position
as will offer the least possible resistance to the passage of a vessel through
the water at those times when the propeller is not employed in moving
the vessel. In carrying this part of my Invention into operation I form
the blades of the screw propeller separately from the boss and with shanks,

page_text: pro-
which are inserted in suitable sockets formed in the central boss, so that
the blades can be turned from any angle or "pitch" suitable for pro-
pelling the vessel, to such an angle in relation to the axis of the screw
shaft as will present the least resistance to the passage of the vessel
through the water when the propeller is stationary. Into the shank of
each blade I insert a key which serves to connect the blade to the boss.
These keys are secured in the shanks of the blades and project through
apertures formed in the sockets in the boss for the reception of the
shanks of the blades, such apertures being so formed as to allow of the
partial rotation of the shanks of the propelling blades within the sockets,
one end of such apertures stopping the keys and blades at the "
pelling pitch," and the other end at the "sailing pitch." In addition
to the keys above named I form the collar of the shank of each blade
with an angular edge, and secure rings upon the boss after the shank of
the blade is inserted so as to hold the angular edges upon the collars of
the shanks, and so assist in securing them to the boss. In order to
cause the blades to perform the partial rotation necessary to place them
in the two positions above named I connect the shank keys to a screw by
means of links within the boss, and when required the screw is caused
to travel by means of a rotating nut, and thus alter the position of the
propeller blades as desired, which may then be secured in position by any
suitable known means. I prefer to form a bearing in the stern post of
the vessel for the boss of the propeller, and to give motion to the
rotating nut by means of bevilled wheels or other suitable appliances,
which can be brought into action when required, and worked from the
deck or other parts of the vessel.
Another method by which I carry out this part of my Invention is as
follows In the shank of cach blade, as before mentioned, I insert a
key, which serves to connect the blades to the boss. These keys are
secured and operate in adjusting the blades as before described. In
order to cause the blades to perform the partial rotation necessary to
place them in the different positions before described I connect the
shank keys to a screwed collar by means of links within the boss jointed
into the shank keys and on to the screwed collar. This screwed collar
is actuated a screw arranged in a line with the screw shaft, or if
preferred it may be hollow and work on the screw shaft itself. The
screw moving the screwed collar when required to set the blades to their
position may be caused to rotate in several ways, one of which I have
already described, but by preference I use the following method:-On

page_text: to one end of this screw I have a friction wheel or clutch for the purpose
of stopping the rotation of the screw when it is required to move the
blades of the propeller. This friction pulley or clutch may be acted upon
by suitable means from the deck or other part of the vessel. When
used I fasten the friction pulley or clutch and cause the propeller shaft
to rotate by working the engines. This will cause the screwed collar to
revolve around the screw, and thus by means of the connecting links
place the blades of the propeller in their required positions.
Another part of my Invention relates to an arrangement of apparatus
wherein two narrow screw propellers are placed one behind the other, both
being secured to the screw shaft. A space is left between the two pro-
pellers of suitable dimensions. In this space, according to this part of
my improvements, I place a set of what I term "reactionary blades."
These blades are stationary, and are fixed to the stern post or keel, or in
other suitable manner, the propeller shaft revolving freely through their
centre; they are set to a much coarser pitch than the blades of the pro-
peller, and the object I attain is an increased speed of the vessel by the
action of the water moved by the propellers forcing the ship forwards
by striking the fixed blades.
Another form of "reactionary blades" may be adopted according to
my Invention in which there is one propeller only used on the screw
shaft and two sets of "reactionary blades," such blades being fixed one
set forward and one set aft of the propeller. The fixing and other
arrangements of these blades are the same as above described where one
set only are employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Griffiths in the Great Scal Patent Office
on the 29th June 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
O GRIFFITHS, of Rhual Issa, near Mold, in the County of Flint, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of December, in the
year of our Lord One thousand eight hundred and sixty-eight, in the

page_text: thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Robert Griffiths, Her special
licence that I, the said Robert Griffiths, my executors, administrators,
and assigns, or such others as I, the said Robert Griffiths, my
exccutors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
excrcise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN PROPELLING VESSELS, AND IN THE ARRANGEMENT AND CON-
STRUCTION OF SCREW PROPELLERS AND APPARATUS CONNECTED THEREWITH," upon
the condition (amongst others) that I, the said Robert Griffiths, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Griffiths, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement thereof, that is to say:-
One part of my Invention relates to improvements by means of which
the blades of screw propellers may be caused to assume such a position
as will offer the least possible resistance to the passage of a vessel
through the water at those times when the propeller is not employed
in moving the vessel.
In carrying this part of my Invention into operation I form the
blades of the screw propeller separately from the boss and with shanks,
which are inserted in suitable sockets formed in the central boss, so
that the blades can be turned from an angle or "pitch" suitable for
propelling the vessel to such an angle in relation to the axis of the
screw shaft as will present the least resistance to the passage of the vessel
through the water when the propeller is stationary. Into the shank
of each blade I insert a key which serves to connect the blade to
the boss. These keys are secured in the shanks of the blades and
project through apertures formed in the sockets in the boss for the
reception of the shanks of the blades, such apertures being so formed as

page_text: to allow of the partial rotation of the shanks of the propelling blades
within the sockets, one end of such aperture stopping the keys and
blades at the "propelling pitch" and the other end at the "sailing
pitch." In addition to the keys above named I form the collar of the
shank of each blade with an angular edge, and secure rings upon the
boss after the shank of the blade is inserted, so as to hold the angular
edges upon the collars of the shanks and so assist in securing them to
the boss. In order to cause the blades to perform the partial rotation
necessary to place them in the two positions above named I connect the
shank keys to a screw by means of links within the boss, and when
required the screw is caused to travel by means of a rotating nut, and
thus alter the position of the propellor blades as desired, which may then
be secured in position by any suitable known means. I prefer to form
a bearing in the stern post of the vessel for the boss of the propeller and
to give motion to the rotating nut by means of bevilled wheels or other
suitable appliances, which can be brought into action when required and
be worked from the deck or other parts of the vessel.
Another method by which I carry out this part of my Invention is as
follows: In the shank of each blade, as before mentioned, I insert a
key which serves to connect the blade to the boss, these keys are
secured and operate in adjusting the blades as before described. In
order to cause the blades to perform the partial rotation necessary
to place them in the different positions before described I connect the
shank keys to a screwed collar by means of links within the boss jointed
into the shank keys and on to the screwed collar. This screwed collar
is actuated by a screw arranged in a line with the screw shaft, or if
preferred it may be hollow and work on the screw shaft itself. The
screw moving the screwed collar when required to set the blades to
their position may be caused to rotate in several ways, one of which I
have already described, but by preference I use the following method:-
On to one end of this screw I have a friction wheel or clutch for the
purpose of stopping the rotation of the screw when it is required to raise
the blades of the propeller. This friction pulley or clutch may be
acted upon by suitable means from the deck or other part of the vessel.
When used I fasten the friction pulley or clutch and cause the propeller
shaft to rotate by working the engines. This will cause the screwed
collar to revolve around the screw, and thus by means of the connecting
links place the blades of the propeller in their required positions.

page_text: Figures 1 to 5 of the Drawings show various views of a propeller
constructed and arranged according to one part of my Invention, the
nature of the various views being written on the Drawing.
a, a, are the blades of the propeller; 6 is the boss; and c a portion of
the propeller shaft. The blades a, a, are formed with shanks a¹, which
are inserted in sockets b¹ formed in the boss. a, a, are keys inserted
and secured in the shanks a¹. The keys a² project through apertures b³
formed in the sockets b', the apertures 62 being so formed as to allow of
the partial rotation of the propelling blades, one end of the apertures b²
stopping the keys a² and blades a at the propelling pitch and the other
end at the sailing pitch. The collars a³ of the blades a are formed with
angular edges by means of which the blades a are further secured. This
may be accomplished by securing rings upon the boss after the shanks
have been inserted so as to hold the angular edges of the collars a³, but
in the Drawing the boss itself is so formed with circular recesses as to
hold the angular edges of the collars a, parts of such circular recesses

page_text: being cut away, as shown in the plan, as well as parts of the angular
edges of the collars a³, so as to admit of the introduction of the collars a
under the edges of the circular recesses, by this means avoiding the use of
screws for holding down the collars a³. a are connecting links, by
means of which the keys a' are connected to the collar d, and according
to the direction in which the collar d is moved so will the blades be
turned into the propelling or sailing pitch. The collar d may according
to my Invention be attached to a screw which may be caused to travel
in either direction by a rotating nut, or the collar d itself may be formed
as a nut, as shown in the Drawing, and moved in either direction by the
rotation of the screw e. The screw e is tubular, and turns upon a
suitably formed part 6 of the boss 6 and within the exterior part thereof,
guiding edges 6 being provided in the boss by which the screwed
collars a are prevented from revolving when the screw e is turned.
Various means may be employed without departing from my Invention
for giving motion to the nut or to the screw e by means of which the
blades a are "feathered," and the parts may be so arranged in
accordance with my Invention that either manual labour or the steam
engine may be employed for this purpose. In the Drawing I have
shown the parts so arranged that the feathering of the blades is effected
by the revolution of the propellor shaft in the following manner :-
The hinder part of the screw e is formed with an annular groove within
which the break f, f, is arranged. The break f is formed in two
parts, and f. g is a vertical axis supported in suitable bearings and
provided at its upper end with a hand wheel g'. The lower end of the
axis g is screwed and passes through the part f of the break, the end of
the axis g being connected to the part of the break. It will be seen
that by turning the axis g in one direction or the other the parts fand f¹
will be caused to close upon and hold, or separate from and releasc,
the screw e, and if when the break is closed upon the screw e the engine
is caused to turn the propellor shaft c the blades a will be "feathered "
in one direction or the other according to the direction in which the
propellor shaft c is turned. After the blades have been feathered the
break must be released. The axis g is tubular, and h is a rod which
passes through the axis g and rests upon the bottom of an eccentric
groove turned in the screw e. The rod I employ as a means of
indicating whether the break has firm hold of the screw, for if the screw
is firmly held the rod / will not rise or fall, but if the screw e is not
firmly held the eccentric part of the screw against which it rests will

page_text: cause the rod h to rise and fall. his.a bell-crank lever connected to
the rod h, and the lever ¹ may be connected with a suitable indicator
placed in the engine room or other convenient part of the ship. The
propellor shaft c is provided with a bearing at the part c', indicated in
the Drawing by dotted lines, but this bearing may be dispensed with, as
shewn at Figure 6, which shews so much of a sectional side elevation of
a propellor constructed and arranged according to my Invention as will
enable me to explain the same, the parts corresponding with those before
described, being marked with the same letters and figures. It will be
seen on reference to Figure 6 that in place of the screw e being formed
hollow and turning around the axis c, such axis is shortened, and the
screw e is formed solid. In other respects the arrangement of parts
shewn at Figure 6 corresponds with that previously described in
reference to Figures 1 to 5. It will be evident that the form and
arrangement of the parts may be considerably varied when constructing
the parts of a propellor according to my Invention so as to be feathered by
means of the keys a², the links a', and the travelling collar d, and that
the screw may be caused to revolve by means of bevilled wheels, and
the screwed collar and other parts for altering the pitch and feathering
the blades can be arranged forward in place of aft of the screw, as shown
in the Drawing. I would also remark that when forming the blades for
a feathering propellor I prefer to form them to a true screw at about one
half the pitch it is intended to employ for propelling, so that the blades
may have less twist and be nearer a line with the keel when feathered.
Figure 7 shews a front, Figure 8 a side view, and Figure 9 a plan of a
propellor arranged to act with "reactionary blades." According to one
part of my Invention i, i, are the propelling blades fixed upon the pro-
pellor shaft j. There are two screw propellors i and i, arranged onc
behind the other, both being secured to the screw shaft. A space is left
between the two propellors, and in this space are arranged according to
this part of my Invention what I term the "reactionary blades "k. The
blades are stationary, and are fixed to the stern post or keel, or in
some other suitable manner, the propellor shaft j revolving freely
through their centre. The blades are set to a much coarser pitch
than the blades of the propellors i and i, the water moved by the
blades i and striking against the fixed blades k, and assisting in
forcing the ship forward.
According to another part of my Invention two sets of the "re-

page_text: actionary "blades k may be employed, one set of such blades being
fixed fore and the other aft of a single screw propeller. I have not
thought it necessary to shew a separate Drawing of this arrangement, as
an intelligent engineer aided by the description herein-before given in
reference to Figures 7, 8, and 9 will readily comprehend and apply this
part of my Invention.
Having now described the nature of my Invention, and the means I
employ for carrying the same into operation, I would have it understood
that I make no claim generally to the "feathering" of propellor blades
nor to the employment of "reactionary" blades; what I claim is,-
First. The construction, arrangement, and combination of parts by
means of which the blades of a propellor are "feathered," substantially
as herein-before described and shown in the Drawings hereunto annexed.
Second. The arrangement and combination of two screw propellors
with a central set of "reactionary blades," substantially as herein-before
described and shewn in the Drawings hereunto annexed.
Third. The arrangement and combination of two sets of "reactionary
blades, one fore and the other aft of a single screw propellor, substan-
tially as hercin-before described.
In witness whereof, I, the said Robert Griffiths, have hereunto
set my hand and seal, this Twenty-eighth day of June, in the year
of our Lord One thousand eight hundred and sixty-nine.
(O'TT)