IMPROVEMENTS IN PROPELLING VESSELS
Year: 1855

page_text: LETTERS PATENT to James Pettigrue, of Drumcree, in the County of
Westmeath, Gentleman, and of 138, Dorset Street, in tho City of Dublin,
for the Invention of "IMPROVEMENTS IN PROPELLING VESSELS."
PROVISIONAL SPECIFICATION left by the said James Pettigrue at the
Office of the Commissioners of Patents, with his Petition, on the 14th
May 1855.
I, JAMES PETTIGRUE, of Drumcree, in the County of Westmeath, Gentle-
man, & of 188, Dorset Street, in the City of Dublin, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN PROPELLING VESSELS
to be as follows:-
My Invention has reference to the mode of propelling by means of a solid
piston or plunger contained within a cylinder open to the admission of water
to be pressed or thrust against by the piston, and consists in the adaptation
and arrangement of the following mechanism for communicating the required
motion to such kind of propeller, whether for advancing or backing the vessel,
such motion being communicated without the agency of cranks and other
ordinary mechanism between the prime mover and the propeller.
There are two steam cylinders in or near the centre of the vessel, through

page_text: stuffing boxes at the ends of which work the rods of the steam pistons con-
tained therein. Each piston rod is connected with the water piston, contained
in one of two water cylinders at the stern of the vessel, for propelling the
vessel forwards, and with the piston of one of two water cylinders of less
diameter at the bows, for backing the vessel. The connection is formed,
however, in such a manner as to admit of the rod of the steam piston
being readily put out of gear with the water piston at the bows when the
vessel is required to be propelled forwards, and out of gear with the water
piston at the stern when the vessel is required to be backed. For this
purpose each end of the steam piston and the end of each water piston
are passed into double links or clutches, which are connected by means of
a rod working over a friction roller mounted between them.
The upper
part of the said link or clutch, in which the end of the steam piston rod is
confined, may be raised on a-hinge-joint by means of a handle in such a
manner as to liberate the end of the rod, thereby cutting off the communication
between such end of the rod and the water piston with which it is in connection
while held in the link or clutch.
The open
ends of the water cylinders at the bows are covered by an external
valve or shutter, which may be readily removed when required; and there are
similar covers to the open ends of the stern cylinders. The slide valves of
each steam cylinder with their induction and eduction passages are also
arranged so as to produce a continuous reciprocating motion of the steam
piston, by using the steam only on one side of the piston except just while
reversing the stroke. The valves may, however, be arranged, if preferred,
in such a manner as to use the steam on both sides of the piston alternately.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Pettigrue in the Great Seal Patent Office on the
14th November 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
PETTIGRUE, of Drumcree, in the County of Westmeath, Gentleman, and of 3
138, Dorset Street, in the City of Dublin, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of May, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me,
tho said James Pettigrue, Her special license that I, the said James Pettigrue,
my executors, administrators, and assigns, or such others as I, the said
James Pettigrue, my executors, 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,
exercise, 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," upon the condition (amongst others) that I, the said
James Pettigrue, by an instrument in writing under my hand and seal,
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 James Pettigrue, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed, and to the
letters and figures marked thereon (that is to say):-
:-
My Invention of "Improvements in Propelling Vessels" has reference to
the mode of propelling by means of a solid piston or plunger contained within
a cylinder open to the admission of water to be pressed or thrust against by
the piston, and consists in the adaptation and arrangement of the following
mechanism for communicating the required motion to such kind of propeller,
whether for advancing or backing the vessel, such motion being communicated
without the agency of cranks and other ordinary mechanism between the prime
mover and the propeller.
There are two steam cylinders in or near the centre of the vessel, through
stuffing boxes at the end of which work the rods of the steam pistons con-
tained therein. Each piston rod is connected with the water piston contained
in one of two water cylinders at the stern of the vessel for propelling the
vessel forwards, and with the piston of one of two water cylinders (of less
diameter) at the bows, for backing the vessel. The connection is formed, how-
ever, in such a manner as to admit of the rod of the steam pistons being readily
put out of gear with the water pistons or plungers at the bows when the
vessel is required to be propelled towards, and out of gear with the water
pistons or plungers at the stern when the vessel is required to be backed.
For this purpose each end of the steam piston rods and the end of each
water piston rod are passed into double links or clutches, which are connected

page_text: by means of a rod working over friction rollers mounted between them. The
upper part of the said link or clutch, in which the end of the steam piston rod
is confined, may be raised on a hinge joint by means of a handle in such a
manner as to liberate the end of the rod, thereby cutting off the communi-
cation between such end of the rod and the water piston or plunger with which
it is in connexion while held in the link or clutch, and at the same time link-
ing the piston rod at its reverse end to the rod of the water piston or plunger
at the bows of the vessel.
The open ends of the water cylinders at the bows are covered by an external
valve or shutter, which may be readily removed when required, and there are
similar covers to the open ends of the stern cylinders. The slide valves of each
steam cylinder with their induction and eduction passages are also arranged
so as to produce a continuous reciprocating motion of the steam piston by
using the steam only on one side of the piston except just while reversing
the stroke. The valves may, however, be arranged, if preferred, in such a
manner as to use the steam on both sides of the piston alternately.
In order, however, that my Invention may be fully understood and readily
carried into effect, I will proceed to describe it more particularly by the aid
of the accompanying Drawing, in which is represented the general arrange-
ment of the mechanism above referred to.
Fig. 1 is an elevation, shewing the steam cylinder and the water cylinders
both at the bows and the stern with their connections; Fig. 2 is a horizontal
section of the same, shewing the steam piston and the water piston of the
stern cylinder respectively at the end of their stroke; Fig. 3 is a similar view,
shewing the same at the commencement of their stroke; Fig. 4 is an end
elevation, and Fig. 5 a transverse section of the steam cylinder; Fig. 6 is a
front view of the valve for closing the open end of each cylinder at the bows
of the vessel when the latter is being propelled from astern; Figures 7
and 8 represent the clutch for connecting the rods of the steam and water
pistons. In all these several Figures the same letters of reference indicate
corresponding parts.
A is one of the steam cylinders, which may be fixed at or near the centre of
the vessel, or in any other convenient part of the same: Bare the steam
pistons, securely keyed or bolted to the rods C. These rods, it will be seen,
pass through stuffing boxes at each end of the cylinders, and are connected at
each end with the rods of the water pistons. D', D, are double links or
clutches, by means of which the steam piston rods C are coupled to the rods E
of the water pistons F, acting within the water cylinders G at the stern of
the vessel. These cylinders, it will be observed, are formed at their outer end

page_text: so as to suit the form of the vessel. H, H, are links or clutches, by means
of which the steam piston rods are connected to the rods of the water pistons I,
acting within the water cylinders J at the bows of the vessel. The outer ends
of these cylinders are also formed so as to suit the form of the vessel. K, K,
are rods connecting the links or clutches of the steam piston rods with those of
the water piston or plunger rods. These rods K are supported and work to
and fro on the friction rollers L, L, which may be arranged as found convenient
both as to number and position. M (Fig. 6) is a valve formed of hinged
plates or boards, and is capable of being raised or lowered within the grooved
guides N by means of a chain and pulley fixed in any convenient position at
the bows of the vessel, and there is a similar valve adapted and applied to
each water cylinder at the stern thereof. These valves are intended to be
lowered, so as to cover the open end of the water cylinders at the bows when
the vessel is being propelled forwards, the similar valves at the stern being also
capable of being lowered as required. O is a rod with a hooked end, con-
nected to the end of the chain for raising and lowering the valve M. When
the valves are required to be raised, the water piston rods I being connected
with the steam piston rods C by means of the links or clutches H, the rod O
will be drawn forward until the collar comes in contact with the stop P
on the upright standard P. By this movement the inclined projection Q on
the rod O will have passed under the similar projection on the handle or
lever R, raised the latter, and on the depression of the lever become locked
behind the said projection, so as to hold the rod O in its forward position and
keep the valve M raised. By raising the handle or lever R, the rod O may
be liberated, and the valve M allowed to drop down again so as to cover the
open end of the cylinder. The valves M may, however, be raised and lowered
S is a cranked rod, by means of
as required by any other convenient means.
which the links or clutches D or H are opened or closed when required, in
order to connect the steam piston rods C with the water piston rods E or I
respectively. It will be seen at Figures 7 and 8 that the clutches are formed
with a hinge joint, to which is connected a tail piece T. This tail piece passes
into the forked end of the cranked rod S, and is acted upon by the attendant
engineer, by turning the cranked rod so as to open the clutch. U is a jointed
ring or collar on the steam piston rod C, to which is connected the lower end
5 of the rod V, which is made to work the pumps of the engine in such a
manner as to give two strokes to the pump at each stroke of the steam
piston. It will be seen, on reference to Fig. 1, that when the rod V is brought
into the vertical position at the middle of the stroke, it will give the down
stroke to the pump rods connected at W, W, and that when the rod is

page_text: brought to its two inclined positions at each end of the stroke, it will give
the up-stroke to the pump rods. X, X, are the fulcra of the pump levers,
the pins of which are passed through an excentric joint, of such a form as to
admit of the pump rods being moved vertically, and these rods should have an
ordinary parallel motion applied to them, which is not shewn in the Drawing.
Y, Y, are the slide valves of the steam cylinders, which are worked so as to
open the steam ports by the striking of the piston B against tappets or pro-
jections Z, fixed to the said valves, when the piston arrives near the end of its
stroke in each direction. a is the steam.pipe; 6 is a valve at the inner end
of the water cylinders, opening outwards of the cylinders to let off any water
that may pass the water piston or plunger; c is the exhaust pipe leading to
the condenser, but which is not shewn in the Drawing.
The action of the above-described mechanism is as follows:-On the water
piston rods E being brought into gear with the steam piston rods C by closing
the clutches D, the pistons B of each steam cylinder being in the position
shewn at Fig. 3, and the steam let in at the back of the pistons B, as shewn
by the arrows, the water pistons or plungers F of the water cylinders Gat each
side of the vessel will be driven forcibly against the water, and propel the
vessel forwards. On the steam pistons B arriving at the positions shewn at
Fig. 2, they will have struck against the tappets Z of one pair of the slide
valves Y, Y, and carried the valves forward so far as to have changed the
passages for the entrance of steam into and its exit from the cylinders, as
shewn by the arrows. It will also be observed that the induction and
eduction passages for the steam are reversed when the piston is driven to
the position shewn at Fig. 3. And I would remark that the slides and steami
valves may be so constructed and arranged as to cut off the steam in the
early part of the back stroke of the piston, or at any point of the stroke that
may be found most convenient in practice. It will thus be evident, that by
the simultaneous action of the steam pistons on each side of the vessel, the
water pistons at the stern will be correspondingly worked against the water,
and the vessel propelled forwards as long as the parts continue in gear, as
represented in the Drawing, and described above. When, however, it is
required to back the vessel, the clutches Dare to be opened and the clutches II
closed upon the rods of the water pistons I, so as to bring them in gear with
the steam piston rods C, the valves M being drawn up from the water
cylinders J, and dropped down, if required, over the open ends of the cylinders G.
As long as the parts are thus in gear, the action of the steam pistons B will
work the pistons or plungers I, so as to back the vessel.
Having thus described the nature of my Invention, and in what manner

page_text: the same is to be performed, I would have it understood that I do not mean
or intend to confine myself to the precise forms and arrangements of the parts
represented and described; neither do I claim any of such parts separately, or
otherwise than as used in combination for the purpose described; but what
I do claim as of my Invention is, the general combination and arrangement of
the mechanism by which the vessel may be propelled forwards or backed, as
required, by the uniform and simultaneous action of a steam piston within a
cylinder placed on each side of the vessel, as described.
year of our
In witness whereof, I, the said James Pettigrue, have hereunto set
my hand and seal, the Seventh day of November, in the
Lord One thousand eight hundred and fifty-five.
Witness,
WILLIAM SPENCE,
50, Chancery Lane.
JAMES PETTIGRUE. (L.B.)