AN IMPROVEMENT IN PROPELLING VESSELS
Year: 1856

page_text: LETTERS PATENT to William Chapman, of Sunderland, for the Invention
of AN IMPROVEMENT IN PROPELLING VESSELS."
Sealed the 11th April 1856, and dated the 17th January 1856.
PROVISIONAL SPECIFICATION left by the said William Chapman at
the Office of the Commissioners of Patents, with his Petition, on the
17th January 1856.
I, WILLIAM CHAPMAN, of Sunderland, do hereby declare the nature of the
5 Invention for "AN IMPROVEMENT IN PROPELLING VESSELS" to be as follows:-
This Invention has for its object an improvement in propelling vessels; for
which purpose a ship or vessel is built with an opening through it on each side
of the keel, and near the stern, within the ship or vessel; and to each of such
openings is affixed a cylinder, with its open end in or through such opening.
The other end of each of these cylinders is closed with an end or cover through
a stuffing box, to which a piston rod works. This piston rod has affixed at its
outer end a piston, which works air and water tight in the cylinder above
mentioned. On the other or inner end of the piston rod is fixed another
piston, which works in another cylinder, which is covered or closed at both
ends in such manner that steam may be admitted between the end cover and
the piston, in order to drive the piston therein to the stern end of the steam
cylinder, and, consequently, the other piston against the water which flows into
the other or open ended cylinder, in such manner that the water may be driven
out at the open end of such cylinder against the water in which the ship or

page_text: vessel is floating, and thereby propels the ship or vessel forward. In thus
moving the two pistons by the pressure of steam, on one of them a vacuum will
be formed on the other side of the piston which is acting on the water, and the
other end of the steam cylinder to that at. which the steam is admitted is also
kept vacuous, so that the piston which drives out the water from the open
cylinder will also be moved by the steam against the pressure of the atmosphere
into a vacuum, and when the steam is allowed to flow out of the steam cylinder
the pressure into a vacuum will bring back both pistons.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Chapman in the Great Seal Patent Office on the
17th July 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CHAPMAN, of Sunderland, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of January, in the year of our
Lord One thousand eight hundred and fifty-six, in the nineteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Chapman, Her special licence that I, the said William
Chapman, my executors, administrators, and assigns, or such others as I, the
said William Chapman, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 "AN IM-
PROVEMENT IN PROPELLING VESSELS," upon the condition (amongst others) that I,
the said William Chapman, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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 im-
mediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Chapman, do hereby declare the
nature of the 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 thereof, that is to say:-

page_text: This Invention has for its object an improvement in propelling vessels; for
which purpose a ship or vessel is built with an opening through it on each side
of the keel, and near the stern, within the ship or vessel; and to each of such
openings is affixed a cylinder with its open end in or through such opening.
The other end of each of these cylinders is closed, with an end or cover through
a stuffing box, to which a piston rod works. This piston rod has affixed at its
outer end a piston, which works air and water tight in the cylinder above
mentioned. On the other or inner end of the piston rod is fixed another piston,
which works in another cylinder, which is covered or closed at both ends in
such manner that steam may be admitted between the end cover and the piston,
in order to drive the piston therein to the stern end of the steam cylinder, and,
consequently, the other piston against the water which .flows into the other or
open ended cylinder, in such manner that the water may be driven out at the
open end of such cylinder against the water in which the ship or vessel is
floating, and thereby propells the ship or vessel forward. In thus moving the
two pistons by the pressure of steam, on one of them a vacuum will be formed
on the other side of the piston which is acting on the water, and the other
end the steam cylinder to that at which the steam is admitted is also kept
vacuuous, so that the piston which drives out the water from the open cylinder
will also be moved by the steam against the pressure of the atmosphere into a
vacuum, and when the steam is allowed to flow out of the steam cylinder the
pressure into a vacuum will bring back both pistons.
Having thus stated the nature of my said Invention, I will proceed more
fully to describe the manner of performing the same.
DESCRIPTION OF THE DRAWING.
Figure 1 shows a side elevation of the after part of a ship or vessel arranged
with machinery according to my Invention; Figure 2 shows a plan of the
propelling machinery partly in section, and on a larger scale than that shewn
at Figure 1. On each side of the kelson of a ship or vessel is formed an
opening to receive a cylinder a, which is open at the end next the water. In
each of those cylinders is a piston b, put in motion by a piston rod c, which
works through a stuffing box d. The piston rods c are at their other ends
connected with pistons e, e, in the steam cylinders f. f. On the piston rods c
are affixed cross heads g, g, which give motion to the pump rods c', d', and to
the axis n', which by means of excentrics to the valve rods n². Provision is made
for admitting the steam from the steam cylinders after it has acted on the
pistons in the steam cylinders to pass into the cylinders a behind the pistons in
those cylinders; and provision is also made to condense the steam in the

page_text: cylinders a after the pistons in those cylinders have completed their strokes
outward, in order to obtain a vacuum behind the pistons in the cylinders a, a.
And the working of the machinery will be as follows:-Steam will be admitted
from the boiler into one of the steam cylinders, which will put the piston in its
cylinder in motion, and also the piston in the cylinder a, by which the water
in that cylinder a will be driven out therefrom and propel the vessel, and the
moving outward of the piston in that cylinder a will be aided by the steam from
the other steam cylinder passing behind the piston in that cylinder.a. Steam
will then be admitted to the other steam cylinder, and the steam from the first-
mentioned steam cylinder will flow into the other cylinder a, and simultaneously
the steam behind the piston in the first-mentioned steam cylinder will be con-
densed, and a vacuum formed therein, by which the pressure of the outer
atmosphere will drive in the water, and force back the piston therein, and this
.will take place alternately. It is not essential that there should be a vacuum
produced behind the pistons in the cylinders a, a, in order to aid in the moving
back of the pistons in those cylinders, for in place thereof the steam from one
steam cylinder may be condensed in the steam cylinders, or they may be
opened to a vacuum maintained by an air pump. In this case I prefer that
the two cylinders a should open into each other, as shewn at Figure 3, which
.is a plan of propelling machinery, somewhat modified from that shown at
Figures 1 and 2. a, a, are two cylinders connected together at a¹. The pistons
in the cylinders a, a, are put in motion by the pistons in the steam cylinders, as
shewn; steam will be admitted into one of the steam cylinders, whilst the steam
which has acted in the other will simultaneously be condensed, and in the
movement of the pistons in the cylinders a the air behind them will be alter-
nately driven from one to the other.
In witness whereof, I, the said William Chapman, have hereunto set
my hand and seal, this Sixteenth day of July, in the year of our Lord
One thousand eight hundred and fifty-six.
'Witness,
S. CARPMAEL.
WILLIAM CHAPMAN. (L.S.)