IMPROVED APPARATUS OR GEAR FOR DRIVING A SCREW PROPELLER WHEN THE ENGINES ARE BROKEN DOWN AT SEA
Year: 1872

page_text: LETTERS PATENT to James Adshead Hodgson, of Blyth, in the
County of Northumberland, Master Mariner, for the Invention
of "IMPROVED APPARATUS OR GEAR FOR DRIVING A SCREW PROPELLER
WHEN THE ENGINES ARE BROKEN DOWN AT SEA."
Sealed the 3rd April 1872, and dated the 18th February 1872.
PROVISIONAL SPECIFICATION left by the said James Adshead
Hodgson at the Office of the Commissioners of Patents, with his
Petition, on the 13th February 1872.
I, JAMES ADSHEAD HODGSON, of Blyth, in the County of Northumber-
land, Master Mariner, do hereby declare the nature of the said Invention
for "IMPROVED APPARATUS OR GEAR FOR DRIVING A SCREW PROPELLER WHEN
THE ENGINES ARE BROKEN DOWN AT SEA," to be as follows:-
The object of my Invention is to provide steam vessels with means of
getting to port in case of the engines being broken down at sea. My
apparatus or gear for this purpose consists of a sheave on the shaft of
the screw propeller, of other sheaves fitted on the deck near the stern of

page_text: the vessel, and of another sheave on the ordinary steam winch. A
chain or messenger is passed round the sheave on the steam winch and
round one of the sheaves on deck, and another chain is passed round
another of the sheaves on deck and round the sheave on the screw shaft.
There is a third sheave on deck of smaller diameter for increasing the
revolutions if required, that is to say, the chain from the winch is
shifted to this smaller sheave when it is required to increase the
revolutions.
From the foregoing explanation it will be readily understood that in
case of the engines breaking down at sea, the screw propeller can be
driven by the apparatus or gear before described at a speed of say about
3 knots in a calm. The ship will therefore be perfectly manageable and
can be got to port with or without the assistance of sails.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Adshead Hodgson in the Great Seal Patent
Office on the 11th April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ADSHEAD HODGSON, of Blyth, in the County of Northumberland,
Master Mariner, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, hearing date the Thirteenth day of February, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Adshead Hodgson, Her special
licence that I, the said James Adshead Hodgson, my executors,
administrators, and assigns, or such others as I, the said James Adshead
Hodgson, 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 "IMPROVED APPARATUS OR GEAR FOR DRIVING A SCREW PROPELLER WHEN
THE ENGINES ARE BROKEN DOWN AT SEA," upon the condition (amongst
others) that I, the said James Adshead Hodgson, my executors or

page_text: 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 James Adshead Hodgson, do hereby
declare the nature of my 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, reference being had to the accompanying
Drawings, that is to say :—
The object of my Invention is to provide steam vessels with means of
getting to port in case of the engines being broken down at sea, and the
Invention consists of apparatus or gear for driving the screw propeller
from the ordinary steam winch or crane. For this purpose I mount a
sheave or wheel on the propeller shaft and another sheave or wheel
on the steam winch or crane and I pass a chain or messenger round these
two sheaves or wheels. Thus by disconnecting the propeller shaft from
the main engines and working the winch or crane, the propeller will be
driven with sufficient power to enable the vessel to make headway and
to travel, say, about 3 knots an hour in a calm. The vessel will therefore
be perfectly manageable and can be got to port with or without the
assistance of sails. The sheave or wheel on the propeller shaft may
be fitted at any convenient part thereof, but if not fitted direct or
plumb from the winch two other sheaves are required on deck for
a fair lead.
My Invention will be fully understood by the annexed Drawings;
Figure 1 being a longitudinal section, and Figure 2 a transverse section.
a is the propeller shaft and 6 the steam winch; c is a sheave on the
shaft a, and d a similar sheave fitted to the steam winch; e is a chain
or messenger passing round the two sheaves c and d; f, f, are two
sheaves (drawn in red) on deck, to be used, as before explained, as a fair
lead when the sheave c is not fitted direct or plumb from the winch.
The chain or messenger from the steam winch in this case passes round
one of the sheaves f, and another chain or messenger g passes round the
other sheave fand round the sheave on the shaft a.

page_text: There may be a third sheave of smaller diameter on the shaft of
these sheaves f for increasing the revolutions if desired, that is to say,
the chain from the winch is shifted to this smaller sheave when it is
required to increase the revolutions.
Figure 3 is an end elevation of the sheaves f, f, looking from aft.
My apparatus or gear can be rigged up or taken down in a short time.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim,
constructing apparatus or gear, substantially as herein-before described,
for driving a screw propeller from the steam winch or crane when the
engines are broken down at sea.
In witness whereof, I, the said James Adshead Hodgson, have
hereunto set my hand and scal, this Third day of April, One
thousand eight hundred and seventy-two.