IMPROVE- MENTS IN AUXILIARY SCREW PROPELLERS
Year: 1869

page_text: LETTERS PATENT to William Bruce Thompson, of Dundee, in the
County of Forfar, North Britain, for the Invention of "IMPROVE-
MENTS IN AUXILIARY SCREW PROPELLERS."
Sealed the 4th March 1870, and dated the 7th September 1869.
PROVISIONAL SPECIFICATION left by the said William Bruce Thomp-
son at the Office of the Commissioners of Patents, with his Petition,
on the 7th September 1869.
I, WILLIAM BRUCE THOMPSON, of Dundee, in the County of Forfar,
North Britain, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN AUXILIARY SCREW PROPELLERS," to be as follows, that is
to say :-
This Invention has for its object the propulsion of sailing vessels when
becalmed at sea, and it consists in attaching a screw propeller on to one
side of the rudder by means of eyes or bearings, which are permanently
fixed to the rudder for the purpose of receiving the propeller shaft.
The inner end of the propeller shaft is provided with a swivel, to which
a rope or chain is attached, and this serves as a guide for "shipping".
the propeller, and when the propeller is "unshipped" the said chain

page_text: or rope remains "rove" through the eyes or bearings on the side of the
rudder. The outer end of the propeller shaft may or may not also have
a swivel, to which a rope or chain is attached; when it is desired to
ship" or " unship" the propeller this latter rope or chain passes over
a pulley on to the deck at the stern of the vessel, and may be detached
when the propeller is in use. The propeller is driven either by a steam
winch on the deck or other engine or by a shaft actuated by hand power,
from any of which a rope or chain extends over pulleys on the stern
down to and over a driving pulley fixed on the shaft of the propeller.
The propeller blades instead of being cast in one piece with the boss as
hitherto, are by preference cast separately and bolted on to the boss, so
that when not in use they may be detached and thus rendered capable
of being stowed away in a much smaller space than usual.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Bruce Thompson in' the Great Seal Patent
Office on the 5th March 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BRUCE THOMPSON, of Dundee, in the County of Forfar, North Britain,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of September, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
33rd year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Bruce Thompson, Her special
license that I, the said William Bruce Thompson, my executors, ad-
ministrators, and assigns, or such others as I, the said William Bruce
Thompson, my executors, administrators, or 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 AUXILIARY SCREW PROPELLERS," upon the condition
(amongst others) that I, the said William Bruce Thompson, by an
instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what
3

page_text: 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 William Bruce Thompson, 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, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:
My said Invention has for its object the propulsion of sailing vessels
when becalmed at sea, and it consists in attaching a screw propeller on
to one side of the rudder by means of eyes or bearings, which are per-
manently fixed to the rudder for the purpose of receiving the propeller
shaft. The inner end of the propeller shaft is provided with a swivel,
to which a rope or chain is attached, and this serves as a guide for
"shipping" the propeller, and when the propeller is "unshipped" the
said chain or rope remains "rove" through the eyes or bearings on the
side of the rudder. The outer end of the propeller shaft may or may
not also have a swivel, to which a rope or chain is attached; when it is
desired to "ship" or "unship" the propeller this latter rope or chain
passes over a pulley on to the deck at the stern of the vessel, and may
be detached when the propeller is in use. The propeller is driven either
by a steam winch on the deck or other engine or by a shaft actuated
by hand power, from any of which a rope or chain extends over pulleys
on the stern down to and over a driving pulley fixed on the shaft of
the propeller. The propeller blades instead of being cast in one piece
with the boss as hitherto are by preference cast separately and bolted
on to the boss, so that when not in use they may be detached and thus
rendered capable of being stowed away in a much smaller space than
usual.
And in order that my said Invention may be properly understood I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, that is to say :-
On the accompanying Sheet of Drawings Figure 1. represents a side
elevation of the stern part of a vessel, and which shows my auxiliary
screw propeller applied thereto; Figure 2 is an end view of the rudder

page_text: showing the propeller applied thereto. In these views corresponding
parts are indicated by the same letters of reference.
The screw propeller A is fixed on the shaft a carried in the bearings
or eyes b, b, which bearings or eyes are permanently fixed to the rudder B.
The shaft a is made to revolve by means of a rope or chain c passing
over the groove pulley C fixed on the shaft a and also over the pulleys D
fixed on the deck or gunwale, and from thence to the steam wench or
other prime mover. The inner end of the shaft a is provided with a
swivel e, to which a rope or chain f is attached, and this serves as a
guide for "shipping" the propeller, and when the propeller is "un-
shipped" the chain or rope fremains "rove" through the bearings or
eyes b, b. The outer end of the shaft a of the propeller is provided
with a swivel (E), as shown, to which a chain or rope (h) is attached;
when it is desired to ("ship" or unship the propeller this latter chain
or rope passes over a pulley on to the deck at the stern of the vessel,
and may be detached when the propeller is in use. The blades of the
propeller are preferably cast separately from the boss and are bolted to
it, so that when not in use they may be detached and thus rendered
capable of being stowed away in a smaller space than would be possible
if the propeller were formed in one piece.
Having now described the nature of my said Invention, and the
system, mode, or manner in or under which the same is or may be used
or practically carried into effect, I would observe in conclusion that
what I consider novel and original, and therefore claim as the Inven-
tion secured to me by the herein-before in part recited Letters Patent is,
the application of an auxiliary screw propeller to vessels by carrying it
in bearings affixed to the rudder, and operating the same in the manner
herein-before described and shown on the annexed Sheet of Drawings..
In witness whereof, I, the said William Bruce Thompson, have
hereunto set my hand and seal, this First day of March One
thousand eight hundred and seventy.
WILLIAM BRUCE THOMPSON. (L.S.)