IMPROVEMENTS IN APPLYING AUXILIARY SCREW PROPELLERS TO SAILING SHIPS, AND IN THE CONSTRUCTION OF SAILING SHIPS TO ADAPT THEM THEREFOR
Year: 1868

page_text: LETTERS PATENT to James Jack, of Liverpool, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN APPLYING
AUXILIARY SCREW PROPELLERS TO SAILING SHIPS, AND IN THE CONSTRUCTION
OF SAILING SHIPS TO ADAPT THEM THEREFOR"
Sealed the 22nd December 1868, and dated the 25th June 1868.
PROVISIONAL SPECIFICATION left by the said James Jack at the
Office of the Commissioners of Patents, with his Petition, on the
25th June 1868.
I, JAMES JACK, of Liverpool, in the County of Lancaster, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN APPLYING AUXILIARY SCREW PROPELLERS TO SAILING SHIPS, AND IN THE
CONSTRUCTION OF SAILING SHIPS TO ADAPT THEM THEREFOR," to be as
follows:-
The object of my Invention is to provide sailing ships with auxiliary
screw propellers capable of propelling them during calms and adverse
light winds and at other times. Such propellers are so arranged and
the ships to which they are fitted so constructed that the screw without

page_text: being removed from the shaft can when not required for propelling
purposes be housed in a recess formed usually within the ordinary
lines in the dead wood of the ship, and thereby be placed beyond the
current of water. When the screw is housed as aforesaid the working
space is filled up and the ship presents an unbroken skin.
In carrying my improvements into effect I first make the screw
shaft and the screw moveable in a piece in the length of the
axis of the shaft. When pushed out the screw is in position for
use in a suitable opening, but when drawn in it occupies a recess
hereafter described in the dead wood. To allow the screw shaft
and screw to be moved I make the thrust bearings or other parts
according to the style of the engine moveable, and I employ a
worm or screw thread on the shaft and a bearing or any ordinary
or convenient means for drawing the shaft and screw propeller in
and out.
Second. Within the dead wood or run of the ship aft I form by
timbers and planks or metal framing and plates a recess, open only
on the aft end, large enough to receive the screw propeller; the said
propeller will require in many instances, so as to retain fine lines, to
be made with narrow blades. The stuffing gland and bearings for the
shaft are formed within the ship forward of the said recess, and when
desired a bearing can be formed on the rudder post.
Third. As means for closing up the space in which the screw operates
I employ a sliding block or blocks let down from the deck. These
are drawn up near or on to the deck before the screw is pushed out
and operated.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Jack in the Great Seal Patent Office on
the 24th December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES 30
JACK, of Liverpool, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of June, in the year of

page_text: our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said James Jack, Her special license that I,
the said James Jack, my executors, administrators, and assigns, or
such others as I, the said James Jack, 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 APPLYING AUXILIARY
SCREW PROPELLERS TO SAILING SHIPS, AND IN THE CONSTRUCTION OF SAILING
SHIPS TO ADAPT THEM THEREFOR," upon the condition (amongst others)
that I, the said James Jack, 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, tho said James Jack, 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, that is to say :-
The object of my Invention is to provide sailing ships with auxiliary
screw propellers capable of propelling them during calms and adverse-
light winds and at other times. Such propellers are so arranged and.
the ships to which they are fitted so constructed that the screw with--
out being removed from the shaft can when not required for propelling
purposes be housed in a recess formed usually within the ordinary lines
in the dead wood of the ship, and thereby be placed beyond the current
of water. When the screw is housed as aforesaid the working space
is filled up and the ship presents an unbroken skin.
In carrying my improvements into effect I first make the screw
shaft and the screw movable in a piece in the length of the
axis of the shaft. When pushed out the screw is in position for

page_text: use in a suitable opening, but when drawn in it occupies a recess
hereafter described in the dead wood. To allow the screw shaft
and screw to be moved I make the thrust bearings or other parts
according to the style of the engine movable, and I employ a
worm or screw thread on the shaft and a bearing or any ordinary
or convenient means for drawing the shaft and screw propeller in
and out.
Second. Within the dead wood or run of the ship aft I form by
timbers and planks or metal framing and plates a recess, open only
on the aft end, large enough to receive the screw propeller; the said
propeller will require in many instances, so as to retain fine lines, to
be made with narrow blades. The stuffing gland and bearing for the
shaft are formed within the ship forward of the said recess, and when
desired a bearing can be formed on the rudder post.
Third. As means for closing up the space in which the screw operates,
I employ a sliding block or blocks let down from the deck. These
are drawn up near or on to the deck before the screw is pushed out
and operated.
On the above-mentioned Sheet of Drawings, which I have appended
that my improvements may be readily understood, the three parts
into which for convenience I have divided my Invention are clearly
delineated by one practicable arrangement of details.
Fig. 1 is a side elevation; Fig. 2 a longitudinal vertical section,
parts being in elevation; Fig. 3 an elevation looking on the stern;
Fig. 4 a plan view shewing the sliding block in the well; and Fig. 5
a horizontal section at the line A, B, all of so much of the stern
portion of a ship fitted with and constructed according to my improve-
ments as is necessary fully to illustrate them. Like letters denote the
same parts in a'l the views.
a is the screw shaft, and 6 the screw; c, stern tube; d, thrust bearings;
the other inboard bearings are of any convenient description. A screwed
shaft e free to turn in its bearings and capable of being rotated on
its axis by a lever handle or other means passes through the thrust
bearings block, so that thereby when the ship is put under sail, or at
other times when required, the screw and shaft may be drawn in in one
piece into the position shewn in Fig. 5 and indicated by dotted lines

page_text: in Figs. 1 and 2, and the screw housed in the recess or space f. By
rotating the said screw shaft e in the opposite direction, the screw
and shaft are pushed outwards until the screw rests in the open space g,
where when at work it rotates. The recess f need not be as long as
the breadth of the screw; sometimes it may be advantageous to make
it only a few inches long, and in such cases the sliding block would
be made as thin as possible. An outer bearing is shewn provided on
the rudder post at *; this may be dispensed with if desired, but its
use prevents vibration and irregular wearing of the stern tube and
stuffing gland. Instead of a movable thrust block and screwed shaft
a worm or screw thread on the shaft and a bearing or any other
mechanical arrangement suitable for moving the screw shaft and screw
in and out may be used. is a sliding block built of boiler plates
and angle iron; it is formed with two feathers which pass one on either
side of the stern post, and a projecting portion near the top to take
into a groove constructed on the forward side of the well. The said
sliding block as well as the sides i of the recess or space f have given
to them a slight swell so as to allow of the use of a screw with a
full width of blades. In ships with full lines and ordinarily in wooden
ships there will be sufficient space within the lines. j is a screw passing
through a nut in the sliding block. A wheel k on the end of j gears
with another wheel on the shaft m; by rotating these parts the sliding
shutter is raised or lowered at pleasure. A chain from a winch or
any other suitable means can be used for raising and lowering the
sliding block. In Fig. 1 the sliding block is shewn closing the space
in which the screw operates; and in Fig. 2 it is raised. To fill up
the space two or more blocks may be used.
Having now described the nature and particulars of my said Inven-
tion, I would have it understood that I do not confine myself to the
details of the whole parts or of any parts so long as the leading features
of my improvements are retained; what I claim is,―
First. Moving the screw shaft and screw outwards and inwards in
one piece for the purpose set forth.
Second. Forming a recess in the run or dead wood aft for the pur-
pose set forth.
Third. The use of a sliding block or blocks for the purpose set forth.

page_text: And, fourth. The combination of any two or the whole of the im-
provements above claimed for the purpose set forth.
In witness whereof, I, the said James Jack, have hereunto set
my hand and seal, this Twenty-first day of December, in
the year of our Lord One thousand eight hundred and sixty-
cight.
Witness,
JOHN T. KING,
Patent Agent,
Liverpool.
JAMES JACK. (L.S.)