IMPROVEMENTS IN THE MODE OF DRIVING AND IN APPLYING SCREW PROPELLERS TO THE PROPULSION OF VESSELS
Year: 1856

page_text: LETTERS PATENT to George Napier, of Bath Street, Glasgow, in the
County of Lanark, and of the Adelphi, in the County of Middlesex, and
John Miller, of Cavendish Street, Glasgow, in the County of Lanark, for
the Invention of "IMPROVEMENTS IN THE MODE OF DRIVING AND IN APPLYING
SCREW PROPELLERS TO THE PROPULSION OF VESSELS."
Sealed the 5th August 1856, and dated the 6th February 1856.
PROVISIONAL SPECIFICATION left by the said George Napier and John
Miller at the Office of the Commissioners of Patents, with his Petition,
on the 6th February 1856.
I, GEORGE NAPIER, of Bath Street, Glasgow, in the County of Lanark, and
of the Adelphi, in the County of Middlesex, and I, JOHN MILLER, of Cavendish
Street, Glasgow, in the County of Lanark, do hereby declare the nature of the
said Invention for IMPROVEMENTS IN THE MODE OF DRIVING AND IN APPLYING
SCREW PROPELLERS TO THE PROPULSION OF VESSELS, to be as follows:-
Our improvements in driving & applying screw propellers consists in-fitting
them as herein-after described, whereby they may be depressed below or raised
above the level of the keel while in action. For this purpose I place the
propeller on a short shaft mounted in a sliding frame, which, by preference;
I place in the dead wood, in which it has bearings down to the keel; a portion
of the dead wood & rudder, or stern post, supports the sliding frame in the.

page_text: A
rear, while it is similarly supported by the dead wood in front. This propeller
frame slides in a vertical direction, & comes up through the deck.
vertical driving shaft is fitted to this sliding frame, & moves up and down
therewith, the propeller shaft being actuated by bevel gear. The vertical
shaft in the sliding frame receives motion through bevel wheels, one of which
is fitted to the shaft, which slides through it freely to permit of the rising or
lowering motion of the propeller frame, while at the same time transmitting
the rotary motion; the other wheel is fitted to the shaft communicating with
the engine or other driving power. By lowering the propeller below the keel
of the vessel, great resistance of water is offered to the propeller by reason of
the increase of density in that body at greater depths. The sliding propeller
frame may be fitted with rack & pinion gear for the purposes of elevation &
depression, & in order to render that more easy to be accomplished, the whole
weight may be suitably counterbalanced. In order to prevent the propeller
touching the ground when below the keel, we employ what we term a feeler.
It consists of a hinged rod which projects down below the lowest depression
of the propeller. This feeler is placed forward in the ship, & immediately it
comes in contact with the ground it is folded up, the action at the same time
being transmitted by suitable connections to the propeller frame, which is
thereby raised & withdrawn from danger of contact. For this purpose the
rack & pinion gear must be withdrawn, & the propeller frame nicely counter-
balanced.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Napier and John Miller in the Great Seal Patent
Office on the 6th August 1856.
.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
NAPIER, of Bath Street, Glasgow, in the County of Lanark, and of the
Adelphi, in the County of Middlesex, and JOHN MILLER, of Cavendish Street,
Glasgow, in the County of Lanark, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her.Letters
Patent, bearing date the Sixth day of February, 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 us, the
said George Napier and John Miller, Her special licence that we, the said
George Napier and John Miller, our executors, administrators, and assigns, or
.such others as we, the said George Napier and John Miller, our executors,

page_text: 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 THE MODE OF DEIVING AND IN
APPLYING SCREW PROPELLERS TO THE PROPULSION OF VESSELS, upon the condition
(amongst others) that they, the said George Napier and John Miller, their
executors or administrators, by an instrument in writing under our or one of
our, 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, the said George Napier, on behalf of myself
and the said John Miller, do hereby declare the nature of our 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
Sheet of Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
Our improvements in driving and applying screw propellers consists in
fitting them, as herein-after described, whereby they may be depressed below
or raised above the level of the keel while in action. For this purpose we
place the propeller on a short shaft mounted in a sliding frame, which by
preference we place in the dead wood, in which it has bearings down to the
keel; a portion of the dead wood and rudder, or stern post, supports the sliding
frame in the rear, while it is similarly supported by the dead wood & stern'
post in front. This propeller frame slides in a vertical direction, and comes
up through the deck. A vertical driving shaft is fitted to this sliding frame,
and moves up and down therewith, the propeller shaft being actuated by
bevel gear. The vertical shaft in the sliding frame receives motion through
bevel wheels, one of which is fitted to the shaft, which slides through it freely
to permit of the rising or lowering motion of the propelled frame, while at
the same time transmitting the rotary motion; the other wheel is fitted to the
shaft communicating with the engine or other driving power. By lowering
the propeller below the keel of the vessel, great resistance of water is offered
to the propeller by reason of the increase of density in that body at greater
depths. The sliding propeller frame may be fitted with rack and pinion gear
for the purposes of elevation and depression, and in order to render that more :
easy to be accomplished, the whole weight may be suitably counterbalanced..

page_text: Figure 1 of the Sheet of Drawings annexed represents the side view of
a vessel fitted with a screw propeller according to our Invention. It is placed
in the usual position in the dead wood or between the stern and rudder posts,
but so fitted that it not only can be slid up on deck through a trunk in the
usual manner, but can be projected below the keel to a considerable.depth.
The propeller is thus readily immersed in dense water, which offers great
resistance, and it obtains a better hold for propelling than when only immersed
below the surface.. Figure 2 represents a. longitudinal vertical section of the
stern of the ship, and propeller; Figure 3, a. transverse vertical section on.
the line 1, 2, Figure 1; and Figure 4, a deck plan of the ships stern..
Figure 5 represents the propeller and propeller frame on an enlarged, scale,.
and Figure 6 a horizontal section of the same, shewing also a section of the
stern and rudder posts c,, d. a,,a,, is the propeller, which, so far as regards.
the form of the blades and its action on the water, is the same as ordinary;
b, b, 61, 61, is a rectangular frame, in which the propeller a is fitted on bearings.
e, f, fixed thereto. This frame b, b, is fitted between the stern and rudder
posts c and d, or it may be in any other convenient position in the, dead wood.
or other part of the ship.. It is fitted so as to slide vertically up and down, in
order to rise and bring the propeller within the limits of the keel, as seen
in Figure 1, or to permit its depression entirely below the keel, as seen in
Figure 2. The propeller frame consists of a single part 6 on the one side,.
which is fitted to slide vertically, and at the same time be firmly sustained by
the rudder, post d,, as seen in the cross section Figure 6. The side b¹, b', is
divided into two limbs. (see sections Figures 3 and 6); to permit the passage
of the main driving shaft g from the engine,, which I place close. under, the
deck. The propeller frame is furnished with a shaft h, whereby the power is.
transmitted to the propeller. It is supported on the block of bearing e at the
lower end, and in a suitable bearing i at the top; by which it, is sustained. in
a position parallel to the motion of the sliding frame b, b₁, so that it, may slide
freely through the pinion k. This pinion is sustained in a. fixed position,
and always in gear with the bevel wheel on the.engine shaft. g. The pinion
k is fitted in a bearing m supported from the stern post or other part of
sufficient strength, in which it rotates freely, but is prevented moving up or
down, so that when the propeller frame is so moved, the shaft h slides through
the pinion k. This shaft h may be square, and, fitted in a. square, eye of the
pinion, whereby it may slide through that pinion o, & at the same time
impart any rotary motion to the pinion that may be communicated to the shaft
b

page_text: h by the wheel.l. A suitable bevel wheel o is fixed on the boss or centre of
the propeller, the propeller being otherwise simply fitted in its bearings e, f..
The bevel pinion p. fixed to the lower end of h is always in gear with o, and
imparts rotary, motion to the propeller by the motion of shafts 9 and.h.
Instead of using, a square shaft h, I prefer to make; that shaft. round, with
a grove, q,. in which a;feather fixed in the pinion k slides, and provides for the
rotation of pinion, by the motion of the shaft h. at the same time, with
sufficient freedom.for the, shaft to slide through the pinion.
".
The propeller frame b, b', being strongly constructed. and mounted in suit-
able slide bearings, is sustained by the pinions r, r, fixed on a shaft s.. The
pinions, r, take into racks v, v, fixed or formed on the propeller frame b, b¹.
The shaft sis sustained on standards t, t, from the deck, and. furnished with
a worm wheel w fixed to: shafts, into which an: endless worm. or screw
gears. The endless worm shaft u is furnished with a cross.handle, whereby it.
may be turned for the. purpose of elevating or depressing the propeller frame,;
which it effects by the motion imparted. by the pinion shaft's and racks. v, v..
The screw gear will in; itself. sustain the propeller frame .in- any required.
position, or in addition to the hold it may derive from friction. The cross:
handle may be secured in any, convenient. manner. As the engine shaft g
receives motion from the engine, it will be obvious that the motion so
communicated will be transmitted to the propeller in any position within its
range of up and down motion, exhibited in Figures 1 and 2, and that it
may be elevated or depressed during its action for the purpose of projecting
it below the keel of the vessel, or of bringing it up above that point for safety
in shoal water. When the propeller is at its highest position, the lower part of
the frame b', b, forms a line with the keel, the propeller being still in a position
for effective propelling, but when the vessel is in deep water, and no danger of
accident to the propeller is to be apprehended,, the frame b, b',.is lowered,
down to the lowest or other intermediate position that may be desirable.
This raising or lowering of. the: frame b, b, and propeller, can be effected
during and without interfering with the action of the propeller, the shaft /
sliding through the pinion k while it receives motion from the wheel / on the
engine shaft; these wheels, as well as wheels p and o, being always in
the same relative position, and in driving communication with each other..
The arched part y, y, of the ship immediately above the propeller may be
permanent, in which case the propeller could not be brought on deck, or a
trunk, as shown in dotted lines n, n, Figures 3 and 4, may be constructed,
through which the propeller and. frame b may be lifted above deck, as well
understood in fitting ships with screw propellers. For this purpose it will be

page_text: necessary to remove bearing m, wheel 1, and to withdraw the engine shaft g
from frame b'. Instead of placing the propeller in the dead wood, it may be
situated in the bow of the ship immediately abaft the stern, in which position
we believe it will be equally effective in propelling when below the keel, and
with great advantages in steering the ship. The fullness of the bow will
detract from the effect of the propeller when above the level of the keel, but
in that position its effective propulsion will be of secondary importance.
In order to strengthen the rudder post or the stern, it may be necessary to
apply iron stays z,, as seen dotted in Figures 1 and 3, in which case these
stays should present as little obstruction to passing through the water as
possible.
Having described the nature of our Invention, and the manner it which it
may be performed, we would have it understood that what we claim and
desire to protect under the before in part recited Letters Patent is, driving
and applying screw propellers to ships and other vessels in the manner and
for the purposes herein-before described, so that they may be depressed below
or elevated above the keel of the vessel, either while in action or otherwise, as
herein-before described.
In witness whereof, I, the said George Napier, have hereunto set my
hand and seal, this Sixth day of August, in the year of our Lord One
thousand eight hundred and fifty-six.
Witness,
W. CLARK,
Patent Agent,
53, Chancery Lane, London.
GEO. NAPIER. (L.S.)