CERTAIN IMPROVEMENTS IN MACHINERY USED FOR PROPELLING VESSELS BY STEAM POWER
Year: 1843

page_text: RACE
MAUDSLAY, of Lambeth, in the County of Surrey, Engineer, send greeting.
WHEREAS I did by petition humbly represent unto Her present most
Excellent Majesty Queen Victoria that I had invented "CERTAIN IMPROVEMENTS
IN MACHINERY USED FOR PROPELLING VESSELS BY STEAM POWER;" and Her said
Majesty, being willing to give encouragement to all arts and inventions which
may be for the public good, was graciously pleased, by Her Letters Royal
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Thirteenth day of July, One thousand
eight hundred and forty-three, in the seventh year of Her reign, for Herself,
Her heirs and successors, to give and grant unto me, the said Joseph Maudslay,
my exors, adñiors, and assigns, Her especial license, full power, sole privilege
and authority, that I or they, by myself or themselves, or by my or their
deputies, servants, or agents, or such others as 1 or they should agree with, and
no others, during the term of fourteen years from the date of the said Letters
Patent, should and lawfully might make, use, exercise, and vend my said
Invention within that part of Her said Majesty's Dominions called England,
Her Dominion of Wales, and Town of Berwick-upon-Tweed, in such manner
as to me, my exors, adñiors, and assigns, shall seem meet, and as that I or
they shall enjoy the whole profit and advantage arising by reason of the said
Invention during the said term of fourteen years; and for that end Her said
Majesty requires and strictly commands all Her subjects whatsoever within

page_text: England, Wales, and Berwick-upon-Tweed aforesaid that they shall not,
directly nor indirectly, make, use, or put in practice my said Invention, or any
part thereof, nor in anywise counterfeit, imitate, or resemble the same, nor make
any addition thereto or subtraction therefrom, whereby to pretend himself or
themselves to be the inventor or inventors thereof. And whereas the said
Letters Patent contain a proviso obliging me, the said Joseph Maudslay,
particularly to describe and ascertain the nature of any said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, and to cause the same to be enrolled in Her Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Joseph Maudslay, do hereby declare that my said Invention is described and
ascertained in manner following, and by the aid of the two Sheets of Drawings
hereunto annexed, that is to say:-
My improvements in machinery used for propelling vessels by steam power
consists, firstly, in a peculiar application, herein-after described, of endless ropes
circulating with repeated convolutions of the same rope around pairs of grooved
drums, for the purpose of communicating rapid rotatory motion from the steam
engine or engines to revolving propellers of the kind which have been hitherto
usually denominated screw propellers, but which may be of various forms, and
sometimes resembling the sails of windmills rather than screws. The revolving
propellers, to which rapid rotatory motion is to be communicated by means of
this first part of my improvements, may operate by means of any kind of oblique
acting surface or surfaces which is or are attached to an axis, disposed in the
direction of the lengthway of the vessel, parallel or nearly parallel to the keel
thereof, or parallel or nearly parallel to the direction in which the vessel is to
advance endway forward, the said axis being low enough down in the vessel
to cause the revolving propeller or propellers to be wholly (or almost wholly)
immersed below water; and rapid rotatory motion being communicated to such
axis the oblique acting surface or surfaces of the propeller or propellers will be
carried round in the water with circular motion in planes which are at right
angles (or nearly so) to the direction of the lengthway of the keel, or to the
direction in which the vessel is to advance endway forwards by the propelling
effort resulting from the obliquity wherewith the acting surface or surfaces of
the propeller or propellers operate in the water when so carried round therein
with circular motion. Revolving propellers of the kind aforesaid require to be
turned round more frequently than the cranks of the steam engines are

page_text: commonly turned round, and therefore toothed wheelwork has usually been
employed for turning the axes of the propellers with multiplied rapidity of
revolving motion; in other cases, drums and endless straps of leather have
been used. According to this first part of my improvements, an endless rope
or ropes circulating with repeated convolutions of the same rope around a pair
or pairs of grooved drums may be used for giving the requisite multiplication
of the rapidity of revolving motion to any kind of revolving propellers which
may require such multiplication. In the Drawing hereunto annexed, Figure 1,
Sheet I, is a transverse vertical section of a steam vessel, shewing so much of
the machinery therein as is to be constructed according to this first part of my
improvements; and Figure 2 is a longitudinal vertical section of the vessel
corresponding to Figure 1, and shewing the same machinery sideways. The
same letters of reference are used to denote the same parts in both Figures.
The axis of the crank (or cranks) of the steam engine (or engines) is
disposed parallel to the lengthways of the vessel, and that axis is prolonged
by another axis, A, A, disposed in the same line with the axis of the crank
or cranks, and on that prolongation A, A, a large cylindrical drum B, B, is
fastened, having a number of grooves around its circumference suitable for
receiving an endless rope a, a. The axis of the propeller (or rather a pro-
longation of that axis represented by D, D,) is parallel or nearly parallel to
the axis A, A, and a small cylindrical drum E, E, is fastened on the axis D, D,
having grooves around its circumference corresponding to the grooves around
the large drum B, B. The endless rope a, a, is carried over the large drum B, B,
and under the small drum E, E, with a series of convolutions around the two
drums in the grooves of each drum respectively. To trace the course of the
endless rope, it may, for the purpose of description, be supposed to commence
by being passed over the large drum B, Figure 2, in the endmost groove r
thereof, or that groove which is nearest to one end of the drum. Then the
rope is carried down under the small drum E in the endmost grooves of that
drum; then the rope is carried up again over the large drum B in the endmost
groove but one, t, of that drum; then down again under the small drum E in
the endmost groove but one, u, thereof; and so on, the rope is carried around the
two drums with succeeding convolutions, enveloping both drums in each convo
lution; the rope occupying adjacent grooves of each drum at each succeeding
convolution, and applying itself upon more than half round the upper part of
the circumference of the large drum B, and beneath rather less than half round
the lower part of the circumference of the small drum E at each such convolu-
tion. In this manner, by advancing from one groove to the next adjacent
groove of each drum at each succeeding convolution that the rope makes

page_text: around the two drums, it progresses along the drums from one end to the other
of each of the two drums respectively; so that having, for the purpose of descrip-
tion as aforesaid, supposed the convolutions of the rope to commence by being
passed over the endmost groover of the large drum B, it will conclude its series
of such convolutions by being passed under the last groove of the small drum at a,
and from thence the rope is carried upwards in an inclining direction at y (see
also Figure 1), to a leading pulley F, over which it makes a quarter turn, and is
carried in the direction of the lengthway of the drums at v, to another similar
leading pulley G, under which it also makes another quarter turn, and thence is
carried upwards in an inclining direction to the endmost groover of the large
drum B, where it has been supposed, for the purpose of description, that the
convolutions commenced; but in fact it was only a supposed commencement,
because the rope is endless, its two ends being spliced together, and the whole
of the convolutions which it makes around the two drums B and E, including
its passage at y, v, and z, around the two leading pullies F and G, is one
continuous series returning into itself, without any assignable beginning
or end. The leading pullies F and G are disposed with their axes in inclining
directions, and so placed as that the endless rope, in proceeding towards or
away from their circumferences in the direction of tangents thereto, will be in
the planes of the endmost grooves of the two drums; for instance, when the
rope is proceeding upwards in an inclining direction at y, from the endmost
groove of the small drum E, that inclining direction y is a tangent to the
pulley F, and so the inclining direction z of the rope, in proceeding to the end-
most groover of the large drum B, is a tangent to the pulley G, and in passing
at from the leading pulley F to the leading pulley G, the rope makes its
return all at once in the direction of the lengthways of the drums, from being
opposite to one end of each of the two drums at x, to become opposite to the
other end of each of the two drums at r; and thus (by such return) counter-
acting the effect of all the progress that the rope makes contraryways along
the said lengthway of the two drums in making its successive convolutions
around them, and progressing at each such convolution from each groove of
each drum to the next adjacent groove thereof, in the manner already described.
And in order to give a proper tension to the endless rope, so that it may apply
itself properly in the grooves of the two drums and avoid slipping therein,
another small drum II, Figure 1, (which may have grooves around its circum-
ference corresponding to those around the small drum E,) is applied with its
axis in a direction parallel to that of the two drums B and E, so that
its circumference will bear against the endless rope at one part of each of the
several convolutions thereof, so as to bend the rope into the space between

page_text: the large drum B and the small drum E, with more or less of deflection from
the straight direction that the rope would assume in passing from the grooves
of one of those drums to the corresponding grooves of the other of those
drums, as would be the case if there were no such bending action by the drum
H, in order by such bending to give the requisite tension to the rope. The
pivots at the two ends of the drum H are mounted in bearings formed in two
levers, whereof one is shewn in Figure 1, at i, I, k, the fixed centre of motion for
that lever being at the end i, and the bearing for the pivot of the drum H being
near the mid-length; and at the extreme end of the same lever a bar extends
from it across in a horizontal direction to the corresponding end of the other
lever at the other end of the drum H, which other lever is similar to that which
is represented, and has the bearing for the other pivot of the drum E near its
mid-length. The said bar, which extends from the extreme end k of one of the
said levers to the corresponding end of the other of them, unites those
two levers into a sort of moveable frame wherein the drum H is included, and
by which it is sustained, with liberty to turn freely round upon its pivots at
each end of it, and a screw J is applied to the said bar, which extends from
one lever to the other, in order to sustain the said moveable frame and the
drum H, and so as to raise or lower the same by turning that screw J, and by
that means to cause the drum H to bear with its circumference against the
rope, in order that it may bend the rope less or more into the space between
the large drum B and the small drum E as may be required, in the manner
already mentioned. The said bending of the rope will cause it to apply around
a greater portion of the circumference of the small drum E than would be the
case without such bending, and there is one such bending in the rope for each
of the convolutions that it makes around the two drums B and E; and by
turning the screw J from time to time, so as to give more and more of such
bending, the
proper tension of the rope can be kept up, although the rope may
be stretching out and gradually increasing in length in the course of continual
working. When a new rope is put on, it should have the two ends spliced or
united together, so as to form an endless rope of such length that the several
convolutions of the rope will apply with a proper tension around the two drums
Band E, to avoid slipping in the grooves thereof without requiring much of the
aforesaid bending of the rope by the drum H at first; but as the new rope
extends in length by stretching in working, the screw J must be turned so as
to raise the frame wherein the small drum H is mounted, in order to bear that
down against the rope until it bends the same as much as may be requisite for
keeping the rope to a proper teusion; such regulation by the screw J being
repeated from time to time, and gradually, but as fast as the rope may (by its

page_text: stretching) have a tendency to diminish in its tension, so as by means of the
screw J to counteract that tendency. And when the rope has lengthened
so much as to require all the bending that the drum H can produce, in order
to keep up the requisite tension, then the rope must be shortened at its ends,
and those ends united together again, so as to restore the endless rope to its
original length, when, as already mentioned, it will not require much bending
by the drum II, in order to produce the requisite tension. Note:-The
tension of the rope may be regulated by substituting for the drum H a single
leading pulley, similar to F or G, but mounted vertically (that is, with its axis
of motion horizontally), in a moveable frame, the said pulley being applied to
any one of the convolutions that the rope makes around the two drums B and E,
so that the rope, in passing from one of those drums to the other, will also pass
around the said single leading pulley, and, according to the position into which
that pulley is moved, the rope may be thereby bended in a direction away
from the drums B and E, with less or more of deflection from the straight
direction that the rope would assume in passing from one drum to the other,
as would be the case if there were no such bending action by the said single
leading pulley, which by means of the moveable frame wherein it is mounted
may be removed by turning a screw, so as to cause less or more of such
deflection. The extent of motion that must be given by such screw to the
said moveable frame containing a single leading pulley in order to counteract
the effect of any given extent of lengthening of the rope by the stretching
thereof and keep up its tension, will be greater than will be required to be
given to the drum H in order to counteract the effect of the same extent of
lengthening of the rope and keep up its tension, inasmuch as that the drum
H by acting upon the rope at several places produces as many deflections
thereof, whereas the single leading pulley acting only at one place can only
produce one deflection of the rope. Or two or more such leading pullies, each
mounted in a moveable frame of its own, which can be moved by a screw,
may be applied to two or more parts of the rope at as many of the separate
convolusions that it makes around the drums B and E. Note:-The grooves
around one of the drums (B, for instance) should be opposite to the intervals
or spaces between the grooves on the other drum (E, for instance). The
endless rope may be made of hemp spun into yarus, which are twisted
together into strands, and which strands may be either twisted or plaited
together into a rope; or any other suitable material may be used, such, for
instance, as strips of strong hides plaited together in the same manner as the
tiller ropes used for steering large ships are made. A small proportion of tar,
or of tar mixed with dissolved india-rubber, may, if preferred, be introduced in

page_text: the making of the rope, if it is of hemp, or otherwise it may be made without,
in the manner of what is called untarred rope. The strands of the rope should
not be very hard twisted, but rather soft laid, so as to be flexible. The ends of
the rope may be joined together to form the endless rope by splicing in the
manner of what seamen term a long-tapered splice. Note:-Instead of one long
endless rope, two endless ropes of half the length may be used and applied on
distinct drums, such as B and E, Figure 2, except being of little more than half
the length there represented, and fastened one at the end of the other, on the
same axis A, A, and D, D; so that the said two drums will occupy nearly the
same places on each of those axes (except occupying rather more length therein)
as the drum B occupies on the axis A, A, and as the drum E occupies on the axis
A, A, and as the drum E occupies on the axis D, D, in Figure 2. Or the
two drums may be as there represented, only rather longer, with a few more
grooves in each drum, and having one of the said two endless ropes, of half the
length of that represented, applied around the grooves of both drums for
rather less than one half of the length of each drum B and E respectively;
but that rope making only half as many convolutions around the two drums
as is represented in Figure 2, and having two leading pullies similar to F and
G, and suitably placed for causing the return of the said rope from one
extreme of so many of the grooves as it does occupy by its convolutions around
the two drums to the other extreme of these said grooves; and the other of
the said two endless ropes, of half the length of that represented, being
applied in like manner in the remaining grooves at the other half of the length
of each drum B and E respectively, but that rope making only half as many
convolutions around the two, as is represented in Figure 2, and having two
leading pullies of its own, similar to F and G, for causing the return of the
rope in manner aforesaid; so that there will be two pairs of the leading
pullies similar to F and G, that is, one pair for causing the return of each of
the two endless ropes. The four pullies constituting the said two pairs must
be placed so as to avoid any interference of one pulley with another; and if
the pullies are made rather smaller in diameter than is represented in the
Figures, they may all four be sustained (without interference) in as many
suitable frames aflixed to the beam L, Figure 1, in the same manner as two
pullies can be supported thereby; but interference of the pullies may be
avoided by disposing one pair of them for one of the two endless ropes on the
beam L, at one side of the drum D, as the pullies F, G, appear in Figure 1,
and disposing the other pair of leading pullies for the other of the two endless
ropes on another similar beam to I, but fixed at the opposite side of the drum
B. And with two endless ropes there must be two of the drums, such as H,

page_text: but each one of little more than half the length represented at E, E, in
Figure 2, the two being disposed one at the end of the other, but each one
being mounted in a pair of levers, like i, I, &, of its own, and the two levers
constituting each pair being united together by a horizontal bar, and having a
screw similar to J, in order to form two distinct moveable frames, wherein the
two short drums, such as H, are mounted, so as that each of those drums will
be capable of being applied, by means of its own screw, to act against one of
the two endless ropes without any interference with the other of those endless
ropes; and therefore the requisite tension of each of the two endless ropes can
be kept up by means of its own screw J, moveable frame I, and drum H,
independantly of the tension of the other of these ropes, each one being treated
in the manner already described respecting one endless rope. In consequence
of the repeated convolutions made by each such endless rope or ropes around
the drums B and E respectively, the combined strength and action of as many
endless ropes as there are convolutions is rendered available for transmitting
the rotatory power of the steam engine or engines to the revolving propeller,
with a multiplied rapidity of revolving motion; and every convolution of the
same endless rope will have an equality of tension for causing the necessary
holding to prevent slipping of that rope in the grooves of the drums, and that
equal tension of all the several convolutions of the same endless rope can be
kept up to the requisite degree of tension by only one regulation for the tension
of the same endless rope, and consequently by only two such regulations in
case two endless ropes are used. In case of two revolving propellers being
used for the same vessel, they are usually mounted on two axes disposed
parallel to each other on each side of the centre of the width of the vessel,
instead of the one axis D, D, at that centre. In such case, one of the said
revolving propellers may be turned round by one of the two endless ropes above
described, and the other propeller by the other of those ropes, each axis of the
propeller having a small drum fastened upon it similar to E, except being half
the length represented at E, E, in Figure 2. One of the said two endless
ropes will make its convolutions around grooves at one end or half of the
large drum B, and around as many grooves on one of the small drums (similar
to E), for one of the propellers; but the other endless rope will make its
convolutions around the remaining grooves at the other end or half of the
length of the drum B, and around as many grooves on the other of the small
drums (similar to E), for the other propeller. Revolving propellers have been
hitherto disposed at the stern of the vessel, but have been proposed to be at the
head of the vessel; the first part of my improvements, as herein-before
described, is applicable in either case. No part of the steam engine or engines

page_text: is shewn in the Drawing, and any kind of steam engines which can be used on
board vessels may be used. The axis A, A, being (as already mentioned) a
prolongation of the axis of the crank or cranks of the steam engine or engines,
it may be connected therewith, in the same manner as one of the axes for one
of the paddle wheels is usually connected with the said axis of the crank or
cranks in ordinary steam vessels, except as to the direction of such axes being
lengthways of the vessel, or fore and aft, instead of crossways or athwartship.
The diameter of the large drum B must be as many times greater than the
diameter of the small drum E as the revolving motion trasmitted by the
endless rope or ropes from the steam engine or engines to the revolving
propeller or propellers is required to be multiplied.
And, secondly, another part of my said improvements consists in applying
revolving propellers of the kind hitherto usually denominated screw propellers
(and being of the oblique action kind which has been already explained at the
commencement of this Specification) behind or abaft of the stern post of the
vessel which is to be propelled thereby at the place usually occupied by
the rudder, the axis of the propeller being amidships or nearly so, that is in
the middle or nearly in the middle of the breadth of the vessel, and substi-
tuting for the ordinary rudder two rudders, whereof one is disposed beneath
each of the stern quarters of the vessel for the purpose of steering the same.
In Sheet II. of the Drawings hereunto annexed, Figure 3 is a lateral cleva-
tion, Figure 4 a transverse section, and Figure 5 an elevation of the stern,
and Figure 6 a horizontal plan of so much of the sternmost part of a steam
vessel as is to be constructed according to this second part of my improve-
ments. d, D, is the axis of the revolving propeller disposed parallel or nearly
parallel with the keel, or nearly in the direction in which the vessel is to
advance when propelled forwards, that axis passing through the stern post
N, N, of the vessel, and projecting out behind the same far enough for fasten-
ing the revolving propeller O, O, on the end d of the axis; or, instead of
passing through the substance of the stern post N, N, the axis d, D, may pass
close to one side thereof, so as to avoid weakening the stern post, but never-
theless so as to be sufficiently near to the centre of the width of the vessel for
enabling the propeller O, O, to exert nearly the same propelling action on the
vessel as if the axis were in that centre. The axis d, D, passes through a
stuffing box m, m, Figure 2, to prevent entrance of water by the axis in the
usual manner of passing the axes for revolving propellers through from the
interior to the exterior of vessels. The axis d, D, is sustained in a bearing
n, fixed to the stern post N, N, and the propeller O, O, is fastened on the
end d of the axis d, D, near to the bearing n; the other end D of the axis

page_text: within the vessel is connected in the usual manner to another axis (or to other
axes) for prolongation of the axis of the propeller to that part of the vessel
containing the steam engine or engines. The axis D, D, Figure 2, Sheet I.,
is part of such a prolongation of the axes of the propeller as is usual in vessels
with revolving propellers; and some suitable means of disconnecting should be
provided at any convenient part of the said prolongations, in order to be able
to leave the propeller at liberty to turn round freely when the vessel is to be
advanced by her sails without action of the propeller, all which may be as
usual. The axis D d, Sheet II., may be turned round by application of the
first part of my improvements. A grooved drum, such as E, Sheet I., being
fastened upon its prolongation for receiving an endless rope (or ropes) as
herein-before described; or otherwise a toothed pinion may be fixed on the
said prolongation in place of the drum E, for turning the same by toothed
wheelwork in the most usual manner of turning screw propellers; or any
other mode of turning the axes d, D, of the propeller, with a suitable rapidity
of revolving motion, may be used as may be preferred; for although the two
parts of my improvements may be used in concert, there is no necessity for
doing so, as they may be used one part without the other; that is to say,
revolving propellers applied behind the stern post of a vessel at the place
usually occupied by the rudder according to the second part of my improve-
ments may be turned round by means of endless ropes applied with repeated
convolutions around pairs of grooved drums, according to the first part of my
improvements, or else by any other means which have been or can be used for
turning revolving screw propellers; and endless ropes, applied as aforesaid accord-
ing to the first part of my improvements, may be used for turning revolving
propellers applied according to the second part of my improvements, or else for
turning any revolving propellers of the kind already explained at the commence-
ment of this Specification, when the same are applied in any manner in which such
propellers have been or can be applied for propelling vessels. The two rudders
which, as already mentioned, are to be substituted for the one ordinary rudder,
are marked P, Q, in the several Figures in Sheet II., one of those rudders P
being beneath the larboard quarter, and the other rudder Q beneath the star-
board quarter of the vessel; each of those rudders being an upright cylindrical
axis of iron b, see Figure 4, passing down through the interior of an upright
tube of metal e, e, see Figure 4, which is fixed securely in the vessel by the
upper end of the tube ascending through the deck, and the lower end descend-
ing through the side of the vessel where her quarter overhangs, and both ends
of the said tube e, e, being securely fastened with water-tight junctions to the
deck and to the vessel's side around the exterior of each end of the tube e, e.

page_text: The lower end of the said upright axis b, of each rudder is enlarged to form a
broad thin blade P or Q, of any suitable form for acting in the water in the
manner of a rudder. Part of the surface of such blade may be before the
central line of the axis b, if that line is supposed to be prolonged downwards,
as is dotted at f; but the larger and chief part of the said surface of the blade
P must be abaft or behind such supposed prolongation of that central line.
The blade P or Q is then clgeways, in order that it may pass easily through
the water. At the borders and lower part of the blade P or Q the edges are
as thin (for cutting edges) as strength will permit, and the thickness increases
very gradually from the borders inwards towards the dotted central line f, and
upwards towards the upright axis part b, to acquire such a thickness as is
requisite at the upper part for an effectual junction of that part with the
upright axis b, which, as well as the said junction, must have adequate strength
for sustaining the blade P or Q firmly in the water by means of that axis, and
in consequence of the same being fitted into the interior of the tube e, e, at
the upper and lower ends thereof, but with liberty of turning freely round in
that interior for the purpose of steering the vessel. The upper end of each
axis b ascends above deck through the upper end of the tube e, e, and a lever
or tiller R is fastened on that upper end of each axis b, for turning the same,
and consequently turning the blade P or Q at the lower end thereof in the
water for steering. When the said tillers R, R, are in their fore and aft
direction or pointing lengthway of the vessel, the blades P and Q will be in the
same direction, see Figure 6, and will advance through the water with their
thin border edges foremost so as to offer but little resistance, and will then
have no effect of steering the vessel; but on turning the tillers R, R, to either
side (larboard or starboard), their upright axes b will transmit a like turning
motion to the blade P and Q in the water so as to place the same in an
oblique direction to the lengthways of the vessel, in which case they will
operate by oblique action in the water in the same manner as an ordinary
rudder would do for steering the vessel. The two rudders P and Q may be
used in concert for so steering, for although each one will produce its own
effect of steering independantly of the other one, it may be preferred to employ
both of them with convenient effect, which may be done by moving the tillers
R of both rudders in like manner at the same time; and for convenience of
doing so, the two tillers R & R of the two rudders P and Q may be con-
nected together at their foremost ends (or at their aftermost ends in case they
are tillers which go backward from their axes b) by a link extended horizon-
tally across from one of those foremost (or aftermost ends) to the other of
them, and jointed to both those ends, and then any turning motion which may

page_text: be given to one tiller R, and rudder P, will be equally given to the other
tiller R, and rudder Q. Or one central tiller may be applied on a centre or
axis fixed up amidship, or at the middle of the deck, in the usual position of
the tiller of an ordinary rudder, and that central tiller may be connected by
links proceeding therefrom horizontally across each way (larboard and starboard)
to the said foremost (or aftermost) ends of the two tillers R and R of the two
rudders P and Q, and jointed at one end of each of the said links to the said
central tiller, and jointed at the other end of cach link to the said end of one
of the two tillers R and R, and by the connection of such cross links any
motion which is given to the said central tiller will be transmitted equally to
both the tillers R and R, and to both the rudders P and Q, for steering the
vessel, as already mentioned; and such central tiller may either be moved by
hand in the manner of steering by a simple tiller, or any suitable kind of
steering wheel may be used with the ordinary kind of barrel for winding up
ropes or chains, which are passed around suitable leading pullies and applied
to the end of the central tiller. Or such ropes or chains may be applied to
the ends of the two tillers R, R, (without having any such central tiller or
links as aforesaid,) and the said ends of the two tillers R, R, being connected
together by a short rope or chain or link, both tillers R, R, will be moved
together with equal motions whenever the steering wheel is turned in the usual
manner for steering a vessel by a wheel. Or, instead of connecting the two
tillers R & R with a central tiller by means of such horizontal cross links
as above mentioned, flexible chains may be used by way of links for connect-
ing the foremost ends of the two tillers R, R, with the central tiller above
mentioned, in order that such chains may not transmit any pushing action to
cause the foremost end of either tiller R to be pushed farther away from the
centre of the vessel than the midship direction of the tiller, although such
chains will transmit a pulling action to cause the foremost end of either tiller
R to be drawn nearer towards the centre of the vessel than the midship direc-
tion of the tiller. Wherefore, in steering with a central tiller so connected by
chains, the rudders will never be turned in the water by force of the steersmen
so as to turn their aftermost ends inwards towards the stern part of the vessel,
as would be the case if inflexible links were used for connecting the foremost
ends of the tillers R, R, with the central tiller. For although it may be pre-
ferred to employ both rudders with concurrent effect for steering (and then
both rudders should be turned at the same time with like motions), neverthe-
less it may be thought objectionable to turn the aftermost part of either rudder
inwards towards the stern part of the vessel in cases when there might not be
adequate space left for the water to pass freely away between the vessel and

page_text: the said aftermost part of the rudder when the same is so turned inwards.
And both the kinds of links above mentioned may be provided for connecting
the foremost ends of the two tillers R, R, with a central tiller; viz., a pair of
inflexible links jointed at one end of each link to the cental tiller, and jointed
at the other end of each link to the foremost end of one of the two tillers
R, R, so as by such links to transmit a pushing action as well as a pulling
action from the central tiller to the foremost ends of the two tillers R, R;
and also a pair of flexible chains to be substituted for such inflexible links
when required, which chains, as already mentioned, will transmit a pulling
action, but not a pushing action; and one kind or other of the said links may
be used according as it may be found by experience that the steerage of the
vessel can be most advantageously performed with one kind or with the other
kind of links. If the pair of inflexible links are used, both rudders will be
turned alike in steering so as to obtain their concurrent effect; but if the pair
of flexible chain links are substituted, then that rudder alone which is on the
same side of the vessel as her head is required to be turned to will be opera-
tive, and that said rudder will be turned with its aftermost end outwards
away from the stern part of the vessel; but the chain link will leave the other
rudder at liberty to assume such a direction as the water will give to it, with-
out forcing that rudder to turn its aftermost end inwards towards the stern
part of the vessel, which (as already mentioned) might be objectionable in
case there is not sufficient space then left for a free passage of the water.
Note: Although it is represented in the Drawing, Sheet II., and has been
already mentioned, that the broad thin blade part of each rudder P and Q
which acts in the water may have part of its surface before the central line
of the upright axis b, as shewn by the dotted line f, nevertheless the broad
thin blade part of each rudder P and Q which acts in the water may be
wholly abaft or behind such central line f, if preferred. The revolving pro-
peller 0, 0, is represented with four oblique blades, but that is only by way of
illustration, for it may have three such oblique blades, or it may be a screw
with one thread, or a screw with two threads, or any revolving propeller by
oblique action of the kind mentioned at the commencement of this Specifica-
tion may be fastened on the end d of the axis D d. This second part of my
improvements having no reference to the particular form of revolving pro-
peller, but only to the applying of a revolving propeller behind or abaft the
stern post, at the place usually occupied by the rudder, and substituting for
the ordinary rudder two rudders, in the manner before mentioned; whereas in
the vessels hitherto constructed with what are commonly called screw pro-

page_text: pellers, the said propellers have usually been placed in an opening in what has
been called the dead wood of the vessel before the real stern post to which the
rudder is applied, whereby the said stern post and the rudder follow in the water
after the screw propeller; whereas according to this second part of my improve-
ments the revolving propeller follows in the water after the aftermost stern post
of the vessel, and after the two rudders which are substituted for the ordinary
rudder. It may be said of some of the vessels which have been constructed
with screw propellers, that there are two stern posts, situated one before the
other, with the screw propeller applied in the space between them, the keel of
the vessel extending beneath the propeller to sustain the aftermost stern post
to which the rudder is applied; nevertheless in such case the said aftermost
stern post, together with the rudder, follows in the water after the screw pro-
peller; whereas according to this second part of my said improvements there
is no stern post or rudder or any other part of the vessel which follows in the
water after the revolving propeller. Note:-In case no central tiller nor
links of the kind herein-before mentioned is used, but a steering wheel and
barrel with ropes or chains applied (as herein-before mentioned) to the ends
of the two tillers R, R, those ropes or chains may, if preferred, be so con-
nected with the said ends of the two tillers R, R, as that neither of the
rudders P or Q will ever be moved (by such ropes or chains) any nearer
inward towards the stern part of the vessel than their fore and aft direction,
P, Q, Figure 6, or not much farther inwards than there shewn, and a steering
wheel, with its ropes or chains so applied, will perform the steering of the
vessel in a similar manner (as to the action of the two rudders) as a central
tiller with the flexible links herein-before described would do.
Having now described my said improvements, I, the said Joseph Maudslay,
do hereby declare, that what I claim as new Invention under the said Letters
Patent consists,-
Firstly, in the improvement in machinery used for propelling vessels by
steam power, which consists in the application (in the manner herein-before
described) of an endless rope (or endless ropes) circulating with repeated con-
volutions of the same rope around a pair (or around pairs) of grooved drums,
for the purpose of transmitting rotatory motion from a grooved drum (or
grooved drums) upon the revolving axis of the steam engine (or engines), with
a multiplied rapidity of such rotatory motion to a grooved drum (or grooved
drums) upon the axis (or axes) of any such revolving propeller (or propellers)
by oblique action of the kind mentioned at the commencement of this Specifi-
cation, as may require the rotatory motion of the steam engine (or engines)

page_text: to be so multiplied in rapidity for propelling the vessel by the oblique action
resulting from the rapid rotatory motion so transmitted to such revolving
propeller or propellers.
Secondly, in the improvement in machinery used for propelling vessels by
steam power, which consists in the application (in the manner herein-before
described) of any revolving propeller by oblique action of the kind mentioned
at the commencement of this Specification, such propeller being situate behind
or abaft the stern post of the vessel which is to be propelled thereby at the
place usually occupied by the rudder, and substituting for the ordinary rudder
two rudders of the kind herein-before described, whereof one is disposed beneath
cach of the stern quarters of the vessel, so that the said two rudders shall be
more forward in the length of the vessel than the revolving propeller, and so
as that no stern post or rudder or any other part of the vessel shall follow the
propeller in the water; but I make no claim to the application of two rudders
to or beneath the stern quarters of a vessel for the purpose of steering the
same, except when used as aforesaid in combination with a revolving pro-
peller by oblique action of the kind mentioned at the commencement of this
Specification.
In witness whereof, I, the said Joseph Maudslay, have hereunto set my
hand and seal, this Thirteenth day of January, One thousand eight
AND BE IT REMEMBERED, that on the Thirteenth day of January, in
the year of our Lord 1844, the aforesaid Joseph Maudslay came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Thirteenth day of January, in the year of our Lord One
thousand eight hundred and forty-four.