INVENTION OF IMPROVEMENTS IN THE PROPULSION AND STEERING OF VESSELS
Year: 1877

page_text: In the Matter of Letters Patent granted to JACOB JOACHIM KUNSTÄDTER,
of 14, Guildford Street, Russell Square, in the County of Middlesex, Civil
Engineer, for the " INVENTION OF IMPROVEMENTS IN THE PROPULSION AND
STEERING OF VESSELS," bearing date the Thirteenth day of June, One
thousand eight hundred and seventy-seven, No. 2294.
DISCLAIMER AND MEMORANDUM OF ALTERATION proposed to be filed
by the said Jacob Joachim Kunstädter in the Great Seal Patent Office, with
the Specification to which the same relatos, according to the Statutes in that
case made and provided.
WHEREAS Her Majesty Queen Victoria, by Her Letters Patent, under the
Great Seal of the United Kingdom of Great Britain and Ireland, bearing date the
13th day of June 1877, No. 2294, did give and grant unto the said Jacob Joachim
Kunstädter, his executors, administrators, and assigns, the sole privilege of making,
using, exercising, and vending within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and the Isle of Man, the said Invention of "IMPROVE-
MENTS IN THE PROPULSION AND STEERING OF VESSELS" for the term of fourteen
years from the date of the said Letters Patent:
And whereas since the filing of the Specification in pursuance of the said Letters
Patent the said Jacob Joachim Kunstädter has ascertained that the claim made
theroin is too wide, and may be construed so as to comprise as forming part of the
said Invention improvements which were not new in the United Kingdom at the
date of the said Letters Patent; and also that parts of the said Invention as therein
described and claimed are not of sufficient practical utility to induce me to retain
them as parts of my said Invention :
And whereas I, the said Jacob Joachim Kunstädter, for the reasons aforesaid, am
desirous, by and with the leave of Her Majesty's Solicitor-General, of disclaiming
the portions of the said Specification herein-after mentioned, and of confining the
claim of the said Specification to the modifications of the apparatus for steering

page_text: represents the joint in position it would occupy at about a quarter revolution of
the shaft, and with the framing or rudder at an angle of about 45°.
Figures 5 and 5ª are plan and section respectively of the joint plate or ring piece
carrying the studs or centres, upon which the forks of the screw and driving shafts
are jointed and worked.
Figure 6 shews arrangement of hollow slotted cone, and pinned or studded dome
piece, the studs whereof gear with the slots of hollow cone, and from a universal
joint capable of working to an angle of 45°, or thereabouts.
Figure 7 and 70 shew the two parts of device represented in Figure 6 separated.
Figure 8 represents arrangement of metal bearing piece for support of end of
shafts of outside screws; and, Figure 9, detail of slide and bearing block.
Figures 10 to 15, Sheet 2, are shewn details of construction of joint.
Figures 16 and 17 are diagrams illustrating and comparing the steering of
vessels (1) by rudder and (2) by means of my improved universal joint and rudder
screw.
Throughout the Drawings the dotted line a, b, represents the line of motion of
the rudder and of the universal joint.
In Figure 1, A is the driving shaft capable of being advanced and drawn in its
bearings, and to couple at its outer end A¹ with the main screw shaft B, the main
screw is disconnected with the rudder screw shaft C, said coupling being effected
substantially in ordinary manner by socket in the screw shaft, or by a coupling on
the end of the driving shaft, into which the screw shaft fits and adjusts itself; when
the main screw is not disconnected, its shaft B will be the driving shaft of the
rudder screw, shaft C. D is the universal joint connecting driving shaft with the
shaft of the rudder screw E. At F is indicated in dotted lines a catch piece,
actuated through a hinged lever piece by a rod passing through the stem of the rudder;
and by means of this catch piece the rudder screw will when desired be secured
with its blades in position to afford the least possible projecting surface. For this
reason, and also for the facility with which it may be repaired in case of accident,
a two-bladed "Griffiths" screw is preferred to be used for the rudder screw. .
"
-
Instead of fitting the screw E in an opening in the rudder blade G, as hero shewn,
the blade of the rudder may be cut finer, that is, narrower, and the said screw be
fitted up and work outside and beyond the rudder, but the first described arrange-
ment is preferrable, as in either case the advantages of "outside screws is secured,
but in that shewn the disadvantage of such screws being overhung is avoided, and
with it the heavy strain and rapid wearing of the bearings. When, however, the
screw is fitted up outside the rudder, the catch piece for fastening said scrow will be
arranged to work horizontally, and be actuated through perpendicular rod and bell-
crank lever and link, or as convenient. In order, however, to further reduce the
strain in this case of outside screw, and such screws generally, I provide, as shewn
in Figs. 8 and 9, a metal bearing piece, secured to the sterm d, and curved and
extending outwards and downwards to the keel e, and centrally of said bearing
piece I form a curved guide or slide f, the curve whereof is the arc of a circlo struck
from the centre of the universal joint, and extending horizontally on each side, so
as to allow of sufficient play following the movements of the rudder in steering, and
in this arc-shaped guide is fitted a guide block g; pierced for the reception of the
neck of the screw shaft.
The guide block will be made as a box for reception of grease for lubricating the
slide, and further means for lubrication are secured by channelling the faces of the
slide internally, and conducting oil thereto by tube or channel laid along the bear-
ing, and supplied from deck, cabin, or hold. Rollers may also be used in this bearing
to reduce friction. The bearing will be supported by bracings h of band iron õr
wire rope
I stretched therefrom and secured to the hull of the vessel.
In Fig. 2 g is hinged framing or rudder, shewing bearings G¹, G³, of rudder screw
shaft. The propeller screw E, here represented, is an ordinary two-bladed screw
(but a three or four-bladed screw may be used), and proportionately larger than

page_text: that shewn in Fig. 1, as it is intended to act as propeller, or “auxilliary" propeller,
to paddle or sailing vessels, as well as for steering purposes. The rudder fixings are
made sufficiently strong to receive the "end thrust" of the rudder screw shaft, the
bearing G² being particularly useful in relieving the joint D from undue strain from
this cause.
When the screw is not required to be used the driving shaft will be fixed in
position, as shewn, and the catch pieces indicated at F will, as before explained,
The movements of the rudder in
be brought into action to steady the screw.
steering and of the connections of the driving and screw shafts will now be around
La common centre in F. A is respresented arrangement for fitting small craft, such
as steain launches, gunboats, and the like with rudder screw. G is a framing, in
which the outer end or rudder screw shaft is carried, and through which the
rudder-like movement is given to the screw. Q' is a wrought metal framing serving
as a.stern-post, and secured to the stern at d, and to the keel at e. The bearings
of the rudder framing are rivitted or bolted to this stern-post G³, and said stern-
post is formed with an opening at Gs, shewn partially broken away for illustration,
through which opening the double-coupling joint is capable of working. The pro-
peller screw and coupling joint are not shewn.
The universal joint D, represented in Figs. 2 to 5ª inclusive, consists of a nut
joint plate or ring piece H, carrying pins or studs I, which serve as centres upon
which the forks of the screw and driving shafts are jointed and work. The edgos
of these parts are cleaned down and turned, so as to bring them to an edge on
those sides, which in revolving strike the water, thereby proventing resistance.
The joint shewn in Figs. 6 to 7a is an arrangement of universal joint, which in
some cases it may be desirable to employ.
In making up the joint nut and centres, shewn partly in section in Fig. 10, I
take the ring or nut H and drill out 4 radial holes therein, and tap said holes with
a female screw thread for reception of the screw-threaded end of the 4 joint studs I,
and then having screwed the said studs equally into the ring or nut, as represented
or secured on the head of a
in Fig. 11, the said ring or nut so fitted is "chucked"
lathe, and the adjacent points are drilled away, as represented in Fig. 12, and the
hole thus produced is tapped with female screw thread for the reception of a
fastening or locking scrow stud H³, as shewn in Fig. 10.
In putting the joint together the spanner or forks at the ends of the shaft to be
coupled are placed in relation to the ring or nut H, so that the studs I can be
passed through the holes in the extremities of the forks and screwed into place,
whereupon a fast locking or securing of the studs and forks of the joint will be
effected by screwing in the central locking stud H'. To take the joint apart the
stud His first unscrewed, and then the studs I.
In some cases, and for smaller work particularly, the spanners or forks are made
of a piece with the shaft, or the rudder shaft alone is so made, and the base of the
fork of the main propeller shaft is made with a shank or collar part, as shown in
Fig. 2, and is keyed to the extremity of the main shaft; in other cases the base of
the forks are both made with a shank or collar part, and these are keyed to the
main and rudder screw shafts, as shewn in Figs. 4, 4ª, and 14.
The joint, shewn in section, Fig. 13, consists of the nut H, the screwed studs I',
and the pin I, the ends of the screwed studs I being grooved or channelled, as
shewn at Is, to fit against the sides of the pin 12. In fitting this joint together the
studs I are first passed through the holes in the fork of one shaft, and screwed into
the nut, so that their grooved ends will allow of the passing through of the pin I³,
but to bear against the sides thereof, which will prevent their turning or
unscrewing.
The pin I is shewn screwed at one side to take into a female thread H³ on one
side of the nut, and when the forks of the shafts are thus jointed a screwed pin or
rivet I' is passed through the nut H and pin 12; or I may make the pin I without
the screw H. and fit it tight in the nut F, and then secure it by pin or rivet I.

page_text: It is obvious that when fitted with the screw at H² one end of the pin I³ will be
slightly smaller than the other, and the whole in the arın of the fork corresponding
thereto will have to be of corresponding size.
In Fig. 15 is shewn an arrangement of joint fork, which is divided through the
shank lengthwise, and secured to shaft by a sleeve piece K and cotter pin K', which.
will make a firm attachment; this is designed to be used when the joint nut H and
centres or studs I are made of a solid piece.
In the diagram, Fig. 16, is illustrated the action of steering as in the ordinary
manner, and in Fig. 17 that by means of supplemental or rudder screw.
The line 1, 1, represents the forward course of the vessel, and it is presumed that
the course is to be altered in each case to that of the lines 2, 2. For this purpose
let the rudder be placed as indicated by line 3.
•
For the purpose of illustration, forward movement of the vessel is not indicated,
merely the turning thereof.
Now, in the first case, on turning the rudder a direct retarding action in direction
of the arrow 4 will result, but in the second case the retarding action will be neu-
„tralized by the propelling action in direction of line 3.
In the 1st case the vessel turns upon a centre at the stem, and the head travels
to the point 5 on line 2, 2. In the 2nd case the vessel turns upon a centre amid-
ships in taking up its position in the direction of line 2, 2, which movement will
obviously be effected in less than half the time, as the distance which the head has
to travel in less than half, and in addition there is no loss of power by retarding.
From experiment I have found that a vessel fitted with my apparatus will
complete a full circular or elliptical turn in once and a half to twice her length.
It is obvious therefore that for rapid evolutions, such as are desirable for war vessels
and for river traffic, the practicable application of an adjustable rudder screw is a
great desideratum.
Having now described the nature of my said Invention, and the means whereby
the same is to be carried into practical effect, I would remark that I am aware it
has been proposed to mount a propeller screw in the rudder, or in a framework
having a rudder-like motion, for the purpose of facilitating the steering of vessels,
but hitherto without practical success; I therefore do not claim broadly the use of
a rudder screw, nor do I claim the mechanical parts herein-before mentioned other-
wise than as combined and used substantially as herein described, and shewn
respectively in those Figures of the Drawings which are referred to by numbers in
the following claiming clause, but what I claim is, the improvements in effecting
the propulsion and steering of vessels as herein specified, and shewn by those
Drawings, which in Figs. 1, 2, 24, and 8 and 9 shew the combinations, which are
modifications of my apparatus as a whole, and which in Figs. 10, 11, and 12, and
Fig. 13 shew modifications of my universal joint, to which modifications I confino
my claim.
Jacob 1
A
In witness whereof, I, the said Joachim Kunstädter, have hereunto set my
hand and seal, this Twelfth day of December, in the year of our Lord One
my claim.
Jacob
A
"1
In witness whereof, I, the said Joachim Kunstädter, have hereunto set my
hand and seal, this Twelfth day of December, in the year of our Lord One
thousand eight hundred and seventy-seven.
In witness whereof, I, the said Jacob Joachim Kunstädter, have hereunto set
my hand and seal, this Thirtieth day of October, in the year of our Lord
One thousand eight hundred and seventy-eight.

page_text: I hereby grant my fiat, giving leave to the above-named Jacob Joachim
Kunstädter, to file in the Great Seal Patent Office, with the Specification to which
the same relates, the above-written Disclaimer and Memorandum of Alteration..
HARDINGE GIFFARD,

page_text: LETTERS PATENT to Jacob Joachim Kunstädter, of 14, Guilford Street,
Russell Square, in the County of Middlesex, Civil Engineer, for the Invention
of "IMPROVEMENTS IN THE PROPULSION AND STEERING OF VESSELS."
Sealed the 21st August 1877, and dated the 13th June 1877
PROVISIONAL SPECIFICATION left by the said Jacob Joachim Kunstädter
at the Office of the Commissioners of Patents on the 13th June 1877.
JACOB JOACHIM KUNSTADTER, of 14, Guildford Street, Russell Square, in the County
of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE PROPULSION AND STEERING
OF VESSELS.
This Invention has for its object improved apparatus for facilitating of steering
of vessels, which apparatus may be used either as an addition to the screw pro-
peller at present in use, or may be used independently of the said screw propeller,
in which latter case the improved apparatus acts both as a propeller, and also as
apparatus for facilitating the steering of the vessel.
The improved apparatus consists of a screw propeller, which I call the "rudder
screw," mounted in the blade of the rudder or on the after or hinder part of the
said blade of the rudder, or mounted independently of the rudder.
If the said
"rudder screw
"be mounted in the rudder, there must be in the said rudder blade
an opening large enough to receive the "rudder screw" and allow the same to
revolve.
"
If the rudder screw is mounted in or on the rudder blade, the shaft of the
"rudder screw " is carried by the rudder, but if not, it is carried by independent
"
rudder screw either from
framework, and motion is given to the said shaft and
the main screw shaft or from an independent shaft, to either of which the shaft of
the "rudder screw may be attached by a ball-and-socket joint, a Hoole's or other
universal joint, or round faced bevil gearing, or any convenients means which may
cause the rudder screw to revolve and at the same time allow the rudder to be
moved from side to side.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jacob Joachim Kunstädter in the Great Seal Patent Office on the
13th December 1877.
JACOB JOACHIM KUNSTÄDTER, of 14, Guilford Street, Russell Square, in the County
of Middlesex, Civil Engineer. "IMPROVEMENTS IN THE PROPULSION AND STEERING
OF VESSELS."
This Invention has for its object improved apparatus for facilitating the steering
of vessels, which apparatus may be used either as an addition to the screw propeller
at present in use, or may be used independently of the said screw propeller, in
which latter case the improved apparatus acts both as an "auxillary" propeller,
and also as apparatus for facilitating the steering of the vessel.
A propeller screw, called the "rudder.screw," is mounted in the blade of the
rudder, or on the after or hinder part of the said blade of the rudder, or mounted
independently in a movable framing, which in this case will serve in place of the
rudder. If the said rudder screw be mounted in the rudder, there must be in the
said rudder blade an opening large enough to receive the rudder screw and allow
the same to revolve.
If the rudder screw. is mounted in or on the rudder blade, the shaft of the rudder
screw. is carried in bearings in the rudder, but if not, it is carried by independent
framework capable of turning upon a contre post or bearings thereon, and motion is
given to the said shaft and "rudder scrow either from the main screw shaft or from
an independent shaft, to either of which the shaft of the rudder screw will be
attached by a universal joint constructed as herein-after described, which will
connect with and drive-the rudder screw shaft, and at the same time allow the rudder
or framing to be moved from side to side.
In the annexed Drawings,—
Fig. 1 répresents in sectional side view an arrangement of main scrow, with
provision for disconnecting same, and supplemental or steering screw mounted
in the rudder, and attached to and and worked from the main screw shaft by
universal joint.
Fig. 2 represents arrangement of rudder screw alone, mounted in a framing or
rudder hinged on a stern post, and connected by universal joint with the, driving
shaft.
Fig. 2 represents arrangement of fitting for small craft.
Fig. 3 is an end view of the universal joint shown in Fig. 2, seen from the right-
hand side of said Figure.
Fig. 4 is a top view of Fig. 3; and
Fig. 4 represents the joint in position it would occupy at about a quarter revo-
lution of the shaft, and with the framing or rudder at an angle of about 45°.
Figs. 5 and 5 are plan and section respectively of the joint plate or ring piece
carrying the studs or centres upon which the forks of the screw and driving shafts
are jointed and work.
Fig. 6 shows arrangement of hollow slotted cone and pinned or studded dome
piece, the studs whereof gear with the slots of hollow cone, and form a universal
joint capable of working to an angle of 45° or thoreabout.
Figs. 7 and 7 show the two parts of device represented in Fig 6 separated.
Fig. 8 represents arrangement of metal bearing piece for support of end of shafts
of outside screws, and Fig. 9 detail of slide and bearing block.
Figs. 10 to 15, Sheet 2, are shown details of construction of joint.
Figs. 16 and 17 are diagrams illustrating and comparing the steering of vessels
(1) by rudder, and (2) by means of my improved universal joint and rúdder screw.
Throughout the Drawings the dotted line a, b, represents the line of motion of the
rudder and of the universal joint.
In Fig. 1 A is the driving shaft, capable of being advanced and withdrawn in its
bearings, and to couple at its outer end A' with the main screw shaft B; or, when

page_text: the main screw is disconnected with the rudder screw shaft C, said coupling
being effected substantially in ordinary manner by socket in the screw shaft or by
a coupling on the end of the driving shaft, into which the screw shaft fits and
adjusts itself. When the main screw is not disconnected, its shaft B will be the
driving shaft of the rudder screw shaft C. D is the universal joint, connecting
driving shaft with the shaft of rudder screw E. At F is indicated in dotted lines
a catch piece actuated through a hinged lever piece by a rod passing through the
stem of the rudder, and by means of this catch piece the rudder screw will when
desired be secured with its blades in position to afford the least possible projecting
surface. For this renson, and also for the facility with which it may be repaired in
case of accident, a two-bladed "Griffith's" screw is preferred to be used for the
rudiler screw.
Instead of fitting the screw E in an opening in the rudder blade G, as here shown,
the blade of the rudder may be cut finer, that is, narrower, and the said screw be
fitted up and work outside and beyond the rudder, but the first-described arrange-
ment is preferable, as in either case the advantages of "outside" screws is secured, but
in that shown the disadvantage of such screws being overhung is avoided, and with
it the heavy strain and rapid wearing of the bearings. When however the screw is
fitted up outside the rudder the catch piece for fastening said screw will be arranged
to work horizontally, and be actuated through perpendicular rod and bell-crank
lever and link, or as convenient. In order however to further reduce the strain in
this case of outside screw and such screws generally, I provide, as shown in Figs. 8
and 9, a metal bearing, piece secured to the stern d, and curved and extending
outwards and downwards to the keel e, and centrally of said bearing piece I form a
carved guide or slide f, the curve whereof is the arc of a circle struck from the
centre of the universal joint and extending horizontally on each side, so as to allow
of sufficient play following the movements of the rudder in steering, and in this
arc-shaped guide is fitted a guide block g pierced for the reception of the neck of
the screw shaft.
The guide block will be made as a box for reception of grease for lubricating
the slide, and further means for lubrication are secured by channelling the faces of
the slide internally, and conducting oil thereto by tube or channel laid along the
bearing and supplied from deck, cabin, or hold. Rollers may also be used in this
bearing to reduce friction. The bearing will be supported by bracings h of band
iron or wire rope stretched therefrom and secured to the hull of the vessel.
27
In Fig. 2 G is hinged framing or rudder, showing bearings G', G³, of rudder
screw shaft. The propeller screw E here represented is an ordinary two-bladed
screw (but a three or four bladed screw may be used), and proportionately larger
than that shown in Fig. 1, as it is intended to act as propeller or "auxiliary
propeller to paddle or sailing vessels, as well as for steering purposes. The rudder
fixings are made sufficiently strong to receive the "end thrust" of the rudder screw
shaft, the bearing G³ being particularly useful in relieving the joint D from undue
strain from this cause.
When the screw is not required to be used the driving shaft will be fixed in
position as shown, and the catch piecos indicated at F will, as before explained, be
brought into action to steady the screw. The movements of the rudder in steering
and of the connections of the driving and screw shafts will now be around a
common centre.
In Fig. 2 is represented arrangement for fitting small craft, such as steam
launches, gun boats, and the like, with rudder screw. G is a framing in which the
outer end of rudder screw shaft is carried, and through which the rudder-like move-
ment is given to the screw. G' is a wrought metal framing serving as a stern post,
and secured to the stern at d, and to the keel at e. The bearings of the rudder
framing are rivetted or bolted to this stern post G³, and said stern post is formed
with an opening at Gʻ, shown partially broken away for illustration, through which
opening the double coupling joint is capable of working. The propeller screw and
coupling joint are not shown.

page_text: The universal joint D, represented in Figs. 2 to 5* inclusive, consists of a nut,
joint plate, or ring piece H, carrying pins or studs I, which serve as centres upon
which the forks of the screw and driving shafts are jointed and work. The edges
of these parts are cleaned down and turned, so as to bring them to an edge on
those sides which in revolving strike the water, thereby preventing resistance.
The joint, shown in Figs. 6 to 7, is an arrangement of universal joint, which in
some cases it may be desirable to employ.
In making up the joint, nut, and centres, shown partly in section in Fig. 10, I
take the ring or nut H and drill out four radial holes therein, and tap said, holes
with a female screw thread for reception of the screw-threaded ends of the four
joint studs I, and then having screwed the said studs equally into the ring or nut,
as represented in Fig. 11, the said ring or nut so fitted is "chucked " or secured on
the head of a lathe, and the adjacent points are drilled away as represented in
Fig. 12, and the hole thus produced is tapped with female screw thread for the
reception of a fastening or locking screw stud H', as shown in Fig. 10.
In putting the joint together, the spanner or forks at the ends of the shaft to be
couppled are placed in relation to the ring or nut H, so that the studs I can be
passed through the holes in the extremities of the forks and screwed into place,
whereupon a fast locking or securing of the studs and forks of the joint will be
effected by screwing in the central locking stud H¹. To take the joint apart the
stud His first unscrewed and then the studs I.
In some cases, and for smaller work particularly, the spanners or forks are made
of a piece with the shafts, or the rudder shaft alone is so made, and the base of the
fork of the main propeller shaft is made with a shank or collar part, as shown in
Fig. 2, and is keyed to the extremity of the main shaft; in other cases the
base of the forks are both made with a shank or collar part, and these are kejed
to the main and rudder screw shafts, as shown in Figs. 4, 4, and 14.
The joint shown in section, Fig. 13, consists of the nut H, the screwed studs I',
and the pin 13, the ends of the screwed studs I¹ being grooved or channelled, as
shown at I, to fit against the sides of the pin 1².
In fitting this joint together, the studs I' are first passed through the holes in
the fork of one shaft and screwed into the nut, so that their grooved ends will
allow of the passing through of the pin 12, but to bear against the sides thereof
which will prevent their turning or unscrewing.
The pin I is shown screwed at one side to take into a female thread H* on one
side of the nut, and when the forks of the shafts are thus jointed a screwed pin
or rivet I is passed through the nut H and pin 12; or 1 may make the pin I³ with-
out the screw at H³, and fit it tight in the nut H, and then secure it by pin or
rivet I. It is obvious that when fitted with the screw at H one end of the pin 1*
will be slightly smaller than the other, and the hole in the arm of the fork corre-
sponding thereto will have to be of corresponding size.
In Fig. 15 is shown an arrangement of joint fork, which is divided through the
shank lengthwise, and secured to shaft by a sleeve piece K and cotter pin K', which
will make a firm attachment. This is designed to be used when the joint nut H
and centres or studs I are made of a solid piece.
In the diagram, Fig. 16, is illustrated the action of steering as in the ordinary
manner, and in Fig. 17 that by means of supplemental or rudder screw.
The line 1, 1, represents the forward course of the vessel, and it is presumed that
the course is to be altered in each case to that of the lines 2, 2. For this purpose let
the rudder be placed as indicated. by line 3. For the purpose of illustration, forward
movement of the vessel is not indicated, merely the turning thereof.
Now in the first caso, on turning the rudder, a direct retarding action in direction
of the arrow 4 will result; but in the second case the retarding action will be
neutralised by the propelling action in direction of line 3.
In the first case the vessel turns upon a centre at the stern, and the head travels
to the point 5 on line 2, 2. In the second case the vessel turns upon. a centre
amidships in taking up its position in the direction of line 2, 2, which movement

page_text: will obviously be effected in less than half the time, as the distance which the head
has to travel is less than half, and in addition, there is no loss of power by
retarding.
From experiment I have found that a vessel fitted with my apparatus will com-
plete a full circular or elliptical turn in once and a half to twice her length. It is
obvious therefore that for rapid evolutions, such as are desirable for war vessels and
for river traffic, the practicable application of an adjustable or rudder screw is a
great desideratum.
Having now described the nature of my said Invention and the means whereby
the same is to be carried into practical effect, I would remark that I am aware it
has been proposed to mount a propeller screw in the rudder or in a framework,
having a rudder-like motion for the purpose of facilitating the steering of vessels,
but hitherto without practical success, I therefore do not claim broadly the use of a
rudder screw; but what I claim is the improvements in effecting the propulsion
and steering of vessels, as herein specified and shown by the Drawings.
In witness whereof, 1, the said Jacob Joachim Kunstädter, have hereunto set
my hand and seal, this Twelfth day of December, in the year of our Lord
One thousand eight hundred and seventy-seven.
0 Witness,
WALTER A. BARLOW,
Patent Agent & Engineer,
6, St. Paul's Churchyard,
E.C.
J. J. KUNSTADTER. (L.S.)