IM- PROVEMENTS IN APPARATUS FOR PROPELLING AND STEERING VESSELS
Year: 1866

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent, for the Invention of "IM-
PROVEMENTS IN APPARATUS FOR PROPELLING AND STEERING VESSELS."-A
communication from abroad by Joseph Athanase Ganeval, Professor, of
90 Boulevart. St. Martin. Paris.
PROVISIONAL SPECIFICATION left by the said William Clarke at the
Office of the Commissioners of Patents, with his Petition, on the 30th
August 1866.
I, WILLIAM CLARK, of 58, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR PROPELLING AND STEERING
VESSELS," to be as follows:-
This Invention relates to an improved submarine propeller applicable to
ships of war and the merchant service. This system of propelling apparatus
possesses the following advantages:-1st, it utilizes the centrifugal force
which is at present lost without assisting in the propulsion of the vessel;
2ndly, a better support is afforded to the propelling apparatus; 3rdly,
increased speed and power is obtained; 4thly, there is less wear and tear of
the engines; 5thly, there is increased smoothness in the action of the pistons,
connecting rods, and other parts; 6thly, an absence of all shocks; 7thly,

page_text: great economy in the expense of repairs; 8thly, sail may be carried without
fear of accident; 9thly, the vessel may be very rapidly moved ahead or
astern, or turned in either direction.
This system comprises three parts:-1st, the propeller; 2ndly, the fixed
open cage for protecting it; 3rdly, the steering parts which serve as a
substitute for the rudder.
The propeller is placed like a screw at the stern of the vessel in a vertical
plane passing through its centre; the frame enclosing it is open at the rear
and the whole entirely submerged. The form of the ordinary screw is
such that there is not any propelling power exerted at the centre, but
only at the periphery, and in order to increase this power the screw requires
rapid rotary motion, which in a short time wears away the bearings in
which its shaft turns, and occasions a very considerable loss of power by
acting on and throwing the water tangentially and otherwise without bene-
ficial result.. In the second place the arrangement of the screw is such
that the water projected backwards comes against that part of the keel
and rudder post to which the rudder is attached, which tends to form.
an obstacle to the progress of the vessel and produces a loss of power;
these disadvantages are provided against in the improved propeller of this
Invention, which is disposed on the horizontal shaft projected beyond the
frame. The propeller consists of several blades of similar dimensions disposed
one behind the other, as seen at Figure 1; these blades are mounted obliquely
on the shaft, and present an inclined surface to the water, the obliquity of the
blades being the same in each. The propeller is made of the same metal as
the sheathing of the vessel, the ordinary means being adopted to prevent
oxidation. The action of this propeller is the same as an ordinary screw, it
being fixed to a horizontal shaft rotating in bearings in the vessel. It may
thus be substituted for a screw without other modifications than those
resulting from the opening made in the stern frame and the abolition of the
rudder; by this means the dimensions of the propeller may be increased, and
so augment the propelling power; this condition-is thus better fulfilled in this
arrangement than in a screw. By increasing the width of the blades when
the framing will admit of it I may increase the propelling surface propor-
tionately; this may also be effected by increasing the number of blades;
these blades should, however, be of such number and dimensions that the
sum of the resistance remains below that of the sum of the impulsive force,
which could not be the case were the blades of too large dimensions or too
numerous. The blades may be made of the same length as in the screws of
those vessels to which these improvements are applicable, but their width

page_text: may be increased as much as the steering parts to be herein-after described
will permit. I would remark that the increase in the propelling surface of
the blades by reducing the number of revolutions necessary for covering the
same extent of motion, as compared with that actually traversed by a screw,
proportionally reduces the number of strokes of the piston, thus economizing
the production of steam and the fuel. Further, this modification in the speed
prevents that tangential loss of power resulting from the rapid motion of the.
screw, consequently the effective force of the propeller will be much greater.
The machinery will also work with a smoothness unattainable in screw
propulsion; hence it results that the engines will last longer, there will be
less expense for repairs, and increased power and speed; also by the adoption
of these improvements engines need no longer be built so disportionately
for the single purpose of 'driving screws at a high speed, which increases the
wear of all their parts; this propeller may be driven by any suitable engines;
sail may also be carried without danger of accidents to the screw in case of a
mast being carried away, when the. cordage often becomes coiled round the
screw, and either breaks it or retards its motion. The cylindrical caging,
Figure 2, which is fixed' to the framing of the vessel is intended to protect
the propeller from contact with any floating bodies; it is made of the same
metal as the propeller, the longitudinal and transverse bars affording free
passage for the water, they being for this purpose made of thin metal as wide
apart as possible. The free end of the propeller axis passes through the
centre of its base and turns freely therein; this cage is of secondary.
importance, and is only necessary for sea-going vessels, and may be dispensed
with in other cases, when the open end of the frame is provided at its centre
with a strong horizontal metal bar forming a bearing for the propeller shaft.
On each side of the vessel, which from the arrangement of the propeller are:
left free, is made a rectangular opening provided with an axis parallel and in
the same plane as the propeller shaft; in this opening, on an axis at right:
angles to the first-mentioned, are placed propeller blades similar to the
propeller, but of smaller dimensions, see Figures 3 and 4. The axis is:
furnished with coupling gear, which by the aid of a lever is placed in
communication with the propeller shaft or thrown out of gear therewith..
The rotary motion of the shaft is transmitted to the steering blades by the
aid of bevil gearing. The two steering propellers should act simultaneously,
and for this purpose the blades of the one are set in the opposite direction to
those of the other; this simultaneous movement greatly increases the rapidity
of turning the vessel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
2
by the said William Clark in the Great Seal Patent Office on the
23rd February 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters.
Patent, bearing date the Thirtieth day of August, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Clark, Her special licence that I, the said William Clark,.
my executors, administrators, and assigns, or such others as I, the said.
William Clark, my executors, administrators, and assigns, should in any
time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVE.
MENTS IN APPARATUS FOR PROPELLING AND STEERING VESSELS," a communication
to me from abroad by Joseph Athanase Ganeval, Professor, of 29, Boulevart
St. Martin, Paris, upon the condition (amongst others) that I, the said
William Clark, 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, the said William Clark, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the follow-
ing statement, that is to say :-
This Invention relates to an improved submarine propeller applicable to
ships of war and the merchant service; this system of propelling apparatus
possesses the following advantages
:-
Firstly, it utilises the centrifugal force which is at present lost without
assisting in the propulsion of the vessel; secondly, a better support is afforded
to the propelling apparatus; thirdly, increased speed and power is obtained;
fourthly, there is less wear and tear of the engines; fifthly, there is increased
smoothness in the action of the pistons, connecting rods, and other parts;

page_text: sixthly, an absence of all shocks; seventhly, great economy in the expense of
repairs; eighthly, sail may be carried without fear of accident; ninthly, the
vessel may be very rapidly moved ahead or astern, or turned in either
direction; it comprises four parts:-1st, the propeller; 2d, the tubular
canal; 3rd, the fixed open cage for protecting the propeller; and, 4th, the
steering parts which serve as a substitute for the rudder.
The said Invention is represented in the Figures of the accompanying
Drawings, the same letters of reference of which indicate similar parts.
Fig. 1 is a rear view in elevation of a ship or vessel; Fig. 2, a side view
in elevation of a propeller with four blades; Fig. 8, a vertical view of one of
the steering organs; Fig. 4, a view of the propeller, of the steering organs,
and of their shafts all brought together; Fig. 5, a horizontal section through
the driving shaft and the shafts of the steering organs.
A is the shaft of the propeller; A¹, the shaft of the steering organs; b, b,
are the branches of the canal; C is the square opening containing the pro-
peller; C, rear opening of the canal; E, conical junction of the driving
shaft by which the steering organs are rendered independent of the propeller ;
E', junction of the shafts of the steering organs; e, gearing of the movement.
of the steering organs; e¹, e¹, are the bevil wheels of that movement; F, F,
openings for the steering organs; L, L, levers commanding the movement
of steering organs; M, spot where the machine is placed; M', nave of
propeller; S, S, supports of bevil wheels; V, V, steering organs.
1stly. Diminution in the Loss of Tangential Power.―This loss arises from
the ease with which the water, rapidly struck by the screw, escapes by the
tangent of the circle of revolution. The rapid motion of the propeller is the
cause of this, to diminish which, therefore, the rotation of the propeller must
be slackened. The arrangement which I propose to adopt will mitigate this
loss of power, not only because the rotation of the propeller will be less rapid,
but also because it will retain the water so that it give way less rapidly when
acted upon by the propeller.
2dly. Improvement in the Support of the Propeller.-The insufficiency of.
the support of the propeller is owing, 1st, to the fluidity of the water in which
the screw rotates; 2dly, to the necessity of increasing the speed of rotation of
the screw, the impulsive power of which is effective only at the periphery..
The same modification may mitigate both these effects. The water easily gives
way to the action of the propeller, and that the more readily as it is subjecte'l to a
more rapid, rotation; to remedy this inconvenience it must be brought under the
action of a propeller which rotates more slowly, so that this slackened motion
may not influence in any wise the speel of the vessel, the striking surface of;
:

page_text: the propeller must allow of resolving the same impulse whilst striking the
water with less velocity, this surface, therefore, must be amplified. It may
be augmented without augmenting the total area of the propeller, I take any
Screw, that of the French frigate "La Gloire" for instance. It's dimensions
are, diameter 3 mètres; width, 75 centimètres ; area, 7 metres, 7 centimetres
square; mean width of a blade, 388 millimetres. According to these data the
surface of a blade is nearly equal to 0-388 x 1.50 (half the diameter) =0:58,
and as that screw has 4 blades, the striking surface is 0.58×4=2mq. 32.
The area of the propeller being 707 it is evident that the striking surface
is a little less than the third of that area. I substitute a wheel having the
same number of blades to this screw, these blades have a uniform and the
same width as that of the said screw. The striking surface becomes 0-75X:
1-504, that is to say, 4 48°, it is therefore twice as large as the former
and occupies more than half the area of the propeller. The result is that
the propeller will then strike the water with less velocity in order to produce
the same impulse, there is consequently less recoil, and it follows that the
power of the propeller is increased; it remains to be seen whether the resistence
offered by this increase of surface will influence in any way the march of the
vessel. The resistance offered by the water to a blade is expressed by the
formula R 60 XS (U-V), in which formula R represents the resistance of
a blade in kilogrammètres, 60 the value in kilogrammètres of the resistance
of a plane surface, one mètre square, striking the water at the rate of one mètre
per second; S the surface of the blade in square mètres; U the speed of a
blade, in mètres per second; V the speed in mètres per second with which
the water flies away relatively to the axis of rotation. If I substitute in this
formula the letters by their value I shall have for the screw of "La Gloire,"
supposing that U=6 and V=2, R=60×0.58 (6.2), =60×0.58 x 16=
556.80. The mean working per second reckoned in kilogrammètres is
represented by the formula T=RX U, I shall have therefore T=556, 80×6=
3340.80. If in these two formulas I replace the letters by the dimensions
above calculated, I shall have R=60 x 1.12×16=107520 and T= 1075,
20×6=6451km. 20; by deducting 3340-80 from the sum of the last of these two
formulas I have a difference of 3110.40 over. The resistance is included as
a factor in the product which expresses the mean working; therefore, if I
increase it I also increase that working, and consequently the power of the
propeller, since the power of a propeller is equal (relatively to its working)
to the corresponding working of the machine on the driving shaft.
3rdly, Increase of Speed and Power.-The calculations above established,
and the conclusions to which they have led me, clearly show that there is

page_text: increase of power and of speed. But these advantages, evident by calculation,"
would remain unapplied if a modification of the actual arrangements did not
render it possible; this modification will allow of an increase of speed, of over-
coming more easily the resistance of the water in front, and of improving the
support of the propeller; this modification concerns especially the improvement
of the propeller, which without it would labour under difficulties in the working:
In order to do away with the known inconveniences of the screw I establish
in the vessel, and below the float line, a tubular canal, at the rear part of
which I place the propeller.
By adopting this arrangement the following effects will result:-10: The
play of the propeller will exercise a suction on the water in front which will
diminish the resistance at that part. 2°. This resistance being lessened, a less
rapid movement of rotation might be given to the propeller, and it follows
that the support will be further improved. 3°. The water in front com-
municating with the rear the propeller will constantly come in contact with
water which the blades have not yet touched, the propeller will therefore turn
in a more settled medium. 4°. The resistance offered by this water to the:
propeller will be great; the motive working of the machine will be turned to
account as much as possible, which will give to the vessel a degree of speed
incomparably greater than any obtained up to the present day. The length
and width of the tube will naturally agree with the length of the vessel and
the diameter of the propeller. In order to avoid the loss of speed occasioned
by the shock of the water thrown by the screw on the support of the
rudder, I propose to place at the rear of the vessel and on each side of the
propeller a couple of steering organs, the description of which will be given
further on.
4thly, 5thly, 6thly, and 7thly, Longer Usage of the Machine ; Absence of
Shrivelling in the Different Organs; Absence of Shocks and Trepidations;
Economy of Repairs. These advantages evidently result from what has
already been said. The inconveniences resulting from the rapid movement
given to the screw, it is clear they will no longer exist by reason of that
movement (from the several caures adduced) being considerably diminished!
I shall set forth the other advantages it offers after having described
the new system. Several parts constitute this system. They are, 1st, the
propeller; 2d, the tubular canal; 3d, the grating; 4th, the steering
apparatus.
1st. The Propeller.-The propeller is placed like a screw at the stern of the
vessel, only instead of being put in a sort of cage, closed before and behind, it
will be set in a caging in the stern post. This caging will be open at the

page_text: back as represented in Fig. 1. On a nave placed at the extremity of the
driving shaft, one behind the other, shall be placed blades of the same
dimensions and having the same width as the nave on which they rest; they
will offer an oblique surface to the water; the obliquity will be equal and at
the same angle of inclination in all the blades. The propeller will be made
of the same metal as the sheathing of the vessel; its shaft is to run with the
axis of the tubular canal, at the extremity of which the propeller will be set
in motion. The ordinary means are adopted to prevent oxidation. This
organ is represented by Fig. 2. Whilst giving four blades to my propeller I
wish it to be understood that I do not intend to limit the same to that number,
which may vary, and must be such that the sum of resistance be always
inferior to that of impulsion; so also with regard to the dimensions to be
given to the blades, the requirements of installation and the power of the
motive machine must serve as guides in these questions. The diameter of
the propeller will be as large as the draught of the vessel will permit, with
this restriction, that under ordinary circumstances a layer of water equal to
about one-sixth of that diameter shall still remain above the screw. It is well
known that complete immersion adds to the power by preventing the splashing
of the agitated water.
2d. The Tubular Canal.-As shown in Fig. 5, this canal branches off at
the rear; the two branches open into the rear aperture at a little distance
from the propeller. This arrangement is necessitated by the position of the
machine, which should, if the canal extended directly from the fore part to the
stern be complicated with gearing to set in motion a driving shaft under
water, an arrangement which it is well known is prejudicial, and only
enfeebles the resisting point of the said driving shaft; this branching off will
also facilitate the steering of the vessel by momentarily intercepting the
current of the water in the one or the other of these two branches; it will
further have the advantage of not displacing the vessel's centre of gravity, and
of not so much diminishing the tonnage as would a direct canal having in all
its length the same diameter as its rear orifice. The fore part of the two
branches will be screened by a grating. The friction of the water in the
branches of the canal will certainly give rise to a loss of power; but I would
here remark that this water will be animated with a motion of its own, that
it will in consequence rub less than it would if compressed by a propelling
apparatus placed in front and throwing it forcibly behind it; the water will
yield rather to the suction which the propeller determines, and this action will
have an influence upon the watery particles very different from that which
would result from a pressure borne by them. The development I give to the

page_text: I
blades of my propeller allows of it being able to work in the current produced
by the tubular canal; the screw actually in use is incapable of effecting this.'
may add that the adoption of this canal will entail no alteration in the form
of the vessel, and that consequently the draught of the water will not be
increased; I would also add that this canal is nearly in the hold; the
quantity of water it lets in is inconsiderable in weight when compared with
the load that part of the vessel in which the canal is situate usually bears.*
As shown in the Figures 4 and 5 of the accompanying. Drawings the diameter
of the rear opening of this canal is less than that of the propeller. This
diminution is intended to prevent the periphery alone from having to bear the-
whole power of impulsion; in that way it is shared by the centre, which
allows of still more diminishing the rotation movement of that organ.
3rd. Grating which Protects the Propeller.-The simplicity of this organ
dispenses a detailed description. It will be placed at the rear opening of the.
framing and made of metallic blades sufficiently thin and resisting to be near
enough to each other and not obstruct the free passage of the flowing water.
The free end of the propeller's axis passes through its centre.
4th. Steering Organs, Figures 3 and 4.-At each end of the lateral parts
of the space enclosing the propeller is a rectangular window traversed.
horizontally by an axis parallel with the driving shaft. In that window and
on a shaft perpendicularly to the first, will be set a wheel similar to the pro-
peller, capable of rotating horizontally when impelled by the driving shaft,
under the action of which its axle might be placed by means of levers which
would allow of approaching or distancing the necessary gearing; these levers,
the free end of which would be on deck, would be handled by the pilot. The
two steering organs should act simultaneously, and for that reason the blades
of the one will present to the water an obliquity contrary to that of the blades'
of the other; their use will only be needed when a very rapid tacking round-
is required. To steer round slowly it is merely necessary to intercept the
water in one of the branches of the canal by means of a moveable closing-
fixture. As may be inferred from Fig. 4 of the accompanying Drawings
these two organs may be set in motion independently of the propeller when'
stationary; acting alone at the stern they will steer round the vessel as on a
pivot; rapid evolutions may therefore be effected, so that broadside after
broadside might be fired, larboard firing whilst starboard is loading, and so-
keep up a continuous and well-nigh unintermittent artillery.
8thly and 9thly, the Sails may be Retained without Fear of Accident; a
Rapid Tacking Round on the Spot may be effected.-These advantages result

page_text: from the above descriptions. The arrangement of the propeller will allow of the
sails being retained without fear of accident, which generally takes place when
the falling of a mast throws the rigging into the water as bits of rope get wound
round the propeller and occasions a. rupture, or at least a prejudicial slackening
in the speed. The two steering organs acting simultaneously allow of steering
the vessel round as rapidly as possible on the spot when acted upon without.
the assistance of the propeller, which takes place by means of the shaft being.
helved on the propeller.
Comparative table showing the quantity of motive power utilised by a vessel
like the French frigate "La Gloire.".
.. By the screw now used:
llorse-power.
Rough power of machine 900..
From which deduct:-
Tangential loss
Loss by shock of
framing
682.60
-
31.06
726.
6.12
Do. by change of
water
By that now proposed
Horse-power.
Rough power of machine 900.
From which deduct:_
Tangential loss
Loss by friction of
227.
428.06
3.06]
⚫ water in canal . 188.
Loss by recoil

page_text: allowing of the vessel being turned round rapidly on the spot without either
advancing or receding.
In witness whereof, I, the said William Clark, have hereto set my
hand and seal, this Twenty-third day of February, in the year of
our Lord One thousand eight hundred and sixty-seven.
W. CLARK. (L.S.)