CERTAIN IMPROVEMENTS IN PROPELLING VESSELS
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GASPARD
MALO, of Dunkirk, in the Republic of France, Ship Owner, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twentieth day of June,
One thousand eight hundred and fifty, in the thirteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Gaspard Malo, my exors, adiñiors, and assigns, Her especial licence, full
power,
sole privilege and authority, that I, the said Gaspard Malo, my exors, admors,
and assigns, or such others as I, the said Gaspard Malo, my exors, adñiors, or
assigns, should at any time agree with, and no others, from time to time and
at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, and in the Islands of Guernsey, Jersey, Alderney,
Sark, and Man, and also in all Her said Majesty's Colonies and Plantations
abroad, my Invention of "CERTAIN IMPROVEMENTS IN PROPELLING VESSELS;" in
which said Letters Patent is contained a proviso that I, the said Gaspard Malo,
shall cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, by an instrument in writing under
my hand and seal, to be inrolled in Her said Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said in
part recited Letters Patent, as in and by the same, reference being thereunto
had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Gaspard Milo, hereby declare that the nature of my said Invention, and in what
manner the same is to be performed, are fully described and ascertained in and
by the present Specification thereof, reference being had to the Drawings
hereunto annexed, and to the figures and letters marked thereon, that is to
say:
My Invention consists, firstly, in the employment for propelling vessels of a
screw consisting of a series of moveable vanes or wings, which, when the appa-
ratus is not in motion, are brought one behind the other, and the whole set
behind the dead wood, so as not to interfere with the progress of the vessel
when sailing.
Secondly, in a new arrangement of the end bearing of the propeller shaft, by
which the bearing is made quite independent of the stuffing box, so that it (the
bearing) may be examined, repaired, tightened, readjusted, or changed, when
needful, without it being necessary to unfix the shaft, screw, or stuffing box.
Thirdly, in surrounding the aperture made in the dead wood to receive the
screw, as also the recess in which the end bearing is placed, with a metallic
frame strengthened by stays. This frame is made of one piece of gun metal,
and is so placed as to form a rabbet joint with the outside planking, thereby
strengthening the dead wood, so as to render it as solid as if there had been no
opening made to receive the screw and bearing.
Fourthly, in facilitating the condensation of the steam for low-pressure
engines when applied to the propelling of screw vessels, by means of two water
tauks placed in the hold, and thereby doing away with the holes which are
now bored in the bottom of vessels for condensing purposes.
I will now proceed to describe the details of these four branches of my
Invention.
I. THE MOVEABLE PROPELLING VANES.
There have been hitherto two methods in use for applying the screw as an
auxiliary or occasional means of propulsion, viz', either to fix the screw in
such a manner that when not in use it may be detached from the propellor
shaft and hoisted up into a sort of well, or else it is so fixed that when the
shaft is not in gear with the engine the screw shall hang loosely and turn
round with the water according to the speed of the vessel. Both these plans
..

page_text: screw to its progress when sailing; moreover, the screw, hanging loose on the
end of the shaft, wears out its end bearing almost as much as when in
actual use; consequently, if after the vessel has been sailing for some time
it becomes necessary to employ the screw, it will sometimes be found impos-
sible to do so, owing to the bearing having become worn out before much or
any use has been made of the screw itself. Thesc serious objections deprive
merchant vessels and large men of war of the important advantages which they
might expect to derive from the employment of an auxiliary screw.
Now my Invention has for its object to remedy these defects, by employing
a screw with moveable vanes, and of a large diameter, in manner following:
The construction of this screw is represented in detail in the annexed Drawings,
Figures 1 and 2. It is composed of two or three pairs of independent vanes
or wings. One of these pairs is fixed on the extreme end of a shaft in the
ordinary manner. A second pair is keyed on the end of a tube which encircles
the shaft of the first pair. A third pair, if necessary, can be fixed in the same
manner on the end of a second tube encircling the first tube. The two or three
concentric shafts thus arranged one within the other, are passed, after the
manner of simple shafts, into a tubular stuffing box. Beyond this stuffing box
and the bearing connected therewith, these shafts aro uniformly increased
in diameter, and have then holes cut in them, through which (the holes of each
shaft being brought exactly in a line with those of the other or others of then)
a strong key or keys is or are passed so as to fix the two or three shafts
together and unite them as one shaft, either in the position which they respec-
tively occupy when the screw is in movement, or in that which they occupy
when it is at rest and folded back. In order to pass from one of these positions
to the other, it is requisite to turn one of the shafts within the other, about
one-fourth or one-sixth of a revolution, according as there may be two or three
pairs of vanes. This adjustment is effected (when required) by hand, that is
to say, by turning an endless screw which works into a pinion fixed on the
inner shaft; any other suitable mechanical arrangement may be employed
for the same purpose. Between the concentric shafts a small annular space is
left of about 4th or th of an inch, which extends throughout their whole
length, except at the bearings, and at the hinder end where the innermost
shaft is slightly increased in diameter for about the length of three and a half
to four inches, and comes in contact for that space with the other shaft.
Should the water enter the vessel through this small annular space, that end of
the outermost shaft which enters the hold should be well packed with hemp
or any other suitable material. In order to diminish or prevent the possibility
of the shafts sticking together, some concrete fatty matter is poured into the

page_text: annular space, in order to prevent the entry of water at that place. The two
or three pairs of vanes or wings are so placed and curved as to project one over
the other, and in the least possible space. There remains thus, between the
superposed vanes, only about two inches of play. The screw, thus composed,
may, in a vessel having a large draught of water, have a large diameter, say of
thirteen or fourteen feet, and even sixteen feet. For an apparatus of mode-
rate power the screw should have a sufficiently large surface, with a width of
vane or wing not exceeding the thickness of the stern post; four vanes
or wings should suffice, but six may be used if preferred; each of the vanes
should be in the shape of a large oar, and made pretty much in the same
manner. The breadth of the opening made in the dead wood to receive such
screw need only be of about from twenty to twenty-four inches from front to
back. Thus, in ships of a great draught, a sufficient portion of dead wood will
be left intact above and below, to render the poop solid, and this opening
will allow of a sufficient width behind it to permit the stern-post to be
strengthened. These arrangements may be made in a ship already built and
launched, without any damage being done to it, and without any modification
n the shape of the bottom or submerged part of the hull. The Drawing,
Figure 1, represents the fixings of a screw for an auxiliary apparatus of
150 horse power in a man of war. The screw is there represented with four
vanes or wings, but it is easy to conceive the same with six or any
number of vanes instead of four. Figure 2 is a back or stern view of the
apparatus. The usual shape of the stern has been almost entirely retained,
the extreme ends of some water lines only having been altered, as indicated by
the dotted lines in Figures 9 & 10. The shaft of the screw is placed at
about nine or ten feet above the keel; and it may be either fixed borizontally,
or it may slope upwards towards the bow, so as to be at a suitable height to
allow of the attachment of any direct acting motive apparatus. The diameter
of the screw is about fourteen feet and a half to fifteen feet. The three shafts
should each be capable of resisting one-third of the entire torsion, and have
together an outer diameter of about eleven inches. If the shaft were of one
piece only for a common screw of the same diameter, the same thread, and the
same rapidity of rotation (say from 40 to 50 turns), it would require to be
about 9 inches in diameter. The stuffing box should be about 13 feet
in length. Behind the stuffing box the outer shaft is increased in diameter for
about three-fourths of an inch, which obviates the usual play left in the stuffing
box. This increased diameter affords, besides, greater strength for placing the
keys which fix the vanes on their shafts. It gives also greater strength to the
rubbing surface in the bearing.
other

page_text: II. THE IMPROVED END BEARING FOR THE PROPELLER SHAFT.
Hitherto an end bearing for the shaft has been very generally dispensed
with, the stuffing box being made to answer the purpose of a bearing, by
inserting a small collar at the stern end; the result of this objectionable
arrangement is, that when this part of the stuffing box becomes worn away by
friction, the shaft shakes about loosely in this bearing; consequently, when
it is too much worn away, it becomes requisite, in order to remedy the mischief,
to unship the screw, the shaft, and the whole of the stuffing box, which is a
long, difficult, and expensive. operation, and not practicable with the means
ordinarily at disposal on board ship. Sometimes bearings have been placed on
the frame of the screw in ships in which the screw (when not required)
is hoisted up into a well. These bearings, which wear out quickly, owing to
their shortness, can be easily got at and repaired, but still they do not do away
with the necessity of another bearing at the end of the stuffing box. Now
my improved bearing, represented in Figure 6, is placed in a sufficiently
large recess or opening made to receive it on the fore part of the opening
through which the screw shaft passes. This recess is surrounded by the
metal frame which follows the outline of the hole made for the screw.
The stuffing box only begins at the fore edge of the recess, and therefore
does not come through the recess at all. Over the lower edge of this
recess there is in the metal of the frame a wide dove-tail shaped groove,
in which sliding supports are inserted. Between the supports and the shaft
is a packing, composed of several segments or pieces of about four inches
in length, so that these pieces may be removed, when required, by with-
drawing them from between the shaft and the back of the sliding supports.
Above the shaft is placed another packing, composed of two or three lengths.
The cap of the bearing may also be, if required, composed of two or three
pieces in the direction of its length. Then a metal wedge is driven between
the top of the bearing and the upper edge of the recess, so that whatever
part of the dead wood may have been cut away in order to form this recess, it
is compensated for by substituting these metallic pieces, which are as suitable
as the wood for supporting the weight of the upper woodwork. Lastly,
for the purpose of more securely connecting together the upper and lower
parts of the recess, they may be strengthened by iron plates. It is evident
that the top of the bearing, as also every piece of the upper and lower packings,
may be removed, readjusted, and replaced, without unshipping any other
piece but the bearing itself, and this, when the ship is aground, can be got
at from all sides. This bearing may be made of great length in order not to
may be made 25, 80, or even 40 inches long.
wear out rapidly.
It

page_text: III. THE IMPROVED FRAME.
The improved screw with moveable vanes requires to have, in a large ship
already built, an opening, of which the length from front to back may not be
so extensive as to require any important alteration in the construction
of the vessel; so to speak, the opening might be made by just sawing
through the dead wood and planks, and this without damaging the hull; the
metallic frame, previously filled with wood, such as is represented in Figure 2,
is then to be put in its place. This frame is made in one piece, and is
nailed firmly to the dead wood. It is curved into a knee form, and forms
a rabbet joint with the ribs of the planking. Its angular section gives it con-
siderable rigidity without requiring it to be of great thickness; at the same
time this form of section facilitates the motion of the water. In a ship, while
building, the frame should be put in place, either before the ribs, or at the
same time with them, and then filled in with wood. Although this frame
as thus constructed is very rigid, it may nevertheless be thought farther
advisable to secure it by means of metal straps, so as to enable it to resist
successfully the enormous pressure attending the caulking of the rabbets.
This frame incloses also the recess made for the end bearing. In its cross
section this frame is very massive throughout, and of substance sufficiently
strong to hold the bearing and stuffing box.
IV. THE WATER TANKS.
In screw steamers there exist two considerable difficulties (with respect to
the steam engine machinery) which are not so important in paddle wheel
vessels. One of these is the air pump, and the other the numerous holes
which one is obliged to make in the bottom of the vessels. In using the
screw it is necessary to drive the steam engine machinery at a more rapid
rate than in boats propelled by paddle wheels. As long as the obstacles
which exist in the application of high-pressure engines to ocean navigation
are not overcome, there will be difliculties to surmount in order to adapt air
pumps to engines working at great speed, especially on board large ships. In
fact, the engines should be at the bottom of the hold, especially in ships of
war. It is not enough that the air pump should make a vacuum as usual,
for it must also lift the water about 16 or 19 feet, which increases the risk of
rupture in the interior of the pump and in all the tubes. It has been
endeavored to remedy this evil by so arranging matters that the air pumps
shall perform two or three times fewer strokes than the engine; but this adds
to the complexity of the machinery, and increases the weight and obstruction,
because the size of the air pump must be increased in the same proportion,

page_text: and there must be a corresponding enlargement of the opening by which the
water is expelled, all these changes tending to disturb the equilibrium of the
machinery. In short, it has not been found that as good a vacuum would be
obtained by this means. In a ship in which the propelling apparatus is only
used occasionally, the existence of five or six holes several feet below the line
of floatation becomes a source of great inconvenience, especially since
any one of them might endanger the safety of the ship. It is true that
these holes might be bored only at the line of floatation, and might be
made to communicate by tubes with the different parts of the apparatus,
but there is still the obstruction and fresh risks of rupture, and moreover,
in ships of war, the machinery would not be out of the reach of shot. In
order to obviate or to lessen these various defects, and facilitate as much
as possible the action of the air pump, I propose that within reach of the
engines, near to the well pump, there should be placed two sheet iron reser-
voirs or tanks, each of about 200 cubic feet in capacity. These two reser-
voirs or tanks are, when the vessel starts, to be filled with potable water,
which will probably serve for the use of the crew before the ship has found it
requisite to make use of its auxiliary screw apparatus. One of these tanks
may easily be put in communication (by means of hose) with a moveable
watering cock, such as is usually placed in the neighborhood of the well
pumps of ships of war, so as to draw therefrom the entire quantity of cold
water necessary for purposes of condensation, and the water may be car-
ried thence to the condenser by a pipe. The other tank or reservoir is put
into communication with the air pump, in order to receive the waste hot
water. This tank is connected half-way down with a perpendicular pipe
placed along the side of the well pump, and through which pipe the lifting
action of the air pump will force up water for throwing on to the deck. The
upper half of the reservoir is to be filled with air, which will act as a cushion
to protect the machinery from shocks. In case of any damage being done, or
if it is desired to set part of the crew to work to relieve the air pump, and
consequently to increase slightly the power of the steam engine, the water of
this tank can be raised from the hold by means of common pumps, which can
be easily be put into communication with it. If the vessel should leak con-
siderably, the steam can be condensed with the water from the hold, and the
water of condensation expelled by the action of the air pump.
This is a
valuable expedient, which is important in diminishing the risks of damage.
The former of these two tanks may furnish water for feeding the boilers, for
supplying the ship's fire pump, and for extinguishing cinders. The second
tank may be put into communication with the lower part of the boilers for the

page_text: extraction of water when saturated with salt. This water will be expelled
simultaneously with the water which has served for purposes of condensation.
Thus this advantage is hereby gained, that it is not necessary to bore any
holes in the bottom of the vessel which may be stopped up by shell fish or sea-
weed when the machinery has remained stationary for some time, or which
may give rise to serious leaks. No bursting of pipes need any longer be
feared, and all parts of the apparatus may be inspected and repaired during
the voyage. The rapid action of the air pump becomes as little dangerous as
that of the same pump in paddle wheel vessels, because all shocks are
deadened by the intervention of a very large reservoir of air. The power of
pumping water from the hold with the engine is still retained. To obtain all
these advantages it is sufficient to put on board two large tanks, the weight
and obstruction of which cannot be objected to, since they serve to hold
potable water.
DESCRIPTION OF THE DRAWINGS.
A is the deadwood; B, the wing transom; C, stern post and inner post;
D, keelson, which is cut away to allow the stuffing box to pass through.
Two ties should be added here to strengthen this weak part of the ship.
a, a, a, a. outline of the opening to be made in the deadwood of a ship
already built. On the part b, b, b, which forms the back part of this outline,
a small angular piece of wood is placed, in order to facilitate the clearance of
the water expelled by the screw. d, d, d, d, is the metal frame made in
one piece. This frame is to be filled in, as before stated, with wood
before being put in its place, in the case of ships already built; but in
ships to be built, the frame, having been first set in its place, should be filled
up with wood in proportion as the pieces composing the deadwood are put
in their place. This frame is made angular in its cross section, in order to
facilitate the movement of the water, and to obtain the greatest possible
strength from the quantity of material employed. This frame is of solid
metal throughout the parts surrounding the recess for the bearing. It forms
a rabbit joint throughout its circumference, and can he caulked at right
angles. This frame, which is nailed throughout to the deadwood, and may
be strengthened by two or four straps, does away with all necessity for any
other ironwork to compensate for the portion of the deadwood cut away for
the passage of the screw. E, the inner shaft which carries the second pair of
the vanes of the screw. This shaft is increased in diameter on the front of the
bearing I, in order to compensate for the stuff cut away to form the mortise
to receive the wedge, whereby the shaft is enabled to resist the power of

page_text: torsion of the entire screw.
coupling to the iron shaft which continues it on to the engine. The reaction
of the screw in backing the vessel is thrown on the bearing I by means of an
increase in diameter of the shaft E. The more important reaction required
for the forward course is supposed to be exerted on a point at the end of the
front shaft of the engines. F is a hollow shaft which carries the first pair of
vanes or wings, and is also increased in diameter in front of the bearing I.
This shaft is concentric with the preceding, and is separated from it by an
annular space about one quarter of an inch throughout its length, except at
the points e, f, where the shafts come in contact. The space between this shaft
and the preceding is filled with concrete palm oil or any other suitable lubri-
cating substance. H is a common stuffing box. It begins at the back of the
recess in the aperture made for the screw, where it is fitted with a washer K
bedded in the thickness of the frame d, d, d, and secured by screws if it is
feared that the stuffing box may yield towards the front. To prevent the
stuffing box from receding towards the back there is a projection at c², which
presses against the front face of the frame. Between the tubular stuffing box
and the shaft F there is an annular space of about half an inch, into which the
water enters freely. This tube terminates in front in a collar or neck, to
which a cap is bolted. I, bearing on the inner standard of the shaft of
the screw.
The standard is strongly secured to the keelson, and should be
brought as near as possible to the stuffing box. It is on this bearing
that the reaction of the screw in backing is exerted. L, L, the first
pair of vanes or wings attached to the extremity of the shaft F, and secured
by keys. The vanes have the degree of thickness indicated by the cross
sections at O, O. This pair of wings or vanes is, like the other, about
fourteen feet in diameter, and the pitch of the thread is also about four-
teen feet. N, N, the second pair of vanes or wings fixed on the shaft E
with keys, and also further secured by a pin passed through the shaft E.
P, Q, R, S, is the end bearing. This bearing should be very long, so as to
wear out slowly; say, for example, as represented in the Drawings, about
30 inches. It is fixed in such a manuer that it may be casily got at to be
examined, repaired, or changed. P is the sliding support made in one piece
of metal fixed by a dovetail groove on the lower side of the frame of the
recess. This piece, which cannot wear out, is supposed to be placed before
the wings or vanes of the screw have been fixed in. Q is the cap of the
bearing, which is secured to the support by bolts as usual. This cap can be
unfixed when the wedge T is removed; and it may be either in one piece, or
composed of two or three parts combined lengthwise; and in either case the
This metal shaft is united at its front end by a

page_text: portion of the deadwood above the recess is connected by means of iron plates
to the portion below it. This cap ends in a large flat part arranged to receive
the wedge T. R, lower packing of the bearing; it is divided into pieces
sufficiently small to allow of their being passed between the back of the
bearing and the first pair of vanes or wings Ļ, so that this bearing may be
changed without unfixing any thing. S, upper packing of the bearing; it is
divided into several pieces, in order that it may be unfixed without meeting any
impediment in the fixing of the iron plates herein-before referred to, but
which are not shewn in the Drawing. T, wedge which is forcibly driven in,
in order to bear the weight which is above the recess on the pieces which are
below. The action of this wedge, combined with that of the iron plates
before referred to, restores to the whole deadwood as much solidity as if there
had been no aperture made for the placing of the bearing. V, iron wedge
which fixes the shaft F on the shaft E, so that the pair of vanes L project
over the pair N, and on the stern post, so that these two branches may make
between them a right angle. Y, a pinion fixed on the shaft F, by means of
which a movement of rotation round the shaft E is given by the crank and
endless screw K² mounted on the frame J, J, so as to place the pair of vanes L
in a position of rest or in a position of action. Z, coupling in wrought or cast
iron, and in one or more pieces, which connects the shaft F with the iron
shaft m, which prolongs it on to the engines. The shaft E and the shaft m
should be adjusted with respect to one another, or to the coupling, in such
manner that in the forward course the reaction of the screw may be exerted
on the end of the shaft in front of the engines.
Figure 1 is a longitudinal section through a plan of the stern of the boat,
shewing the keel, stern post, wing, transom, deadwood and screw, (the vanes
of which are represented as projecting one over the other,) the details of the
screw shaft, bearing frame, &c.
Figure 2 represents a section through a transverse plan of the aperture of the
screw. The wings or vanes of the screw are here shewn in their unfolded state.
Figure 3 represents a section through a horizontal plan on the lines p, p.
The wings or vanes are here shewn projected one over the other.
Figure 4 is a section of the end bearing, shewing the wedge which com-
pletes the filling in of the recess.
Figure 5 is a plan representing several of the details, especially those of the
stuffing box.
Figure 6 is a repetition of Figure 4, on a scale four times larger.
Figure 7 represents on a larger scale the details of the machinery for
turning by hand one pair of wings or vanes.

page_text: Figure 8 represents the details of the end of the shafts of the screw of the
stuffing box, &c. on a scale about one-fifth of the real size.
Figures 9, 10, and 11 arc diagrams of the lines of a ship's timbers.
The three last Figures refer to a ship of the line. The full lines indicate
the actual shape of a vessel supposed to be built. The dotted lines indicate
the shape as modified by the introduction of a screw with moveable vanes
or wings.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that what I claim is as
follows,-
First, I claim the employment for propelling vessels of a screw composed of
a number of folding and expanding vanes or wings, as before described.
Second, I claim the improved bearing for the ends of screw propeller
shafts, as before described.
Third, I claim the strengthening of the apertures made in the deadwood
for the screw and end bearings by means of a metallic framing, as before
described.
And, fourth, I claim the employment, in aid of the air pump in screw-
propelled vessels, of two water tanks, as before described.
In witness whereof, I, the said Gaspard Malo, have hereunto set my hand
and seal, this Fourteenth day of December, in the year of our Lord
One thousand eight hundred and fifty.