CERTAIN IMPROVEMENTS IN VESSELS MOUNTED AS FLOATING BATTERIES
Year: 1862

page_text: LETTERS PATENT to Marc Antoine François Mennons, of the British
and Foreign Patent Offices, 24, Rue du Mont Thabor, Paris, in the
Empire of France, for the Invention of "CERTAIN IMPROVEMENTS IN
VESSELS MOUNTED AS FLOATING BATTERIES."-A communication from
Jean Antoine Alexis Cambon de la Valette, residing at Montauban
(Dept. de Tarn-et-Garonne), in France.
COMPLETE SPECIFICATION filed by the said Marc Antoine François
Mennons at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 12th July 1862, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARC
ANTOINE FRANÇOIS MENNONS, of the British and Foreign Patent Offices,
24, Rue du Mont Thabor, Paris, in the Empire of France, send greeting.
WHEREAS I am in possession of an Invention for "CERTAIN IMPROVE-
MENTS IN VESSELS MOUNTED AS FLOATING BATTERIES," communicated from
Jean Antoine Alexis Cambon de la Valette, a person resident at Montauban,
(Dept. de Tarn-et-Garonne), in France, and have petitioned Her Majesty
to grant unto me, my executors, administrators, and assigns, Her Royal
Letters Patent for the same, and made solemn declaration that it is a
communication.

page_text: NOW KNOW YE, that I, the said Marc Antoine François Mennons, do
hereby declare that the following Complete Specification, under my hand
and seal, fully describes and ascertains the nature of the Invention, and
the manner in which the same is to be performed, reference being had to the
Figures of the accompanying Drawing, and to the letters marked thereon, that
is to say:-
The object of this Invention is so to modify in certain points the construction
and internal arrangement of vessels intended for floating batteries as to permit
the discharge of ordnance from below the water line, and the consequent
direction of the projectiles towards the corresponding part of the enemy's
ship.
Figure 1 of the accompanying Drawing represents in cross section the
hull of a gunboat thus arranged. A, A, A, A, is the outline of the vessel,
which should be constructed to run at a high speed and be rendered in all
points as invulnerable as possible; B is a porthole formed at, say, for instance,
ten feet below the water line W, W, and fitted with slideways in which run
the two metallic plates or shutters C, C'; D is a moveable frame, also running
in slideways in the porthole, and fitted with a diaphragm d, in canvass or
thin sheet metal of sufficient strength to resist when uncovered the pressure
of the water from without; F, F', are iron draw rods sliding in suitable packing,
and serving to raise and lower in their grooves the plates C, C'; G is an
iron beam or bent lever, to one arm of which is attached the free end of the
draw rod F, while the other is articulated to the breech-loading cannon H;
G' is a second beam, connected by one extremity with the rod F, the other
being left free to be worked as occasion may require by hand or by suitable
machinery I, I, I, is a species of fluo constructed of strong plate or sheet
metal, adjusted by one extremity to the framework of the vessel round the
porthole B and by the other to the deck, where it is closed by a shot-proof
grating J. The lower part of this flue towards i, i, should be formed of plates
sufficiently thick to resist accidental contact with the passing projectiles;
K, K, is an opening piorcod in the buck of the flue in line with the porthole
B, and giving passage to the fore part of the cannon H mounted on slideways
.of any suitable construction. The adjustment of the gun to the aperture and
slides should of course bo as exact as possible. L is an elongated steel-pointed
and explosible shot, scen apart in Figure 4, but which may be replaced by
any other projectile of suitable form. Figures 2, 3, are cross and vertical
sections of the flue or fire chamber I, I, I. Figure 5 is a section of the frame
in which are set the sliding plates or shutters C, C¹. Figures 6, 7, 8,
represent the moveable frame D, with its central diaphragm d and maintaining

page_text: bar d. It will be understood that the arrangement above described as
applied to a single porthole may be adapted to any number of guns carried by
the vessel below the water line, the details of execution being varied according
to circumstances. In all cases the joints of the frames and other parts exposed
to the water should be rendered as tight as possible and the slideways be
coated with grease to facilitate the movement of the closing plates. The
diaphragm d, when formed of canvass or other permeable material, should also
be provided with a coating of grease, caoutchouc, or other repellent matter.
To prepare for action the vessel armed as above, the slide plate C is raised
by the hand or by suitable mechanism to the point shewn in the Drawing,
where it remains ready for use in case of the second plate C being accidentally
disabled. On running forward the cannon previous to firing, this second plate
is raised in its slides by the action of the beam G, leaving the porthole closed
by the diaphragm d only. While these manoeuvres are being executed the
vessel is run into the required position as closely as practicable to its opponent,
say to within a distance of from ten to twenty yards. This done, the cannon is
discharged and the projectile tearing the diaphragm by which the porthole is
masked passes horizontally through the water towards the lower part of the hull
of the adverso ship. Simultaneously with the discharge, the cannon recoils on
its slides and carrying with it the arm of the beam G causes the plate C to
descend in its grooves, thus closing up the porthole against the water. A fresh
diaphragm is then substituted to the one just destroyed; the cannon being
recharged is again run into position, and so on as required. The small quantity
of water admitted through the ruptured diaphragm during the fraction of time
which intervenes between the transit of the projectile and the descent of the slide
plate is drawn off by any suitable means through the purge pipo M set in the.
bottom of the flue 1. The gases resulting from the explosion in the flue are
carried off by the grating J, their escape being accelerated if necessary by
ventilating apparatus of any suitable description. The effect produced by an
elongated shot thus thrown through a mass of water may be thus calculated.
In taking as example a projectile of, say, 42 inches in diameter by 28 inches in
length, and weighing 90 lbs., flying at an initial velocity of 650 yards per second,
we obtain a power of 5825 lbs. The forces opposed to the flight of such a
projectile consist of the weight of the liquid column pressing on its surface of
section, say 78 lbs., plus the friction, which may be estimated at a maximum
of 60 lbs., in all, a resistance to be overcome equivalent to 183 lbs. Even in
admitting the possibility of a vacuum being formed behind the projectile, the
resistance would only be increased by about 250 lbs., giving a total of 383 lbs.
as opposed to 5325 lbs. It is therefore evident that few vessels as at present

page_text: constructed with a vulnerable space between the water line and the keel could
withstand the action of the. projectile at a distance of twenty yards or even
more.
Having now described the nature of the said improvements, and the
manner in which they may be. carried into effect, I would have it understood
that I do not confine myself to the precise details of execution above laid down,
as these may obviously be modified without deviating from the principles or
characteristic features of the Invention; but what I claim and desire to protect
by Letters Patent is, the novel combination of fittings or apparatus applied to
vessels mounted as floating batteries, by means of which projectiles may be
directed from below, the water line of such vessels against a corresponding
point of the enemy's ship, the said combination being composed of the following
principal elements :-
1stly, a submarine porthole provided with a moveable obturator so arranged
and> connected with the cannon as to open up when the latter is run into
position for firing and to reclose under the action of the recoil immediately after
each discharge..
2dly, a moveable diaphragmn of strong canvass or other suitable material,
serving as temporary mask to the uncovered porthole, and giving passage
to the projectile at each discharge.
3dly, a metallic flue or fire chamber leading from the porthole to the deck of
the vessel, and pierced at the back to admit the barrel of a breech-loading cannon
so arranged as to fill up the aperture in which it is set while sliding freely to
and fro immediately before and after each discharge. The whole constructed,
applied, and operated in manner and for the purpose substantially as herein set
forth and shewn in the annexed Drawing.
In witness whereof, I, the said Marc Antoine François Mennons, have
hereto set my band and seal, this Fifth day of July, in the year of
our Lord One thousand eight hundred and sixty-two.
M. F. MENNONS. (L.S.)