A NEW AND IMPROVED APPARATUS FOR INCREASING THE BUOYANCY OF SHIPS AND OTHER VESSELS
Year: 1856

page_text: PROVISIONAL SPECIFICATION left by Henry Laxton at the Office of the
Commissioners of Patents, with his Petition, on the 9th April 1856.-A.
communication.
I, HENRY LAXTON, of the firm of William and Henry Laxton, of the Office
for British and Foreign Patents, No. 19, Arundel Street, Strand, in the County
of Middlesex, Civil Engineer, having a communication from Alexander Le Mot,
of the United States of America, do hereby declare the nature of the said
Invention for "A NEW AND IMPROVED APPARATUS FOR INCREASING THE BUOYANCY
OF SHIPS AND OTHER VESSELS," to be as follows:-
The Invention consists of a series of floats of a spheroidal form, attached to
the side of a ship or vessel by means of chains or ropes, such chains or ropes
being made to pass through hollow metal tubes, the said metal tubes having
slits continued their whole length. These tubes are fixed or built into the sides
or ends of a ship or other vessel. Windlasses and other apparatus are used for
drawing the chains backward and forward, so as to cause the floats to be fixed
or placed at such part of the ship or vessel as may be required, in order to raise
it, either for repair, or for floating it over sand banks, rocks, or other obstruc-
tions, or for floating it in shallow water. The floats are of two shapes, viz.,
elongated and cylindrical, or spheroidal. The longitudinal floats are in 3 pairs
of equal length, but each pair may differ in width from the other two, so as to
graduate the buoyancy as desired. The spheroidal floats are four in number, two
for the bow and two for the stern of the vessel. The floats are constructed of
any material uniting the conditions of strength, pliability, and impermeability to

page_text: water; but it is preferred to make them of canvass doubled, so that the edges
lying flat on each other and meet on one side, and between the two thicknesses
of canvass is spread a layer of any of the known waterproof varnishes, cements,
or compositions. A tube formed of a double thickness of canvass with an
intervening layer of waterproof substance is then firmly attached to a rope, and
a seam is then formed close to this rope by sewing the four thicknesses of
canvass and two layers of waterproof composition firmly together. Before
closing the seam, the hose for the inflation, being a continuation of a cable hose,
is introduced into the float, so as to be covered and enclosed within the seam
which is sewn over it. The seam is then stiffened and made smooth by
impregnating it with varnish or drying oil. A slip of canvass is cemented in
the inside of the tube so as to cover the seam, and the edges of the slip are
firmly sewn to the side of the tube; both ends of the tube are then carefully
closed so as to be air-tight. Parallel with the vessel's line of floatation when
fully loaded, and at a distance under this line of about half the diameter of the
widest longitudinal float, a line is marked on both sides of the hull, and two
other lines, parallel to the same and between it and the keel, so as to be about
equidistant from each other and from the keel. Then three lines, extending
from near the bow to near the stern on both sides of the vessel, are traced for
the reception of three pairs of tubular rails, by means of which the longitu-
tudinal floats are applied to perform their office. Two other pairs of similar
rails, descending at the bow and stern to the
the reception of the four spheroidal floats.
of a diameter admitting the easy passage of
made with an external slit, with lips turned
whole length of the tube, wide enough to permit the passage of the float seams,
but too narrow to allow the chains or ropes to be pulled or torn through them,
so that the float when introduced into the rails can be easily slided along them
forwards or backwards, but cannot be pulled out through the slits. When the
floats are inflated, the force resulting from the displacement acts not to tear.
tear them out of the rails, but rather on the rails as hinges or handles for
lifting up the vessels to which they are attached. The rails may be attached to,
the vessel in several ways, and may, when running close to the side wheel of a
steamer, be fixed by standards or brackets; a row of claws at the top of the
standard holding the rails must present a line offering the least resistance. The
rail may be attached to old ships by nut and screw bolts, cast in a body with
the rail, passed through the sides of the ship and screwed or rivetted to it; or a
plank may be taken out of the side and replaced by another thick enough to
permit a groove to be cut into it to receive the rail, so as to make its surface
:
keel of the vessel, are provided for
All these rails of tubular form are,
the float ropes or chains, and are
over on each side, continued the

page_text: flush with the side of the ship, and by that means avoid any projection; or there
may be employed two bolts with heads entering into the recesses under the lips
of the slit. In new vessels, the rails may be let into planks and made flush
with the sides of the vessel, or if the vessel be of iron, then the rails are cast in
one body with the plates that compose the sides of the vessel. In new vessels.
the construction of the rails may be made into one body, by metallic bars
connecting them together round the bow and stern, so as to constitute a frame-
work for the hull, and thereby greatly increase the strength of the vessel. The
longitudinal rails ascend at both ends by gentle curves, in a direction nearly
perpendicular towards the port holes or other openings, made for the purpose
near the bow and stern; there they, as well as the upright rails, are slightly
curved towards the deck, so as to present their mouths, which are somewhat
widened and curved, close to or rather in the deck floor, where they open onl
the deck.
In vessels that are coppered, it will be expedient to interpose a strip of
vulcanized gutta percha between the rails and the copper at all the points of
contact, to prevent the-galvanic action which would otherwise result. 'There is
hooked on the last link of the chain which passes through the rails a metal
sweep or scraper, with a grooved surface just fitting the tube of the rails, and a
projection passes through the slit and is then widened and flattened so as to
press against the lips of the slit. This scraper is intended for effectually
cleaning the rail of any thing that might get into it or become caught in the
slit; the cleaning being performed by hauling the chain through the rail
before attaching the float. For the perfect protection against wearing the
seam of the float by friction as it passes and repasses along the slit, it would be
prudent to sew over it on each side a strip of canvass that could be replaced as
often as worn out. The means provided for keeping the floats in any required
position in the rails, as well as for their first introduction, are capstans with
their fittings. The capstans, two in number, exactly alike, are placed one in the
bow and the other in the stern, in the position best adapted for conducting the
float and chain in the most direct line to the mouth of the rails. These capstans
are placed between decks, their base in the lowest gun deck; each has three
horizontal axletrees superposed above each other; each axletree carries a pully
or gear so arranged as to give motion to one, two, or all the axletrees; a roller
for the float so arranged as to revolve or not, as desired, with the revolution of
each axletree respectively, and a roller for the chain similarly arranged. The
middle axletree has also a bevel gear to give motion to a bevel wheel and the
roller connected therewith, which motion is transmitted to the roller by the
bevel wheel, it being necessary the rollers revolve in opposite directions. This

page_text: is accomplished in the simplest way by a single gear, in consequence of the
angular position of the rollers, and gears with reference to the axletrec. The
gears may be arranged by any known mechanical means, so as to throw them
in or out of gear at pleasure. In the front of the capstan is a dial, so connected
by clockwork with the power wheels as to indicate the number of revolutions
of the axletrees, and thereby the progress of the floats in the rails. These
rollers are provided with the following appendages, viz:-Each chain roller
carries a chain long enough to reach from the periphery of the roller to the
mouth of its appropriate rail, where the chaiu ends in a hook linked in a loop,
constituting the butt end of the hose cable, from the point where the hose
cable continues as an ordinary cable, the whole length of the float, until it ends
in a loop to receive the hook of the chain. If now it be assumed that the
chain of a chain roller of the stern be unrolled, and consequently passed through
its appropriate rail, its butt end will be retained in the mouth of the said rail
on the bow by a disc with a notch in it, and in this case on the corresponding
Hoat roller of the bow, the chain, the cable, and the longitudinal float will be wound
up. If the longitudinal floats are to be used, the hook of the chain of the stern is
linked with the butt end of the hose cable of the float of the bow, and thus an
uninterrupted communication is established between the two capstans, so that
the motion imparted to one must be followed by the motion of the other.
Hence, on withdrawing the disc, and applying power to either capstan, the
chain will be withdrawn from the rail and wound up on its chain roller of tho
stern, the hose cable of the bow following in its track, and the float succeeding
down and along the rail until it reaches its due position. As soon as the butt
end of the hose cable has reached the mouth of the rail, it must be connected
by means of the ordinary gas pipe coupling with its appropriate faucet of a
pipe conduit, communicating with an air pump placed in any convenient part
of the vessel. The inflation of the floats being completed, the hook of the chain
can be withdrawn from the loop of the cable, to be out of the way after the
latter has had its end made fast by the interposition of the disc. The same
process may take place simultaneously, if so deemed necessary, on both sides of
the ship. The whole process is reversed when the floats, after being exhausted
of air, are to be withdrawn. The rollers on the capstan carry endless bolts, and
on them cylindrical or spheroid floats. The endless belt consists of a hose
cable, equal in length to a line drawn from the top of these rollers to the point
where the float is in its lowest position, a common rope forming a continuation
of the bose cable all along the seam of the float, and a chain, forming the
complement of the endless belt, which passes round the rollers, thence down
the mouth of the upright rails to their bottom, where they are gently secured,

page_text: thence up the other closed parts of the same rails to their round mouth, and up
again round the rollers. The construction of the upright rails is double, being
two tubes fixed side by side and connected together; one of them is provided
with a slit for the ascent and descent of the float; the other forming a perfect
tube, as it only gives passage to the chain. The floats, when not in service, are
kept wound round the rollers, and on the rollers being put into gear and
power applied to the capstan, the endless belt moves, as above described, and
the float descends, when it reaches the required depth, as shewn by the dial, as
before explained; the butt end of the hose cable is connected with its
appropriate faucet, and the float is inflated by the air pump. When the float
is withdrawn it is not exhausted of its air at once, but the fixture which retains
it in position during use is withdrawn, and it then rises by its own buoyancy,
assisting in revolving the rollers; all the floats may be used together, or any
one or more of them separately or together. One or two air pumps are placed
in any convenient position, with their recipients branching off into the conduits,
which in any convenient way are carried under the floor close to the mouths of
the rails. The conduits opposite these mouths are furnished with stop-cocks
and faucets for connection with the hose. Each branch is provided with a
manometer for indicating the pressure.