AN IMPROVED MODE OF STOPPING SHOT HOLES AND LEAKS IN IRONCLAD AND OTHER SHIPS AND VESSELS, AND IN THE APPARATUS THEREFOR
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Euston Witney Duppa at the Office of
the Commissioners of Patents on the 1st March 1878.
EUSTON WITNEY DUPPA, of 23, Southampton Buildings, London. "AN IMPROVED
MODE OF STOPPING SHOT HOLES AND LEAKS IN IRONCLAD AND OTHER SHIPS AND
VESSELS, AND IN THE APPARATUS THEREFOR"
This Invention consists,-
Firstly. Of a novel mode of stopping shot holes or leaks in ironclad and other
ships and vessels by the application of gutta percha in a semi-liquid state.
And, Secondly. Of the apparatus used for injecting the gutta percha into the
fissure or leak, and the cradle or machine for lowering the apparatus to the bottoms
or sides of ships pierced by shot or when a leak has been sprung.
It consists of a cylinder about 8 feet long by 12 inches in diameter in the inside,
which is accurately turned and countersunk / inch in depth for about one-fifth of
its length at one end; the other end is closed by a sliding lid so fitted as to be
capable of being entirely lifted out and hinged back. This cylinder is of wrought
steel throughout of about one inch in thickness.
A cylinder, also of steel, turned on the outside so as to permit it to fit accurately
into the countersunk chamber of the before-mentioned cylinder, and which it
entirely occupies, is furnished with a neck at one end (which has a worm on the
outside to admit the condenser being screwed on), and in the neck is a plug which
opens or closes the only aperture in the cylinder, the plug being worked by a key.
A piston or cap of steel (with a high rim) at least one inch thick fits perfectly
air-tight in the first-described cylinder, and yet capable of being easily worked up
or down.
An outer cylinder enclosing the first-mentioned cylinder, and fitted with an
aperture closed by means of a screw top, is also formed of steel, but of no great
thickness, and is in its turn surrounded by an outer cylinder of felt about five
inches thick, protected on the outside with copper sheeting so as to render the
whole apparatus waterproof.

page_text: To load the machine it is first, for convenience, placed in the stand, where it
swings on the axle, and in this manner either side can be easily canted up or down
as occasion requires.
The cylinder having been loaded with compressed air is then lifted into its place
by means of the countersunk handle, and the lid is then closed and secured.
A block of gutta percha of nearly the same length and diameter as part of the
first-described cylinder below the second-described cylinder is placed inside it
together with a little grease or oil to prevent the gutta percha from sticking to the
sides, and the slide is then closed.
The outer cylinder is then filled with oil heated to about 20° above boiling-water
point, and after a lapse of about 30 minutes the machine is ready for use.
The machine is then lifted off the stand and placed in the cradle and lowered
over the ship's side until the slide is opposite the shot hole, when the man in charge
draws up the slide and then turns the key, when the compressed air is liberated and
drives the piston to the bottom, and thus forces the semi-liquid gutta percha into
the shot hole. The piston is stopped at the bottom of the cylinder by three small
studs. If, however, the machine is not immediately required it is left in the stand,
and the felt caps are fitted on to the top and bottom to retain the heat; and the
gutta percha will by these means retain its plasticity for upwards of twelve hours,
and can be made to do so for an indefinite time by changing the oil.
In practice it would perhaps be best to first heat the cylinder with steam, so that
the oil will not have to part with any of its heat to warm the cylinder.
The machine is made waterproof on the outside in order that with the assistance
of a diver it may be used under water as well as above.
The cradle is of two kinds, one kind consisting of long arms provided with
suckers of vulcanized india-rubber which attach the arms to the ship's side, the
other kind being somewhat similar, but the arms are changed for a wheel about
6 feet in diameter, the face of which is covered with vulcanized india-rubber, and
hollow saucers or cavities are here and there sunk in the surface, which act as
suckers and cause adhesion to the sides of the ship also, and is intended for the
stem and stern of vessels where the long arms of the first kind of cradle would be
inconvenient to use.