IMPROVED MEANS AND APPARATUS FOR RAISING SUNKEN SHIPS AND OTHER SUBMERGED BODIES
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Thomas Arthur Dillon at the Office
of the Commissioners of Patents on the 6th May 1879.
THOMAS ARTHUR DILLON, of 55, Rutland Square, in the City of Dublin,
Ireland. "IMPROVED MEANS AND APPARATUS FOR RAISING SUNKEN SHIPS AND
OTHER SUBMERGED BODIES."
This Invention consists of further improvements on my Inventions for which I
have already obtained Lotters Patent, respectively dated the 13th day of October
1875, No. 3550, and the 28th July 1876, No. 3034, and has reference to more
improved methods of raising sunken ships and other submerged bodies, which will
greatly add to the practical value of the Inventions already specified.
I will now proceed to describe the new Inventions and discoveries and the
practical method of carrying out of which I consider to be novel and useful
The original Patents clearly describe the method covering a sunken ship by a
canvas sheet or diving bell, attaching said bell to the wreck, inflating the bell with
air, which then lifts the wreck as a balloon lifts its car.
I have discovered and invented a method and apparatus which enables me to
dispense with attachments between the said bell and ship, and whereby the ship rises
automatically inside the bell as the latter comes to the surface of the water, although
no communication exists between the ship and bell
But inasmuch as it is absolutely requisite that the mouth of the said bell shall
be held down to the ground on which the ship rests while the inflation is being
accomplished, and that a facile method of releasing the sail from such holding down
attachments is also necessary in order that it shall rise and bring up the ship with
it, I have discovered and invented a method and apparatus whereby such attach-
ment may frequently be dispensed with.
In order that my Invention may be more easily understood I will describe one
form of the improved apparatus, which may be varied in detail without departing
from the principle and method which I have discovered and rendered practicable.
Supposing a ship size of the Vanguard wreck, now lying off the Irish east coast,
in say a mean tidal depth of 100 ft., I prepare to adopt the following method and
plan for raising her :-
-
A diving hell shaped canvas cover is allowed to descend and cover the ship so
that she will be inside a great tent in the manner described in my previous Patents
for ship mising Inventions

page_text: To each side of this bell, which will be oblong or oval shaped, are attached to
reversed bells, counterparts of the centre bell, except that they look upwards, while
the centre bell looks downwards.
They are filled with inlet valves and outlet valves, so that when lowering the
sail bag or bell over the ship the water rushes in through the inlet valves and fills
the side bells, so that when their mouths come to the surface the difference of
specific gravity between air and water will operate, but in the opposite way, in
which it tells in the action of the centre or diving bell compartment. The water
being expelled in the one case (that of the diving bell) by force of air the bell
becomes specifically lighter than an equal volume of water. In the other case, as
the side reversed bells come to the surface, they resist the efforts of the centre bell
of the amount of weight of water which they contain, and the difference of
weight between water and air, as is well understood by scientific and practicable
men.
It is occasionally more convenient to use two ships, one on either side of the bell,
with cross chains between them, to which cross chains the top of the canvas diving
bell is attached, and against which it presses.
Let it be supposed that a sunken ship is to be raised, the canvas diving bell is
brailed or buoyed up between the two ships, which moving at the same speed will
tow it over the wreck, and let its mouth drop over the latter, as already
described.
The ships must keep as far apart as possible. On the air being forced into the
diving bell, which, as before stated does not touch the ship, the water will be
expelled from beneath the bell, the pressure of the latter will come against the
chains, which extend between the ships; the strain will be upwards, and the
tendency will be to raise the ships out of the water, but inasmuch as the united
weights of the two ships will necessarily exceed the weight of the ship to be lifted,
which latter weight is represented by the pressure of the bell upwards, the bell
cannot rise although it has been emptied of water until the cross chains which
keep it down are let go; then as the bell rises instantly by reason of its lighter
specific gravity the ship, as already stated, will follow it inside, and remain afloat
sufficiently long to have loose canvas flaps attached to the mouth of the bell,
tightened beneath it, and separate chains likewise passed beneath it, so that the
sunken wreck would have its own floating power to sustain it, to which is super-
added the sustaining power and towing force of the two side ships.
It is obvious that in place of the ship's side pontoons or rafts may frequently be
used. In some cases I use screw piles and anchors, sand bags, and such like weights
separately or in combination with the foregoing methods. In order that the short
space of time which elapsos between the ebb and flow of tide, I prefer as far as
possible to have the air necessary for inflation of the bell previously compressed in
reservoirs, which may be carried in the ships or pontoons alluded to, or in any
other convenient manuer. To prevent the lifting or upward pressure of the bell
which comes against the cross chains acting injuriously on the equilibrium of the
side pontoons or ships, I pass chains around such pontoons or ships, and throw
the strain of the cross chains upon the upper part of the chains which I havo so
passed round the pontoons or ships, the result will being naturally to keep the
ships in an upright position, instead of canting them over.
It will be necessary
that the pontoons or ships shall be strongly anchored on the two sides which are to
seaward of the bell, because of the rising of the bell and the strain of the cross
chains will have a powerful tendency to induce the ships to come together.