IMPROVEMENTS IN THE MEANS OF AND APPARATUS FOR RAISING SUNKEN VESSELS, AND ALSO FOR PREVENTING THEM FROM SINKING
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by John William Couchman at
the Office of the Commissioners of Patents, with his Petition, on
the 13th October 1875.
I, JOHN WILLIAM COUCHMAN, of Tottenham, in the County of
Middlesex, Civil Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MEANS OF AND APPARATUS FOR RAISING
SUNKEN VESSELS, AND ALSO FOR PREVENTING THEM FROM SINKING," to be as
follows:
―
My Invention has for its object the raising of sunken vessels by means
of bags distributed in the several chambers and unoccupied parts
throughout the vessel, into which bags atmospheric air is forced,
whereby they are caused to expand and force out the water from the
said chambers and unoccupied parts to such an extent as to diminish the
specific gravity of the whole vessel and cause it to rise in the water.
For this purpose the several bags intended to operate throughout the
vessel are connected together so as to form a system of flexible receivers,
in communication with a common feed pipe or pipes or apparatus,
through and by means of which atmospheric air may be forced into the

page_text: said bags or receivers after they have been severally placed in their
respective positions within the cavities of the vessel, and distributed as
required throughout the whole area of the interior of the vessel in such
a manner as to admit of their combined operation when the atmospheric
air is forced into them.
From what has been stated it will be seen that the peculiarity of the
Invention consists in the employment of bags suitably distributed in the
interior of the vessel, and forming in the aggregate with their connections
and the apparatus for forcing air into them a means of displacing
water from the interior of the vessel, and thereby diminishing the
specific gravity of the whole body so as to admit of its rising in the
water in which it is immersed to the extent required for moving it as a
floating body.
The bags are not required to be of any specific form, and any con-
venient number of them may be deposited in a chamber or unoccupied
part of the vessel; also the connections between them are intended to be
formed by means of flexible pipes and union joints with suitable valves
opening into the respective bags.
The bags may be made of canvas or other suitable material rendered
air and water-tight, and they should be of sufficient strength and
capacity to bear the internal pressure of the air and its expansion
within them as the vessel rises and the external pressure of the water on
them is reduced, and in proportion to the compression of the air under a
given column of water. If preferred, the bags may be of cellular con-
struction.
The equalization of pressure as required is produced by the connection
and intercommunication of the several bags, and also by means of
suitable cscape valves adapted and applied thereto, and also by con-
structing or applying the bags of sufficient capacity to allow for
expansion of the air within them, or by a combination of the escape
valves and the surplus capacity of the bags.
The above described arrangements are also applicable to preventing
vessels from sinking in case of accidents at sea.