AN IMPROVED MODE OF AND APPARATUS FOR LIFTING SHIPS OUT OF THE WATER
Year: 1872

page_text: LETTERS PATENT to Sidengham Duer, of Harewood Square, in the
County of Middlesex, Civil Engineer, for the Invention of "AN
IMPROVED MODE OF AND APPARATUS FOR LIFTING SHIPS OUT OF THE WATER."
Sealed the 12th November 1872, and dated the 28th May 1872.
PROVISIONAL SPECIFICATION left by the said Sidengham Duer at the
Office of the Commissioners of Patents, with his Petition, on the
28th May 1872.
I, SIDENGHAM DUER, of Harewood Square, in the County of Mid-
dlesex, Civil Engineer, do hereby declare the nature of the said Inven-
tion for "AN IMPROVED MODE OF AND APPARATUS FOR LIFTING SHIPS OUT OF
THE WATER," to be as follows:-
The object of this Invention is to effect a saving in the cost of the
lifting apparatus employed in raising vessels out of the water for the
purpose of inspecting and repairing their hulls. To this end I supple-
ment the hydraulic or other mechanical lifting apparatus that may be
employed by giving buoyancy to the pontoon or saucer over which the
vessel to be lifted is floated to any desired extent short of neutralising
the guiding power of the lifting apparatus.

page_text: may
The pontoon or saucer I propose to construct with air cells, which
be open
at bottom to the water. These cells I so connect with a
blowing engine or pump as to allow of the displacement of the water
therefrom, and the discharge or admission of air into all or any number
of the cells. Or, instead of changing the construction of the pontoon or
saucer which is to float away the raised ship, I may use the ordinary
pontoon or saucer and lift the same together with the ship by the aid of
buoyant cellular girders, which besides receiving the upward pressure
of air forced or admitted into their cells, will be connected to and
operated upon by the hydraulic lifting apparatus.
The action of the hydraulic or other lifting apparatus, and the dis-
placing of water from the cells may take place simultaneously, and as
the water is displaced from the cells the accumulation of air therein
will render the pontoon, saucer, or girders buoyant, and will assist
materially in raising the load.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Sidengham Duer in the Great Seal Patent Office on
the 27th November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SIDENGHAM
DUER, of Harewood Square, in the County of Middlesex, Civil En-
gineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of May, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Sidengham Duer, Her special
license that I, the said Sidengham Duer, my executors, administrators,
and assigns, or such others as I, the said Sidengham Duer, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "AN IMPROVED MODE OF AND
APPARATUS FOR LIFTING SHIPS OUT OF THE WATER," upon the condition

page_text: or
(amongst others) that I, the said Sidengham Duer, my executors
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was
5 to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Sidengham Duer, do hereby declare
the nature of my said Invention, and in what manner the same is
0 to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawings here-
unto annexed, and to the letters and figures marked thereon (that is
to say) :-
The object of this Invention is to effect a saving in the cost of the
lifting apparatus employed in raising vessels out of the water for the
purpose of inspecting and repairing their hulls. To this end I supple-
ment the hydraulic or other mechanical lifting apparatus that may be
employed by giving buoyancy to the pontoon or saucer over which the
vessel to be lifted is floated to any desired extent short of neutralising
the guiding power of the lifting apparatus.
The pontoon or saucer I propose to construct with air cells, which
may either be permanently open at bottom to the water, or closed and
air-tight. These cells I so connect with a blowing engine or pump as
to allow of the displacement of the water therefrom, and the discharge
or admission of air into all or any number of the cells. Or, instead of
changing the construction of the pontoon or saucer which is to float
away the raised ship, I may use the ordinary pontoon or saucer, and lift
the same together with the ship by the aid of buoyant cellular girders,
which besides receiving the upward pressure of air forced or admitted
into their cells, will be connected to and operated upon as heretofore by
the hydraulic or other lifting apparatus.
The action of the hydraulic or other lifting apparatus and the dis-
placing of water from the cells may take place simultaneously, and as
the water is displaced from the cells the accumulation of air therein will
render the pontoon, saucer, or girders, as the case may be, buoyant, and
will assist materially in raising the load.

page_text: In Sheet I. of the accompanying Drawings Fig. 1 represents in cross
section an hydraulic lift graving dock with my improved construction of
pontoon applied thereto, in which the lifting power is supplemented by
giving buoyancy to the pontoon. A is the pontoon or saucer furnished
with cells a, a, which are formed by constructing a deck or diaphragm
in the pontoon at a convenient height from the bottom, and dividing up
the space below the deck by means of the ordinary transverse and longi-
tudinal web girders of the pontoon. These cells are made air-tight, and
they are severally connected by means of pipes 6 with a pump or pumps
for removing the water therefrom. The pontoon A is shewn as over-
lying the transverse lifting girders B, into which position it has been
floated together with its load C, which represents a ship intended to be
lifted. c, c, represent a series of pipes for supplying air to the cells a as
they are exhausted of water. In order to lift a ship which is sufficiently
heavy to require the use of both the hydraulic or other lifting power of
the dock, and the supplemental buoyancy of the pontoon, the raising of
the ship is commenced by the hydraulic power alone, and when this
becomes insufficient the water in the cells a, a, is pumped out through
the pipes b, b, to render the pontoon buoyant. At the same time air is
admitted by the pipes c, c, into the cells a, a, to take the place of the
water pumped out. As the deck of the pontoon rises to the level of
the water in the dock the water above the deck of the pontoon escapes
through valve openings provided for the purpose. When the water has
escaped the valves are closed and the buoyancy and stability of the
pontoon is thereby secured.
Fig. 2 shews a modified form of pontoon employed in connection with
the hydraulic lift graving dock. In this example the cells a are open at
bottom, and the water is expelled therefrom to give buoyancy to the
pontoon by means of air forced into the cells through the pipes b.
Figures 3 and 4 represent cross sections of hydraulic lift graving docks
in which the lifting power is supplemented by giving buoyancy to the
transverse girders B without requiring any alteration in the construction
of the pontoon A. The girders B in place of being lattice or Warren
girders, as heretofore, are now formed into boxes, which may be either
closed at bottom as in Fig. 3, or open as in Fig. 4.
These boxes may be connected together (some or all of them, as shewn
in the plan view, Fig. 7, Sheet II.), or they may be kept separate as in

page_text: the plan view Fig. 8, and may be subdivided into cells a, a, as required.
In such a dock as is shewn in Fig. 3, when the supplemental buoyancy
is required it is obtained by pumping the water out of the cells a, a,
through the pipes b, b, and allowing air to take its place through the
pipes c, c, as previously described with reference to Fig. 1. In such a
dock as is shewn in Fig. 4, when the supplemental buoyancy is required
it is obtained by forcing air into the cells a, a, through the pipes b, b, as
has been previously described with reference to Fig. 2.
Sometimes it is required to construct hydraulic lift graving docks
without using moveable pontoons. The manner of applying my Inven-
tion to this class of docks is shewn in Sheet III. at Figures 5 and 6,
which Figures represent cross sections of the dock with the girders B
divided into cells a, a, from which the water may be discharged and
buoyancy obtained, as has been before described. The cells a in Fig. 5
are closed, while those shewn at Fig. 6 are open to the external
water.
Figures 9 and 10 shew the mode of applying my Invention to cellular
floating docks.
In these examples my improved pontoon in its two
forms of open and closed cells is shewn as floated into a trough-shaped
cellular dock D, the sides of which ensure the steady rise of the load.
As the water is withdrawn or expelled from the pontoon (which operation
should follow the rise of the dock due to its own buoyancy), the dock
will continue to rise with the pontoon, and thereby maintain the steadi-
ness of the rising load. From the above examples it will be understood
that my improved pontoon may be used with advantage for increasing
the lifting power of the various lifting docks now in use.
Having now set forth the nature of my Invention of "An Improved
Mode of and Apparatus for Lifting Ships out of the Water,” and ex-
plained the manner of carrying the same into effect, I wish it to be
understood that under the above in part recited Letters Patent I
claim,-
First. The use of a lifting pontoon to which buoyancy may be given
as desired in combination with an hydraulic lift graving dock or other
dock for lifting ships out of the water.
Secondly. Giving buoyancy to the lifting girders of graving docks in

page_text: Thirdly. I claim converting floating pontoons or saucers into lifting
pontoons or saucers, as above described, without detriment to their
stability.
In witness whereof, I, the said Sidengham Duer, have hereunto
set my hand and seal, the Twenty-sixth day of November, in
the year of our Lord One thousand eight hundred and seventy-
two.
SIDENGHAM DUER. (L.S.)