IMPROVED MEANS AND APPARATUS FOR GAINING ACCESS TO AND FOR RAISING SUNKEN
Year: 1874

page_text: LETTERS PATENT to George Blaxland, junior, of Brixton Road, in
the County of Surrey, Engineer, for the Invention of "IMPROVED
MEANS AND APPARATUS FOR GAINING ACCESS TO AND FOR RAISING SUNKEN
"
PROVISIONAL SPECIFICATION left by the said George Blaxland at the
Office of the Commissioners of Patents, with his Petition, on the
31st January 1874.
I, GEORGE BLAXLAND, junior, of Brixton Road, in the County of
Surrey, Engineer, do hereby declare the nature of the said Invention
for "IMPROVED MEANS AND APPARATUS FOR GAINING ACCESS TO AND FOR RAISING
SUNKEN VESSELS," to be as follows :—
This Invention has for its object the displacing of the water inside of
a sunken ship or vessel by means of compressed air or gas, and in the
apparatus employed for this purpose.
When a sunken ship or vessel to be raised or gained access to in
accordance with my Invention is fully laden it will first be necessary to ·

page_text: take out a portion of her cargo, say that which lies on the “tween
decks," by means of divers, and when that is accomplished the divers
must proceed to stop all the outlets, such as hatchways, skylights, or
other openings, and then attach the apparatus herein-after described in
carrying out my Invention.
.
According to one part of my Invention I make the vessel herself the
means of holding the compressed air or gas, so as to gain access to and
raise the same without the intervention of tanks, casks, pontoons, bags,
or other similar means.
Another part of my improvements relates to the application of an
apparatus called an "air lock," without the addition of a diving bell, for
gaining access to the interior of a ship after a sufficient quantity of air
has been forced down into her.
My Invention also relates to the application of a tube or pipe fitted
with or without a valve for the outlet of the water from the interior of
the sunken ship or vessel when it is being displaced by compressed air.
My Invention also relates to the application of a valve opening to the
interior of a sunken ship or vessel for readmitting the water to the ship
in case of any accident, by which the compressed air should become so
rarified as to cause an undue pressure from the outside.
In carrying out my Invention the hatchways of a sunken ship or
vessel are first closed by means of a plate suitably strengthened by T or
Lirons, and having wooden fitting pieces combined with india-rubber
or 'gasket" on the face for making the joint on the edge of the
combings perfectly tight. The closing plate is made to overhang the
"combings" sufficiently to allow of bolts being screwed into the deck.
The "air lock" or chamber, by means of which access is gained to
the interior of the sunken vessel, has two doors, one opening to the
outside and the other to the inside of the sunken vessel. Two cocks are
arranged in the air chamber, one for the admission of compressed air
from below, and the other for the escape of it to the atmosphere. The
doors are so fitted that when closed and screwed down they are perfectly
tight, and have very strong glass fitted in them for admitting light to
the interior. Steps are arranged, by which to descend from the air lock
to the interior of the vessel. A door opening to the interior of the
vessel is provided, and need only be used when it is required to remove

page_text: the "air lock," or when it is required to send down a longer piece of
material than will go in between the two other doors before referred to.
An air pipe is arranged, to which is attached a hose leading to the
air pumps, having a cock for shutting off the communication when
required.
An outlet pipe with valve for discharging water from interior of the
vessel is arranged to open outwards, and having a lever attached for
being worked from above. This outlet pipe (or pipes) may be made
telescopic or have a flange, so that its length may be increased or
diminished as may be required.
An inlet valve is also arranged, having a lever, to which is attached a
counterbalance weight arranged so that it only keeps the valve shut
when the pressure inside and outside of the vessel are equal, but when
the pressure on the outside is above that on the inside of the vessel it
shall open and allow the water to enter until an equilibrium has been
established.
Supposing the whole of the apparatus to be attached and a
sufficient quantity of air forced into the sunken vessel to allow of
a man to pass down and under the deck I proceed as follows:-The
upper door of the "air lock" being open and the lower one closed the
workmen enter the chamber and close the upper door (to which it is
advisable to have a counterweight attached to a line passing over a
pulley) screwing the door up hard from the inside by means of "dogs,"
then open the cock in the lower door, and allow the compressed air to
fill the chamber, when the air ceases to flow in the fastenings of the
lower door may be removed and the door lifted and hooked up giving
frec.access to the space below.
The next operation after getting inside the sunken ship or vessel is to
make good such air leaks as the divers have been unable to stop, and
which can be much more efficiently performed from the inside, and are
easily detected by the noise which the air makes in escaping, or by the
application of a lighted candle, the flame of which would be drawn into
any existing leak.
All the leaks having been sufficiently stopped and the water forced
down to or displaced to a sufficient depth any requisite work, such
as the construction of additional bulkheads, securing the decks to

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Blaxland in the Great Seal Patent Offico
on the 30th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
BLAXLAND, junior, of Brixton Road, in the County of Surrey, Engineer,
send greeting,
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirty-first day of January, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said George Blaxland, junior, Her
special license, that I, the said George Blaxland, junior, my executors,
administrators, and assigns, or such others as I, the said George Blaxland,
junior, 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
"IMPROVED MEANS AND APPARATUS FOR GAINING ACCESS TO AND FOR RAISING
SUNKEN VESSELS," upon the condition (amongst others) that I, the
said George Blaxland, junior, my executors or 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 to be performed, and
cause the same to be filed in the Great Seal Patent Office within six

page_text: calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said George Blaxland, junior, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
This Invention has for its object the displacing of the water inside of a
sunken ship or vessel by means of compressed air or gas, and in the
apparatus employed for this purpose.
When a sunken ship or vessel to be raised or gained access to in
accordance with my Invention is fully laden it will first be necessary to
take out a portion of the cargo, say that which lies on her "'tween
decks," by means of divers in the ordinary manner, as is well understood,
and when that is accomplished the divers must procced to stop all
the outlets, such hatchways, skylights, or other openings, and then
attach the apparatus herein-after described in carrying out my
Invention.
According to one part of my Invention I make the vessel herself the
means of holding the compressed air or gas, so as to gain access to and
raise the same by its own buoyancy without the intervention of tanks,
casks, pontoons, bags, or other similar means.
Another part of my improvements relates to the application of an
apparatus called an "air lock," without the addition of a diving bell, for
gaining access to the interior of a ship after a sufficient quantity of air
has been forced down into her.
My Invention also relates to the application of a tube or pipe fitted
with a valve for the outlet of the water from the interior of the sunken
ship or vessel when it is being displaced by compressed air.
: My Invention also relates to the application of a valve opening to the
interior of a sunken ship or vessel for readmitting the water to the ship
in case of any accident, by which the compressed air should become so
rarified as to cause an undue pressure from the outside..
And in order that my Invention may be clearly understood and readily
carried into practice, I will proceed to describe the same more fully,
reference being made to the Drawings hereunto annexed.

page_text: Figure 1 is part of a longitudinal section of a vessel arranged with
apparatus in accordance with my Invention, strengthened by T or L irons
or otherwise, and having wooden fitting pieces W combined with india-
rubber or "gasket" on the face for making the joint on the edge of the
combings B, B, perfectly tight. The closing plate P is made to overhang
the "combings" B sufficiently to allow of bolts being screwed into the
deck E.
The "air lock" L or chamber, by means of which access is gained to
the interior of the sunken vessel, has two doors L', LA, the one marked L
opening to the outer atmosphere, and the other L to the inside of the
air lock L, which is in communication with the interior of the sunken
vessel. Two cocks C, C¹, are arranged in the air chamber, the one
marked C being used for the admission of compressed air from below,
and the other C¹ for the escape of the compressed air to the atmosphere.
The doors L', L², are so fitted that when closed and screwed down they
are perfectly tight, and have very strong glass fitted in them for
admitting light to the interior. Steps L³ are arranged, by which to
descend from the "air lock" to the interior of the vessel. A door N is
provided at the bottom of the "air lock" L opening to the interior of
the vessel, and need only be used when it is required to remove the
"air locks," or when it is required to send down a longer piece of
material than will go in between the two other doors before referred to.
t
An air pipe M is arranged, to which is attached a hose leading to the
air pumps, having a cock for shutting off the communication when
required.
An outlet pipe O, arranged as shown with a valve V, for discharging
water from the interior of the vessel is arranged to open outwards, and
having a lever attached for being worked from above. This outlet
pipe O, or pipes, may be made telescopic or have a flange, so that its
length may be increased or diminished as may be required. The lower
end of the pipe may, when required, be provided with a bent tube O¹
attached by a swivel joint, so that its end will fall by its own gravity;
or a flexible tube O* may be employed in place of the tube 0, 0¹,
previously described. The tube O is formed in lengths so as to be
readily removed.
I is an inlet valve, having a lever and counterbalance weight or spring
so arranged that it only keeps the valve shut when the pressure inside
and outside of the vessel are equal, but when the pressure on the

page_text: outside is above that on the inside of the vessel it will open and allow
the water to enter until an equilibrium has been established.
The apparatus may be fitted together on the shore or on board of an
attendant vessel from which it is to be lowered into the water, and as
the displacement of the tube L is much greater than the whole weight
of the apparatus it will float, and can be towed over the hatchway, for
which it is intended, and then allowed to sink into position by merely
allowing the air to escape from the upper end of the tube or air lock, or
it can be lifted again with a few strokes of the air pump.
Supposing the whole of the apparatus to be attached and a sufficient
quantity of air forced into the sunken vessel to allow of a man to pass
down and under the deck E, I proceed as follows:-The upper door L¹
of the "air lock" being open, and the lower one L² closed, the workmen
enter the chamber L and close the upper door L¹ (to which it is
advisable to have a counterweight attached to a line passing over a
pulley), screwing the door up hard from the inside by means of
"dogs" L*, as shown at Figure 3, then open the cock C in the lower
door, and allow the compressed air to fill the chamber L, when the air
ceases to flow in the fastenings of the lower door I may be removed,
and the door L² lifted and hooked up, giving free access to the space
below.
I would here remark that the operation previously described is well
known, and frequently employed in the formation of foundations in
piers of bridges, and therefore I make no claim thereto apart from its
application for raising sunken vessels.
Having thus gained access to the sunken ship or vessel the workman
then make good such air leaks as the divers have been unable to stop,
and which can be much more efficiently performed from the inside, and
are easily detected by the noise which the air makes in escaping, or by
the application of a lighted candle, the flame of which would be drawn
into any existing leak. All the leaks having been sufficiently stopped
and the water forced down to or displaced to a sufficient depth any
requisite work, such as the construction of additional bulkheads,
securing the decks E by means of chains F' attached to beams F, or by
other suitable means so as to withstand an increased outward or inward
pressure, can be proceeded with. Additional fastenings F³ may also
then be attached to the plate P, as shown or otherwise.

page_text: If the ship or vessel is built in compartments it will be necessary to
have one or more outlet pipes O and valves V at each extremity of the
. compartment, or two valves may be fitted to the hatchway plate, from
which pipes can be led internally to each end of the compartment.
An inlet valve I is arranged in each compartment, but to save expense
one "air lock" L may be used, as it can be transferred from one com-
partment to another, and it will be advisable to test each compartment
separately by forcing out the water beyond the point at which it is
calculated she will rise.
All air leaks having been sufficiently stopped and all requisite stays
put in to hold down the decks I then proceed to lift the sunken vessel
by forcing down air, and thus displacing the water equally in each of
the several compartments. Considering that the weight of the ship has
to be sustained by the decks great care must be taken to secure these
sufficiently. Then so soon as anything beyond the weight of the ship
has been displaced she will commence to rise, one end first, and then it
will be necessary to close the valves of the outlet pipes on the highest
extremity so as to prevent the compressed air from escaping, but still
continuing to force down air; the water will then escape at the other
outlet pipes on the other extremity of each compartment until the other
end of the vessel also rises to the surface, and the vessel will then lay at
a considerable angle almost on her broadside, the ends of the bent
tube O¹ and swivel joint (or its equivalent flexible tube O*) falling by
their own gravity into the water it is continually forced out until the
vessel gradually rights herself, when she can be towed into a place of
safety.
The best cement I am acquainted with for stopping the leaks is
genuine red and white lead well amalgamated, and which will set quite
hard in salt water.
Having thus described the nature of my Invention, and the manner
of performing or carrying the same into practice, I would remark that
I do not confine myself to the exact details herein-before described, so
long as the main features of my Invention are retained; but what I
claim is,―
First. The method of rendering the hull of a sunken vessel available
for holding compressed air or gas in order to gain access thereto, and to
render it buoyant for the purpose of raising the same, substantially in

page_text: the manner herein-before described and represented in the Drawing
hereunto annexed.
Secondly. I claim the construction, arrangement, and application of
the "air lock" apparatus for the purpose of gaining access to the
interior of a sunken vessel to facilitate the raising thereof, substantially
in the manner and for the purpose herein-before described and repre-
sented in the Drawings hereunto annexed.
Thirdly. I claim the arrangement and application of the tubes or
pipes O, O¹, and O* for discharging the water by means of compressed
air from the interior of a sunken vessel, substantially in the manner and
for the
purpose herein-before described and represented in the Drawings
hereunto annexed.
Fourthly. I claim the arrangement and application of the valve I for
readmitting the water to the interior of a sunken vessel to equalize the
pressure on the interior and exterior thereof, substantially in the manner
and for the purpose herein-before described and represented on the
Drawings hereunto annexed.
Fifthly. I claim the improved arrangement and combination of
apparatus for gaining access to and for raising sunken vessels, substan-
tially as and for the purposes herein-before described and represented in
the Drawings hereunto annexed.
In witness whereof, I, the said George Blaxland, have here-
unto set my hand and seal, this Twenty-ninth day of July,
in the year of our Lord One thousand eight hundred and seventy-
four
Witness,
J. G. TONGUE,
Patent Agent,
G. BLAXLAND, J³. (L.S.)
34, Southampton Buildings,
Chancery Lane,
W.C.