CERTAIN IMPROVE- MENTS IN APPARATUS TO BE EMPLOYED FOR RAISING OR LOWERING SUBMERGED VESSELS OR OTHER BODIES
Year: 1873

page_text: LETTERS PATENT to William Elliott Debenham, of Haverstock Hill,
in the County of Middlesex, for the Invention of "CERTAIN IMPROVE-
MENTS IN APPARATUS TO BE EMPLOYED FOR RAISING OR LOWERING SUBMERGED
VESSELS OR OTHER BODIES."
Scaled the 16th May 1873, and dated the 17th March 1873.
PROVISIONAL SPECIFICATION left by the said William Elliott
Debenham at the Office of the Commissioners of Patents, with his
Petition, on the 17th March 1873.
I, WILLIAM ELLIOTT DEBENHAM, of Haverstock Hill, in the County
of Middlesex, do hereby declare the nature of my said Invention for
" CERTAIN IMPROVEMENTS IN APPARATUS TO BE EMPLOYED FOR RAISING OR LOWERING
SUBMERGED VESSELS OR OTHER BODIES," to be as follows:-
The Invention is designed for the purpose of raising heavy bodies with
and lowering them from a floating vessel or combination of vessels, and
in such manner that the weight supported shall bear equally across the
breadth of the supporting vessel or vessels.

page_text: In order that the improved apparatus with its modifications may be
readily understood I will proceed to describe its application and action
during the process of raising a sunken vessel. For this purpose I
support the weight to be sustained by chains from girders which stretch
across an open space between two vessels or the two side limbs of a
horse-shoe-shaped or composite vessel. The girders are supported over
the centre line of each limb (or of each side vessel if the lifting vessel is
made up of several vessels), or from both sides of each limb; or upon
frames connecting the sides and bottom of each limb or side vessel, so that
the weight of the body to be raised or lowered (hereafter called the
wreck), exerts no lateral or wrenching strain upon the lifting vessel, but
merely depresses it in the water.
If more than two vessels are used in the construction of the composite
lifting vessel, each component vessel is made capable of being readily
attached and cast loose by means of a series of loops, tubes, or rings, half
let into each surface and made fast by a moveable pin like that in a
hinge. Each member of the composite vessel may be capable of separate
navigation, and the said members may be readily drawn together into
their composite form by chains attached to the thin ends of tapering
pins or other equivalent. The chains drawing the pins through sockets
fixed on the contiguous members. The limbs or branches of the horse-
shoc vessel, or those members of the composite vessel which represent
these limbs, or both vessels where two only are employed may have
motive power sufficient to propel the combination.
The lifting vessel or combination is brought over the wreck and chains
passed under it are attached to the girders immediately over the points
where the lifting powers are required, or cradles now to be described are
passed under the wreck, and chains from the girders are attached thereto.
The chains have links at regular intervals painted of a distinctive colour
and numbered, or the whole set of links may be numbered.
The cradle consists of a bar or length of metal provided with a fixed
projection or abutment and shackle at one end, and a hinge projection
and shackle at the other end, so constructed that when the cradle is to
be passed under the keel the hinge projection and shackle will lie down
evenly in a line with the body of the bar of metal, so that the same may
be readily passed under the keel of the sunken vessel a distance that will
bring its projecting abutment against the side of the keel. The hinge

page_text: projection is now turned up forming another abutment against the
opposite side of the keel, and the suspending chains may now be (if they
have not previously been) attached to the shackles. A screw or bolt
may be used for holding down the turned up end, and for gripping
the keel.
The lifting power of the floating vessel is exercised either by the tide
(the chains being attached at low water), or by first letting water into
the lifting vessel, and expelling it after attaching the chains. Or by
hydraulic presses placed upon the girders. The presses are used
preferably in pairs, the supporting chains from which pass between the
girders on which the presses rest. Or the chains may be passed over
pulleys on the girders and wound in, or the girders themselves may be
raised by hydraulic presses attached to the frames described for con-
necting the sides and bottom of each side vessel or limb of vessel, or
some of these methods of raising are used in combination.
In some cases in place of or in addition to and at intervals between
the girders cranes are employed, each crane resting over the centre line
of each side vessel or limb; or the alternate cranes in each limb may
bear upon points equally distant from and at opposite sides of the centre
line of the limb. Each crane is capable of being firmly united at its
extremity with that of another crane rising from the opposite limb, so
that the pair of cranes form in effect a girder, and the wrenching strain
which a crane as such necessarily produces is avoided.
Some of the cranes may be employed for unloading into the lifting or
other vessels, or on to a quay.
The girders themselves are in some cases made raised or arched to
give greater height under them.
When hydraulic presses are used upon the girders each cross head or
entablature of the same is provided with a hole through which the
suspending chain passes; and the coupling thereof is by means of a
block and wedge, or "gibb" and "cottar" which may be placed in any
direction across the opening in the cross head to suit the position of the
link. The block or gibb is shaped to fit the bearing part of any link of
the chain so that the link beds upon it instead of touching at a point or
edge merely. Another similar cross head block and wedge are placed
above those bearing upon the rams to hold the chain during the descent

page_text: of the plungers. The hydraulic presses are arranged in communicating
sets, preferably into 4 sets, half of those in use on cach side forming a set,
and any set may be used independently of the others for levelling the
wreck.
; In some cases the lifting vessel is made capable of being entirely
submerged, and is sunk to the bottom around the wreck, the chains are
then attached to the girders and air is forced into or water is pumped out
of the lifting vessel through tubes; the supply of air to replace the water
pumped out may be by means of an outer or surrounding tube reaching
above the surface of the water.
When there is convenient sea or river bottom for the purpose the
wreck may be successively grounded and raised until sufficiently high to
be unloaded and repaired, or may be deposited upon or be floated over or
have drawn under it a saucer or chambered or other raft.
In some cases the wreck is floated over a stage instead of being
grounded on the bottom, and the stage may be a long inclined stage, or
there may be a series of stages of different heights, or the stage may be
supplied with means for being elevated when the wreck has been raised
from it by the lifting vessel or with sufficient power to raise the wreck
when once placed upon it.
It will be advantageous to have the stage or such part of it as is near
the surface of the water of such dimensions as to pass between the
limbs of the lifting vessel. The stage is not necessarily a fixture, but
may be itself a vessel, or may consist of or have upon it a saucer, raft,
or chambered raft for floating away the wreck. It may be of such
dimensions as to fit in the open space between the limbs of the lifting
vessel, and may be carried with it and sunk where the water is of such
depth as to allow the wreck to be floated over or into it.
If a saucer raft without air chambers is used it may either be placed
at such a level that its top edge is above low water mark, or it may rest
upon a stage capable of lifting it, or it may be lifted by chains from the
girders. Rings or other coupling are attached to its sides and bottom
for this purpose.
A raft which I call a chambered raft is sometimes used. This raft
combines floatation by air chambers with the saucer principle. The
sides are hollow and divided into compartments, and the bottom is formed
of strong framing sheathed water-tight.

page_text: serve as additional floats and also to deepen the saucer.
These chambers
may be affixed and detached as required, and may be attached outside to
raise the floor of the raft.
I prefer to sink the raft (after letting water into the saucer) by entirely
filling as many of the lower compartments as may be required; when the
raft has to be deeply submerged air is forced into those compartments
already containing air so as to enable them to resist the pressure of the
external water; a pressure gauge attached to the force pump and
observation of the numbered links of the chains that support the raft
will allow this to be done with sufficient accuracy. Each compartment
has two valves or two valves at each lower corner, one to allow the
passage of water or of air of greater pressure than the surrounding
water into the water, and the other valve (except in the lowest compart-
ments) opening into the compartment beneath. Each of these valves is
capable of being fastened down, and they may be worked in sets. The'
whole number of compartments is divided into three or more sets
(preferably four) and the divisions between these sets are in the upright
direction, so that either side, end, or corner, or corner, of the raft may
have additional or diminished lifting power to keep the raft level. If the
air in the compartments is condensed and the valves opening into the
water (except of the lowest of them) are closed, then as the raft rises the
condensed air in the upper compartment will pass through the valves to
expel the water from the lower ones giving the raft increasing buoyancy.
If it is feared that this is unsafe the valves of communication are closed
or nearly so. In the last case the increased velocity of rise will be
gradual. The raft is provided with gates at one end, and sheet or tube
india-rubber, leather, or other flexible material is fixed outside along the
joints to keep them tight by water pressure when the inside of the raft
is emptied of water. The raft is furnished inside with struts and
clutches or other appliances for securing the wreck, and outside with
rings for attaching extra chambers and for attaching chains for lifting,
lowering, and guiding. This raft is conveniently made of such size as
to be conveyed in the open space of the lifting vessel, and is used by
being so far filled with water that it moves freely and with little weight
under the water. It is sunk to the bottom or supported and placed just
underneath the wreck by chains from the lifting or other vessels. When
the wreck is in position, clutched and strutted in the raft, it is brought to

page_text: the surface by having water pumped out or air forced into the
chambers.
The lifting vessel may have chains from the girders attached to the
raft to assist in the lift or the chains supporting the wreck may be
pulled in or the lift may be entirely accomplished by the air chambers.
When brought to the surface the water contained in the raft may be
emptied so that the bottom of the wreck may be reached dry.
For lowering heavy bodies, such as masonry for lighthouse foundations,
the weight is conveyed either in the lifting vessel or in barges or other
vessels brought into the open space under the girders, the chains which ]
are used for removing the weight from the barges and for depositing it
where required. A wheeled "gantree" may be placed upon the girders
or rest upon the lifting vessels to direct more precisely the position to be
taken by the weight. For allowing greater movement to the "gantree"
some of the central girders may be removed and the weight of the 1
"gantree" may be borne by girders or supports running fore and aft.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Elliott Debenham in the Great Scal.
Patent Office on the 17th September 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ELLIOTT DEBENHAM, of Haverstock Hill, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventeenth day of March, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Elliott Debenham, Her special
licence that I, the said William Elliott Debenham, my executors, adminis-
trators, and assigns, or such others as I, the said William Elliott
Debenham, 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

page_text: "
"CERTAIN IMPROVEMENTS IN APPARATUS TO BE EMPLOYED FOR RAISING OR
LOWERING SUBMERGED VESSELS OB OTHER BODIES,' upon the condition
(amongst others) that I, the said William Elliott Debenham, 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 calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Elliott Debenham, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the Sheet of
Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say) :-
My Invention relates to improvements in the construction of vessels,
and in apparatus employed in connection therewith, for raising sunken
ships, part of which improvements are also applicable for raising and
lowering other heavy bodies in water, such as masonry for lighthouse.
foundations and other submerged structures.
According to my Invention I employ a twin vessel composed of two
hulls connected together by transverse girders or beams from which the
lifting tackle is suspended, so that the weight to be supported shall bear
equally across the whole breadth of each hull. I am aware that it has
before been proposed to use a double vessel consisting of two hulls
rigidly connected together, but the lifting tackle was to be suspended from
the inner side of each hull itself, and not from a support placed over the
intervening space, in consequence of which arrangement a lateral
wrenching strain would be exerted upon the hulls, tending to cant
them inwards and draw them together. To resist this strain great
strength in the construction of the hulls and their connections was
necessary, the undue strain to which they were liable still remaining,
however, as a cause of weakness. This defect is entirely avoided by my
Invention, which, in order that it may be more readily understood I have
illustrated (in outline merely) in the accompanying Drawings.
Figure 1, shows a plan, and Figure 2, an end view of one arrangement

page_text: A, A, are the two hulls, which are alike and of any ordinary and
suitable construction, each being complete in itself and provided with
independent propelling machinery and steam power to drive it and work
the lifting tackle; B, are the transverse girders resting on the two hulls,
which they serve to hold at a sufficient distance apart to admit the body
to be raised (hereafter called the wreck) between them. The girders B
are supported over the centre line of each hull and firmly bolted or
otherwise secured upon the framing at both sides of each hull or upon
frames connected to the side and bottom framing, so that the weight of
the wreck shall be equally distributed over the whole breadth of each
hull. C, C, are the chains or lifting tackle suspended from the girders B
over the intervening space between the hulls. For this purpose, the
girders are preferably made double, each being constructed of two
girders laid parallel side by side, and bolted or stayed together and
otherwise strengthened to ensure the necessary amount of rigidity. The
chains C pass between the double girders, and may either be attached to
hydraulic machinery constructed as hereafter described, and supported
upon the girders B, as shown in the left-hand half of Figure 2, or they
may be passed over sheaves mounted on said girders, as shown in the
right-hand half of the same Figure (the arrangements being of course
alike on both sides), and attached to hydraulic or other machinery on the
decks, or within the holds of hulls A; or the lifting chains may be
simply attached to the girders, when the lifting is effected merely by the
buoyant power of the lifting vessel, or by the rise of the tide.
The lifting vessel having been brought over the wreck, chains passed
under under it are connected to the lifting machinery, or passed over the
sheaves on the girders directly above the point where the lifting power
is required.
Instead of passing chains under the wreck, which is sometimes a
difficult matter to effect, cradles, such as that shown in Figure 3 may
be employed, several of which are passed at intervals beneath the keel
of the wreck and chains from the girders are attached thereto. Each
cradle consists of a metal block D having a fixed abutment E, and a
shackle F at one end, and a hinged abutment G and shackle H at the
other end. The abutment G is hinged at G¹ to the end of block D in
such manner that it will lie down flat in a line with said block, and it is
tapered or wedge-shaped so as to be easily passed beneath the keel of the
wreck. This hinged piece G is provided with a screw by which it is

page_text: secured when turned up against the side of the keel, which is gripped
between the fixed and movable parts E, G. The lifting chains from the
girders are attached to the shackles F, H.
Figures 4 and 5 show elevations of the hydraulic machinery for raising
the wreck. It is preferred to place the lifting machinery upon the
girders, as represented in Figures 4 and 5, and on the left-hand side of
Figure 2, the lifting being effected in the following manner :- _The
presses are used in pairs I, I, supported one on each member of the
compound girder B, as shown in Figure 4. The rams or plungers I¹, I',
of the two presses are connected together by a cross head K provided
with a circular opening L through which the lifting chain C is passed,
as shewn more clearly on an enlarged scale in Figure 5º. This opening
should not be of greater diameter than is necessary for the passage
of the chain. M is a strong frame rising from the girders B, and car-
rying a fixed cross head N having an opening L. Cross head K
which is supported on the two rams of the presses as before mentioned
rises with them at each lift, the chain being temporarily attached to
cross head K. After each lift has been effected the slack is taken in
and the chain made fast to the cross head N, whilst the rams I¹, I', with
cross head M are being lowered to make another lift. The chain is
suspended from either cross head alternately by a block or cross bar and
wedge, somewhat resembling a gib and cottar thrust through the link of
the chain, which rises just through the opening in the cross head. O is
the block or cross bar which is shaped or recessed to allow the link of
the chain to bed in it. This block is of greater length than the diameter
of the opening in the cross head through which the chain passes so that
it may rest upon the cross head, and be readily placed in any direction
across the opening L to suit the position of the link. The block O
having been thus placed through a link the wedge P is introduced
beneath it, in order to key the block into the link and prevent any
undue shock when the strain is brought on the chain. Q is a sheave
over which the slack of the chain is passed into the hold of the lifting
vessel.
The hydraulic presses are constructed to be run along the girders so
that the power may be applied directly over the point where the chains
are applied to the wreck, the presses being mounted on wheels or rollers
(not shown) running on the girders. The hydraulic presses are worked
by suitable pumping machinery located within the hulls A, A, and

page_text: connected to the presses by extensible pipes made telescopic or jointed.
The presses are arranged in communicating sets, preferably in four sets
or series, half of those in use on each side forming a set, and any set
may be used independently for levelling the wreck.
In some cases the girders B may be raised or arched, or in lieu of, or
in addition to the girders B, cranes are employed. This is illustrated
in Figures 6 and 7. Figure 6 is an end view of the lifting vessel when
the girders are entirely replaced by crancs. The cranes are mounted in
the centre line of each hull, and their posts R are carried down to the
bottom of the hold, and supported in suitable bearings in frames con-
structed to resist the strain upon the cranc posts. The jibs S of the
opposite cranes are rigidly bolted together at the extremities, the two
cranes forming in effect an arched beam or girder from which the lifting
of the wreck is effected as above described. All the cranes are thus
connected as shewn, except such as may be useful in raising or
unloading cargo from the wreck into the lifting or other vessels, or on to
a quay.
In Figure 7 half the number of the girders are made straight, as
first described, a pair of cranes being placed alternately with every
girder. The jibs of the opposite cranes, except such as are in use for
unloading, are connected as before to serve the purpose of girders and
strengthen the lifting vessel.
In connection with a lifting vessel constructed in cither of the
methods herein-before described, I sometimes employ what I term a
chambered raft, in which the wreck can be raised and repaired therein
without being taken into dock for the purpose; said raft may also serve
to convey the wreck into a dock which would not admit the lifting
vessel. This chambered raft is illustrated in end view in Figure 8.
The sides T, T, are constructed hollow, and divided into compartments,
and the bottom U is formed of strong framing and sheathed water-tight.
Separate air chambers V are attached by links and chains to the upper
edge all round to increase the floating power of the raft or dock. These
chambers V may be attached and disconnected, as required, and may
be attached outside, as shewn in Figure 9, to raise the floor of the raft.
The ends of the raft or dock are provided with gates capable of being
closed water-tight to admit of the water being pumped out of the
interior of the raft, and allow of the bottom of the wreck being repaired

page_text: whilst in the raft. I sink the raft (after letting water into the interior)
by entirely filling as many of the lower compartments T as may be
required. When the raft has to be deeply submerged air is forced into
those compartments which already contain air, to enable them to resist
the
pressure of the external water. Each compartment has two valves,
one a relief valve, to prevent any excess of pressure therein over the
pressure of the external water. The other valve (except in the case of
the lowest compartments) opens into the compartment below. Each of
these valves is capable of being fastened down, and they may be worked
in sets. If the relief valves be fastened shut, and the air in the chambers
be compressed, it will pass into the lower compartments and force out
the water with which they are filled. This raft may be made of such a
size that it may be received between the hulls of the lifting vessel, and
it is used by being gradually sunk to the bottom. The wreck is then
raised by the lifting vessel and deposited in the raft, and secured by
shores, and the whole is raised to the surface by means of the chains
from the lifting vessel, or by pumping water out of the compartments,
or forcing air into them. When brought to the surface the water in
the raft may be pumped out to allow the bottom of the wreck to be
repaired. .
In some cases the lifting vessel, composed of two hulls connected
together by transverse girders as before, may be made capable of being
entirely or partly submerged, the hulls being in this case divided into
air-tight compartments provided with suitable valves, through which
water or air may be pumped into or out of the compartments. In this
case the pumping or propelling machinery would be placed in another
vessel, the lifting vessel being used merely for raising the wreck by its
power of flotation. For this purpose the lifting vessel is sunk over the
wreck by letting water in the lower compartments, and when it is
submerged the chains passed under the wreck are attached to the
girders. Air is then forced into or water is pumped out of the lifting
vessel through tubes.
For lowering heavy bodies, such as masonry for lighthouse foundations,
the weight is conveyed either in the lifting vessel or in barges or other
vessels brought into the open space under the girders, the chains from
which are used for removing the weight from the barges and for
depositing it where required. A wheeled gantree may be placed upon
the girders or rest upon the lifting vessels to direct more precisely the

page_text: position to be taken by the weight. For allowing greater movement to
the gantree some of the central girders may be removed, and the weight
of the gantree may be borne on supports running fore and aft.
Having described the nature of my said Invention, and the manner
of performing the same, I declare that what I claim as the Invention 5
to be protected by the herein-before in part recited Letters Patent
is,―
1st. The raising of sunken ships and other bodies by hydraulic
machinery or other suitable tackle sustained by beams or girders placed
across the space between two hulls or floating vessels, the said girders 1
being firmly connected to the said hulls and bearing evenly thereon, all
substantially as herein-before described.
2nd. In the hydraulic lifting machinery shown in Figures 4, 5, and 5ª,
the employment with the circular openings in the cross heads for the
chain to pass through of the loose cross bar O and wedge P, substantially 1
as and for the purpose shewn and described.
3rd. The employment of cradles, constructed and applied substantially
as described and shewn in Figure 3, for the purpose specified.
4th. In combination with the lifting vessel and apparatus constructed
as herein described the employment of a chambered raft or dock con-
structed and applied substantially as herein shown and described.
In witness whereof, I, the said William Elliott Debenham, have
hereunto set my hand and seal, this Sixteenth day of September,
in the year of our Lord One thousand eight hundred and seventy-
three.
2