IMPROVEMENTS IN THE CONSTRUCTION OF BREAKWATERS, SEA WALLS, AND OTHER SUBAQUEOUS WORKS
Year: 1872

page_text: LETTERS PATENT to David Cunningham, of Dundee, in the County
of Forfar, North Britain, Civil Engineer, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF BREAKWATERS, SEA WALLS, AND
OTHER SUBAQUEOUS WORKS."
Sealed the 10th October 1872, and dated the 23rd July 1872.
[:
PROVISIONAL SPECIFICATION left by the said David Cunningham at
the Office of the Commissioners of Patents, with his Petition, on
the 23rd July 1872.
'
I, DAVID CUNNINGHAM, of Dundee, in the County of Forfar, North
Britain; Civil Engineer, do hereby declare the nature of the said Inven-
tion of "IMPROVEMENTS IN THE CONSTRUCTION OF BREAKWATERS; SEA WALLS,
AND OTHER SUBAQUEOUS WORKS," to be as follows, that is to say :-
..
This Invention which relates to improvements in the construction of.
breakwaters, sea walls, or other subaqueous works, consists in the
employment of concrete blocks formed with a number of hollow spaces
extending from or nearly from the upper to or nearly to the under
.

page_text: sides of the blocks, as the material of which such breakwaters, sea
walls, or other subaqueous works are constructed, and the object of this
Invention is to diminish the mass of concrete employed in such works,
and at the same time to render the transport of the blocks less costly
and more expeditious.
In constructing the blocks according to one arrangement the hollow
spaces are disposed or arranged in rows throughout the entire area of
the blocks, so that in building the blocks on each other spaces in the
upper block will be situated immediately above spaces in the block
underneath, according to the manner in which they are set upon each
other. Each of the spaces is provided with an air-tight door at its
upper extremity, or the air-tight doors may be made of such dimensions
as to cover the upper extremities of the whole or a series of the spaces
in each block, or the said spaces may be connected together in the body
of the block and terminated in one or more spaces opening to the upper
surface of the block, and which is or are provided with an air-tight door
or doors. Each such air-tight door is provided with a cock or valve or
the equivalent thereof, so that in floating the blocks in the usual manner
to the situation at which the work is being carried on, the spaces being
filled with air materially assist the barge or barges or other means of
transport in buoying up the blocks, and thus blocks may be made, of
much larger dimensions than under existing arrangements of con-
struction. After the block has been submerged its buoyancy may
be increased by compressing the air in the spaces by means of an air
pump.
Blocks constructed as herein-before described may be made in
rectangular or other form, and in cases where the breakwater, sea wall,
or other subaqueous work to be constructed is of considerable breadth,
the concrete blocks employed in the formation thereof may be con-
structed with one or more hollow spaces occupying the entire central
portion thereof, the said spaces being divided from each other by cross
ties or ribs of concrete extending from one side of the block to the other.
The portions constituting the ends or sides, as the case may be, of such
blocks are formed with hollow spaces provided at their upper extremities
with air-tight doors similar to those herein-before described, and corre-
sponding spaces are also formed on the cross tics or ribs and which may
be furnished with the said air-tight doors, or both extremities of the
spaces in the cross ties or ribs may be closed with the material of which

page_text: the blocks are composed, and means may be provided for allowing the
air to escape and so filling such spaces with water when so required.
•
When a block constructed according to any of the arrangements
herein-before described has been placed on its foundation, concrete is or
may be used so as to close up the lower extremities of the hollow spaces
therein, as
well as any vacant space left between the ground and any
part of the block on account of any irregularity of the ground surface;
the remaining portions of such spaces may then be filled up with sand,
clay, stones, or other suitable material, or the whole of such spaces may
be so filled up, excepting, when desired, so much as is necessary to
contain a layer of concrete by which to secure the block immediately
above in position. These spaces may also be wholly or chiefly filled with
concrete itself.
In lieu of closing the lower extremities of the hollow spaces in the
blocks placed in contact with the ground by means of concrete as herein-
before set forth, pipes communicating with an air pump or exhauster
may be attached to the cocks or valves or their equivalent on the doors.
at the upper extremities of the spaces, and the air by this means being
partially exhausted from the hollow spaces the ground underneath.
will be forced into the said spaces and the whole block sunk on its
foundation.
It is obvious that the spaces in the hollow blocks may be used for
facilitating excavations of the ground, when required, after the blocks
are placed in position.
It is to be understood that this Invention is not limited to constructing .
the blocks, herein-before described, wholly of concrete, as such blocks
may be constructed partly of stone or other suitable material, and iron
or other suitable material may be employed for tying them together.
:
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
0 filed by the said David Cunningham in the Great Seal Patent Office
on the 22nd January 1873.
:
TO ALL TO WHOM THESE PRESENTS SHALL. COME, I, DAVID¨¨
. CUNNINGHAM, of Dundee, in the County of Forfar, North Britain, Civil
Engineer, send greeting.

page_text: D
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of July, in the
year of our Lord One thousand eight hundred and seventy-two, in the
36th year of Her reign, did, for Herself, Her heirs and successors,
give and, grant unto me, the said David Cunningham, Her special
license that I, the said David Cunningham, my executors, administrators,
and assigns, or such others as I, the said David Cunningham, my execu-
tors, administrators, or 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 niake, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN THE CONSTRUCTION OF BREAKWATERS, SEA WALLS, AND OTHER SUBAQUEOUS
WORKS," upon the condition (amongst others) that I, the said David
Cunningham, by an instrument in writing under my hand and seal,
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 David Cunningham, 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 accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:
i
My said Invention, which relates to improvements in the construction
of breakwaters; sea walls, or other subaqueous works, consists in the
employment of concrete blocks, formed with a number of hollow spaces
extending from or nearly from the upper to or nearly to the under
sides of the blocks, as the material of which such breakwaters, sea walls,
or other subaqueous works are constructed, and the object of this
Invention is to diminish the mass of concrete employed in such works,
and at the same time to render the transport of the blocks less costly
and more expeditious.
In constructing the blocks according to one arrangement the hollow
spaces are disposed or arranged in rows throughout the entire area of.

page_text: c
the blocks, so that in building the blocks on each other spaces in the
upper block will be situated immediately above spaces in the block
underneath, according to the manner in which they are set upon each
other. Each of the spaces is provided with an air-tight door at its upper
extremity, or the air-tight doors may be made of such dimensions as to
cover the upper extremities of the whole or a series of the spaces in each
block, or the said spaces may be connected together in the body of the
block, and terminated in one or more spaces opening to the upper
surface of the block, and which is or are provided with an air-tight
door or doors. Each such air-tight door is provided with a cock or valve,
or the equivalent thereof, so that in floating the blocks to the situation
at which the work is being carried on, the spaces being filled with air,
materially assist the barge or barges, or other means of transport, in
buoying up the blocks, and thus blocks may be made of much larger
dimensions than under existing arrangements of construction. After
the block has been submerged its buoyancy may be increased by com- .
pressing the air in the spaces so as to fill or nearly fill the said spaces by.
means of an air pump.
.
Blocks constructed as herein-before described may be made in
rectangular or other form, and in cases where the breakwater, sea wall,
or other subaqueous work to be constructed is of considerable breadth,
the concrete blocks employed in the formation thereof may be con-
structed with one or more hollow spaces occupying the entire central
portion thereof, the said spaces being divided from each other by cross
ties or ribs of concrete, extending from one side of the block to the other.
The portions constituting the ends or sides, as the case may be, of such
blocks are formed with hollow spaces provided at their upper extremities
with air-tight doors similar to those herein-before described, and
corresponding spaces are also formed on the cross ties or ribs, which
may be furnished with the said air-tight doors, or both extremities of
the spaces in the cross ties or ribs may be closed with the material of
which the blocks are composed, and means may be provided for allowing
the air to escape, and so filling such spaces with water when required.
When a block constructed according to any of the arrangements
herein-before described has been placed on its foundation concrete" is or
may be used, so as to close up the lower extremities of the hollow spaces
therein, as well'as vacant
any
left between the ground and any
part of the block on account of any irregularity of the ground surface;
space

page_text: 'the remaining portions of such spaces may then be filled up with sand,
clay, stones, or other suitable material, or the whole of such spaces may
be so filled up, excepting, when desired, so much space as is necessary
to contain a layer of concrete by which to secure the block immediately
above in position. These spaces may also be wholly or chiefly filled with
concrete itself.
In lieu of closing the lower extremities of the hollow spaces in the
blocks placed in contact with the ground by means of concrete as
herein-before set forth, pipes communicating with an air pump or
exhauster may be attached to the cocks or valves, or their equivalent on
the doors at the upper extremities of the spaces, and the air by this
means being partially exhausted from the hollow spaces the ground
underneath will be forced into the said spaces and the whole block sunk
on its foundation.
}
;
It is obvious that the spaces in the hollow blocks may be used for 1
facilitating excavations of the ground when required, after the blocks
are placed in position.
:
°
And in order that my said Invention may be properly understood, I
now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into 2
effect, that is to say :—
On Sheet 1 of the Drawings hereunto appended Figure 1 is a side
elevation; Figure 2, a transverse section on the line a, b, Figure 1, and
Figure 3, a plan of a block constructed in accordance with one modifica-
tion of my said Invention, and which is suitable for employment in the 2
construction of breakwaters, sea walls, and other subaqueous or marine
works.
i
As shewn by these Figures the block A is constructed with a space B,
which occupies the central portion thereof, and extends from the upper
to the under side of the block, and around which smaller spaces C and D 3
are arranged at the sides and ends of the block, as more particularly scen
in plan at Figure 3. The spaces D at the ends of the block extend from
the under to near the upper side thereof, and the spaces C at the sides of
the block extend from its upper to its under side. The spaces C at both
sides when the block A is about to be floated in the usual manner from 3
the place of construction to the situation of the breakwater, sea wall, or
other subaqueous or marine work in course of formation are closed at their
upper ends by air-tight doors or covers E, each of which at the Figures

page_text: now under reference are shewn arranged to cover the upper ends of all
the spaces at one side of the block A, but the said doors or covers may
be arranged to cover a series of such spaces only, in which case a greater
number of doors or covers are employed, or an air-tight door or cover
may be provided for each such space C. The air-tight doors or covers Ę
are provided with cocks or valves F, and they are secured in position on
the upper side of the block A by nuts G screwed on to the upper
extremities of rods H, the lower ends of which are formed, bent, or
curved, and are passed down through holes or openings I formed in the
block, as shewn at Figure 3, to near the under side thereof whereat the
bent or curved ends of the rods H are passed under horizontal rods or
bars K, as shewn at Figure 2, which rods or bars extend from one end of
the block to the other. Thus by screwing the nuts G against plates or
rings on the upper sides of the doors or covers E the rods H. are drawn
tightly up against the under sides of the rods or bars K, and the air-
tight doors or covers E are pressed downwards against the upper side of
the block A. Any suitable packing may be inserted between the under
sides of the doors or covers E and the upper side of the block A, in order
to render the space enclosed by the doors or covers air-tight. The rods
or bars K, and the rods H at each end of the block A, whilst in con-
junction with the other similar rods H serving the purpose herein-before
described, also act as suspenders, and sustain the weight of the block
whilst being removed or floated to the situation at which the breakwater,
sea wall, or other subaqueous or marine work is being constructed, the
end rods H being provided with rings or eyes at their upper extremities;
to which chains or ropes are attached, when it is desired to transport the
blocks, the said chains or ropes being also attached to crabs or winches
placed on a barge or barges, or other means of transport. The spaces C
when the blocks have been submerged being filled with air, which is
confined therein by the air-tight doors or covers E, assist the barge or
barges in buoying up the blocks, and the buoyancy of the said blocks
may be increased by compressing air into the spaces so as to fill them or
nearly so by means of an air pump or pumps, the air being conducted
into the spaces C through the cocks or valves F.
Concrete blocks may
under this Invention be made of much larger dimensions than under
arrangements of construction hitherto practised. An air-tight door
furnished with a cock or valve may be provided for the space B at the
central portion of the block A, and in lieu of forming the end spaces D,
closed at their upper ends, as herein-before described and indicated in

page_text: dotted lines at Figure 3, Sheet 1, the said spaces may extend from the
upper to the under side of the block, and be provided with air-tight
doors, similar to those herein-before described.
Under another modification of my said Invention, illustrated in plan
at Figure 4, and in transverse section on the line c, d, Figure 4, at 5
Figure 5, the block A in lieu of being constructed with a large central
space, as herein-before described, and shewn at Figures 1, 2, and 3,
Sheet 1, is formed with a number of spaces B at the central portion
thereof, which may in transporting the block be left open at the upper
ends or covered with an air-tight door or cover, or in lieu of extending 1
the said
spaces B from the upper to the under side of the blocks, as
shewn at Figure 5, the said spaces may be terminated below the upper
side of the block A as indicated in dotted lines at D, Figure 3, in which
case the material of the block forms the cover of the space.
Under another arrangement, illustrated in plan at Figure 6, and in 1
transverse section on the line e, f, Figure 6, at Figure 7,. the central
space or spaces may be dispensed with when a block of lesser breadth is
required.
When a block constructed according to any of the arrangements
herein-before described, and shown on Sheet 1 of the appended Drawings, 2
has been floated to the situation at which the breakwater, sea wall, or
other subaqueous work is being built and placed on its foundation the
air-tight covers are removed from the upper side of the block, and the
lower extremities of the hollow spaces are closed up with concrete, as is
also any vacant space left between the ground and any part of the 2
foundation blocks, on account of any irregularity of the ground surface..
The remaining portions of the spaces within the block are then filled up
with stones, clay, sand, or other suitable material, as shewn at Figure 8,
Sheet 1, which is a transverse section of a sea wall built with blocks
constructed in accordance with this Invention. A layer a of concrete is a
placed in the upper end of each space, and also in the lower end of the
block superposed, as shewn, by which the latter block is secured in
position.
In lieu of employing stones, clay, or sand to fill up the spaces the said.
spaces may be entirely filled with concrete, and in lieu of closing the
lower extremities of the hollow spaces in the blocks placed in contact
with the ground with concrete, as herein-before described, and shewn

page_text: at 6, Figure 8, Sheet 1, pipes communicating with an air pump or
exhauster may be attached to the cocks or valves of the air-tight doors.
or covers, and the air by this means being partially exhausted from the
spaces by the pump or exhauster the ground underneath will be forced
into the said spaces and the whole block sunk on its foundation. By
this means the spaces in the blocks may be used for facilitating excava-
tions of the ground when required after the blocks have been placed in
position.
When the breakwater, sea wall, or other subaqueous work to be con-
structed is of considerable breadth blocks formed in the manner shewn
in longitudinal section at Figure 1, Sheet 2 of the Drawings, in side
elevation at the end of Figure 2, marked X, and in plan at the corre-
sponding end of Figure 3, may be employed in lieu of any of the blocks
hercin-before described, and shewn on Sheet 1 of the Drawings. Under.
this arrangement the block is formed with a central space A, and with
side spaces B, as more particularly seen in plan at Figure 3, the said
spaces A and B being divided from each other by cross ties or ribs C of
concrete, extending from one side of the block to the other. In the
sides of the block and also in the cross ties or ribs C spaces are formed,
which when the block is about to be floated to its destination are closed
by air-tight doors, as shewn, or the upper and lower extremities of the
spaces in the sides and ribs or ties may be closed with the material of
which the block is composed, and means may be provided for allowing
the air to escape and so fill such spaces with water when required.
°
Figure 2, Sheet 2, is a side elevation; Figure 3 a plan; and Figure 4
a transverse section on the line a, b, Figure 3, of a breakwater in course
of construction, and composed of the blocks now last described.
Under another arrangement (not shewn on the Drawins) the spaces
in each block may be connected together in the body of the block and
terminated in one or more spaces opening to the upper surface of the
block and which is or are provided with an air-tight door or doors.
By constructing the blocks as herein-before described, and shewn on
the Drawings, the mass of concrete employed in building breakwaters,
sea walls, and other subaqueous works is diminished, and the transport
of the blocks is rendered less costly and more expeditious.
It is to be understood that this Invention is not limited to constructing
the blocks herein-before described, and illustrated under various modifi-

page_text: cations on the appended Drawings, wholly of concrete, as such blocks
may be constructed partly of stone or other material, and iron or other
material may be employed for tying them together; and it is further to
be understood that I do not confine myself to construct or-arrange the
spaces in the blocks under the systems or modes herein-before described,
and shewn on the Drawings, as the arrangement of such spaces is
capable of further modification.
Having now described and particularly ascertained the nature of my
said Invention, and several systems or modes in or under which the same
is or may be used or carried out in practice, I would observe in conclusion
that what I consider to be novel and original and therefore claim as the.
Invention secured to me by the herein-before in part recited Letters
Patent is, constructing concrete or other blocks employed in building
breakwaters, sea walls; and other subaqueous or marine works with
hollow spaces formed therein, as herein-before described; and illustrated
under several arrangements on the Drawings hereunto appended, or
under any mere modification of such arrangements.
:
In witness whereof, I, the said David Cunningham, have hereunto
set my
hand and seal, this Twentieth day of January, One
thousand eight hundred and seventy-three.
DAVID CUNNINGHAM. (L.S.)