IMPROVEMENTS IN HOPPER DREDGERS
Year: 1876

page_text: LETTERS PATENT to William Simons and Andrew Brown, both of the Town
and County of Renfrew, North Britain, Engineers and Ship Builders, for the
Invention of "IMPROVEMENTS IN HOPPER DREDGERS."
PROVISIONAL SPECIFICATION left by the said William Simons and Andrew
Brown at the Office of the Commissioners of Patents on the 11th November
1876.
WILLIAM SIMONS and ANDREW BROWN, both of the Town and County of
Renfrew, North Britain, Engineers and Ship Builders. "IMPROVEMENTS IN HOPPER
DREDGERS."
This Invention, which relates to improvements in hopper dredgers, has for its
object as follows:-
First. To enable the machinery connected with the bucket ladder or girder as
well as the girder itself to be moved fore and aft independently of the movement
of the hull, for the purpose when moved forwards of excavating a space for the
dredger's own floatation in advance of the dredger, and also to enable it to excavate
close to quays or in confined spaces, which an ordinary dredger could not approach.
This object is effected by supporting the upper end of the bucket ladder or girder,
and the gearing connected with it upon a horizontal fore and aft framing, so that
the bucket ladder or girder, when projected beyond the bow of the dredger, may as
it is advanced outwards upon the horizontal framing make the necessary excavation,
after which it may be travelled aft for the purpose of repeating similar operations
or for ordinary dredging. The shoots for the discharge of the spoil or dredged
material are also connected to that part of the mechanism which travels upon the
horizontal framing, which framing being also by preference of about the same
length as the hopper cavities on each side of the bucket well enables the spoil or
dredged material to be evenly discharged thereinto during the whole time of the
horizontal travel of the mechanism.
Secondly. To effect the discharge of the load or contents of hopper dredgers on
to the adjoining river or canal banks or flats, by means of an improved arrange-
ment which consists in the employment of pumps and connecting pipes leading over
the dredger side or over the bow or stern, and preferably so placed as to be driven
from either the dredging engines or by an independent engine.
[Price 6d1

page_text: Thirdly. To construct the bottoms of flat bottomed hoppers with a maximum of
strength. This is effected by forming both the fore and aft as well as the thwart
ship keelsons of iron or metal box girders, having by preference a triangular section
with the apex of the triangle upwards. At the places where these keelsons intersect
or meet one another at the bottom of the hopper they form a series of square or
rectangular spaces, and against the lower edge of these the hopper doors close, they
being attached thereto by hinges at one side And another feature under this
division of the improvements consists in constructing the mouth or upper part of
the hopper cavity with thwart ship iron or metal box beams, instead of the fore and
aft girder hitherto used for suspending the doors when closed, and also for operating
them by means of winches and chains in combination.
Fourthly. To enable dredgings or spoil to be discharged on shallow or "shoal
ground." This is effected by constructing the hoppers with their bottoms above the
load water line and inclined upwards towards the centre of the hull; also having the
hopper doors at the side above the load water line in such position as to allow
the dredgings or spoil to be discharged from the sides of the dredger at or near the
load water line. By this arrangement, there being no hoppers in the bottom of the
hull, the whole internal space in the vessel becomes available for buoyancy, also
affording ample room for engines, boilers, and other purposes.
Fifthly. In the case of dredgers which have the hoppers on either side of the
bucket well, to enable them to discharge the spoil or dredged material in shallow.
water. The improvement under this head of the Invention consists in placing the
hopper doors in the sides or ends of the bucket well or cavity in which the ladder
or bucket girder works. The doors open into the bucket well and allow the spoil
or dredged material to be discharged therethrough, thus permitting the discharge of
the spoil to be effected in shallower water than is practicable when the doors are
suspended from the bottom of the hopper and project therefrom. The doors in the
sides or ends of the well may be hinged thereto, or they may be arranged to slide,
being operated in this latter case by screws, levers, racks, and pinions, or equivalent
appliances.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said William Simons and Andrew Brown in the Great Seal Patent Office on the
10th May 1877.
WILLIAM SIMONS and ANDREW BROWN, both of the Town and County of
Renfrew, North Britain, Engineers and Ship Builders. IMPROVEMENTS IN HOPPER
DREDGERS."
"
Our said Invention, which relates to improvements in hopper dredgers, has for its
object as follows:-
First. To enable the machinery connected with the bucket ladder or girder as
well as the girder itself to be moved fore and aft independently of the movement
of the bull, for the purpose when moved forwards of excavating a space for the
dredgers own floatation in advance of the dredger, and also to enable it to excavate
close to quays or in confined spaces which an ordinary dredger could not approach.
This object is effected by supporting the upper end of the bucket ladder or girder,
and the gearing connected with it upon a horizontal fore and aft framing, so that
the bucket ladder or girder, when projected beyond the bow of the dredger, may as
it is advanced outwards upon the horizontal framing make the necessary excavation,
after which it may be travelled aft for the purpose of repeating similar operations
or for ordinary dredging. The shoots for the discharge of the spoil or dredged
material are also connected to that part of the mechanism which travels upon the
horizontal framing, which framing being also by preference of about the same
length as the hopper cavities on each side of the bucket well, enables the spoil or

page_text: dredged material to be evenly discharged thereinto during the whole time of the
horizontal travel of the mechanism.
Secondly. To effect the discharge of the load or contents of hopper dredgers on
to the adjoining river or canal banks or flats by means of an improved arrangement
which consists in the employment of pumps and connecting pipes leading over the
dredger's side or over the bow or stem, and preferably so placed as to be driven
from either the dredging engines or by an independent engine.
Thirdly. To construct the bottoms of flat bottommed hoppers with a maximum of
strength. This is effected by forming both the fore and aft as well as the thwart
ship keelsons of iron or metal box girders, having by preference a triangular
section with the apex of the triangle upwards. At the places where these keelsons
intersect or meet one another at the bottom of the hopper they form a series of
square or rectangular spaces, and against the lower edge of these the hopper doors
close, they being attached thereto by hinges at one side. And another feature under
this division of the improvements consists in constructing the mouth or upper part of
the hopper cavity with thwart ship iron or metal box beams, instead of the fore and
aft girders hitherto used for suspending the doors when closed, and also for operating
them by means of winches and chains in combination.
Fourthly. To enable dredgings or spoil to be discharged on shallow or
"shoal
ground." This is effected by constructing the hoppers with their bottoms or floors
above the load water line and inclined upwards towards the centre of the hull; also
in having the hopper doors at the side above the load water line in such position as
to allow the dredgings or spoil to be discharged from the sides of the dredger at or
near the load water line. By this arrangement, there being no hoppers in the
bottom of the bull, the whole internal space in the vessel becomes available for
buoyancy, also affording ample room for engines, boilers, and other purposes.
Fifthly. In the case of dredgers which have the hoppers on either side of the
bucket well to enable them to discharge the spoil or dredged material in shallow
water. The improvement under this head of the Invention consists in placing the
hopper doors in the sides or ends of the bucket well or cavity in which the ladder
or bucket girder works. The doors open into the bucket well and allow the spoil
or dredged material to be discharged therethrough, thus permitting the discharge of
the spoil to be effected in shallower water than is practicable when the doors are
suspended from the bottom of the hopper and project down therefrom. The doors
in the sides or ends of the well may be hinged thereto, or they may be arranged to
slide, being operated in this latter case by screws, levers, racks, and pinions, or
equivalent appliances.
And in order that our said Invention, and the system, mode, or manner of carrying
the same into practical effect may be fully understood, we now proceed to par-
ticularly refer to and describe the two explanatory Sheets of Drawings which we
have hereunto appended, and wherein Figure 1 (Sheet 1) is a side elevation (having
the central part of the side shown broken out) of a hopper dredger, constructed in
accordance with the first and fifth improvements herein-before mentioned.
Figure 2 is a plan corresponding to Figure 1, and Figure 3 a thwartship section
on the line a, b, Figure 1, looking forwards. The bucket ladder or girder A is pro-
vided in the ordinary manner with a chain of buckets B, operated by the tumbler C,
driven in the usual manner from the engines contained in the after part of the hull.
The engines operate the inclined shaft D, and through it the bevil gearing shown at
Figures 1, 2, and 3, Sheet 1, situate between the shaft D and the tumbler C. The
plummer blocks E in which the bearings of the tumbler C are carried are attached
to or form part of the saddle E¹ and rest upon the upper surface of the two hori-
zontal frames F between which the saddle E' is in part situated, as more particularly
seen in the transverse section, Figure 3 (Sheet 1).
The frames F are supported upon the dredger hull in the manner more par-
ticularly shown at Figure 1 (Sheet 1). On the under side of the plummer blocks E
are nuts through each of which a screw, whose position is shown dotted in Figures 2
and 3 (Sheet 1), pass. These screws are for the purpose of moving the bucket ladder

page_text: or girder A, and its connexions horizontally upon the frames F independently of
fore and aft motion of the hull, and these screws are driven by the pinion G gearing
with the spur wheel H on the shaft I, on which are bevil pinions which gear with
the bevil pinions, one in the end of each screw, as more particularly seen at Figure 2
(Sheet 1). By this arrangement the bucket girder or ladder may have its position
relatively with the hull varied so that it may occupy the position which the bucket
ladder usually occupies in a dredger working in the ordinary manner, that is to say,
the position indicated at Figure 1 (Sheet 1); or the bucket ladder or girder A may
be advanced to any desired extent forwards of that position, as shown at X, Figure
(Sheet 1); or still further forward when necessary or required for dredging in
shallow water, or close to quay walls; or for cutting a way or passage in advance
of itself. The shoots I are attached to the saddle between the horizontal sliding
plummer blocks E, which saddle also constitutes the box or receptacle whereinto the
dredgings or spoil falls as the buckets successively upset over the tumbler C. Thus
the shoots I are always maintained in the same constant position relatively with the
bucket ladder, and the upper part of the hopper at each side of the dredger being
formed with longitudinal openings J, it follows that the dredged material or spoil is
at all times discharged into the hopper in every position which the sliding parts
occupy on the frames F.
The second part of our said improvements, namely, that for effecting the discharge
of the load of hopper dredgers on to adjoining river or canal banks, or floats is
carried out preferably in the manner indicated at Figure 3 (Sheet 1) of the appended
Drawings, by placing a centrifugal pump K in any convenient position in the well
of the hopper dredger and connecting it by a passage L at each side with each
hopper, the pump being further provided with a discharge tube M which is led to
the point where it is desired to deposit the dredgings or spoil. By this arrangement,
in place of steaming the hopper dredger out to sea or into deep water whereinto it
has hitherto been the practice to discharge dredgings or spoil, the dredgings or spoil
may be at once discharged on to the river or canal bank or floats, without moving
the dredger from the site whereon it is operating, and without the loss of time
generally involved under the existing practice of steaming the dredger out to sea or
other deep water.
The third part of our said improvements, namely, that relating to the improved
construction of the bottoms of flat bottommed hoppers is shown at Figures 1, 2, and 3
(Sheet 2) of the appended Drawings, of which Figure 1 is a plan of a portion
of the bottom of a hopper dredger, showing the A shaped intersecting keelsons G
running fore and aft and thwartship; Figure 2 is a transverse section corresponding
to Figure 1; and Figure 3, a plan of the bottom of the hopper dredger, showing the
under side of the A shaped fore and aft and thwartship keelsons G. The doors
for closing each of the oblong spaces formed by the keelsons G are closed for holding
dredgings or spoil, and opened for discharging the same by the doors H, each of
which is hinged to one side of each oblong space, and held up or lowered by means
of the chains I which pass over the rollers J, carried in the thwartship beams K, and
tightened or loosened by winches.
The fourth part of our said improvements, namely, that for enabling dredgings or
spoil to be discharged in shallow or "shoal" ground is illustrated in transverse
section of a dredger at Figure 4 (Sheet 1) of the appended Drawings. In this
Figure the floors B of the hoppers A, one of which is on each side of the central
well, are inclined and above the load water line of the dredger. At the outer sides
of the hoppers A there are doors C which are held so as to close the sides by the
chains D coupled to the winches E.
When the winches are rotated so as to
slacken the chains D, the doors fall open into a vertical position, and the dredgings
or spoil slide off the inclined bottom of the hoppers on to the place of discharge.
The fifth part of our said improvements, namely, that for applying the doors for
discharge of the dredgings or spoil on either side of a bucket well is shown as
applied to a dredger at Figures 1, 2, and 3, (Sheet 1) of the appended Drawings, the
doors may either be hinged at the upper edge to the side of the well, or they may

page_text: be fitted or attached to screws for raising or lowering them vertically. This last
arrangement is that which is shown at Figures 1, 2, and 3 (Sheet 1) wherein the
doors are marked O and the screws P. The screws P are actuated by the nuts Q
into teeth, in the exterior of which tangent screws R engage, and by these being
rotated by the winch handles shewn in the Drawings, the screws and doors are
raised or lowered.
Having now described and particularly ascertained the nature of our said Invention,
and the system, mode, or manner in or under which the same is or may be used or
practically carried into effect, we would observe in conclusion that what we consider
to be novel and original, and therefore claim as the Invention secured to us by
the herein-before in part recited Letters Patent is,-
www
First. The arrangement shown at Figures 1, 2, and 3 (Sheet 1) of the appended
Drawings for moving the bucket ladder or girder fore and aft independently of head
and stem motion of the ship, substantially as herein-before described.
Second. Placing pumps in the bucket well in connexion with the lower part of
the hoppers of hopper dredgers for the purpose of discharging the dredgings or spoil,
substantially as herein-before described and shown at Figure 3 (Sheet 1) of the
appended Drawings.
Third. Constructing the bottoms of hopper dredgers of fore and aft and
thwartship triangular box keelsons intersecting one another, also with thwartship
keelsons for holding the chains by which the doors are operated, substantially as
herein-before described and shown at Sheet 2 of the appended Drawings.
Fourth. Constructing hopper dredgers with inclined floors above the load water
line, and with doors at the sides for discharging the dredgings or spoil as herein-
before described and shown at Figure 4 (Sheet 1) of the appended Drawings.
Fifth. Applying vertical doors in the vertical sides of the well of hopper dredgers,
substantially as herein-before described and shown at Figures 1, 2, and 3 (Sheet 1)
of the appended Drawings.
In witness whereof, we, the said William Simons and Andrew Brown, have
hereunto set our hands and seals, the Eighth day of May, One thousand eight
hundred and seventy-seven.
WILLIAM SIMONS. (L.s.)
ANDREW BROWN. (L.S.)