Maritime transportation and distribution system and method for bulk raw materials

A system for maritime transportation and distribution of bulk raw materials includes a series of containers, a carrier vessel, a container unloading dock for unloading material from each container, and a loading dock for loading material into each container, each container having openings in the stern and bow walls for loading and unloading materials, provided with watertight covers and/or valves, and having no hatches on deck so that the containers can be stacked one on the other, the vessel having a hold provided with a port for the flotation loading and unloading of the containers into and out of the hold, the hold comprising retention devices to lock each container to the structure of the carrier vessel, in the stowage position the containers being stacked one on the other in a multilayer arrangement, the unloading dock being a sloping bed graving dock which includes a tunnel located underneath the same in communication with the floor of the dock through openings provided with watertight covers, and a conveyor in the tunnel leading to a store yard, the loading dock being a sloping bed dock provided with a charging hopper located on the head of the dock and fed by a conveyor.

BACKGROUND OF THE INVENTION 
Heavy difficulties were encountered in this last decade by a number of 
industrialized countries in competing in the maritime transportation 
field. A more sophisticated technology of maritime transport, finalized to 
reach higher productivity is requested to allow industrialised countries 
to profitably manage maritime transportation in the proximate future. 
In the sixties a relevant increase of productivity was achieved in many 
sections of maritime transport, due especially to the ship mammothing 
trend. This trend has brought up the ship to encounter the harbour depth 
in many areas of the world. Waterborne crude oil tankers overcame this 
problem by being moored at an open sea pipeline terminal, but in the solid 
bulk raw material transport the harbour depth represents today one of the 
biggest restraints to further increase the ship size and consequently the 
transport productivity. Another restraint is the way unloading operations 
are carried out; particularly the intermittance in the flow of cargo from 
ship to shore and the repetitive translations and movements of the bucket 
are a bottleneck in transport productivity and also a source of 
atmospheric pollution. 
The harbour infrastructure in fact represents today the biggest restraint 
to the increase in transport productivity. Modifications at the harbour 
structures to cope with the new traffic requirements would require very 
long time and also very huge investments; these on the other side are not 
always justified as they would advantage only a section of the industry 
while their weight is supported by all the collectivity. 
The system object of the present invention relates to massive solid bulk 
raw material transport and provides a substantial increase in the maritime 
transport productivity by requesting minor modifications in the harbour 
structure. 
During the past years a number of significant technological developments 
were carried out on the united cargo transportation to solve the interface 
problems between maritime and piggy-backing or river transport. Container 
vessels and barge carrier vessels were built and also flotation loading 
and unloading of barges through a gate on the vessel were developed. Some 
embodiments were also proposed for having barges stowed in a number of 
layers in the hold of the carrier vessel but the solutions proposed call 
for very costly structure of the carrier vessel and elaborate operations 
for loading and unloading of barges. 
Accordingly, it forms the main object of the present invention to provide a 
new system and method of transport such that barges could be stacked one 
on the other into the hold of the carrier vessel in the same way as 
containers are stacked into the container ship. For reaching this target 
barges are to be perfectly watertight and have no hatches; consequently 
the loading and unloading operations of the cargo into the barges can no 
more be done as usually by means of buckets moved by travelling cranes but 
by having barges put in a sloping trim and cargo moved and transferred by 
its own weight. 
A further object of the present invention is the barge carrier vessel 
itself whose structure, fittings and arrangements have to allow the 
stacking operation of barges into the hold. 
Thus, main objects of the present invention are: 
to provide an improved maritime transportation system employing a novel 
type of barge; the barge-container, having no hatches, being perfectly 
watertight and capable to be stacked one on the other; to provide a novel 
type of loading and unloading of the cargo into the barge container in 
which the barge container is placed on a sloping trim and the cargo is 
moved and transferred by its own weight; to provide an improved barge 
carrying waterborne vessel in which barge containers are stacked one on 
the other in a multilayer configuration, and the vessel itself is capable 
to be overimmersed in a proper dredged area in the harbour basin for 
flotation loading and unloading. 
SUMMARY OF THE INVENTION 
The invention calls for means for having the barges stacked one on the 
other in a multilayer configuration in the hold of a barge carrier vessel. 
For such a purpose barges at first are to be sound and watertight when 
completely submerged. They have no hatches but a number of openings on the 
end walls, closed by proper gate valves or watertight covers. 
One or more longitudinal bulkheads are fitted for compartmenting the barge 
especially when in ballast. 
The barge carrier vessel is a dock hold vessel type for transportation of 
heavy cargo, having compartmented double bottoms and wing tanks for 
obtaining a single large hold without any transverse watertight bulkheads. 
The vessel may be of the self-propulsion type or of the integrated 
tug-barge type. Its hold has some longitudinal bulkheads or a number of 
pillars lined on longitudinal plans which split the hold in corridors 
having a proper breadth in accordance with the barges breadth. 
A retention system is provided to lock the barges to the structures of the 
carrier vessel and to maintain the same in their submerged position when 
the hold is flooded. The flotation loading and unloading of barges into 
the hold through a proper gate on the carrier vessel is in fact carried 
out by stowing one layer barge configuration at a time. 
When the first layer of floating barges has entered the hold, the carrier 
vessel is deballasted and gets moving upwards as far as the layer of 
barges comes into contact with the carrier vessel double-bottom; in this 
position the retention system is activated and the barges locked to the 
vessel structures. 
The vessel is then ballasted again and the hold flooded so as to allow a 
second barge layer to enter the hold; when the barges of this second layer 
are in position, the carrier vessel is deballasted again as far as the 
barges are stacked on those of the first layer and in this position locked 
to the structure of the carrier vessel. 
The operation will prosecute as long as the hold is completely loaded. 
The invention also calls for a basin to be dredged on the harbour depth to 
allow huge barge carrier vessels to be overimmersed for loading or 
unloading operations while the carrier vessel is staying safely in the 
harbour. 
It is accordingly a further object of the present invention to provide 
special means for putting the barge in a sloping trim either for its 
loading as for unloading. In one such unloading embodiment the barge is 
let entered in a graving drydock having a proper sloping bed. By emptying 
the dock the barge is placed on the bed. A number of watertight doors are 
placed on the floor of the dock putting in communication the dock itself 
with a tunnel where a conveyor belt system is fitted. By opening the 
watertight doors on the dock floor and the gate valves on the barge, the 
cargo is moved by its own weight from the barge to the conveyor belts and 
translated by these directly to the store yard. 
For the loading of the barge the above mentioned arrangement is modified as 
no watertight door is fitted on the floor of the dock but the cargo is 
transported through a conveyor belt into a charging hopper on the head of 
the dock fitted at the loading opening of the barge.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS 
The Barge-Container of FIGS. 1 to 3 
FIGS. 1-3 show somewhat diagrammatically a barge container A which 
illustrates the main embodiments of the invention. The barge container has 
a hull with a bottom wall 1, side walls 2, a deck wall 3, a stern wall 4 
and a bow wall 5. Two longitudinal bulkheads 6 divide the cargo space into 
three compartments for assuring to the barge proper stability when in 
ballast condition. The loading of the barge is carried out on the stern 
through an opening 7 closed by a watertight cover 8 which could be hinged 
to the structure of the barge. 
Another closing device for the opening 7 could be an electro-hydraulic 
operated watertight door which sliding on its guides enters into one of 
the two recesses 9 aside of the opening 7. 
A watertight bulkhead 11 is fitted on the fore for obtaining a cofferdam 12 
separating the cargo space from the bow wall 5. 
The unloading of the barge is carried out through four openings provided 
with conduits 13. Four sliding valves 14 on the bulkhead 11 separate the 
cargo space from the conduits and four watertight autoclave covers 15 
separate the conduits from the outside. Either the sliding valves or the 
watertight covers 8 and 15 are operated by pneumatic or oleodynamic or 
electric actuators. 
The power for operating the actuators is supplied usually by an external 
source. 
Some proper hooks 16 are arranged on the front and rear walls to allow the 
connection of a number of barge containers to each other by means of 
cables or chains. These hooks will act also as spacers when barges are 
assembled into the carrier vessel. 
The Barge Container Carrier Vessel of FIGS. 4 to 8 
With reference to FIGS. 4, 5, 6, 7, 8 a bow port 17 is fitted on the bow of 
the vessel for the access of the barge containers into the hold. A double 
bottom 18 and a number of wing tanks 19 run alongside the hold for all its 
length. 
A number of pillars 20 extending from the double bottom 18 up to the deck 
21 are lined on longitudinal planes and split the hold in three corridors 
22. Three capstans 23 are arranged at the aft of the vessel hold to be 
used for hauling the trains of barges into the corridors. 
Some rolling fenders 24 at the barge entrance floating level are fitted on 
both sides of a number of pillars to maintain in a straight course the 
movement of barges during their entrance into the hold. 
Movable pawls 25 are fitted on the first pillars in front of the bow port 
for maintaining the barges of each row in contact with each other during 
the upward movement of the carrier vessel. 
These movable pawls slide horizontally on proper guides and are spaced 
vertically nearly half the height of the barges to be sure that the 
longitudinal restraint of the barges be maintained for all the vertical 
relative movement of the same with reference to the carrier vessel. 
Wooden lined guides 26 are fitted on a number of pillars to maintain the 
barges in their proper transverse position during the upward movement of 
the carrier vessel as long as they reach their stowage position. 
Retention devices 27 are fitted on the pillars to lock the barges in this 
position to the structure of the carrier vessel. Said retention devices 
can also be apt to be interposed between the barge container layers so as 
to reduce the load of the upper barge containers on the lower ones. 
A number of sea chest valves 28 are fitted on the sides and also at the aft 
bulkhead of the hold to assure a direct communication of the flooding 
water with the sea and get easy the withdrawal and the entrance of the 
water into the hold during the barges embarking operation. 
The double bottom 18 and the wing tanks 19 are properly compartmented. A 
computer determines and gets activated the opening and the closing of the 
proper valves of the ballast subsystem in accordance with the inputs 
received from the fore and aft draughts of the carrier vessel so that an 
upward even-keel movement of the vessel is obtained during all the stowage 
operation of the barges. 
The embarking operation is carried out from a cargo station arranged in the 
carrier vessel according to the following procedure: 
the carrier vessel enters the embarking harbour and is moored in a proper 
place where a dredged area in the depth provides a basin capable to 
conveniently receive the bottom part of the vessel when the same is 
overimmersed. 
The carrier vessel is then ballasted, its hold flooded and the bow port 17 
opened. The ballast will prosecute as long as the vessel will reach the 
proper draught to receive the first layer of barges. 
The rows of barges taken in tow by a tug arriving at the entrance of the 
hold are hooked to the cables of capstans 23. These are activated from the 
cargo station and the barges rows are hauled into the hold guided by the 
rolling fenders 24, while each tug will work for steering properly its own 
row of barges from outside the vessel. When the first barge of the row 
comes into contact with its pawl 28', the tug will push the barges one on 
the other so that they come into contact with their hooks 16 acting as 
spacers, obliging each barge to reach their proper position. At this stage 
the movable pawls 25 are activated so that all the barges of the row are 
maintained in contact with each other during the upward movement of the 
carrier vessel. 
The system for deballasting the vessel is then activated and the vessel is 
moved upwards in an even-keel trim; during this operation the flooding 
water is withdrawn from the hold through the withdrawal subsystem 
comprising the sea chest valves and the entrance gate too, and the barges 
are forced in their proper position through the wooden lined guides 26 and 
the movable pawls 25. 
When all the barge containers of the first layer come into contact with the 
double bottom, the deballasting will be stopped. The retention system is 
then activated and the barges are locked to the structures of the carrier 
vessel. 
At this stage the vessel is ballasted again allowing the second layer of 
barge containers to enter the hold and the operation will prosecute as 
above detailed until the hold has been filled up. 
The Barge Container Unloading and Loading System 
As illustrated in FIGS. 9 to 13 the barge container unloading system is 
composed by a graving dock 29 and a tunnel 30 located underneath the 
deepest floor of the dock and leading to the store yard ground level. 
A caisson gate 31 separates the dock from the sea. 
The bed of the dock is composed by two sections: a horizontal section 32 
and a sloping bed 33. 
On the floor 34 of the dock a number of openings 35 put into communication 
the dock itself with the tunnel 30. 
Watertight covers 36 are fitted in the openings 35. 
A column type hydraulic jack system 37 is fitted on the horizontal section 
of the bed to support the aft section of the barge when the same is 
starting to rotate around the edge 38 for taking place on the sloping bed 
33. 
The system is composed by a number of jacks lined in a plane nearly normal 
to the sloping bed 33. 
A rigid platform 39, embracing a proper bottom area of the barge, is 
pivoted to each end of the jacks so that it may match and support through 
all the contact area the barge during its rotation. The power for 
operating the system is controlled by the movement of the barge container. 
A barge retention system 40 is fitted on the front wall 41 of the dock to 
support the barge during its sloping operation and to assure the same will 
take its proper position on the bed. 
The retention system is composed by a number of column-type hydraulic jacks 
42 each of them fitted on proper arm structure 43 having a sliding block 
44 sliding on vertical guides 45 fitted on the front wall 41 of the dock. 
A barge embracing element 46 is pivoted on the end of the jack to allow 
its matching with the barge during the sloping operation of the same. 
The system is operated through a double control power: oil is pumped into 
the hydraulic system when the pistons are called to elongate their strokes 
for matching the movement of the barge, while oil is recovered from the 
system when the pistons contract their strokes. 
The vertical movement of the arm structure is carried out through a system 
controlled by the movement of the barge or by the water level in the dock. 
A number of conveyor belts 47 are fitted on the tunnel 30. 
The barge container unloading operation will start with the entrance of the 
floating barge into the dock and the placing of the same in the proper 
position with its bow wall meeting the retention system 40. The caisson 
gate 31 is closed and the water pumped out from the dock. The aft bottom 
of the barge comes then in contact with the platform 39 of the hydraulic 
jack system 37. 
At this stage the jacks 42 of the retention system are put under stress by 
having the hydraulic system at the rated pressure. The jack system 37 and 
the retention system 40 are then activated to match the sloping movement 
of the barge around the edge 38 while water is going to be pumped out from 
the dock. This operation will last until the bottom of the barge comes in 
contact with the sloping bed 33. When the water is completely evacuated 
from the dock the covers 36 are removed, the conveyor belts 47 are 
activated, the barge autoclave covers 15, sliding valves 14 and loading 
watertight cover 8 are opened, and the cargo is moved by its own weight 
from the barge to the conveyor belts 47 and translated by these directly 
to the store yard. 
At the end of unloading operation the sloping angle of the barge is 
increased by activating the hydraulic jack system 37 to allow the complete 
emptying of the barge. 
In FIG. 13 a loading system is illustrated. At the loading station a barge 
sloping trim lower than that of the unloading station is requested and 
also the complete evacuation of the water from the dock is not necessary. 
For these reasons the sloping bed 33' has been arranged facing the entrance 
of the dock; no tunnel and no hydraulic jack system are requested. 
The retention of the barge on the sloping bed is realised by shaping the 
bed with a step 48 where the barge lower bow end abuts. 
A charging hopper 49 is fitted on the head of the dock and a conveyor belt 
(not shown) is arranged for feeding the charging hopper. 
While the present invention has been described with reference to a 
particular embodiment, many alterations and modifications may be practiced 
without departing from the spirit and scope thereof. It is therefore the 
intent that the present invention not be limited to the above, but only be 
limited as defined in the following claims.