Cargo transport including quick loading and unloading of a cargo ship

Abstract

 For transporting cargo in a ship (2), a barge (6-16) carrying cargo is received in a cargo space (27), a transport bottom (44) of the cargo space being partially flooded and the barge (6-16) floating into the cargo space (27). The barge (6-16) passes into the cargo space (27) through an access door (49). The door is closed and water is discharged from the ship (2) until the barge (6-16) is carried by the transport bottom (44). The ship then sails to a destination, where the door (49) is opened, the transport bottom (44) is flooded again at least until the barge (6-16) floats; and the barge (6-16) is delivered from the cargo space (27) via the opening of the access door (49). A method for loading, a shipping system and a cargo transfer station specifically adapted for use in combination with that method are also described.

Description

TECHNICAL FIELD AND BACKGROUND ART

[0001] The invention relates to a method for transporting cargo by ship, to methods for loading and unloading a ship and to a cargo shipping system and a sea cargo transfer station for use in such methods.

[0002] In "Shortsea" traffic involving the transportation of general cargo, the cargo is generally transported in a cargo space and as deck load on a weather deck above the cargo space. Especially for roll-on roll-off cargo, it is advantageous to transport the cargo on a weather deck, because this allows the cargo to be loaded quickly and without hoisting.

[0003] Since the duration of voyages in "Shortsea" traffic is relatively short, a relatively large portion of the operational time of a ship is spent during loading, unloading and waiting, even if the cargo is containerized but in particular if general cargo including discrete items are transported which is not suitable to be containerized. In practice, it is not unusual to spend 4 to 5 days of an average voyage of about 10 days loading, unloading and waiting. Another problem that is of particular importance in short voyages is that the sailing time often dictates a time of arrival in a port, which is incompatible with working hours of port facilities. For this reason, it is generally attempted to arrive in a port briefly before the beginning of working hours in the port and only on working days. However, this results in sailing at speeds above or below the optimum speed. Furthermore, the need to arrive in a port before normal working hours puts additional strain on the crew.

[0004] In international patent application WO 00/38976 a heavy-lift cargo ship is described which has a floodable and freeable bottom and side tanks for loading and unloading cargo according to the float-on/float-off and/or roll-on/roll-off principle. Heavy-lift cargo ships are suitable and primarily used for transporting large and heavy objects such as complete drilling platforms, harbour cranes, and medium to large naval vessels or parts thereof. For this purpose, the rear portion of the ship has an open transport platform and the ship can be ballasted until the platform is immersed under the water surface. Then, a floating object or a pontoon carrying an object can be manoeuvred into a position above the transport platform to load the ship, or away from that position to unload the ship. Next, the ballast is pumped out of the ship again until the platform is above the water surface. If rolling cargo is transported, it is usually not feasible to also load floating cargo onto the transport bottom and vice versa in view of the adverse effect on rolling cargo of flooding the transport platform. Furthermore, such a ship would be inefficient when used for transporting general cargo and does not provide the cargo protection required for most general cargo.

SUMMARY OF THE INVENTION

[0005] It is an object of the invention to provide a solution that allows a more efficient sea transport of general cargo.

[0006] According to the present invention, this object is achieved by transporting cargo in accordance with claim 1. The invention can also be embodied by methods according to claims 5 and 6 with which the loading and unloading for the method of claim 1 can be realized. The invention can further be embodied in a ship according to claim 16 and in a sea cargo transfer station according to claim 21, which are both specifically adapted for use for use in conjunction with the methods according to claims 1, 5 and 6.

[0007] By causing barges carrying the cargo to be transported to float into and out of the cargo space of the ship. Loading of the ship can be carried out very quickly, so that the time the ship spends while being loaded and unloaded is significantly reduced. Furthermore loading and unloading of the barges requires so little personnel that it will generally not be bound to standard working hours of harbour workers, accordingly the times at which ships can call at a port to be unloaded and loaded are not limited by working hours of harbour workers. The more laborious and time consuming operation of unloading cargo items from the barges and loading cargo items into the barges can be carried out after a ship from which the barges have been unloaded has left the harbour and before the ship into which loaded barges have to loaded arrives in the harbour. Thus, the operation of loading and unloading is to a large extent made independent of the presence of the ship and can be carried at times which accommodated to working hours of harbour workers and may take a relatively long time, because it does not require the presence of a ship. This, in turn, is advantageous because the use of resources can be evened out over time.

[0008] Particular embodiments of the invention are set forth in the dependent claims.

[0009] Further features, effects and details of the invention are set forth in the detailed description with reference to examples shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 

Fig. 1 is a schematic top plan view of a cargo transfer station with full shelter weather protection and a rear end of ship loading a barge from that cargo transfer station,

Fig. 2 schematic side view in cross-section of a quay area of a harbour and a rear end of a ship moored adjacent that quay,

Fig. 3 is a view in cross-section along the line III-III in Fig. 4, and

Fig. 4 is a top plan view along the line IV-IV in Fig. 3.

DETAILED DESCRIPTION

[0011] In Figs. 1 and 2 an example of a sea cargo transfer station according to the invention is shown. The sea cargo transfer station includes a quay 1 for mooring a ship 2 floating in water 3 in front of the quay 1. A basin 4 is located behind the quay 1. A passage 5 intersects the quay 1 for allowing barges 6-16 (see also Figs. 3 and 4) to pass from a position in front of the quay 1 to the basin 4 and vice versa. Land transport areas 17, 18 extend along the basin 4. In this example, the land transport areas 17, 18 are paved so that land transport vehicles can drive over the land transport area. However, the land transport areas can also be adapted for use with other land transport facilities, such as conveyor belts. Two portal cranes 19, 20 each span a portion of the basin 4 and the land area 17, 18 for transferring cargo 21-23 between barges 6-12 in the basin and land transport implements 24 in the land areas 17,18. The portal cranes 19, 20 each include a pair of guide tracks 25, 26 of which one track 25 extends above one of the land transport areas 17, 18 and the other track 26 extends across the basin 4 at such a height above the water in the basin 4, that barges 6-12 carrying cargo of dimensions which can be accommodated in a cargo space 27 of the ship 2 can also pass underneath the track 26. A portal 28 extends between and transversally to the tracks 25, 26. The portal 28 is displaceable along the tracks 25, 26. A cart 29 provided with hoisting winches 30 and hoisting cables 31 extending from the hoisting winches 30 is adapted to run along the portal 28, so that the areas between the tracks 25, 26 are within the operating ranges of the portal cranes.

[0012] Although portal cranes are specifically suitable to cover an essentially rectangular operating range formed by the cargo spaces of a number of barges 7-10 moored alongside each other, it is also possible to use other types of cranes, such as cranes having pivotable hoisting arms.

[0013] In the basin 4 behind quay 1, the barges 6-16 can be loaded and unloaded efficiently and relatively undisturbed by external influences. The positions of the barges can easily be controlled and driven from the sides of the basin. Furthermore, the barges 7-10 are adequately sheltered from wind, waves and shipping in the harbour, which minimizes the risk of damage to the cargo during loading and unloading. Via the passage 5 intersecting the quay 1, the barges 6-16 can easily be displaced from the cargo space 27 of the ship 2 moored closely in front of the quay 1 to the basin and vice versa without having to use tug boats and the like.

[0014] For driving lateral displacement of the barges 6-16 in the basin 4, drive units 35, 36 are installed along the sides of the basin 4 transverse to the access canal 5. The drive units 35, 36 are provided in the form of endless chains drives extending along the sides of the basin 4 and engageable by tow lines or mooring lines attached to the barges. At least one of the wheels over which each of the chains run are driveable to entrain a barge engaged to the chain. Preferably, the controls of the motors for driving chains along opposite sides of the basis 4 are interconnected for controlling the motors such that simultaneous movement in the same sense and with identical speeds is ensured. The motors can be controlled automatically (for instance with feedback of detected barge displacement), semi-automatically (for instance for lateral displacement per unit of barge width) or manually. Barges floating alongside each other are interconnected, so that only one of the barges needs to be driven by the drive units. Displacement of the barges can also be driven using the portal cranes 19, 20.

[0015] For driving movement of the barges in longitudinal direction, a launching and retraction system 34 aboard the ship 2, endless chains along the access canal and/or hauling winches can be used. Hauling winches can also be used as an alternative for the endless chains drives 35, 36 along the sides of the basin 4. Furthermore, instead of endless chains, also other endless flexible pulling members, such as endless cables or endless belts can be used. Furthermore, the flexible pulling members extending along the sides of the basis need not be endless, but can also co-operate with hauling drives at the ends of the respective sides.

[0016] A roof 32 covers the basin 4 and the land transport areas 17, 18 along the basin 4. This allows carrying out the loading and unloading sheltered from precipitation. In colder climates, this also counteracts accumulation of snow and ice in the barges and in hot climates it is advantageous that the roof shelters workers and cargo from the sun. This also allows to use the cargo terminal in combination with the barges in the basis as a warehouse for temporary stocking goods to be transported. Since the stored goods are ready for transport, this allows to respond very quickly to fluctuations in demand for the stored goods.

[0017] According to the present example, protection from adverse weather conditions is further enhanced, because the basin 4 and the land transport areas 17, 18 are also surrounded by walls 37-40. Further protection is provided by a roof 33, walls 41, 42 and a sliding door 43 which also protect the access canal 5. By also covering the access canal 5, load can be moved out of the cargo space 27 and into the cargo transfer station without any significant weather exposure. This is of particular advantage when transporting large items which are difficult to package, but which are sensitive to exposure to humidity, such as rolls of paper or cardboard and steel coils.

[0018] The basin 4 is rectangular and the access canal 5 is arranged centrally in one side of the basin 4. This allows barges to be positioned in two loading and unloading areas 63, 65 to the left and to the right of the entrance formed by the access canal 5. In one loading and unloading area 65, barges 7-10 can be loaded with cargo in anticipation of loading the barges into the ship 2. In the other loading and unloading area 63 barges 6, 11, 12 (and one not shown) unloaded from the ship can be received so that the cargo can be unloaded from the barges in this loading and unloading area. As soon as the last one of the barges 6, 11, 12 (and one not shown) is positioned in the other loading and unloading area 63, the barges 7-10 pre-loaded with cargo can be loaded into the ship and the ship can leave as soon as the four barges 7-10 have been received in the cargo space 27. Thus, the unloading of the cargo from the barges 6, 11, 12 (and one not shown) unloaded from the ship can take place completely or at least partially after the ship 2 has left. In the present example, it is assumed that all the barges present in the cargo space of a ship are discharged and that the ship is reloaded with barges up to its maximum capacity. However, it is also possible for a ship that calls on a port, to unload only one or some of the barges and to load no barges or only one or more barges without filling the cargo space to its maximum capacity.

[0019] The basin 4 has a size in longitudinal direction of the barges, which is equal to the sum of the length of the barges (or at least the longest one of the barges) and a clearance required for dimensional tolerances and manoeuvring of the barges. It is also possible to dimension the basin to accommodate two or more barges in longitudinal alignment. In that case the size of the basin in longitudinal direction of the barges is preferably equal to the sum of an integer multiple of the (preferably standardized) length of the barges and a clearance to accommodate for manufacturing tolerances and manoeuvring. Similarly, the size of the loading and unloading area in the direction of the width of the barges is preferably adapted to the width of the barges, which is also preferably standardized, by providing that the size of the loading and unloading areas is equal to the sum of one or an integer multiple of the width of the barges and a clearance to accommodate for manoeuvring and manufacturing tolerances.

[0020] Two of the land transport areas extend along opposite sides of the basin transverse to the side in which the access canal is arranged. This allows to supply and transport away cargo on opposite sides of the basin. Furthermore, the total width of a pack of barges 7-10 in a loading and unloading area is generally smaller than the length of the barges. For this reason, when unloading cargo from the barges 7-10 in lateral direction of the barges 7-10, the average distance over which cargo is to be transferred to the nearest side 17, 18 of the basin 4 is smaller than in longitudinal direction of the barges. Therefore, the cargo can generally be unloaded more quickly in lateral direction of the barges than in longitudinal direction of the barges.

[0021] Particularly suitable for quick loading and unloading in lateral direction of a pack of barges of which the cargo spaces form a generally rectangular area are the portal cranes 19, 20 having a portal 28 extending parallel to the side of the basin 4 in which the access canal 5 is arranged and moveable along tracks 25, 26 parallel to the sides of the basin 4 alongside which the land areas 17, 18 extend.

[0022] The barges form floating modules for carrying the cargo and can for instance be provided in the form of a standardized design, such as "Euro barges". In principle, the minimum number of barges required for shipping cargo in barges in a ship is equal to c(n +1) in which c is the capacity of the ship expressed in number of barges and n is the number of ports the ship calls on. However, since the ship is provided with a cargo space, it can also be loaded with discrete cargo items such as containers and even bulk cargo in a conventional manner. Furthermore, at least some of the barges can also be distributed and recollected using tugboats and/or push-boats.

[0023] An example of a cargo shipping system specifically adapted for use in combination with a cargo transfer station of the type as described above is shown in most detail in Figs. 3 and 4. The system includes a ship 2 and barges 13-16.

[0024] The ship has a transport bottom 44 for carrying cargo. The cargo space 27 above the transport bottom 44 is horizontally surrounded by walls 45, 46, 47, 48 and an access door 49 in an access door opening 50 (see Fig. 2) for allowing access to the cargo space 27.

[0025] For flooding the transport bottom 44 by lowering the transport bottom 44 below a surface 51' of water 3 in which the ship 2 floats and for returning the transport bottom 44 to a position above the water surface 51, the ship 2 is provided with ballast tanks 52-57; and a pump 58 arrangement of which the sense of operation is reversible.

[0026] On opposite lateral sides of the cargo space 27 buoyancy compartments 71 are provided. These buoyancy compartments 71 increase the stability of the ship in lowered condition and make the ship in lowered condition less sensitive to addition of loads, such as rolling cargo on the weather deck. The buoyancy compartments are particularly effective for increasing the stability of the lowered ship because the compartment project above the transport bottom 44 and, when the ship is lowered, above the level of the surrounding water in which the ship floats.

[0027] It is observed that providing that the feature that the transport bottom 44 is in a position above the level of the surrounding water in which the ship floats when the ship is raised is advantageous for safety of the ship, because in principle water will not enter the cargo space when the access door fails. However, provided the access door closes off the access opening sufficiently reliably, the transport bottom can also be located at such a level that it is below the surface of the water surrounding the ship when the ship is in its raised condition. In that situation, water is discharged from the cargo space by first closing the access door and then pumping the water out of the cargo space. In the event of failure of the access door, a particular safety feature is that the barges start to float in the event of unintended flooding of the transport bottom, so that the weight of the cargo and the barges ceases to have a negative influence on the overall buoyancy of the ship. In the meantime, the barges in the cargo space remain sheltered from waves, so that the risk of flooding the barges is limited. Dunnage members can be employed to reduce the risk of damage due to movement of barges in the cargo space.

[0028] The barges 13-16 and the cargo space 27 are dimensioned for accommodating the barges 13-16 in the cargo space. Thus, the proposed cargo shipping system is specifically adapted for the efficient loading transportation and unloading of general cargo pre-loaded in barges 13-16. In the presently most preferred embodiment shown in Figs. 3 and 4, the number of barges 13-16 that can be received in the cargo space 27 is four. However, it is also possible to dimension the cargo space and the barges such that only a single barge or pontoon fits into the cargo space 27. Preferably, a plurality of modular ones of the barges is moved into and out of the cargo space. This is advantageous for increasing the flexibility, because not the whole content of the cargo space needs to be loaded or unloaded and because cargo can be loaded into and unloaded from the barges in different areas. Furthermore, relatively small barges can be handled more easily than barges covering the whole footprint of a cargo space of a sea ship.

[0029] For providing efficient and flexible transportation, it is further preferred that the cargo space 27 has a length equal to the sum of the length of the barge or an integer multiple of the length of each of the barges and a clearance and that the cargo space 27 has a width equal to the sum of the width of the barge or an integer multiple of the width of each of the barges and a second clearance. The first and second clearances are preferably dimensioned to accommodate manoeuvring and dimensional tolerances and for instance at most 4 % and preferably at most 1.5 to 2 % of the associated dimension. An average gap of about 0.5 to 1.5 % and preferably about 1 % of the associated dimension will generally be sufficient to allow for manoeuvring and dimensional tolerances.

[0030] Another advantage of barges closely fitting into the cargo space 27 is that relatively little water needs to be displaced to flood the transport bottom until the barges therein start to float and to clear the transport bottom from water after loading of barges to be transported.

[0031] In the present example, the cargo space 27 has a width equal to the sum of twice the width of each of the barges 13-16 and a second clearance, so that two barges fit into the cargo space alongside each other. However, the access door 49 has a width equal to the sum of the width of the barge and a third clearance, the third clearance being smaller than the width of the barge. Thus, only one barge at a time can pass through the access door 49. The relatively narrow access door provides the advantage, that, next to the access door, room is left for loading other cargo. In this example, a ramp 59 is provided next to the access door 49 via which trailers 61 and/or other rolling cargo are rolled onto and from a deck 61 above the cargo space 27.

[0032] During loading of barges into positions out of line with the access opening 50, at least one of the modular barges received in the cargo space 27 is moved transversally to the longitudinal direction from a position longitudinally in-line with the access opening 50 into a position transversally displaced from the position longitudinally in-line with the access opening 50. Next, at least one next barge may be brought into a position in-line with the access opening 50 and alongside the transversally moved barge. During unloading, the opposite procedure may be followed.

[0033] For reliably keeping the barges 13-16 positioned in the cargo space, even when sailing in stormy conditions, the cargo space is further provided with cradle members 67-70 (not all cradle members are designated by reference numbers). The cradle members 67, 68 and 69 are arranged along lateral sides of the cargo space 27 and along a longitudinal centre line of the cargo space and retain the barges 13-16 laterally in position. The cradle members 66-69 have guide surface facing each other and converging in downward direction for laterally centering the barges in the respective positions as the barges 13-16 are lowered to the floor. Similarly, the cradle members 70 have guide surface facing each other and converging in downward direction for longitudinally centering the barges 13-16 in the respective positions as the barges 13-16 are lowered to the floor.

[0034] In operation, according to the present example, after mooring the ship 2 with the access door opening 50 in its stern facing the access canal 5 intersecting the quay 1 and in-line with the access canal 5, valves in a conduit 62 are opened and water is allowed to enter into ballast tanks 52-57. This causes the ship 2 to be lowered from a position in which the water surface is at a level 51 to a position in which the water surface is at a higher level 51' relative to the ship 2. Furthermore, the access door 49 has been opened, preferably before the ship is lowered, so that water is allowed to enter the cargo space 27 and floods the transport bottom 44. This, in turn causes the barges 6, 11, 12 in the cargo space 27 to float and cargo 22 is unloaded from the cargo space by displacing one or more of the floating barges carrying the cargo through the access opening 50 out of the cargo space 27. In the course of that operation, the barge or barges 6, 11, 12 are moved from a position above the flooded transport bottom 44 to an unloading area spaced from the ship 2. In Fig. 1 this unloading area 63 is formed by the area of the basin 4 to the left of the area 64 of the basin 4 in-line with the access canal 5.

[0035] Cargo 22, 23 is unloaded from the barges 6, 11, 12 which have been unloaded from the ship 2 in the unloading area.

[0036] Immediately after as all barges 6, 11, 12 to be unloaded have been unloaded from the ship 2 and have been brought into the unloading area to the left of the area of the basin 4, barges 7-10 which have been loaded beforehand with cargo 22, 23 in the other one 65 of the loading areas in the basin 4 are loaded into the cargo space 27 by displacing the floating barges 7-10 carrying the cargo 22, 23 from the loading area 65 through the access opening 50 into the cargo space 27 into a position above the flooded transport bottom 44. Then, the pump 58 pumps water out of the ballast tanks 52-57 via the conduit 62 until the surface of the water in which the ship 2 floats is back at a level 52 relative to the ship 2. This causes water to be discharged from the cargo space 27 as well, so that the barges are subsequently carried by load bearing strips 66 of the transport bottom 44 as can be seen in Fig. 3. Then, the access door 49 is closed and the ship is ready to be released from the mooring to sail to its next destination, where barges can be unloaded and unloaded in a similar manner, with or without the use of a loading an unloading basin.

[0037] To keep the time the ship 2 needs to stay in the port as short as possible, loading of the barges 7-10 which are subsequently moved into the cargo space 27 is preferably carried out before cargo is unloaded from the barges which have been moved out of the cargo space 27.

[0038] To reliably complete the loading of the barges 7-10 in good time before the barges are to be loaded into the ship 2, at least a portion of the loading of the barges 7-10 which are subsequently moved into the cargo space 27 is preferably carried out before the barges 6, 11, 12 from which cargo is to be unloaded have been moved out of the cargo space 27.

[0039] At least a portion of the unloading of the barges 6, 11, 12 from which cargo is to be unloaded is preferably carried out after the loaded barges 7-10 have been moved into the cargo space 27, so that a particularly high cargo transfer capacity of the cargo transfer station is not required.

[0040] For efficiently loading and unloading the barges 6-12, it if further preferred to load and unload the barges 6-12 in the loading or unloading areas 63, 65 while the barges are arranged in side-by-side relationship. This allows several barges to be in the operating range of a single crane and requires relatively small averages transfer distances between the barges and the land transport areas 17, 18.

[0041] In the present example, the area 63 into which the barges 6, 11, 12 unloaded from the ship 2 are moved and where these barges 6, 11, 12 are unloaded forms the unloading area for these barges. After these barges 6, 11, 12 (and preferably a fourth barge which is not shown) have been unloaded, these barges are loaded again in the same area 63. The same applies to the other loading and unloading area 65 in the basin 4 in which loading and unloading alternates with loading and unloading in the area 63. Accordingly, barges do not have to be stored temporarily outside the basin 4

[0042] Because the barges 6-12 are moved into and out of the basin 4 via a single access canal 5, the basis 4 can be sheltered from wind, waves and other external influences relatively easily and control over the barges being loaded and unloaded can be exerted easily from the sides of the access canal 5. For this purpose it is further advantageous that the barges are moved into or out of the basin 4 in their longitudinal direction and laterally shifted inside the basin 4. In the basin 4, the barges are less likely to make undesired movements and skew of a barge relative to the basin 4 can easily be eliminated by pulling the barge against the quay of one of the land transport areas 17, 18 or against another barge already moored in the basin 4. The cranes 19, 20 can be employed to pull the barges sideways through the basin. By using a two towing lines connected to the barges in spaced apart positions, a towing triangle is formed which prevents the barges from substantially skewing in the basin during sideways movement thereof.

[0043] According to the present example, a particularly positive control over the barges 6-12 during loading and unloading is obtained, because the cargo ship 2 is moored with the access door 49 in line with the access canal 5 for passing barges 6-12 into and out of the access canal 5 and because, during transfer between the ship 2 and the basin 4 the barges 6-12 enter the access canal 5 before being completely free from the ship 2 or vice versa.

[0044] It is observed that the present invention is not limited to the example shown and described above, but that many variants thereof are conceivable. For instance, the number of barges which can be accommodated in the cargo space can be different and barges can be of different sizes, preferably within a modular system. Furthermore, if a cargo transfer station including a sheltered barge basin is employed, it can also be of a different design, for instance with an entry canal and an exit canal and barge boxes between the entry and the exit canal.

Claims

1. A method for transporting cargo in a ship (2) having a transport bottom (44) and, above the transport bottom (44), a cargo space (27) horizontally surrounded by walls (45-48) and an access door (49) in an access opening (50), comprising:

receiving a barge (6-16) carrying cargo in the cargo space (27), the transport bottom (44) being partially flooded and the barge (6-16) floating into the cargo space (27), the barge (6-16) passing into the cargo space (27) through the access opening (50);

closing the access door (49) and discharging water from the ship (2) until the barge (6-16) is carried by the transport bottom (44);

travelling to a destination;

at the destination, opening the access door (49) and flooding the transport bottom (44) at least until the transported barge (6-16) floats above the transport bottom (44); and

delivering the floating barge (6-16) from the cargo space (27) via the opening of the open access door (49).

2. A method according to claim 1, wherein a plurality of modular ones of said barges (6-16) is moved into and out of the cargo space (27).

3. A method according to claim 2, wherein the cargo space (27) is elongate in longitudinal direction of the ship (2), wherein at least one of the modular barges (6-16) received in the cargo space (27) is moved transversally to the longitudinal direction from a position longitudinally in-line with the access door (49) into a position transversally displaced from a position longitudinally in-line with the access door (49), and wherein at least one next barge (6-16) is moved into a position in-line with the access door (49) and alongside the transversally moved barge (6-16).

4. A method according to any one of the preceding claims, further comprising rolling cargo onto a deck of the ship (2) via a ramp transversally neighbouring the access door (49).

5. A method for unloading cargo from a cargo space (27) horizontally surrounded by walls (45-48) and an access door (49) in an access opening (50), the cargo space (27) having a flooded transport bottom (44), comprising:

displacing at least one floating barge (6-16) carrying the cargo through the access opening (50) out of the cargo space (27) from a position above the flooded transport bottom (44) to an unloading area spaced from the ship (2); and

unloading the cargo from the at least one barge (6-16) in the unloading area.

6. A method for loading cargo into a cargo space (27) horizontally surrounded by walls (45-48) and an access door (49) in an access opening (50), the cargo space (27) having a flooded transport bottom (44), comprising:

loading at least one floating barge (6-16) with the cargo in a loading area spaced from the ship (2); and

displacing the at least one floating barge (6-16) carrying the cargo from a loading area spaced from the ship (2) through the access opening (50) into the cargo space (27) into a position above the flooded transport bottom (44).

7. A method according to claim 5 or 6, wherein

a plurality of modular ones of said barges (6-16) is displaced into or out of the cargo space (27) and in that, in the loading or unloading area, at least some of the cargo is unloaded from said plurality of modular barges (6-16).

8. A method according to claim 7, wherein the barges (6-16) are loaded or unloaded in a loading or unloading area arranged in side-by-side relationship (2).

9. A method according to at least claims 5 and 6, wherein loading of the at least one barge (6-16) which is subsequently moved into the cargo space (27) is carried out before cargo is unloaded from the at least one barge (6-16) moved out of the cargo space (27).

10. A method according to claim 9, wherein at least a portion of the loading of the at least one barge (6-16) which is subsequently moved into the cargo space (27) is carried out before the at least one barge (6-16) from which cargo is to be unloaded is moved out of the cargo space (27).

11. A method according to claim 9 or 10, wherein at least a portion of the unloading of the at least one barge (6-16) from which cargo is to be unloaded is carried out after the at least one loaded barge (6-16) has been moved into the cargo space (27).

12. A method according to any one of the claims 5-11, wherein the at least one barge (6-16) is at least loaded or unloaded in a basin (4) and at least moved into the basin (4) before unloading cargo therefrom or moved out of the basin (4) after having been loaded with cargo.

13. A method according to claim 12, wherein the at least one barge (6-16) is moved into and out of said basin (4) via a single access canal (5).

14. A method according to claim 12 or 13, wherein the at least one barge (6-16) is moved into or out of the basin (4) in its longitudinal direction and laterally shifted inside the basin (4).

15. A method according to any one of the claims 12-14, wherein, at the destination, the cargo ship (2) is moored with an access door (49) in line with an access canal (5) for passing barges (6-16) into and out of the access canal (5) and wherein during transfer between the ship (2) and the basin (4) the at least one barge (6-16) enters the access canal (5) before being completely free from the ship (2) or vice versa.

16. A cargo shipping system including:

a transport bottom (44) for carrying cargo;

a cargo space (27) above the transport bottom (44) and horizontally surrounded by walls (45-48) and an access door (49) in an access door (49) opening for allowing access to the cargo space (27);

means for flooding the transport bottom (44) by lowering the transport bottom (44) below a surface of water in which the ship (2) floats and for returning the transport bottom (44) to a position above the water surface; and

a barge (6-16), the barge (6-16) and the cargo space (27) being dimensioned for accommodating the barge (6-16) in the cargo space (27).

17. A cargo shipping system according to claim 16, wherein the transport bottom (44) includes at least one upwardly projecting transport cradle member (67-70) for horizontally positioning a barge (13-16).

18. A cargo shipping system according to claim 16 or 17, further comprising buoyancy compartments (71) on opposite lateral sides of the cargo space (27).

19. A shipping system according to any one of the claims 16-18, further comprising a plurality of modular ones of said barges (6-16),
   wherein the cargo space (27) has a length equal to the sum of the length of the barge (6-16) or an integer multiple of the length of the barge (6-16) and a first clearance; and
   wherein the cargo space (27) has a width equal to the sum of the width of the barge (6-16) or an integer multiple of the width of the barge (6-16) and a second clearance;

the first and second clearances being dimensioned to accommodate manoeuvring and dimensional tolerances.

20. A shipping system according to claim 19, wherein the cargo space (27) has a width equal to the sum of an integer multiple of the width of the barge (6-16) and a second clearance, and wherein the access door (49) has a width equal to the sum of the width of the barge (6-16) and a third clearance, the third clearance being smaller than the width of the barge (6-16).

21. A sea cargo transfer station including a quay for mooring a ship (2) in front of the quay, a basin (4) behind the quay, a passage in the quay for allowing barges (6-16) to pass from a position in front of the quay to the basin (4) and vice versa, at least one land transport area (17, 18) along said basin (4) and at least one crane (19, 20) spanning at least a portion of said basin (4) and said land transport area (17, 18) for transferring cargo between barges (6-16) in said basin (4) and said land transport area (17, 18).

22. A station according to claim 21, further including a roof (32) covering at least a portion of said basin (4) and said land transport area (17, 18).

23. A station according to claim 21 or 22, wherein said basin (4) is rectangular, wherein said access canal (5) is arranged centrally in one side of said basin (4) and wherein two of said land transport areas (17, 18) extend along opposite sides of the basin (4) transverse to a side of the basin (4) intersected by the access canal (5).

24. A station according to claim 23, wherein the crane (19, 20) is a portal crane having a portal (29) extending parallel to a side of the basin (4) intersected by the access canal (5) and moveable along tracks (25, 26) parallel to the sides of the basin (4) alongside which said land transport area (17, 18) extends.

Drawing