AU2004200321A1 - Cargo transshipping unit - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): DAVID TOMS RALPH DOWNHAM Invention Title: CARGO TRANSHIPPING UNIT The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 CARGO TRANSSHIPPING

UNIT

FIELD OF THE INVENTION The present invention relates to transportation of bulk materials from shore to a vessel lying at anchor or at moorings offshore and loading of this material into the vessel.

BACKGROUND TO INVENTION Barges and lighters, both self-propelled and towed by tug boats, have been employed for many years to load cargo into or unload cargo from vessels lying in relatively deep water offshore which are unable to enter a port or moor at a jetty due to a lack of adequate water depth.

However many of the larger modern bulk carriers are not equipped with cranes to transfer cargo from or to barges alongside themselves. For example in the year 2002 there were approximately 1000 bulk carriers of between 60,000 and 70,000 tonnes deadweight (termed "Panamaxes") in the world merchant fleets but fewer than 50 of these were equipped with deck cranes. Vessels so equipped command a premium for their hire and at the same time the presence of these cranes on deck is often a disadvantage when unloading cargo in a port equipped with its own high-speed cranes for this purpose.

SUMMARY OF THE INVENTION According to the present invention there is provided a cargo transshipping unit for transferring cargo in a cargo compartment of a small cargo vessel to a large bulk carrier or similar vessel, the unit comprising: an unloader adapted to traverse the cargo compartment to pick-up cargo in the cargo compartment and to raise the H:\mcamp\keep\speci\P51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 3 picked-up cargo to a height sufficient to enable it to be transferred into a hold of the large vessel.

Preferably the unloader is configured to be mounted on a cargo transshipping vessel having a floating hull on or in which is the cargo compartment.

Also according to the present invention there is provided a cargo transshipping vessel comprising: a floating hull having a cargo compartment within or on the hull; and a cargo transshipping unit for transferring cargo in the cargo compartment to a large bulk carrier or similar vessel, wherein the cargo transshipping unit comprises an unloader adapted to traverse the cargo compartment and to pick-up and raise the cargo to a height sufficient to enable it to be transferred into the hold of the large vessel.

Preferably the cargo transshipping unit further comprises a transfer means for transferring the picked-up and raised cargo from the unloader to the hold of the large vessel.

Preferably the unloader comprises a pick-up means and a transport means, wherein the pick-up means is arranged to pick-up cargo in the cargo compartment, and wherein the transport means is arranged to receive the cargo picked up by the pick-up means and to raise the height of the picked up cargo to the sufficient height.

Preferably the cargo transshipping vessel arranged to be towed or pushed by a tugboat. Alternatively the cargo transshipping vessel further comprises a propulsion means.

Preferably the cargo compartment is comprised of inclined side and end walls.

H:\mcamp\keep\speci\P1930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 4 Preferably the unloader further comprises a gantry arranged to travel on a guidance system along the length of the vessel. Preferably the guidance system is in the form of a pair of longitudinal rails mounted on each side of a deck of the hull or along the top of the cargo compartment side walls.

Preferably the pick-up means is in the form of an excavator mounted for pivotal and/or lateral movement on the gantry. A plurality of unloaders, each on a separate gantry may be provided, alternatively two or more excavators may be installed on a single gantry.

In one embodiment the cargo transshipping unit is arranged to transfer the picked up and raise cargo into a barge or a truck, or onto a jetty.

In one embodiment the unloader may be removed from the hull of the cargo transshipping vessel. This facilitates transfer of the unloader to the hull of another cargo transshipping vessel.

Furthermore according the present invention there is provided a cargo transshipping unit transfer station comprising: a guidance means on which an unloader of the cargo transshipping unit can travel; and a coupling means for coupling the transfer station guidance means to a similar guidance means of a cargo transshipping vessel on which the cargo transshipping unit is mounted, whereby in use the cargo transshipping unit may travel from one cargo transshipping vessel to the transfer station guidance means and then from the guidance means to another cargo transshipping vessel.

H:\mcamp\keep\speci\P51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 5 Preferably the guidance system of the cargo transshipping unit transfer station and the similar guidance means of the cargo transshipping vessel are rails. Preferably these rails are arranged to be directly connected end to end by a suitable link span so that the cargo transshipping unit may be moved between one cargo transshipping vessel and the other.

Alternatively the cargo transshipping unit transfer station is arranged to lift the cargo transshipping unit off its cargo transshipping vessel so that is may be lowered onto another cargo transshipping vessel.

In one embodiment the cargo transshipping unit transfer station is stationary. In another embodiment the cargo transshipping unit transfer station is adapted to be mounted on a floating base. In this embodiment the cargo transshipping unit transfer station may be mounted on a tugboat.

Also according to the present invention there is provided a cargo unloader for unloading cargo from a vessel, the unloader comprising: a pick up means adapted to be positioned over the cargo in the vessel and further adapted to transverse the cargo to pick up and raise the cargo; and a transfer means adapted to receive picked up cargo and transfer it off the vessel.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 6 DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention are described by way of non-limiting examples by reference to the following figures: Figure 1A is a side elevation of a preferred example of a cargo transshipping vessel according to the present invention with a cargo capacity of about 7500 tonnes of coal; Figure lB is a plan view of the cargo transshipping vessel of Figure 1A shown alongside a Panamax bulk carrier in the act of transferring coal to this vessel; Figure 1C is a cross sectional elevation of the vessel and bulk carrier of Figure IB; Figure 2A is a close up side elevation of the cargo transshipping vessel of Figure 1A showing a preferred form of a cargo transshipping unit in accordance with the present invention; Figure 2B is a close up plan view of the vessel and unit of Figure 1B; Figure 2C is a close up cross sectional elevation of the vessel and unit of Figure 2A; Figure 3A is a side elevation showing a first stage of transference of a cargo transshipping unit from one cargo transshipment vessel to another; Figure 3B is a side elevation showing a second stage of transference of the unit; H:\mcamp\keep\speci\PS1930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 7 Figure 3C is a plan view showing transference of the unit from one vessel to the other; Figure 4A is a side elevation of a floating cargo transshipping unit exchange station according to the present invention; and Figure 4B is a plan view of the exchange station of Figure 4A; Figure 4C is a cross sectional view of the exchange station of Figure 4A; Figure 4D is an end elevation view of the exchange station of Figure4A; Figure 5A is a side elevation view of a pusher tug of catamaran configuration linked to a cargo transshipping vessel of Figure 1A; Figure 5B is a cross sectional view of the section A-A of Figures 5A and Figure 5C is a plan view of the tug of Figure Figure 5D is a side elevation of the tug of Figure showing a cargo transshipping unit when this is moved from one cargo transshipping vessel to another; Figure 5E is a cross sectional view through the section B- B of the Figures 5D and 5F; and Figure 5F is a plan view of the tug and unit of Figure DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT

INVENTION

H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 8 An example of a cargo transshipping vessel according to the present invention is shown in Figures 1A to 2C.

The CTV comprises a rectangular pontoon hull 12 with "swim" ends 14 subdivided longitudinally and transversely into a series of watertight compartments 16, some or all of which may be equipped to receive water ballast. On a deck 18 of the hull 12 is a main cargo hopper preferably equipped with sloping side walls 22 and end walls 24 of a volume to hold the required tonnage of bulk cargo 32. Rail tracks 26 or another guidance device extend along the top of the side walls or alternatively along the deck at each side, for the full length of the hull.

The CTV has a transshipping system 28 for unloading cargo in the hopper 20 and loading it in a hold 34 of a Panamax vessel 30. The transshipping system 28 comprises an unloader 36 able to move along the length of the hull 12, above the cargo, that can reach down to pick up a portion of cargo 32 and unload it. The unloader 36 includes a gantry 38, pick up unit 40 and transport system 42. The gantry 38 is able to travel over the full length of the tracks 26, preferably by powered wheels 44, but it could for example be hauled by one or more winches at each end of the hull. The gantry 38 is of a height sufficient to span above the cargo 32 when the hopper 20 is fully loaded. In some embodiments two unloaders may be installed, with one gantry each, either linked together or able to be operated independently. This configuration, whilst more expensive, has two advantages over a single unit. Firstly the speed with which cargo can be transhipped is doubled and secondly in the event of one unloader becoming inoperable for any reason the other unloader is still able to transfer the cargo to the bulk carrier H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 9 The pick up unit 40 is located on the gantry 38. This pick up unit 40 comprises an arm 46 with a bucket 48 at the end for scooping up cargo 32, such as coal. The arm 46 is arranged to rotate about a fixed vertical axis and is articulated so that the bucket 48 can reach the entire cargo volume when its motion is combined with the longitudinal motion of the gantry 38. Preferably the pick up unit 40 is a standard excavator with its tracks removed, equipped with a standard bucket or alternative buckets appropriate to the range of material densities to be handled. The pick up unit 40 may however comprise any other system for digging bulk materials from the hopper such as a bucket chain, rotary bucket wheel or an elevator system. Additionally the pick up unit 40 may be fixed in one position on the gantry 38 or may be capable of movement on suitable wheels and/or tracks. In some applications two pick up units 40 may be mounted side-byside on the gantry 38.

The pick up unit 40 delivers the bulk cargo to a transfer hopper 50 and then by the transport system 42 comprised of one or more conveyor belts 52 transfer the cargo up to an appropriate height and position to transfer the material on to a transfer unit 54. In one embodiment the transfer unit 54 may take the form of a slewing and luffing boom conveyor 56. In Figures 1A and 2C the conveyor is shown stowed as 56'. Since the axis of rotation of the pick up unit 40 is always in the same position relative to the transfer hopper 50 the motion of the pick up unit 40 once it has filled its bucket 48 with cargo may readily be automated, to ensure that dumping the cargo into the transfer hopper 50 can be faster and consistently more accurate than is possible with manual control, thus speeding up the overall loading rate and minimising the likelihood of damage to the pick up unit 40 or to the transfer hopper H:\mcamp\keep\speci\51930 CARGO TRANSHIPHENT UNIT CAP.doc 28/01/04 10 If two gantries 38 and other units of the transshipping system 28 are linked together it will be apparent to a skilled worker that by a suitable arrangement of conveyors 52 both systems can serve a single transfer unit 54 which may be preferred in certain applications.

At the end of the transfer unit 54 provision may be made to suspend a "flinger" 58, a device which can be rotated and which throws the material being loaded horizontally to ensure that the vessel's hold is fully loaded. In appropriate circumstances the boom of the transfer unit 54 may be made telescopic to cater for vessels of different breadths. This boom is mounted at a height sufficient to clear the open hatch cover 60 of a large bulk carrier which is floating at its light ballast draft when the CTV alongside is fully loaded, after allowing an appropriate margin for relative movement between the two craft arising from waves and swells creating pitch, heave and roll motions.

To improve the efficiency of the transshipment operation as ship-loading proceeds, or when loading into vessels of relatively small size, the support column or other structure 62 carrying the transfer unit 54 may be made vertically telescopic or otherwise adjustable to vary the height of the horizontal pivot point 64 of the shiploading boom conveyor 56 to the minimum necessary to clear any obstructions on the vessel 30 being loaded, as its draft and that of the CTV changes during the transshipment process.

In Figures 3A to 3C, the transfer of a transshipping system 28 directly from one CTV 10 to another 10' is illustrated. In a typical application the first CTV would be empty, having completed unloading, and the second CTV 10' would be full or in the process of being loaded.

H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 11 The first CTV 10 is depicted lower in the water due to some of the compartment 16 bearing ballast water. The first CTV 10 is equipped with a section of rails 70 at the bow 72, able to move vertically, together with a "mating system" 74 above deck level to ensure that when the two craft come together one behind the other the rails are in alignment.

The rails 70 on each side at the bow 72 of the first CTV are linked together to form a short elevator 76 able to be moved vertically by hydraulic rams 78 or other devices.

The second CTV 10' "mates" with the stern 80 of the first and locks itself into position with the locking pins 82.

The rams 78 are operated to bring the elevator 76 into alignment with the fixed rails 26' at the stern of the second CTV 10'. Then the complete transshipping system 28 is propelled or hauled across on to the second CTV l0' and moved to a transit location where it is secured in position. As soon as this movement is completed the locking pins 82 are withdrawn and the first CTV 10' is free to move away.

In a situation where there is a regular traffic up and down a river or other waterway it may be preferable to station a separate transshipping system exchange unit at a suitable location. Such as for example where the bulk material to be loaded into a vessel at an anchorage has to be taken from a loading point a considerable distance up a river or other waterway, several cargo transshipment vessels may be required to achieve an acceptably short loading time for the large vessel and it may not be practicable for a single cargo transshipment vessel to be replenished by barges as described above. In such a situation the transshipment system exchange unit may be sited in calm water as close as possible to the anchorage. This may well reduce the total number of H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 12 removable unloaders needed to two although four or more cargo transshipment vessels, without transshipment systems 28, may be required.

In another application a bridge-or similar obstruction across the waterway may prevent the passage of cargo transhipment vessel due to the height of the unloader.

This problem can be circumvented if an unloader exchange unit is located downstream of the obstruction.

Figures 4A to 4D show one variant of such a transshipment system exchange unit 90 in the shape of a floating catamaran, but for example a piled structure set in the bed of a waterway would serve as an alternative. The unit 90 comprises two catamaran hulls 92 supporting a bridge 94. The unit 90 may be moored to a jetty or held in position by spuds 96 as shown.

The CTV 10 carrying a transshipping system 28, probably, but not necessarily, empty having transferred its cargo into a seagoing vessel 30, enters the exchange unit 90 and is positioned so that the gantry 38 may be lifted slightly by the bridge 94 to clear the rails 26 on the CTV 10. The transshipping system 28 is temporarily suspended from the bridge 94. At an appropriate time a second CTV 10' is positioned within the exchange unit 90 and the suspended transshipping system 28 is lowered into position on the rails 26' of this CTV 10', which may then proceed to go alongside a vessel 30 at an anchorage and begin to transfer cargo.

In a preferred application, instead of actually hoisting the gantry 38 from the bridge 94, water ballast tanks 98 above water level at each side of the exchange unit 90 are emptied once the gantry 38 is linked to the bridge 94, which causes the entire unit to lift clear of the CTV taking with it the transshipment system 28. These tanks H:\mcamp\keep\speci\P51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 13 98 may be refilled at any time in readiness to lower the system 28 on to the second CTV 10' which will normally be loaded and at a deeper draft than the first CTV An alternative to a fixed or floating exchange unit 90 is shown in Figures 5A to 5F. In this embodiment the motive power for movement of one or more of the CTVs is provided by one or more pusher tug boats 100 of catamaran or other multi-hull configuration. When a tug 100 is positioned at the stern 80 of a loaded CTV 10 it is partially supported by double sided ramps 102 and secured in position by locking devices 104 at each side of the CTV 10. Thus there is no relative movement between the two craft.

The tug 100 is equipped with rails 106 at each side in alignment with the rail tracks 26 on the CTV 10 when the two craft are located as above. The transshipping system 28 which is in position on the rails 106 of the tug 100 may now be moved into place on the CTV 100 in readiness to start the transfer of cargo 32 into a vessel 30 at anchor.

On completion of the transfer of cargo the gantry 38 is propelled or otherwise moved back on to the rails 106 on the tug 100 and secured there (shown as 28' in broken lines).

The movements of the tug 100 on and off each CTV 10 are facilitated by the fact that the tug 100 would normally leave an empty CTV 10, aided by gravity down the ramps 102 when the locking devices 104 are released. Conversely, when the tug 100 is being positioned on a second CTV this latter vessel would normally be partially or fully loaded enabling the tug 100 to float into position over the ramps 102 and to engage the locking devices 104 without difficulty. The admission of water ballast into tanks 110 on the tug, by opening flooding valves 30, will ensure that the tug 100 is held securely, partially supported by the ramps 102 on this second CTV 10'. When H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 14 the transfer of cargo 32 from this CTV 10' into a bulk carrier 30 is nearing completion the water ballast in tanks 110 may be drained out by re-opening the valves 108 which at this stage are above water level.

At this point release of the locking devices 104 will allow the tug 100 and transshipping system 26 to slide down the ramps 102 until it is fully waterborne. The tug 100 may then propel itself to the stern 80 of another CTV 10" and the process described above may be repeated Alternatively the tug 100 complete with transshipment system 26 may travel to a suitable location ashore where the gantry 38 may be moved along rails 106 to a workshop for repairs, major maintenance or relocation elsewhere.

The CTV 10 is towed or pushed by a tug 100 between an onshore loading point and a vessel 30 at anchor, or it may be self-propelled. Once in position alongside the vessel 30 receiving the cargo 32 it uses the transshipment system 26 to empty its cargo compartment 20 into the large vessel and then returns to the loading point for additional cargo 32 or remains alongside the receiving vessel 30 and has its cargo compartment 20 replenished with bulk material by barges and continues the transshipment process.

A particularly advantageous feature of the vessel of the invention is that the unloader is mounted above the cargo to be transferred into a ship whereas in many other unloading systems the cargo is initially allowed to fall on to a conveyor positioned at a very low level within the vessel. Thereby this cargo must be raised much further to reach the hatches of the ship into which it is to be loaded.

H:\mcamp\keep\speci\PS1930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 15 Modifications and variations may be made to the present invention without departing from the basic inventive concept.

Although the cargo transshipment vessel is intended primarily to transship cargo from a shore loading point into a sea-going vessel at an anchorage, it will be apparent to the skilled worker that it may also be used to transfer bulk materials into other barges or on to a jetty, using its unloader. The outreach of the conveyor is sufficient to allow a stockpile to be built up on a jetty equivalent to the full cargo capacity of the cargo transshipment vessel, or alternatively to load into trucks via a feeder hopper.

Such modifications and variations as would be obvious to the skilled addressee are intended to fall within the inventive concept described herein.

H:\mcamp\keep\speci\PS1930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04

Claims (38)

1. A cargo transshipping unit for transferring cargo in a cargo compartment of a small cargo vessel to a large bulk carrier or similar vessel, the unit comprising: an unloader adapted to traverse the cargo compartment to pick-up cargo in the cargo compartment and to raise the picked-up cargo to a height sufficient to enable it to be transferred into a hold of the large vessel.

2. A unit according to claim 1, wherein the unloader is configured to be mounted on a cargo transshipping vessel having a floating hull on or in which is the cargo compartment.

3. A unit according to either claim 1 or 2, wherein the cargo transshipping unit further comprises a transfer means for transferring the picked-up and raised cargo from the unloader to the hold of the large vessel.

4. A unit according to any one of claims 1 to 3, wherein the unloader comprises a pick-up means and a transport means, wherein the pick-up means is arranged to pick-up cargo in the cargo compartment, and wherein the transport means is arranged to receive the cargo picked up by the pick-up means and to raise the height of the picked up cargo to the sufficient height.

A unit according to any one of claims 1 to 4, wherein the cargo compartment is comprised of inclined side and end walls.

6. A unit according to any one of claims 1 to 5, wherein the unloader further comprises a gantry arranged to travel on a guidance system along the length of the vessel. H:\mcamp\keep\speci\P1930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 17

7. A unit according to any one of claims 1 to 7, wherein the guidance system is in the form of a pair of longitudinal rails mounted on each side of a deck of the hull or along the top of the cargo compartment side walls.

8. A unit according to claim 6, wherein the pick-up means is in the form of an excavator mounted for pivotal and/or lateral movement on the gantry.

9. A unit according to claim 6, wherein the cargo transshipping unit comprises a plurality of unloaders, each on a separate gantry.

A unit according to claim 6, wherein the cargo transshipping unit comprises two or more pick up units on a single gantry.

11. A unit according to any one of claims 1 to wherein the cargo transshipping unit is arranged to transfer the picked up and raise cargo into a barge or a truck, or onto a jetty.

12. A cargo transshipping vessel comprising: a floating hull having a cargo compartment within or on the hull; and a cargo transshipping unit for transferring cargo in the cargo compartment to a large bulk carrier or similar vessel, wherein the cargo transshipping unit comprises an unloader adapted to traverse the cargo compartment and to pick-up and raise the cargo to a height sufficient to enable it to be transferred into the hold of the large vessel.

13. A vessel according to claim 12, wherein the cargo transshipping unit further comprises a transfer means for transferring the picked-up and raised cargo from the unloader to the hold of the large vessel. H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 18

14. A vessel according to claim 12 or 13, wherein the unloader comprises a pick-up means and a transport means, wherein the pick-up means is arranged to pick-up cargo in the cargo compartment, and wherein the transport means is arranged to receive the cargo picked up by the pick-up means and to raise the height of the picked up cargo to the sufficient height.

15. A vessel according to claims 12 to 14, wherein the cargo transshipping vessel arranged to be towed or pushed by a tugboat.

16. A vessel according to any one of claims 12 to 14 wherein, the cargo transshipping vessel further comprises a propulsion means.

17. A vessel according to any one of claims 12 to 16, wherein the cargo compartment is comprised of inclined side and end walls.

18. A vessel according to any one of claims 12 to 17, wherein the unloader further comprises a gantry arranged to travel on a guidance system along the length of the vessel.

19. A vessel according to any one of claims 12 to 18, wherein the guidance system is in the form of a pair of longitudinal rails mounted on each side of a deck of the hull or along the top of the cargo compartment side walls. A vessel according to claim 18, wherein the pick-up means is in the form of an excavator mounted for pivotal and/or lateral movement on the gantry.

H:\mcamp\keep\speci\51930 CARGO TRANSHIPNENT UNIT CAP.doc 28/01/04 19

21. A vessel according to claim 18, wherein the cargo transshipping unit comprises a plurality of unloaders, each on a separate gantry.

22. A vessel according to claim 18, wherein the cargo transshipping unit comprises two or more pick up units on a single gantry.

23. A vessel according to claim 18, wherein the cargo transshipping unit is arranged to transfer the picked up and raise cargo into a barge or a truck, or onto a jetty.

24. A vessel according to claim 18, wherein the unloader may be removed from the hull of the cargo transshipping vessel.

A unit according to any one of claims 1 to 11, wherein the unloader comprises a control means to transfer the load from the unloader and to raise it to be discharged into the larger vessel automatically.

26. A vessel according to any one of claims 12 to 24, wherein the unloader comprises a control means to transfer the load from the unloader and to raise it to be discharged into the larger vessel automatically.

27. A cargo transshipping unit transfer station comprising: a guidance means on which an unloader of the cargo transshipping unit can travel; and a coupling means for coupling the transfer station guidance means to a similar guidance means of a cargo transshipping vessel on which the cargo transshipping unit is mounted, whereby in use the cargo transshipping unit may travel from one cargo transshipping vessel to the transfer H:\mcamp\keep\speci\P51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 20 station guidance means and then from the guidance means to another cargo transshipping vessel.

28. A transfer station according to claim 27, wherein the guidance system of the cargo transshipping unit transfer station and the similar guidance means of the cargo transshipping vessel are rails.

29. A transfer station according to either claim 27 or 28, wherein these rails are arranged to be directly connected end to end by a suitable link span so that the cargo transshipping unit may be moved between one cargo transshipping vessel and the other.

30. A transfer station according to either claim 27 or 28, wherein the cargo transshipping unit transfer station is arranged to lift the cargo transshipping unit off its cargo transshipping vessel so that is may be lowered onto another cargo transshipping vessel.

31. A transfer station according to any one of claims 27 to 30, wherein In one embodiment the cargo transshipping unit transfer station is stationary.

32. A transfer station according to any one of claims 27 to 30, wherein the cargo transshipping unit transfer station is adapted to be mounted on a floating base.

33. A transfer station according to any one of claims 27 to 30, wherein the cargo transshipping unit transfer station may be mounted on a tugboat.

34. An a cargo unloader for unloading cargo from a vessel, the unloader comprising: a pick up means adapted to be positioned over the cargo in the vessel and further adapted to transverse the cargo to pick up and raise the cargo; and H:\mcamp\keep\speci\51930 CARGO TRANSHIPMENT UNIT CAP.doc 28/01/04 21 a transfer means adapted to receive picked up cargo and transfer it off the vessel.

A cargo transhipping vessel substantially as herein before described with reference to the accompanying drawings.

36. A cargo transhipping unit substantially as herein before described with reference to the accompanying drawings.

37. A cargo transhipping unit exchange station substantially as herein before described with reference to the accompanying drawings.

38. An unloader substantially as herein before described with reference to the accompanying drawings. Dated this 30 th day of January 2004 ALVIN DAVID TOMS RALPH DOWNHAM By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia H:\mcamp\keep\speci\P51930 CARGO TRANSHIPMENT UNIT CAP.doc 30/01/04