WO1993004914A1

WO1993004914A1 - Jumbo barge carrier fast sealift and port system

Info

Publication number: WO1993004914A1
Application number: PCT/US1992/007411
Authority: WO
Inventors: Stephen J. Smith; Axel Wallenberg
Original assignee: Strategic Maritime Corporation
Priority date: 1991-09-06
Filing date: 1992-09-02
Publication date: 1993-03-18
Also published as: AU2579092A

Abstract

A jumbo barge carrier fast sealift and port system enables the rapid transport and deployment of massive amounts of cargo. The system includes: a barge-carrying vessel (10) capable of transoceanic navigation carrying a plurality of indepently-floatable barges and further capable of loading and unloading the barges by floatation; at least one cargo carrying barge (110, 120, 130, 140, 150); a transportable port system comprising at least one platform (200, 210) capable of being secured in water of sufficient depth to enable floatation and mooring of the cargo-carrying barge for loading and unloading; and a causeway (400) extending from the platform to land. The system has particular applicability to military and relief operations which require rapid, massive, and survivable loading, transport and mobilization of men, material, and supplies to any designated destination regardless of the existence or capabilities of port facilities.

Description

JUMBO BARGE CARRIER FAST SEALIFT AND PORT SYSTEM

DESCRIPTION

Technical Field

The present invention is directed to a system which enables the rapid transport and deployment of extremely large amounts of cargo as is needed to meet economic, humanitarian, and military contingencies.

In one of its more particular aspects, the invention meets a great humanitarian need by enabling immediate, effective delivery of relief to populations threatened by natural disaster with massive mobilization, transport, and implementation of evacuation, medical, shelter, and feeding operations as required. The invention, in another of its aspects, has particular applicability to military operations which require rapid, massive, and survivable loading, transport and mobilization of men, material and supplies to any designated destination regardless of the existence or capabilities of port facilities. Versatility on a massive scale is often necessary to take advantage of strategic, operational, tactical or economic opportunities as well as to meet humanitarian needs in times of natural disaster. Unfortunately, opportunities can be lost if shipping and port facilities of sufficient capacity are not readily available to move personnel and material in amounts effective to capitalize on them.

Given an unlimited amount of time, logistics can be planned to meet most requirements. However, in the world of commerce and when faced with crisis, time is usually very limited. If shipping capacity or port facilities are insufficient, business, human or military losses can be suffered.

Background Art

Until the present time there has never been a sea-based transportation system which could both move large quantities of cargo and operate independently of existing port facilities.

Several prior workers have identified shipping systems which either have portable causeways for driving vehicles from ships directly onto land or to float off individual barges for unloading in the conventional manner. Representative of the first of these are U.S. Patent No. 2,694,996 to Poche and U.S. Patent No. 4,043,288 to Volovic. In U.S. Patent No. 4,697,533, Bordreuil et al provide a ramp for hoisting a boat aboard a ship. In U.S. Patent No. 4,075,860, Hansen describes a mobile ship loading and unloading facility which includes portable roadways and platforms which can be carried by a displacement vessel and operated with it to moor cargo ships and load and unload them. The platforms and the vessel are elevated on legs to a position where they are unaffected by wave action.

Representative of the teachings regarding float-on, float-off cargo-carrying barges are the disclosures of U.S. Patent No. 3,318,276 to Nemec, U.S. Patent No. 3,417,721 to Vienna, U.S. Patent No. 3,556,036 to Wells, U.S. Patent No. 3,786,772 to Broes, U.S. Patent No. 3,841,254 to Dragonas et al , U.S. Patent No. 4,077,350 to Nishino et al , U.S. Patent No. 4,319,540 to Koskivirta, U.S. Patent No. 4,898,112 to McGlew et al, and British Patent Speci- fication No. 2 075 432, to B.W. Tornqvist.

In each on this latter list, the vessels are designed to enable loading and unloading cargo-carrying barges from a ship by floatation. A variety of means are described for enabling or assisting the loading and unloading operations. Most ballast at least a portion of the ship to lower a cargo deck below the water line. For example, in U.S. Patent No. 3,318,276, Nemec, after discussing the art prior to his, describes a barge-carrying vessel with several decks accessed by an elevator to reduce the need for drastically ballasting to lower the vessel as would be necessary to permit floatation of barges from the upper cargo deck. Also in this regard, in U.S. Patent No. 4,075,860, Hansen discloses that the stern alone can be lowered to permit buoyant platforms to be winched. In other disclosures, the necessary draft can prohibit entry into many ports. For example, in British Patent Speci¬ fication No. 2 075 432, Tornqvist describes a vessel the size of a super tanker which ballasts down sufficiently to load and unload a number of very large barges. Tugs are necessary to move incoming barges from the vessel to a port and to move outgoing barges to the vessel. While offering great promise in terms of load carrying capability and certain economies due to this size, the large vessels, as proposed by Tornqvist, are not capable as presently constituted to operate at other than the world's most sophisticated ports.

There is a present need for a sea-based transportation system which can be relied upon to take advantage of opportunities for effecting relief, economic gain, and military advantage as they arise — and to be able to achieve one or more of these objectives wholly - independent of the size or the tonnage of the cargo or the existence or condition of port facilities.

Disclosure of Invention

It is an object of the invention to enable the rapid transport and deployment of massive amounts of cargo.

It is another object of the invention to provide versatility on a massive scale as is often necessary to take advantage of humanitarian, strategic, operational, tactical or economic opportunities.

It is yet another object of the invention to provide a sea-based transportation system which can both move large quantities of cargo and operate independently of existing port facilities.

It is an object of the invention, in one of its more particular aspects, to enable delivery of immediate, effective relief to populations threatened by natural disaster with massive mobilization, transport, and implementation of evacuation, medical, shelter, and feeding operations as required.

It is an object of the invention, in another of its more particular aspects, to support or enable military operations which require rapid, massive, and survivable loading, transport and mobilization of men, material and supplies to any designated destination regardless of the existence or capabilities of port facilities.

It is another and related object of the invention to minimize lost opportunities because shipping and port facilities of sufficient capacity are not readily available to move personnel and material in amounts effective to capitalize on the opportunities.

It is yet another and related object of the invention to provide a sea-based transportation system which can be relied upon to take advantage of opportunities as they arise, fully independent of the size or the tonnage of the cargo or the existence or condition of port facilities.

These and other objects are achieved by the present invention which provides a transportation system and a method of transoceanic transport of cargo between two shores, at least one of which lacks port facilities sufficient in size, water depth, or equipment or transportation sophistication to handle a large or super-large barge-carrying vessel.

The transportation system according to the invention comprises: a barge-carrying vessel capable of transoceanic navigation carrying a plurality of independently-floatable barges and further capable of loading and unloading the barges by floatation; at least one cargo-carrying barge; and at least one transportable port system comprising a platform capable of being secured in water of sufficient depth to enable floatation and mooring of a cargo-carrying barge for loading and unloading and a causeway capable of being supported between the platform and a landing area.

The vessel is configured to comprise means for flooding a cargo deck supporting the barges, and preferably further comprises means to take on water ballast sufficient to lower the cargo deck below the water line, to enable floatation of at least one cargo-carrying barge. According to its preferred aspects, the vessel further includes means for transporting at least one t gboat, and the transpor- table port further comprises a plurality of support columns adapted for vertical adjustment to support the platform in a substantially horizontal position. Desirably, the platform is comprised in a shallow-draft barge adapted to be carried by the vessel. In one embodiment, at least one tugboat is carried on the mother ship or in a float-on, float-off barge adapted to permit the tugboat to float-on and float-off of the ship or barge. In other preferred aspects, the causeway is supported by at least one floata¬ tion escalation or suspension device.

To achieve optimal stability and performance, the vessel will preferably have a trapezoidal hull cross section and will comprise an inner hull, the upper surface of which defines a cargo deck capable of supporting a plurality of independently-floatable, cargo-carrying barges, and an outer hull. The inner hull is preferably separated from the outer hull by a plurality of sealable chambers, and the cargo deck is positioned above the vessel water line during ocean transport. At least some of the sealable chambers can be capable of maintaining buoyancy of the vessel in the event of injury to the outer hull. These chambers can be employed if desired, alone or in possible addition to others, to load and unload ballast to raise and lower the cargo deck in relation to the water line.

The method involves operations for both loading and unloading at individual ports or landing areas, as well as an integrated method of transoceanic transport of cargo between two shores.

According to one aspect, the invention provides a method of loading a vessel for transoceanic transport of cargo between two shores, comprising: moving at least one floatable cargo-carrying barge to a barge-carrying vessel capable of transoceanic navigation with a plurality of barges supported on a cargo deck; flooding the cargo deck to permit at least one barge to be guided over the cargo deck; guiding at least one barge over the cargo deck; also loading onto the vessel at least one portable port system comprising a platform capable of being secured for loading or unloading a barge or other vessel; discharging the water which flooded the cargo deck; and navigating the vessel from the vicinity of one shore.

In another aspect, the invention provides a method of unloading a vessel which comprises: flooding the cargo deck to buoy at least one barge sufficiently to permit it to be guided free of the vessel and independently floated; guiding at least one barge free of the cargo deck; moving a portable port system, comprising at least one platform, from the vessel; assembling and securing the platform in water of sufficient depth to enable floatation and mooring of a cargo-carrying barge for unloading; extending a causeway between the platform and a landing area; unloading at least a portion of the cargo from the barge and onto the platform; and moving unloaded cargo across the causeway from the platform to the landing area.

According to another aspect, the invention provides a method of transoceanic transport of cargo between two shores, comprising: moving at least one floatable cargo- carrying barge to a barge-carrying vessel capable of transoceanic navigation with a plurality of barges supported on a cargo deck; taking onto the vessel sufficient ballast to lower the cargo deck below the waterline to permit at least one barge to be guided over the cargo deck; guiding at least one barge over the cargo deck; also loading onto the vessel at least one transpor¬ table port system comprising a platform capable of being secured in water of sufficient depth for floatation and mooring of a barge for loading or unloading; discharging su ficient ballast to raise the cargo deck above the water line; navigating the vessel from the vicinity of one shore to the vicinity of another; taking sufficient ballast onto the vessel to submerge at least a portion of the cargo deck to buoy at least one barge sufficiently to permit it to be guided free of the vessel and independently floated; securing at least one platform in water of sufficient depth to enable floatation and mooring of a barge to enable loading and unloading; extending a causeway between the platform and a landing area; unloading at least a portion of the cargo from the barge and onto the platform; and moving unloaded cargo across the causeway from the platform to the landing area.

Brief Description of the Drawings

The invention will be better understood and its advantages will be better appreciated from the following detailed description, especially when read in light of the accompanying drawings wherein:

Figure 1 is a perspective view showing a preferred embodiment of the jumbo barge carrier fast sealift and port system of the invention in one fully-deployed configuration;

Figure 2 is a perspective view of a fully-deployed transportable port system comprising a jackable platform in operation with two causeways supported between the platform and a landing area, with a portion of the surrounding water being cut away to illustrate one manner of supporting it on the ocean floor;

Figure 3 is a perspective view of a jumbo barge carrier arriving into a staging area, near a port;

Figure 4 is a perspective view of the carrier of

Figure 3, now in ballasted, partially-submerged condition with the cargo deck below the water line to permit cargo-carrying barges to be floated off for delivery to port by means of tugboats;

Figure 5 is a perspective view similar to Figure 4 but showing outbound barges being loaded onto the mother vessel with tug assistance;

Figure 6 is a perspective view showing the completion of an entire barge exchange operation, with ballast dis- charged and the mother vessel underway;

Figure 7 is a perspective view of a fully-loaded, super-large mother vessel shown carrying six jumbo barges, partially in section; Figure 7A is a cross-sectional view taken along line a-a in Figure 7;

Figure 8 is a side elevation view of a large, as contrasted to a super-large, mother vessel capable of holding two jumbo barges;

Figure 9 is a top plan view of the vessel shown in Figure 8, which shows one of the barges carrying six tugboats in float-on, float-off configuration;

Figure 9A is a side elevation view of the tug boat carrying barge shown in Figure 9;

Figure 9B is a cross-sectional view taken along line b-b in Figure 9A;

Figure 10 is a side elevation of one form of float-on, float-off cargo-carrying barge which can be employed in the system of the invention; and

Figures 10A through 10E are cross-sectional views taken amidships of various barges configured for different missions.

Description of the Preferred Embodiment

The invention will be described below with reference to several representative embodiments with particular emphasis placed on potential military applications. It will be understood, however, that humanitarian and purely commercial uses are contemplated. It is in fact an advantage of the invention that several fleets of jumbo barge carriers can be deployed with a portion dedicated to military, a portion to commercial, and a portion for joint commercial and military or humanitarian purposes, and that they can all be united in an integrated operation to meet civilian and military surge requirements. It is of great advantage that this can be accomplished on a truly massive and immediate basis without regard to existing port facilities. It is another advantage that the costs for all of these uses can be shared due to the unprecedented capabilities and flexibility of the system.

A jumbo barge carrier fast sealift and port system which enables the rapid transport and deployment of massive amounts of cargo is illustrated in Figure 1. This Figure shows a perspective of a preferred embodiment of the system in fully-deployed configuration. The system includes: a barge-carrying vessel, shown here on the horizon as mother vessel 10; cargo-carrying barges, shown here in various configurations as 110, 120, 130, 140, and 150; and portable port facilities including at least one platform (two are shown here, namely 200 and 210) and a causeway 400 extending from the platform to a landing area, shown here as a beach.

Figure 1 highlights the capabilities of the system for military operations which require rapid, massive, and survivable loading, transport and mobilization of men, material and supplies to any designated destination — regardless of the existence or capabilities of port facilities. This same configuration would also serve great humanitarian purposes in enabling immediate, effective relief to populations threatened by natural disaster. In the illustrated configuration, barges 110 and 120 are designed to hold a large number of vehicles for roll-on and roll-off operation. In addition to wheeled vehicles, armament, aircraft, amphibious vehicles, large naval vessels, construction equipment, desalination facilities, electrical power generating equipment, manufacturing facilities, raw materials, semi-finished goods and materials, airfield construction and operational equipment, railroad construction and operational equipment, personnel, and supplies including water, petroleum, and packaged goods including food, clothing, medical supplies, ammunition and shelter, can be carried. The barges can be configured to include quarters for essential operations and support personnel alone or to include quarters for numbers on a larger scale. A third barge 130 is shown as a fully- supplied hospital, complete with access by helicopter and wheeled vehicles. Yet two other barges are shown floating in the water. One, 140, is shown as a fully-equipped heliport which includes hangar and repair areas, crew quarters and fuel storage. The other, 150, can be a tanker holding a variety of petroleum products to support the various needs of the vehicles, vessels, aircraft and other power needs of the operation.

one of the principal advantages of the invention derives from its capability to transport assembleable port facilities as well as cargo with it. In its preferred form, a platform 200 suitable for mooring cargo-carrying barges or cargo ships is comprised in a shallow-draft barge adapted to be carried by the barge-carrying vessel. The two platforms 200 and 210 shown in Figure 1, are in fact shallow draft barges which have been moved from the mother vessel 10 by tugboat and secured in place, in this case supported on the ocean floor by means of columns 220. A plurality of support columns 220 are provided and are adapted to be vertically adjusted to support each platform in a substantially horizontal position. Desirably, these platforms include ballast tanks and pumps to permit them to take on ballast, increasing their mass, to provide better stability during docking operations. They can also be raised above the water line, when desired, to minimize the effect of wave action.

In a preferred form of the invention, these columns can be raised and lowered by means of jacks of conventional construction, e. g. , hydraulic means 221 shown in dotted lines. The columns can be of many designs including telescoping sections, assembleable sections, folding sections, rachet-locking fittings cooperative with fittings on the platform, boltable fittings, terrain-adjusting bottom supports, tractor bottom supports, and like and alternative means. The platforms can be jackable platforms, preferably capable of being secured to the ocean floor in water of sufficient depth to enable floatation and mooring of the barges for loading and unloading. They can be, for example, of a construction as shown in U.S. Patent No. 4,075,860 to Hansen, one of the references cited herein, or they can be stabilized by various means known for stabilizing oil drilling platforms.

Figure 2 is a perspective view of a jackable platform in operation with two causeways 400 and 410 supported between the platform and a landing area, with a portion of the surrounding water being cut away to illustrate one manner of supporting it on the ocean floor 300. Each causeway is shown to be supported by at least one floatation device 401. They can also be supported by other suitable means including escalation or suspension means. By causeway is meant, any structure which provides a surface which can support a vehicle. Causeways of the military type, both powered and unpowered, can be used with great facility. In one exemplary situation, a military causeway having an overall dimension of 92 feet in length, 22 feet in width, and 5 feet in height, and assembled from 45 individual floatable elements, can be used effectively. It is an advantage of this invention that causeways of this size and larger can be stacked and transported fully assembled for rapid deployment.

Figure 3 is a perspective view of a jumbo barge carrier 10 arriving into a staging area, near a port. The vessel, alternatively referred to as the mother vessel, is shown here loaded with six jumbo barges 111, 112, 113, 114, 115 and 116. The series of Figures 3 through 6 shows the general sequence of operations performed at the mother vessel, independent of the nature of the port facilities. It is an advantage of the invention that transportable port facilities can be unloaded from the mother vessel and assembled to establish or improve port facilities, making them suitable for conducting the operations.

The carrier or vessel can be of any construction capable of carrying the loads with adequate speed and stability. The vessel is of the displacement type, having a dead weight from 50,000 to 250,000 metric tons (MT) typical of a large or super-large vessel. For a large vessel, the dead weight will be from 50,000 to 100,000 MT, and for a super-large vessel, from 100,000 to 250,000 MT, in preferred forms.

in its preferred form, the vessel has a trapezoidal hull cross section. This shape can be seen by viewing the stern of the vessel in Figure 7 as well as the cross section shown in Figure 7A. The vessel preferably com¬ prises an inner hull 11 and an outer hull 12. The upper surface of the inner hull defines a cargo deck 13 capable of supporting a plurality of independently floatable, cargo-carrying barges. The cargo deck should be con¬ structed as necessary to permit it to be flooded for loading and unloading the barges. The cargo deck is shown here in the preferred configuration, positioned above the vessel water line during ocean transport.

The vessel shown causes the cargo deck to be flooded by taking on ballast to lower it with respect to the water line. To accomplish this in the preferred embodiment, the vessel further comprises means to take on water ballast sufficient to lower said cargo deck below the water line to enable floatation of at least one cargo-carrying barge. Sealable chambers 14 can be seen broken away in Figure 7 and in the cross section shown in Figure 7A.

Figure 4 is a perspective view of the vessel, now in ballasted, partially-submerged condition with the cargo deck below the water line to permit cargo-carrying barges 113, 114, 115, and 116 to be floated off for delivery to port by means of tugboats 500 and 510. Figure 5 shows outbound barges 121, 122, 123, 124, 125, and 126 being loaded onto the mother vessel with tug assistance. One or more of these barges can comprise the transportable port exchange system. Figure 6 shows the completion of the entire barge exchange operation with ballast discharged and the mother vessel 10 underway.

The transportation system in its preferred form will further include means for transporting at least one tug- boat. Figure 7 is a perspective view of a fully-loaded mother vessel, partially in section, showing loaded barges carrying cargo and tugboats. The tugboats can be off¬ loaded by several means. The tugs are shown here supported in a barge, capable of being floated .on and off of the mother ship and, once in the water, capable of being ballasted in the same manner as the mother ship to permit the tugs to float off into the water. The barge can be employed as a floating dry dock for the barges. This will be described in greater detail in connection with Figures 9 and 9A. In another arrangement, barges can be¹ sized to leave space at the end of the cargo deck for holding several tugs, one or more barges can be omitted to leave room for a larger number of tugs, or a special port barge could be employed with docking wells. Military barges could be employed to cradle a barge for lifting into the water. Once in the water, the tugs can assist in the movement of the barges during loading and unloading operations.

The super-large mother vessel shown in Figure 7 is roughly the size of a super tanker in its preferred form. The size enables heavy lift capability, enabling the vessel to function as a high-powered floating dry dock, capable of lifting all but the largest ships in the world. It can, for example, be employed to retrieve an aircraft carrier from the water and hold or transport it for repair. It can also hold and transport four destroyers of the Arleigh Burke class, or ten mine sweepers of the Avenger class along with ten LCU's of the #1466 class and twenty-eight LCM's of the #8 class.

The strategic and economic advantages of the transportation system are enhanced by its high surviv- ability in its preferred form. In addition to the double hull design, the vessel is provided with a number of features effective in this regard. The inner hull is separated from the outer hull by a plurality of sealable chambers 14. This can be seen in cut away with reference to Figure 7 and the cross section of Figure 7A. A sufficient number of these sealable chambers are strategically placed to enable the vessel to maintain buoyancy in the event of injury to the outer hull. These and/or other chambers can be employed to take on and discharge ballast as necessary to raise and lower the vessel, and thereby the cargo deck, in the water. It is further advantageous that virtually all of the cargo is contained in or loaded on barges which can float free of the mother vessel in the event of catastrophic damage to the mother vessel itself.

Chamber 14 is filled with ballast as necessary, preferably according to control signals generated by a computer-based control system, having means responsive to the ocean floor and the water-line to determine the proper amount and location of ballast for each operation. The actual construction of vessels of this type is well known, shown for example in the British patent to Tornqvist identified above.

Figure 8 is a top plan view of another embodiment of mother vessel. Figure 9 is a side elevation of this same vessel. This vessel is designated large, and is shown carrying two barges 170 and 180 (as opposed to six of the same size by the super-large vessel of Figure 7) , one of which (170) carries six tugboats 501 in float-on, float-off configuration.

Figure 9A is a side elevation view of a tug-carrying barge as shown in Figure 9. It is shown here without the tugs, but illustrates in dotted lines docking bays 171 and 172 at opposite ends of the barge and a central service section which will be fitted with rooms for storage, work, communications, quarters, eating and the like. The barge thus becomes a floating dry dock and base for tug opera- tions. To facilitate operations, including movement on and off the mother vessel without tug assistance, it can be powered. Figure 9B is a cross-sectional view taken along line b-b in Figure 9A. This view shows ballast tanks 175 and a petroleum storage tank 176 as well as three decks 177 which can be loaded with supplies or used as described above. The main cargo deck for supporting the tugs can be specially configured to mate with the tug hulls or special cradles can be provided.

Figure 10 is a side elevation of one form of float-on, float-off cargo-carrying barge which can be employed in the system of the invention, and Figures 10A through 10E are cross sectional views taken amidships of various barges configured for different missions.

The barge shown in Figure 10 is a basic type and is shown loaded on top with six lengths of cargo containers of standard size. The storage under the deck can be arranged to accommodate any one of a number of different cargos, as for example are shown in the subsequent Figures. It can be powered if desired and can have ballast tanks as necessary to stabilize the load in the water and to assist in loading and unloading operations.

Figure 10A shows a barge configured to hold con¬ tainers 181 and bulk solid materials 182 like coal or grain. Figure 10B in addition to these types of cargo includes roll-on, roll-off (RO-RO) decks 183 for trucks and smaller wheeled vehicles. Figure 10C shows RO-RO decks 183 and liquid (e.g., petroleum) tanks 184. Figure 10D shows all containers 183, and Figure 10E shows all liquid storage 184. The possible cargo combinations are virtually unlimited given a number of barge designs, and even with only one design, great flexibility in cargo can be achieved. The following example is presented to further illustrate and explain the invention and is not to be taken as limiting in any regard.

EXAMPLE

This example illustrates with reference to actual quantities and dimensions of several components of the jumbo barge carrier fast sealift and port system of a preferred form of the invention in the context of a scenario for transoceanic transport of cargo between two shores.

A jumbo barge carrying vessel is employed having a trapezoidal double-hull design. It has the capability of taking on ballast to lower the cargo deck from about 15 feet above the water line to about 40 feet below. The vessel is about 1400 feet from stem to stern with an average breadth of about 246 feet. Fully loaded and underway at service speed of 24 knots, the vessel will draw about 37 feet of water. Its total displacement empty is about 65,000 MT and loaded is about 205,000 MT.

Six barges, four of which are cargo-carrying and two carry tug boats and portable port facilities, are moved into the vicinity of the vessel. One cargo-carrying barge has a length of about 414 feet, a width of 105 feet, and a draft of from 16.5 to 30 feet at 12,500 DWT and 28,000 DWT, respectively. One cargo-carrying barge equipped with five decks surmounting a bulk oil storage hold will have 30,000 square feet of deck space and carry 15,000 MT of liquid bulk. The vessel takes on roughly 300,000 tons of water as ballast, dropping the vessel in the water to a draft of about 80 feet. At this depth, the vessel is ready to discharge six incoming barges from its cargo deck and receive six outgoing barges. The ballasting takes about three hours. The incoming barges are then guided off the vessel by means of tugboats, and the six outgoing barges are loaded on. This procedure takes about two hours. Ballast is then discharged sufficiently to raise the cargo deck about 15 feet above the water line to a draft of about 37 feet. This operation takes about three to four hours.

The vessel is then navigated to the vicinity of a distant port, and anchored in water of about 90 feet depth. Again, ballast is taken on to lower the vessel to a draft of about 80 feet and the six barges are floated off with tug assistance. The first barges off are shallow draft barges, displacing about 2,500 MT at a draft of about 5 to 6 feet. These shallow draft barges are towed to a suitable shore area and secured in place, supported on columns and connected with the beach by a steel framework and mesh roadway which forms a causeway effective for driving wheeled vehicles to and from the platform formed by the barges. The other barges are brought along side the port facilities formed by the barges, and self-sustaining cranes on the platform facilitate loading and unloading operations. Cargo is unloaded from the barges, placed on the platform, and then taken from there and across the causeway by trucks and other wheeled vehicles.

The above description is for the purpose of teaching the person of ordinary skill in the .art how to practice the present invention, and it is not intended to detail all of those obvious modifications and variations of it which will become apparent to the skilled worker upon reading the description. It is intended, however, that all such obvious modifications and variations be included within the scope of the present invention which is defined by the following claims. The claims are meant to cover the claimed elements and steps in any arrangement or sequence which is effective to meet the objectives there intended, unless the context specifically indicates the contrary.

Claims

1. A transportation system comprising: a barge-carrying vessel capable of transoceanic navigation carrying a plurality of independently-floatable barges and to be further capable of loading and unloading the barges by floatation; at least one cargo-carrying barge; at least one transportable port system comprising a platform capable of being secured in water of sufficient depth to enable floatation and mooring of said cargo-carrying barge for loading and unloading; and a causeway capable of being extended from said platform to a landing area.

2. A transportation system according to claim 1 wherein said causeway is supported by at least one floatation, escalation or suspension device.

3. A transportation system according to claim 1 which further includes means for transporting at least one tugboat.

4. A transportation system according to claim 3 wherein said tugboat is carried in a float-on, float-off barge adapted to permit the tugboat to float-on and float-off of the barge.

5. A transportation system according to claim 1 wherein said platform comprises a plurality of support columns which are adapted to be vertically adjusted to support the platform in a substantially horizontal position at a desired depth relative to the water line.

6. A transportation system according to claim 1 wherein said platform is comprised in a shallow-draft barge adapted to be carried by said barge-carrying vessel.

7. A transportation system according to claim 1 wherein said vessel has a trapezoidal hull cross section.

8. A transportation system according to claim 1 wherein said vessel comprises an inner hull the upper surface of which defines a cargo deck capable of supporting a plurality of independently-floatable, cargo-carrying barges and separated from an outer hull by a plurality of sealable chambers, said cargo deck being positioned above the vessel water line during ocean transport.

9. A transportation system according to claim 8 wherein at least some of the sealable chambers are capable of maintaining buoyancy of the vessel despite injury to the outer hull.

10. A transportation system according to claim 8 wherein said vessel further comprises means to take on water ballast sufficient to lower said cargo deck below the water line to enable floatation of at least one cargo-carrying barge.

11. A transportation system comprising: a barge-carrying vessel capable of transoceanic navigation carrying a plurality of independently-floatable barges, said vessel comprising an inner hull which defines a cargo deck, an outer hull separated from an inner hull, and means positioned between the hulls for holding ballast and air in effective amounts to enable loading and unloading barges by floatation; means for transporting at least one tugboat; at least one tugboat; at least one cargo-carrying barge; at least one assembleable port comprising a platform and a plurality of support columns adapted to be vertically adjusted to support the platform in a substantially horizontal position and secure it to the ocean floor in water of sufficient depth to enable floatation and mooring a cargo-carrying barge for loading and unloading; and a causeway supportable by at least one floatation device and being capable of being extended from said platform to a landing area.

12. A transportation system according to claim 11 wherein said tugboat is carried in a float-on, float-off barge adapted to permit the tugboat to float-on and float-off of the barge.

13. A transportation system according to claim 11 wherein said platform is comprised in a shallow-draft barge adapted to be carried by said barge-carrying vessel.

14. A transportation system according to claim 11 wherein said vessel has a trapezoidal hull cross section.

15. A method of unloading cargo from an ocean-going vessel comprising a floatable cargo deck, the method comprising: flooding the cargo deck to buoy at least one barge sufficiently to permit it to be guided free of the vessel and independently floated; guiding at least one barge free of the cargo deck; moving a portable port facility, comprising at least one platform, from the vessel and assembling and securing the platform in water of sufficient depth to enable floatation and mooring of a barge for unloading; extending a causeway from the platform to a landing area; unloading at least a portion of the cargo from the barge and onto the platform; and moving unloaded cargo across the causeway from the platform to the landing area.

16. A method of loading a vessel for transoceanic transport of cargo between two shores, comprising: moving at least one floatable cargo-carrying barge to a barge-carrying vessel capable of transoceanic navigation with a plurality of barges supported on a cargo deck; flooding the cargo deck to permit at least one barge to be guided over the cargo deck; guiding at least one barge over the cargo deck; also loading onto the vessel at least one portable port comprising a platform and a causeway; discharging the water which flooded the cargo deck; and navigating the vessel from the vicinity of one shore.

17. A method of transoceanic transport of cargo between two shores, comprising: moving at least one floatable cargo-carrying barge to a barge-carrying vessel capable of transoceanic navigation with a plurality of barges supported on a cargo deck; taking onto the vessel sufficient ballast to lower the cargo deck below the waterline to permit at least one barge to be guided over the cargo deck; guiding at least one barge over the cargo deck; also loading onto the vessel at least one platform capable of being secured to the ocean floor; discharging sufficient ballast to raise the cargo deck above the water line; navigating the vessel from the vicinity of one shore to the vicinity of another; taking sufficient ballast onto the vessel to submerge at least a portion of the cargo deck to buoy at least one barge sufficiently to permit it to be guided free of the vessel and independently floated; securing at least one platform to the ocean floor in water of sufficient depth to enable floatation and mooring of a barge to enable loading and unloading; extending a causeway from the platform to a landing area; unloading at least a portion of the cargo from the barge and onto the platform; and moving unloaded cargo across the causeway from the platform to the landing area.

18. A transportation system according to claim 17 wherein, in addition to said platform, the portable port comprises a plurality of support columns which are adapted to be vertically adjusted to support the platform in a substantially horizontal position.

19. A transportation system according to claim 17 wherein said barge-carrying vessel comprises an inner hull defining the cargo deck, an outer hull separated from an inner hull, and means positioned between the hulls for holding ballast and air in effective amounts to enable loading and unloading barges by floatation.

20. A transportation system according to claim 17 wherein said platform is comprised in a shallow-draft barge adapted to be carried by said barge-carrying vessel and having means for taking on and discharging ballast water to adjust its height in the water.