EP0025793A4

EP0025793A4 - Plural-tiered, barge-carrying waterborne vessel and method relating thereto.

Info

Publication number: EP0025793A4
Application number: EP19800900582
Authority: EP
Inventors: William Everett Kirby
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-03-26
Filing date: 1980-10-08
Publication date: 1981-08-28
Also published as: EP0025793A1; WO1980002015A1; JPS56500368A

Abstract

In transporting cargo in waterborne vessels, the loading and unloading of goods from small river barges to ocean going vessels, and vice-versa, is time consuming and expensive. By using a barge vessel (50) having a plurality of tiers of floodable holds (54, 55, 57, 58) extending the length of the vessel and controlled by gates (71), locks (72), lock gates (110, 111), etc., and lock-changing and trimming system (150, 156), cargo containing barges can be floated into the large vessel (50). Preferably, there are a plurality of holds on each of upper, middle and lower decks of the vessel (50). Furthermore, in order to carry roll-on, roll-off cargo, the vessel (50) can have its buoyancy tanks (52, 53), charge tanks (150-154) and lock (72) filled to lower the stem (64) into alignment with a cooperating cargo carrying support to allow roll-on, roll-on movement of the cargo. By the structural design of such a vessel, both floatable cargo carrying barges and larger roll-on, roll-off upper deck loads can be readily transported.

Description

Reference to Related Application This application is a continuation-in-part of application Serial No. 23,890 filed March 26, 1979.

Background of the Invention This invention relates to a barge-carrying waterborne vessel with at least two tiers of barge holds and a cargo-carrying deck. It also relates to methods employing such a vessel.

Many problems, often related to the high cost of labor, have recently changed the economic and technical natures of shipping. For example, for many centuries materials have been transported by barges on rivers, lakes, canals, and inland waterway systems to ports near the river mouth, unloaded there from the barges, loaded on ocean-going vessels, sent to other ports across the sea, unloaded there, reloaded in many instances on barges, and shipped up another river system. In recent years, however, the cost of loading and unloading cargo has risen higher and higher. Containerized cargoes have helped somewhat, but even then, as well as in bulk-loaded barges, there has remained the necessity of unloading the barges at one port, placing the container and other cargo on a pier, and then loading from the pier into an ocean-going vessel, only to require the reverse procedure in the ports to which the cargo is carried by that vessel. All this adds considerably to the ultimate cost of the product concerned.

An apparent answer to the problem is to ship the barges themselves. Since they cannot undergo an ocean voyage directly in the water, this would require loading the barges aboard an ocean-going vessel. However, few vessels are capable of carrying a series of barges aboard, and the problem of loading barges on the vessels must be confronted. The barges are often very large, and cranes or elevators to lift them would be very expensive. In fact, large river barges are not designed to be lifted by cranes. Recent inventions such as our U.S. Patent No. 3,913,512, issued October 21, 1975, have proposed flotation loading of barges and other cargo-carrying containers. Since the barges are already in the water, flotation loading can be employed with a specially constructed ship that has a suitable hold and a gate through which the barge may be floated into the hold.

However, barges are not as easily handled as are smaller cargo-carrying containers; so particular provisions have had to be made for them. Many barge types are . relatively long for their beam. The barges used on the Mississippi and Rhine rivers, for example, are very long compared to their width—the Mississippi barges are nearly 60 meters long and less than 11 meters wide. For a bargecarrying system to be practical, the ocean-going, bargetransporting vessel must be able to carry many barges. A ship able to accommodate only a single line of barges would be extraordinarily long and narrow. This general problem was solved in our U.S. Patents Nos. 3,978,806, issued September 7, 1976; and 4,135,468, issued January 23, 1979. Those patents relate to a vessel having a plurality of longitudinal holds, side by side, either two or three parallel holds, each of which can take the full width of a barge and each of which can accommodate several barges in line or tandem. Also, the problem of loading and unloading the vessel with barges was alleviated by mechanisms shown, for example, in our U.S. Patent No. 4,147,123, which issued April 3, 1979.

Even then, however, there remained a problem in developing an adequate payload which would include both barges and deck cargo and would make a barge-transport system economically practicable. Calculations indicated that with only a single tier of barges under the flotationloading system, the payload was somewhat marginal economically. Thus, an important object of the invention is to provide a barge-transporting vessel for accommodating more than one tier of barges in a flotation loading and unloading system.

Heretofore, no one has proposed a feasible system of this kind. For example, the vessel shown in the Vargas U. S. Patent No. 3,939,790, which issued February 24, 1976. involves flotation loading and unloading and accommodates three tiers of relatively small lighters, especially designed to be lifted or hung by the ends, but not full-size river barges. In fact, that system would not be workable for such barges, partly because it requires an expensive combination of support apparatus and lighter or barge hangers in addition to the flotation apparatus. That system complicates the loading and unloading, slows it down greatly, and makes it too expensive to build and to use. It also loses many of the advantages of true flotation loading and unloading.

The present invention relates to the problem of how to provide for flotation loading and unloading of barges into two or more different levels within the same ship and how to do so in a simple and economical manner.

A problem that arises as soon as one attempts to load two or more tiers of barges in one vessel, is the problem of draft. While there are many ports which can accomodate drafts up to 75 or 80 feet, which is much more than most vessels have and which would be adequate for a ship that would load two tiers of barges, there are many ports with draft of only about 40 feet. A system restricted to voyages between deep-draft ports would not be economically practical. It is, therefore, an object of the present invention to provide an efficient and simple system for loading two or more tiers of barges into an ocean-going vessel whether the vessel is at a deep-draft port or at a relatively shallow-draft port. As will be seen, this object is attained by providing the barge-transporting vessel with a lock system analagous to canal locks.

With such a vessel, it is also important to be able to minimize the total amount of water to be pumped in and out and to keep the vessel properly stable and trimmed at all times. Hence, another object of the invention is to solve these problems as well, in a ship able to take two or more tiers of barges by flotation loading and unloading.

Barges come in a variety of types and sizes. Some carrier vessels can transport only one special type and size. A versatile barge-transporting vessel accommodating barges of various sizes and types would have many advantages. Hence, an object of this invention is to provide a barge-transporting vessel capable of carrying a wide variety of types and sizes of barges.

When the structure and mechanisms that solve the problems just discussed are available, as they are in the present invention, then it becomes possible to attack another problem. This problem relates to cargo not transportable by barges. For example, there are many cargoes which are not capable of flotation loading and unloading, but which are very voluminous and heavy; and ordinary vessels find it very difficult, in fact often impossible, to accommodate some of these structures. When, for instance, it is desired to transport an entire factory or a huge structure zs tall as a ten-story building and very heavy, involving much steel, it has been almost impossible to load and transport such cargoes. The present invention makes it possible to trim the vessel during loading in such a way that these large, heavy cargoes can be rolled onto the main deck, using machinery like that developed for moving large missiles on land, and to achieve the loading from the dock to the ship. The ship can then be trimmed back to her normal waterline. Moreover, this can be done in conjunction with the transport of barges, depending, of course, on total weights involved.

Many other objects and advantages of the invention will be seen in the following description, and it will be also seen there that other problems have been solved.

Summary of the Invention The invention comprises a barge-carrying waterborne vessel having a hull with rigid supporting and hullreinforcing structure, a bow, a stern, and sidewalls providing a series of buoyancy compartments. The hull has a hollow interior defining a plurality of tiers of barge holds, at least one upper longitudinal hold and at least one lower longitudinal hold, each extending most of the length of the vessel. There may be more than two such holds. Flooding means enable placing water into each hold.

A first gate means at one end of the vessel, usually the stern end, is opened for flotation loading and unloading of a plurality of barges into each hold, when that hold is flooded. Between the first gate means and both of the holds is a single, deep, loading passage. Second gate means lie between the loading passage and the lower hold; and, preferably, third gate means lie between the loading passage and the upper hold enabling use of the loading passage as a lock.

Each hold preferably has a barge-retention means for holding each barge down against the bottom of its hold. This prevents movement of the barges during the ocean voyage and enables exchange of buoyancy between the vessel and each barge in the lower hold when the lower hold is flooded. This is an important factor for ship safety in the event of damage to the vessel's hull.

Preferably, the vessel is provided with bargemoving means in its hollow interior. Where the vessel is primarily or often used in deepwater ports, where the lock system is not used, this may comprise a plurality of flowcreating means like those of our U. S. Patent No. 4,147,123 for causing flow of water to move barges in each hold In one direction during flotation loading and in the other direction during flotation unloading. Alternatively, and preferably when using the lock system, a cable and winch system like that of U. S. Patents Nos. 3,913,512 and 3,973,806 may be used.

There may be two or three tiers of barge holds. There may be a plurality (preferably two or three) of upper barge holds and a plurality (preferably two or three) of lower longitudinal barge holds, separated from each other on each level by longitudinal bulkhead means. There may also be a plurality (preferably two or three) of similar intermediate holds. Thus, the hollow interior of the hull may define a plurality of upper longitudinal barge holds separated by longitudinal bulkhead means, a plurality of lower longitudinal barge holds separated by longitudinal bulkhead means (and a plurality of intermediate such barge holds, if desired), and loading passage means at the stern end of the hull having a deck on the level of the lower hold and walls extending up as high as those of the upper hold. There may be a separate loading passage for each series of vertically aligned rows of holds, or there may be a single loading passage serving all the holds. In a vessel having a single loading passage, there is then an upper lateral transfer area on the same level as the upper hold, and this may comprise an upper portion of the loading passage. There is also a lower lateral transfer area on the same level as the lower hold, in between the lower hold and the loading passage and separated from it by a lock gate. The hold-flooding means places water into the lower lateral transfer area when it puts water into, the lower holds. The two upper holds may have separate lock gates and be separately flooded. The transfer areas are provided with water-jet systems for accomplishing the lateral transfers, similar in nature to those shown in our U. S. Patent No. 4,147,123.

Special buoyancy or charge tanks are preferably provided adjacent the loading passage for storage of lock water, which may comprise upper and lower tanks on each side of the loading passage and also a tank beneath the loading passage. A special water-circulation system passes seawater directly into and out from the loading passage or lock and directly into and out from the special buoyancy or charge tanks.

In addition, there may also be buoyancy tanks at the bow end of the vessel for trim compensating from lock water weight aft, with pumping means for pumping seawater directly into and out from them. Another water-circulation system is provided for filling or discharging water from the special buoyancy trim tanks, in order to balance weight during operation of the internal lock system.

Brief Description of the Drawings In the drawings :

Fig. 1 Is a schematic view in side elevation and in section taken along the lines 1-1 in Figs. 2 and 3, of a vessel embodying the principles of the invention, showing a load of barges in two tiers, and also deck cargo. Fig. 2 is a view in -horizontal section taken along the line 2-2 in Fig. 1, showing the upper tier of barge holds; and a portion of the main deck aft is also shown.

Fig. 3 is a view in horizontal section taken along the line 3-3 in Fig.1, showing the lower tier of barge holds

Fig. 4 is an enlarged stern end view of the vessel, as viewed along the line 4-4 in Fig. 1, showing, in solid lines, the stern loading gate in its closed position. A partially raised position of this gate is shown in broken lines. A portion of the gate-operating mechanism is shown by breaking away the covering structure.

Fig. 5 is a fragmentary view in side elevation and partly insection of the posts for support of the stern gate of Fig. 4, viewed along the line 5-5 in Fig. 4.

Fig. 6 is a further enlarged view along the line 6-6 in Figs. 4 and 8 of a portion of one side edge of the stern gate and its seating, showing a gasketing arrangement thereof.

Fig. 7 is a fragmentary, simplified, isometric view of the stem end of the vessel of Fig. 1 showing the stern door or gate in its raised, open position.

Fig. 8 is a similar view with the stem gate in its lowered, closed position.

Fig. 9 is a hydrostatic pressure-loading diagram, showing the hydraulic load on the stern gate when the loading passage is dry.

Fig. 10 is a similar diagram with the loading passage filled. Fig. 11 is a fragmentary isometric view of the loading passage, showing the retractable barge-support beams.

Fig. 12 is a view in section taken along the line 12-12 in Figs. 1-3, showing the loading passage fully loaded with barges.

Fig. 13 is an enlarged view in section taken along the lines 13-13 In Figs. 1-3, showing the barges secured within their respective holds.

Fig. 14 is an enlarged view in section taken along the lines 14-14 in Figs. 1-3 showing the barges secured at another location in the ship.

Fig. 15 is a similarly enlarged view in section taken along the lines 15-15 in Figs. 1-3, showing the inner lock gates.

Fig. 16 is a similarly enlarged view like Fig. 12 showing the loading passage or lock with a barge in the upper portion thereof being transferred laterally by water acting on one side of the barge.

Fig. 17 is a fragmentary isometric enlarged view of a portion of the upper hold and upper lock chamber, showing the upper lock gates, one of which is shown partially open in solid lines and fully open in broken lines.

Fig. 18 is a view in front elevation of one of the upper lock gates of Fig. 11 showing the operating mechanism for watertight dogging.

Fig. 18A is a fragmentary isometric view of the dogging mechanism of Fig. 18. Fig. 19 is an enlarged view of a portion of one lock gate of Fig. 11 and its operating mechanism, taken along line 19-19 in Fig. 18.

Fig. 20 is a fragmentary isometric enlarged view of a portion of the lower hold and the lower portion of the loading passage or lock, showing the gate between them and its actuation system.

Fig. 21 is an exploded isometric diagrammatic vie of the loading passage or lock and its associated charge tanks and pumping system:

Fig. 21A is an enlargement of a portion of Fig.21 to show the piping more clearly.

Fig. 22 is a series of diagrammatic transverse view A, B, C, D, and E of the loading passage or lock and of the charge tanks of Fig. 21, with a barge in the lower portion of the loading passage and showing the charge tanks as they are at various stages in the proceeding. The base or minimum water level in the lock is shaded by hatch lines in one direction; hatching in the other direction shows the water thereabove at various stages.

Fig. 23 is a series of diagrammatic lengthwise views F, G, H, I, J, and K of the vessel showing the status .of the flooding of -the holds, the loading passage or lock, the charge tanks, and the trim ballast tanks during loading of the upper holds.

Fig. 24 is a similar series of views L, M, N, 0. P, and Q showing the loading of the lower holds and of the loading passage or lock itself. Fig. 25 is a view of a vessel of the invention so trimmed that a very large and heavy load which may be as high and voluminous as a 10-story building and correspondingly heavy may be loaded onto the vessel from a floating barge.

Fig. 26 is a similar view of an alternative system in which the pier or dock itself is provided with a ramp and the vessel is floated and trimmed at a different level.

Fig. 27 is a view like Fig. 1 of a modified form of barge transporting vessel, also embodying the principles of the invention.

Fig. 28 is a plan view in horizontal section of the upper barge hold of the vessel of Fig. 27.

Fig. 29 is a plan view in horizontal section of the lower barge hold of the vessel of Fig. 27.

Fig. 30 is a fragmentary isometric view of the stern end portion of another vessel embodying the principles of the invention.

Fig. 31 is a vertical sectional view thereof.

Fig. 32 is a fragmental sectional view thereof.

Fig. 33 is a view in elevation and partly in section of a modified form of barge-carrying vessel embodying the principles of the invention, with barges stored therein. It is taken along the line 33-33 in Figs. 34, 35, and 36. This vessel has three tiers of barge stowage decks or holds. The starboard stern gate is shown in solid lines in its closed positions and in broken lines in its raised positions.

Fig. 34 is a top plan view of the vessel of Fig. 33 showing its uppermost barge stowage hold. It may be considered. as a view taken along the line 34-34 in Fig. 33.

Fig. 35 is a view in section taken along the line 35-35 in Fig. 33 and serving in effect as a plan view of the middle or intermediate barge stowage holds.

Fig. 36 is a view taken along the line 36-36 in Fig. 33 and constituting a plan view of the lowermost barge stowage holds, of the vessel of Fig. 33.

Fig. 37 is a view similar to Fig. 34 showing one particular barge in several positions, illustrating how that barge is moved to its barge stowage position with the aid of a small tug, which is shown here diagrammatically.

Fig. 38 is a view in section taken along the line 38-38 in Fig. 33.

Fig. 39 is a view in section taken along the line 39-39 in Fig. 33.

Fig. 40 is a view taken along the line 40-40 in Fig. 33.

Fig. 41 is a view in side elevation of a small tugboat used in connection with the loading and unloading of th barges in the vessel of Figs. 33 to 40.

Fig. 42 is a rather diagrammatic plan view of the tugboat of Fig. 41 roped to one side of a barge.

Fig. 43 is a view similar to Fig. 33, but broken in the middle to conserve space, of a non-self-powered vessel, being pushed by a tugboat, embodying the principle of the invention in a modified form, taken along the lines 43- 43 in each of Figs. 44, 45, and 48. Fig. 44 is a fragmentary plan view of a rear portion of the vessel of Fig. 43 looking down on the upper deck.

Fig. 45 is a similar fragmentary plan view looking down on the intermediate deck.

Fig. 46 is a similar fragmentary plan view looking down on the lowerst deck, with the tugboat shown in outline.

Fig. 47 is a view in section taken along the line47-47 in Fig. 43.

Fig. 48 is a somewhat schematic view in side elevation and in section, taken along the line 48-48 in Fig. 49, of another modified form of vessel with the loading gate and lock at the bow of the vessel.

Fig. 49 is a view in horizontal section taken along the line 49-49 In Fig. 48, showing the intermediate hold.

Fig. 50 is a view in horizontal section taken along the line 50-50 in Fig. 48 showing the lowest hold.

Fig. 51 Is a fragmentary enlarged isometric view of a portion of a longitudinal stanchion bulkhead, such as is also shown in Fig. 49.

Fig. 52 is a similar view of a plated bulkhead, such as is also shown in Fig. 50, with portions broken away. Description of Some Preferred Embodiments The vessel in general (Figs. 1-3): Figs. 1-3 show a vessel 50 having a hull 51 with sidewalls comprising a series of port and starboard buoyancy tanks 52 and 53. There also are bottom buoyancy tanks 52a. The vessel has a pair of upper barge holds 54 and 55 separated by a longitudinal bulkhead 56 and a pair of lower barge holds 57 and 58 separated by a longitudinal bulkhead 59. There is also an upper or main deck 60, which is preferably flat and substantially without openings through it, for accommodation of loads on the top thereof, such as the cargo containers 61 shown in Fig. 1. This deck 60 may have a crane 62 movable therealong. A ramp 63 may be pivotally mounted near the stern 64. A barge tender 65 (See Fig. 2) may also be stowed on the deck 60.

The vessel 50 is provided with engine compartments 66 and 67 (Fig. 3), the engines driving two propellors 68 and 69, one on each side (See Figs. 1, 4, 25 and 26). Moreover, there is a Master Control Room 70 (Fig. 2) near the stem with apparatus for control of the loading, and unloading of barges B.

The stern gate 71 (Figs. 1-10): A gate 71 (See Figs. 1-10) Is provided at the stem 64, opening into a loading passage or lock 72. The gate 71 is shaped generally to match the cross-section, of the loading passage 72, which has a lower, narrow central portion 73 at the level of the lower barge holds 57 and 58 and an upper portion 74 approximately twice as wide located at the level of the upper holds 54 and 55. Thus, the gate 71 has a lower, narrow central portion 75 and a wider upper portion 76. The gate 71 is supported by two posts 77 and 78 located at the outboard aft comers of the main deck 60. A portion of the gate post 78 is shown in Figs. 4 and 5, partly broken away, the opposite post 77 being substantially the same. At each post 77,78 a motor 80 (Fig. 5) may rotate a shaft 81 which drives a traction pulley 82 and raises and lowers the gate 71 via a cable or chain 83, having a counterweight 84 at one end and attached to the gate 71 at the other end. Instead, hydraulic force may be used.

The gate 71 is suitably gasketed and is made very strong so that it can meet the unusual demand of accommodating pressures from varying heads of water on either side of it. (See Figs. 9 and 10.) As will soon be seen in Fig. 9, the seawater exerts an unbalanced inward pressure on the gate 71 when the loading chamber or passage 72 is completely dry inside. On the other hand, when the water inside the loading passage 72 is at a much higher level than the water outside (Fig. 1.0), the pressures are larger and bear in the opposite direction Consequently, the gate must be able to withstand that type of hydraulic force. The gate 71 is therefore made strong and heavy; it may weigh about 100 tons.

To prevent leakage around the gate 71, a gasketing structure like that shown in Fig. 6 may be used. The ship 50 has a transom 85 which has a V-shaped channel 86 around the gate opening. The gate 71 has its edges 87 correspondingly V-shaped; the edges 87 are provided with a pair of bearing bars 88 that engage the channel 86 and a pair of inflatable pneumatic gaskets 89. The channel 86 includes a pair of compression bars 90 that engage the gaskets 89. A hydraulic mechanism 91 in the transom 85 has a bar 92 that engages in an opening 93 of the gate 71 to lock the gate 71 in place at both its fully open or fully closed position, there being at least two such bars 92 and openings 93, one for the open position and one for the closed position. The loading passage or lock 72 (Figs. 1-3, 7, 11, 12, 16, and 22): The loading passage or lock 72 (See Figs.7 and 11) has a bottom deck 95 for its lower portion 75 with sidewall 96 and 97 leading up to a pair of shelves 98 and 99 at the lower end of the upper level 74, and sidewalls 100 and 101 extend thereabσve. The loading passage 72 is somewhat longer than the longest barge B to be loaded, but not a great deal. It will also act as a stowage compartment for one, two, or three barges B, one being stowable in the low level 73, and two in the upper level 74. The upper level 74 also acts as a transfer hold to move barges B, from one side to the other to get them into and out from either of the two upper barge holds 54 and 55.

Figs. 11 and 12 show how two barges B may be stowed in the upper portion 74. Retractable barge-support beams 102 can be moved out through openings 103 in the walls 96 and 97 by suitable hydraulic machinery (not illustrated) In well-known manner, thereby in effect widening the shelves 98 and 99. For such stowage, the two barges B are floated in directly at the upper level 74. As will soon be apparent, this two-barge stowage can be used only for transport between deepwater ports. Otherwise, only one barge B is stowable at the upper level 74 for loading and unloading at shallow-water ports. This is explained below.

The upper portion 74 of the loading passage 72 functions also as a transfer bay for the barges to be loaded into or out from the upper holds. The idea is to transfer each barge laterally from a central position to either side, and vice versa. For this purpose, a series of water jets 105 (See Figs. 11 and 16) is provided in the walls 100 and 101. Their structure and operation may be identical to those of the transfer jets in our U. S. Patent No.4,147,123, the description and operation there, hereby being incorporated by reference herein. The upper lock gates 110, 111 (Figs. 2, 15, and 17-19): Preferably, at the forward end of the loading passage or lock 72 on the upper level 74 are a pair of lock gates 110 and 111 which close off the two respective upper barge holds 54 and 55. (Lock gates here would not be essential if the vessel 50 is to be used only for deepwater flotation loading or unloading, but even then they are useful safety devices.) While various structures are suitable, a presently preferred structure for the lock gates 110 and 111 is shown in Figs. 17-19. As shown there, each lock-gate 110,111 is made in two sections 112,113 hinged together by hinges 114 along the center, with suitable gasketing there (not shown). The gates 110 and 111 are each mounted for rotation relative to a stationary vertical pivot 115. The gates 110 and 111 are opened by folding the gate portion 113 against the portion 112 and while swinging the portion 112 into a recess 116 in the wall 100 or 101. One way of doing this is (See Fig. 17) to use a hydraulic closure system with one cylinder-piston assembly 117 for swinging the portion 112 into the recess 116 and a second cylinder-piston assembly 118 for swinging the portion 113 against the portion 112 and, with it, into the recess 116. The gates 110 and 111 are thus two-section watertight pontoon steel doors hydraulically opened and closed.

A dogging mechanism is shown in Figs. 18, 18A, and 19, using an hydraulically actuated gang bar 119, one on the top and one on the bottom of each lock gate 110,111, secured to the deck above and below the gate. As shown in Fig. 19, a hydraulic actuator 120 may operate each gang bar 119 via a shaft 121, which acts in concert with a gang dog 122 on a shaft 123. A gasket 124 and a compression bar 125 on the gate frame 126 cooperate with a series of wedges 127 on the lip 128 of the gate 110 or 111 to prevent leakage, and a steel stop 129 limits movement. Thus, the gates 110 and 111, when closed, resist hydrostatic pressure in either direction to maintain watertightness. The lower lock gate 130 and lower transfer bay

(Figs. 3, 14, 15, and 20):

On the lower level there is a single lock gate 130 leading into a transfer bay 131 as wide as the width of the two lower barge holds 57 and 58 and having direct access therein to the two lower barge holds 57 and 58.

Fig. 20 shows a suitable lock gate 130 for this position. It is made in two sections 132 and 133, each slidable horizontal into a respective recess 134 and 135 for opening the gate 130. The gasketing and dogging may be similar to that shown for the upper gates 110 and 111. Hydraulic actuators 136 and 137 may move the gate portions 132 and 133. This gate 130 must withstand considerable pressure from the loading passage or lock side when the lock is full.

The lower transfer bay 131 is substantially like that described in our U. S. Patent No. 4,147,123, with jets 138 like the jets 105 for the upper transfer bay 74.

The barge holds 54, 55, 57, and 58: The barge holds 54, 55, 57, and 58 may be substantially like those described in our U. S. Patent No. 4,147,12 although different hold-down devices may be used.

Fig. 13 shows cable-type hold-downs, with cables 140 anchored to bits 141 on the barges B and secured by an anchor 142 to a sidewall of the hold or at the other side of the barge B by an anchor 143 located in the bulkhead 56 or 59, each of which is provided with suitable passages and recesses therefor.

The number of barges B that can be accommodated in the vessel 50 will vary, of course, according to the type of barge B involved and the ship design. As an example, a construction is shown in Figs. 1-3 which has six barges B retained on the lower level and as many as eight on the upper level. Of these, four are in the two holds 57 and 58 at the lower level, that is, two in each hold; one is retained in the transfer bay 131 (See Fig. 14 where anchors 144 for the cables 140 are in the floor); and the sixth in the lower portion 73 of the loading passage 72 (See Fig.16). On the upper level there are six barges B in the holds 54 and 55, that is, three in each of the two holds; and two may be (at times) retained in conjunction with the shelves 98 and 99 and retractable beams 102, with cables 140 anchored to a beam 102 at a recess attachment 145.

Where deepwater loading is employed, a waterflow system like that shown and described in our U. S. Patent No. 4,147,123 may be used. As shown in Fig. 1, there may be a sump 146 at each hold level, and a pump 147 in conjunction therewith for pumping in from the sea or out to it to induce longitudinal waterflow in a fore or aft direction.

When the lock-type loading is used, a winch-type of barge-moving system is preferred. As is shown in Fig. 23-H, a winch 148 and endless cable 149 are used with hooks 149a on the cable 149 for attachment to a tow line 149b on each barge B.

Charge tanks and trim tanks

(Figs. 21-24) A very important feature of the present invention is its ability to be used in both deepwater ports and in shallow-water ports. In use in deepwater ports, the process is relatively simple, because the ship can have a draft of sufficient depth to enable direct flotation loading of the upper tier of barges. However, in a shallow-water port, the operation is necessarily different, because the ship cannot use its deep draft as it can in a deepwater port; hence, it is necessary to use a very novel type of operation provided by this invention using the loading passage much as a canal lock aboard the ship. The combination of the gates 71, 110, 111, and 130 makes possible this type of operation, and the efficiency of the operation is aided greatly by the use of charge tanks and trim tanks.

Thus, there is preferably one bottom charge tank 150 directly below the loading passage or lock 72; there are two side charge tanks 151 and 152, one on the port side and one on the starboard side on either side of the loading passage's lower portion 74; and there are two upper side charge tanks 153 and 154 above the lower tanks 151 and 152, one on the port side and one on the starboard side of the vessel 50. This is shown in Figs. 21 and 22, Fig. 21 being an exploded view thereof.

Furthermore, at the bow end of the vessel, lock trim ballast tanks 155 and 156 are also provided to control the fore-and-aft trim of the vessel 50 to compensate for lock water located at the aft end of the vessel. (Figs. 23 and

24) Lock-charging system (Figs. 21-24): The lock-charging and trimming system comprises the lock charging tanks 150, 151, 152, 153, and 154; piping and valves between the transfer passage 72; the lock trim tanks 155 and 156; the outside sea (for lock spill and make-up) and the outside weather (for venting); pumps; pump drivers; controls; and indicators. The lock-charging tanks 150, 151, 152, 153, and 154 are arranged in elevation so that some of the pumping energy required in transferring water between them and the loading passage or lock 72 is partly recovered, thus reducing the pumping energy required for locking the barges B up and down.

This reduction of energy is accomplished by arranging some of the lock charge tank volume below the level of the lock 72. In operating the lock-charging system, the controls sequence the filling and emptying of the lock-charge tanks so that the pumps are augmented by gravity flow during part of the lock charge and discharge cycle.

The volume of water in the lock 72 and in the barge holds 54, 55, 57, and 58 will change as a result of loading or unloading barges B and cause a difference in level between the lock 72 and the outside sea. This difference in level is overcome by opening equalizing valves and pipes between the lock 72 and the outside sea to make-up or spill lock water as necessary.

The longitudinal location of the lock-charging tanks 150, 151, 152, 153, and 154 is maintained at about the same longitudinal position in the ship as the lock 72 so that minimal change of trim will occur when locking barges up or down.

Diesel engines 160 and 161 drive pumps 162 and 163. The pumps 162 and 163 are connected to a series of pipes and valves. The pipes 164 and 165 lead to the transfer passage or lock 72. The pipes 164 and 165 may be connected to the bottom charge tank 150 through pipes 166 and 167 and valves 168 and 169. Or, the pipes 164 and 165 may be connected by valves 170 and 171 and pipes 172 and 173 leading to the respective tanks 151 and 152. Pipes 174 and 175 and valves 176 and 177 connect the pipes 164 and 165 to the upper charge tanks 153 and 154. Pipe 178 and valves 179 and 180 lead from the lock 72 to the sea via a sea chest 181. If the lock 72 should receive an excessive amount ofwater, overflow can pass via a pipe 182 into the tank 154 via a check valve 183 or into the tank 152 via pipe 184 and check valve 185. Deepwater port operation: For a deepwater port the flotation loading and unloading is relatively easy, and this does not change according to whether the vessel 50 was originally loaded in a shallow water port, or whether the original loading is in the deepwater port. It is normal for the loading procedures and transport procedures to differ somewhat according to the number of barges B and deck cargo 61 to be transported. For example, if there is to be only deck cargo 61 transported, then, of course, there is no flotation loading and unloading of barges; although it should be noted that if there are barges B already present, deck cargo 61 can be loaded and unloaded quite satisfactorily anyway. This can be done by roll-on, roll-off methods, and, of course, can also be done by cranes, if that is desired.

If no deck cargo 61 is to be transported and up to six barges B are to be transported, then they are preferably all transported on the lower level in the barge holds 57 and 58, the transfer bay 131, and the lower portion 74 of the loading passage 72. The vessel 50 is ballasted to the proper level, the lower hold transfer area 131 and loading passage 72 flooded, the gates 71 and 130 opened, the loading done as in our previous patents, and then the gates 71 and 130 are all closed, and the holds, transfer bay, and loading passage preferably pumped dry.

The barges B are retained in place by suitable hold-down means which will retain them down even against the force of buoyancy of the water tending to lift them. This means more than a simple retention in place, since considerable force must be exerted. This feature is shown in each of our earlier patent numbers referred to earlier and may be applied in exactly the same way here. This hold-down is particularly important on the lower level since a leak Into that level endangering the safety of the ship is to some extent counteracted by the transfer of buoyancy between the barges and the ship, especially if the barges are only lightly loaded. Hold-downs are also provided on the upper level, but there a lighter force may be used since there is no reason for providing for a transfer of buoyancy on the upper level.

The vessel 50 can accommodate not only six barges B in the lower level but eight on the upper level. The loading in a deepwater port may be done by ballasting the ship to the level necessary for loading the lower holds, opening the gates 71 and 130 and loading the lower barge holds 57 and 58, securing the barges B in place, loading the transfer bay 131 and securing a barge B in place there, closing the lower lock gate 130,,then increasing the ballast, flooding the upper holds 54 and 55, opening the gates 110 and 111 there, loading the upper barge holds 54 and 55 and the upper transfer bay 74, loading the lower portion 73, and then deballasting the ship for sea.

Loading operations, in case there is deck cargo 61, then proceeds according to how many barges B there are. Up to six barges B may be carried in either the upper holds 54 and 55 or in the lower holds 57,58, and extra barges B may be put into the other hold up- to the final total, depending upon how much load is on deck and how much load is in the barges.

Lock-type loading operation (Figs. 22-24): In a relatively shallow port, that is where the draft does not exceed perhaps 40 feet, a different loading procedure must be employed if the upper barge holds 54 and 55 are to be loaded; because the ship 50 will not be able to be ballasted deep enough to load the upper holds directly by flotation. A very important feature of the present invention is its ability to accommodate this type of shallow-port loading by utilizing a lock type of operation. The steps may be as follows: 1. Fig. 23—F: The upper barge holds 54 and 55 may be flooded by their pumps to the required depth for handling barges B by flotation. With the lower lock gate 130 closed and the upper lock gates 110 and 111 also closed, the loading passage or lock 72 is flooded by water directly from the sea to equalize with the ship's draft, while at the same time the trim tank 155 at the bow end of the vessel is flooded to about half its depth to eliminate trim from the lock flooding. This tank 155 may have several compartments, if desired. The stern gate 71 is then opened, and the first barge B floated into the lock 72.

2. Fig. 23—G: The stern gate 71 is then closed and water is pumped from the sea to raise the level of water in the lock 72 up to the level of the water in the upper barge holds 54 and 55. At the same time, water is added forward in the lock trim ballast tanks 155 and 156 to maintain a zero trim.

3. Fig. 23—H: The barge B is shifted laterally in the lock portion 74 by the jets 105 to be in line with one of the barge holds 54 or 55, and then the lock gate 110 or 111 for that hold is opened and the barge B floated into the hold 54 or 55. This may be aided by a winch system, as used in our U. S. Patent No. 3,913,512. The first barge B thus has been lifted as in a lock and then floated into the hold. 4. Fig. 23--I and Fig. 22--A: After the first barge B has been floated into that hold 54 or 55 and while it is being moved forward there, the lock gate 110 or 111 is closed, and the lock water is then pumped out of the lock 72 into the lock charge tanks 150, 151, 152, 153, and 154. Since the lock 72 will now have excess water displaced by the barge B that has been loaded in the upper hold 54 or 55, its level must be equalized with the vessel's draft by opening the equalizing valve 181.

5. Fig. 23--F to I and

Figs. 22--B, C, D, and E: Then the stern gate 71 is opened, and the lock operation repeated to load barges B, one at a time, into the upper holds 54 and 55. Each time the operation is repeated in substantially the same manner as before except that the interchange of water is now from the charge tanks 150, 151, 152, 153, and 154 into the lock 72 and vice versa, as shown in Fig. 22, rather than in and out of the sea each time. Thus, water is first transferred into the lock 72 from the bottom tank 150 (A to B), then from the lower side tanks 151 and 152 (C and D), and finally from the upper side tanks 153 and 154 (E). This results in considerable economy. The trim ballast in the tanks 155 and 156 is also adjusted, as shown in Fig. 23 (F to I) but directly with the sea.

6. Fig. 23—J: The upper barge holds 54 and 55 are both loaded with their full complement of barges B (See J). Then preparations are made to load the lower barge holds 57 and 58. No barges B are yet stowed in the lock 72 at the upper level 74. At this stage, the upper barge holds are pumped dry (J); the water may be pumped directly into the lower barge hold. The forward trim tanks 155 and 156 are adjusted

(I to J) to eliminate the effect of trim from the lock flooding, which will be less since the upper lock part 74 will not be used again for awhile. With, all of the lock gates 110, 111, and 130 closed, the stern gate 71 is opened (J), and a barge B moved into the lock 72.

7. Fig. 23—K and Fig. 24—L: The stern gate 71 is then closed, the level in the lock 72 is lowered (K), the lower lock gate 130 is opened, and a barge B is moved through the lock gate 130 (L) into the transfer bay 131. The lock gate 130 is then closed. The barge B is laterally shifted in the transfer bay 131 and then floated into one of the lower holds 57 or 58.

8. Fig . 24- -M and N : The height of the water in the lock 72 is raised to match the draft of the vessel 50; then the stem door 71 is reopened (M). The operations of Figs. 23—J, K, L, and M are repeated until the lower holds 57 and 58 are fully loaded, and one barge B secured in place in the transfer bay 131 (N).

9. Fig. 24—N: The lock trim ballast in tanks 155 and 156 is adjusted, the gate 130 closed, and the holds 57 and 58 pumped dry. Thus, all the holds 54, 55, 57, and 58, and the transfer bay 131 are dry by the time Fig . 24- - 0 is reached. That leaves all the hold space loaded except that in the lock 72.

10. Fig. 24—0: With the lock gates 110, 111, and 130 all closed, the stern gate 71 is opened and a barge is floated in. The stern gate 71 is closed, and the level of water in the lock 72 is raised (by water from the charge tanks 150, 151, 152, 153, and 154, while adjusting the water level in the tanks 155 and 156 to maintain trim) to place this barge B on one of the shelves 98 or 99. Only one barge B can be stowed at the upper level 74 of the loading passage 72 in this instance, the buoyancy tanks 52 and 53 being used to adjust the list from the off-center load. The appropriate beams 102 are projected, and that barge. B secured in place.

11. Fig. 24--P: With the lock gates 110, 111, and 130 still closed and the stern gate 71 also, closed, the water level is lowered leaving the latest barge B on a dry shelf 98 or 99, ballast being properly adjusted by the tanks 52 and 53. Then the gate 71 may be opened, and the last barge B may be floated in at the lower level 73.

12. Fig. 24—Q: When the last barge is in place, it is secured, the stern door 71 is closed, all the water is pumped out of the lock 72, and the lock charge water is also pumped out of the charge tanks 150, 151, 152, 153, and 154 and from the trim ballast tanks 155 and 156, simultaneously. With the barges B properly secured with hold-down devices, the ship 50 can begin its voyage. The unloading is done similarly in substantially reverse order.

Handling of very heavy deck loads (Figs. 25 and 26): Normal deck loads can be accommodated while there are barges In the ship 50. However, on occasion it may be desired to transport a very heavy deck load, and this invention makes it possible to do this; although in some instances no barges can be transported simultaneously. This, of course, depends upon the total weight involved, and in some Instances both barges and a relatively heavy load can be transported.

In Fig. 25, for example, a very heavy load module 190 may be transported by transferring it from land onto a barge 191, and then loading it onto the deck 60. For this purpose, a deepwater port is required, in order to obtain an aft draft of about 6.S feet. The vessel 50 is so ballasted that it is trimmed aft, with the bow 192 almost out of the water, resulting in a trim angle of 3° by the stern. This may be done by filling some of the buoyancy tanks 52 and 53 and also by filling all of the charge tanks 150, 151, 152, 153, and 154 and the lock 72, while leaving the trim tanks 155 and 156 empty. The stem 64 of the ship 50 may substantially match the level of the forward end of the barge 191 which can be itself slightly trimmed to equal that of the ship 50 so as to provide a smooth, continuous surface between the two. A roll-on, roll-off type of device 193, such as that used for transporting very heavy missiles on land can be used to load directly onto the deck 60 and to put it. at any desired location thereon.

Fig. 26 shows an alternative system directly loading from a pier 195 by using a ramp 196 on the pier 195 and by having the deck 60 about 20 feet above its water level with a draft aft of about 58 feet, and again the bow 192 almost out of the water. This gives about a 3° trim.

All loading on deck 60 may be roll-on and roll-off or, of course, if desired cranes may be used. Cranes involve no unusual operation, however, except that the ship 50 is capable of taking this kind of load.

A vessel 200 for smaller barges (Figs. 27-29): For uses involving smaller barge types and somewhat shallower water, a vessel 200 like that shown in Figs. 27-29 may be preferable, as for example, in the coasting trade along the West Coast of Africa. Here the barges B' are only about 30 meters long, nearly 11 meters wide, and 5 meters deep.

Basically, the vessel 200 has upper barge holds 201 and 202 divided by a bulkhead 203, quite similar to the holds 54 and 55 with their bulkhead 56 of the vessel 50. Upper lock gates 204 and 205 like the lock gates 110 and 111 may be used, and a stern gate 206 basically like the gate 71 may be used to admit barges to a loading passage or lock 207.

A significant difference is in the lower hold. The lock 207 may be quite short to match the length of shorter barges, with a lower lock gate 208 at its forward end like the gate 130. But there is not sufficient space (due to the need of the charge tanks 150 through 154 and machinery compartments 210 and 211) for the lock 207 to open directly into a transfer bay. Lower barge holds 212 and 213 and their separating bulkhead 214 are indeed like the holds 57 and 58 and the bulkhead 59, and a transfer bay 215 is basically similar, though shorter, than the transfer bay 131; it has jets 216 for lateral transfer. But between the transfer bay 215 and the lock 207 is an additional stowage bay 217.

The upper barge holds 201 and 202 are loaded with barges B' as in the vessel 50, and then the lower barge holds 212 and 213, the transfer bay 215 and the stowage bay 217 are loaded. Then a barge B' is floated in and the lock 207 flooded to bring that barge B' up on a shelf 220 of the lock 207. Beams 221 like the beam 102 are provided for support. Finally, the last barge B' is floated into the lower portion of the lock 207.

Triple-tier structure with three rows of vertically-aligned holds on each tier (Figs. 30-32):

The invention is not limited to two tiers or to two holds per tier. In some instances, much larger bargecarrying vessels will be required or will be desirable, and the invention is applicable to such vessels. Thus, Fig. 30 shows the stern portion of a vessel 250 having three tiers of holds with three holds on each tier. The lowest tier 251 thus has three holds 252, 253, and 254, each of which has a lock gate 255, 256, 257. The outside lock gates 255 and 257 may be substantially identical to the lock gates 110 and 111 described previously, folding and fitting into respective recesses 258 and 259. The lock gate 256 in the center is preferably a divided gate with two portions 260 and 261 each on vertical pivots 262 and 263, which seat In respective recesses 264, and 265, one on each side of its hold 253.

The next tier up, an intermediate tier 270 also has three holds, and they are vertically in line with the corresponding holds 252, 253, and 254 of the lower tier 251. Their gates may be the same as those for the lowest tier. The uppermost tier 271 also has three holds, and they also are vertically aligned, respectively, with those of the two lower tiers 251 and 270. The gates for the upper holds may again be the same as those for the lowest tier 251.

While it is possible to have a single loading gate and a single loading passage or lock, with a vessel so large and a capacity of so many barges B, it is presently preferable to provide three separate stern gates 275, 276, and 277, one for each vertically aligned row of holds, and a separate loading passage or lock 278, 279, and 280 for each. In this instance, there is, of course, no shifting laterally within the loading passage. The lock operations are substantially the same as that described except for the absence of lateral shifting and except for the fact that there are three tiers of holds to be loaded. All three rows may be loaded simultaneously with all the stern gates 275, 276, and 277 open at once, with the locking operation either being simultaneous for the three locks 278, 279, 280 or differing. If desired, one stern gate can be opened at a time, and barges to or from only one hold loaded or unloaded. This might happen in an instance where the vessel 250 is to visit several ports with the barges B loaded appropriately so that all the barges for the first port can be taken out first, and so on, whether or not other barges are to be loaded on board, in exchange.

Otherwise, the invention is the same as that previously described, and the device as given as examples may be used as shown earlier. There are charge tanks and trim tanks, pumps, and so on, all as before or modified for the noted differences. The vessel itself may be self-propelling or may not, and this structure is particularly applicable to a vessel designed for towing.

Any form of the invention shown is capable of taking a variety of sizes of barges. Each particular vessel may be designed with a particular barge in mind, but that may simply be the maximum-sized barge that can be taken, or it may not even be that, depending upon the design. The invention is very versatile in this respect and may carry a wide variety of barges or even lighters and other containers, if that is desired. Other tiering systems can be used; and, of course, it will be apparent that other gate structures can be used, so long as they meet the functional requirements which have been either expressed or implied in the previous description. The Three-Tier Barge Carrier 300 of Figs. 33-42 Figs. 33 to 42 show another three-deck barge carrier 300 which is adapted to deal with some particular situations that will be related in this description.

The barge carrier 300 has three tiers, 301, 302, and 303 of longitudinal barge-stowage holds. The lowermost tier 301 has three longitudinal holds, 304, 305, and 306; the intermediate tier 302 has three longitudinal holds, 307, 308, and 309; and the upper tier 303 has three longitudinal holds, 310, 311, and 312. Each tier thus has a starboard hold, a port hold, and a central hold.

In line with the lowermost central hold 305 is an engine compartment 313 (see Fig.36), which includes the steering gear, the propelling machinery, the diesel engine, and so on. Because of this structure, it is of course not practical to have a central stern gate. In the carrier 300, therefore, there are two stem gates, as shown in Figs. 36 and 39; a starboard stern gate 315, and a port stern gate 316. The starboard stern gate 315 leads into a barge lock 317, closed at the other end by three pairs of lock gates; lowermost lock gates 318 leading into the lowermost starboard hold 304, intermediate lock gates 319 leading into the intermediate starboard hold 307, and uppermost lock gates 320 leading into the uppermost starboard hold 310.

The port stern gate 316 leads directly into a barge stowage area 321 which is in line with the lowermost port hold 306 and is separated from it by a watertight door arrangement 322. The lock gates 318, 319, and 320 and the watertight door 322 may all be as shown in earlier Figs. 17 or 20. The port stern gate 316 is used only for loading the port and central holds 305 and 306 of the lowermost tier 301.

A longitudinal bulkhead 323 divides the central hold 305 from the starboard hold 304, a bulkhead 324 divides most of the central hold 305 from the port hold 306, while a strengthened archway 325 in line with the bulkhead 324 provides beneath it a passageway 326 connecting these two holds 305 and 306. The transfer may be made with the aid of water jets, as described previously, or with winches, and winches may be employed to aid in loading all of the lowermost holds 304, 305, and 306 with barges.

Thus, the central and port holds 305 and 306 are loaded through the stern gate 316, the door 322, and the passageway 326. So far as the lowermost tier 301 is concerned, the starboard stern gate 315 is used to load only the starboard hold 304. Normally, the lowermost tier 301 is the first tier to be loaded and the last to be unloaded.

The intermediate tier 302 and the upper tier 303 are loaded solely through the starboard stern gate 315 with the aid of the barge lock 317. The port stern gate 316 is used only for loading the holds 305 and 306 of the lowermost tier 301.

For the intermediate tier 302 (see Fig.35) the barge lock 317 is operated basically as has been described in connection with Figs. 3 and 21-24. The barges are loaded aboard one at a time and either stowed in the starboard hold 307 or transferred to one of the other two holds 308 and 309 and stowed there. For this purpose there is a longitudinal bulkhead 330 between the starboard hold 307 and the central hold 308 and an archway 331 with a passageway 332 which leads from the starboard hold 307 to the central hold 308 and vice versa. Similarly, there are two bulkheads 333 and 334 in line with each other to separate most of the center hold 308 from the port hold 309, and these are joined together by an archway 335 providing a passageway 336 for transfer between the two holds 308 and 309. An archway 337 and a passageway 338 lead into a supplemental center hold 340. The supplemental hold 340 stows one barge of the large size for which this vessel 300 is primarily designed. The uppermost tier 303 (see Fig.34) is open to the sky; in other words, the holds 310, 311, and 312 have no deck covering them and are open to the sky. This has some advantages, as will be shown later. In this instance, the lock gate 320 is used to move barges into the starboard hold 310, and there may be a short longitudinal bulkhead 345 separating a portion of the hold 310 from the center hold 311; there may also be a short longitudinal bulkhead 346 separating the hold 311 from the port hold 312. There are no arches here, and it will be noted that there is never an arch above another arch. This strengthens the design. There are, however, adequate passageways 347, 348, and 349 for lateral transfer from the starboard hold 310 to the center hold 311 and from the center hold 311 to the port hold 312. The port hold 312 extends full length and must be loaded before the completion of loading of the center hold 311, the loading of which is completed before the starboard hold 310 is fully loaded. There is also a supplemental center hold 350 which is loaded directly from the barge lock 317, preferably after the holds 310, 311 and 312 have been fully loaded. Finally, once the ship is otherwise fully loaded, a barge may be loaded into the barge lock 317 on the lowermost level and retained there. Hold-down devices are used on the barges on at least the lowest level.

The operation of the lock 317 and of the various buoyancy tanks is the same as already has been described. There are several advantages, however, in this special structure. One is that one may use a small electrically powered lock-tug 351 (see Fig. 41) inside the vessel 300 to place the barges in position. (Alternatively, winches may be used and water flow may be used in addition or separately as already described.) The lock-tug 351, shown in Fig. 41, which can be quite small, is built so that it can either push, pull, or attach to the side of a barge to move it. Thus, when a barge has been transferred laterally through one of the passageways 326, 332, 336, 348, or 349, which are not much longer than the length of the barge, the tug 351 may be attached to the barge and the tug may move it fore or aft, depending on what is desired, for a sufficient distance to enable the tug 351 to get into position to push or pull the barge into its desired stowage position. This little tug 351 is used solely inside the vessel 300 and when not in use, may be lifted by a crane 360 and stored on a deck 361.

Use of the tugboat 351 is illustrated in Fig. 37, where its use with one barge 2B4 on the intermediate tier 302 is shown. After the gate 315 has been opened, the barge 2B4 Is floated into the lock 317, in position a. The gate 315 is closed, and water is sent into the lock to raise the barge up to the level of the intermediate tier 302. Then the gate 319 is opened, and the tugboat 351 is connected to the barge by ropes and tows the barge into the hold 307 to position b. The tugboat 351 is then loosed from the barge, and the barge is shifted laterally to position c in the central hold 308, as by water jets. The tugboat 351 is then attached (see Fig.42) as by ropes 352 and 353 secured to its cruciform bitts 354 and 355 to cleats or kevels 356 and 357 along the deck of the barge, and the barge is moved far enough forward to enable the tugboat 351 to get in behind the barge and push it forward to the position d. Again, the barge is laterally shifted, as by water jets or otherwise, to position e in the hold 309. Again, the tugboat 351 is connected by ropes to the kevels or cleats on the barge and the barge is moved forward sufficiently to enable the tugboat 351 to gat in front of it and push it aft to position f. A final lateral shift moves the barge 2B4 into the final stowed position g in the supplementary central hold 350.

The barges shown in positions in Figs 34, 35, and 36 have been numbered to reflect their final position. For this purpose, the barge positions in the uppermost port hold 312 are numbered, from fore to aft, as 1C1, 1C2, 1C3, and 1C4; those in the uppermost central hold 311 are numbered 1B1, 1B2, and 1B3, with the barge in the supplementary central hold 350 numbered 1B4. The barges in the uppermost starboard hold are numbered 1A1, 1A2, and 1A3. Similarly, the barges in the intermediate tier 302 are numbered: 2C1, 2C2, 2C3, 2C4 in the port hold 309; 2B1, 2B2, 2B3 in the central hold 308; the barge 2B4 is in the supplementary central hold 340; and the barges 2A1, 2A2, and 2A3 are in the starboard hold. On the lowermost tier 301, barges 3C1, 3C2, and 3C3 are stored in the port hold 306, and the barge 3C4 is in the stowage area 321; the barges 3B1, 3B2, and 3B3, are in the central hold 305; the barges 3A1, 3A2, and 3A3 are in starboard hold 304; and the barge 3A4 is stored in the lock 317.

Another advantage of the barge-carrier 300 is that on top tier 303, very heavily loaded barges with large size loads may be stored, as shown in Fig. 33. These loads may be far too large to fit into lowermost or intermediate holds, but since the top holds are open to the sky, there is plenty of room there. Note the tanks 362 and 363 shown in Fig. 33. Limitation is determined solely by the amount of clearance provided by the starboard stern gate 315. Since the barges are floated in down near the lowest level, the clearance may be made quite large. Beyond that, the lock 317 also is open to the sky; so once the barge is in the lock 317, the height of its load is no longer a factor.

Furthermore, being open to the sky, the top tier 303 may be loaded by cranes (such as the crane 360) or rollon equipment with ordinary loads or with container loads, when there are no barges to stow there or even if there are some stowed there, so long as space is available.

A non-self-propelled vessel 400 (Figs. 43 to 47) The invention is not limited to self-propelled vehicles. A vessel 400, shown in Figs. 43 to 47, has no engine and no propelling mechanism. Instead it is intended to be pulled or pushed by an ocean-going tugboat 401. In fact, its stern 402 is provided with a keyway 403 into which the prow or bow 404 of a tugboat 401 can fit for engagement into the vessel 400. The vessel 400 is generally like the vessel 300 so far as this invention is concerned, but there are some differences, one of them being that it can accomodate one more barge 3B4 on its lowermost tier 405 of holds 406, 407, and 408, as shown in Fig. 46. The barge 3B4 is loaded via a stem gate 410 (corresponding to the stern gate 316 of the vessel 300), a barge stowage area 411 (corresponding to the area 321), a watertight door 412 (corresponding to the watertight door 322), the hold 408, a passageway 413, and the hold 407, which is extended rearwardly to provide a space 414 for the barge 3B4. The vessel 400 has an intermediate tier 415 of holds 416, 417, and 418, like the tier 302 except that the central hold 417 extends full length, and the loading of the barge 2B4 nearest the stern 410 is therefore more direct. A starboard stern gate 420, a lock 421, and lock gates 422, 423, and 424 are like their counterparts in the vessel 300. Similarly, the uppermost tier 425 of holds 426, 427 and 428 is generally like the tier 303 except that the central hold 427 extends full length. The rearmost central barge 1B4 may be placed in its space either laterally or via the lock 424, as may the barge 1A4 beside it.

A bow-loading vessel 450 (Figs. 48-50) The loading and unloading need not be done at the stern, although that will often be preferred. As shown in Fig. 48, the invention may use a vessel 450 having a visor type bow gate 451 leading into a lock 452, from which a lock gate 455 leads into an intermediate central hold 456. Similar arrangements lead into the uppermost hold, but the gate there is not specifically illustrated, being like the gates 453 and 455, The lower gate 451 may, if desired, be backed up by a collision bulkhead like those shown in our U.S. Patent No. 4,135,468. The central hold 456 on the intermediate level may be separated from a port hold 457 and a starboard hold 458 by respective stanchion bulkheads 459 and 460. In this instance (as in all the longitudinal bulkheads throughout this specification), the bulkheads 459 and 460 do not need to be watertight and therefore may be made, as shown better in Fig. 51, of a series of separated H-beams 461, which may, if desired be connected together by longitudinal aligning members. Watertightness is never required of the longitudinal bulkheads. Similarly, the central hold 454 in the lowermost level may be separated from a port hold 465 and a starboard hold 466 by stanchion bulkheads, or, as shown, by respective plated bulkheads 467 and 468. As shown in more detail in Fig. 52, these may comprise a pair of plates 469 and 470 secured to stanchion beams 461 and with longitudinal strengtheners 471. Arches 472, 473, 474, and 475 may be strategically located in place of bulkheads at certain places to enable transfer between the central holds 454 and 456 and their respective holds 465, 466, 457, and 458. The barge loading operation is basically as described before, except for use of the bow end, the lock 452 being used in the same basic way as the locks previously described. The uppermost tier of holds 476 may be open, as before.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

Claims

AMENDED CLAIMS

(received by the International Bureau on 18 August 1980 (18.08.80))

1. A barge-carrying waterborne vessel having a hull with rigid supporting and hull-reinforcing structure, a bow, a stern, sidewalls providing a series of buoyancy compartments, a hollow hull interior, and a first gate arrangement substantially flush with one end of said vessel for flotation loading and unloading therethrough of the hollow interior with a plurality of barges, characterized in that said hull's hollow interior defines a plurality of tiers of barge holds, one above the other, each hold extending most of the length of said vessel, a loading passage between said first gate arrangement and said holds by which flotation loading and unloading of all said tiers takes place, a second gate arrangement between the loading passage and the lowermost said hold, for converting the loading passage into a lock, when closed, and when open, for enabling transfer by flotation between the loading passage and the lowermost hold, and a system for supplying water to and removing it from each said hold and, separately, for supplying water to and removing it from said loading passage, when all said gates are closed, so that barges can be flotation loaded into their stowage position in the holds.

2. The vessel of claim 1 characterized by a plurality of holds at each said tier, the holds being separated on each tier by longitudinal bulkheads.

3. The vessel of claim 2 characterized in that the holds are vertically aligned in vertical rows from tier to tier, said first gate arrangement comprising a separate gate for each vertically aligned row, said loading passage comprising a separate passage and therefore a separate lock for each vertically aligned row, with a separate second gate arrangement for each hold and separate flooding and draining of each row of each tier for each said lock.

4. The vessel of claim 2 characterized by having two tiers of holds and a single loading passage for both said tiers of holds, said first gate arrangement comprising a single gate for passage therethrough of only one barge at a time, said loading passage being wide enough to provide at its upper level, substantially level with the upper holds, an upper lateral transfer bay, wide enough to load barges simultaneously by flotation into each, upper hold, and shifting apparatus for moving a barge laterally by flotation in said upper transfer bay, the lower portion of said loading passage being wide enough to accommodate a single barge only and a lower lateral transfer bay separated from said loading passage by said second gate arrangement, which constitutes a single gate, said lower transfer bay having shifting apparatus for moving a barge laterally therein by flotation.

5. The vessel of claim 4 characterized by a single-barge-width storage bay between said second gate and said lower transfer bay.

6. The vessel of claim 4 or 5 characterized in that said loading passage is shaped as a central lower portion with a bottom and sidewalls and a wider upper portion having sidewalls joined to those of the lower portion by shelves, and a retractable barge-support projectable out from the upper portion of said sidewalls of the lower portion substantially on the level of said shelves.

7. The vessel of any of claims 1 to 3 characterized in that there are three said tiers and a third gate arrangement for the tier in between the upper and lower tiers in between the hold and the loading passage, the system for supplying water to the holds and locks providing flotation loading and flotation stowage for each tier of the holds.

8. The vessel of any of claims 1 to 7 characterized by having at each tier a gate between the loading passage and each hold of that tier.

9. The vessel of any of claims 1 to 8 characterized by having a barge-retention system in said hold for holding each said barge down against the bottom of its said hold, for preventing movement of the barges, and for enabling exchange of buoyancy between each said barge in said lower hold and said vessel when said lower hold is flooded.

10. The vessel of any of claims 1 to 9 characterized by a barge-moving system inside said hollow interior, comprising a plurality of flow-creating apparatus for causing flow of water to move barges in each said hold in one direction during flotation loading and in the other direction during flotation unloading.

11. The vessel of any of claims 1-10 characterized by a plurality of charge tanks, one directly below said loading passage and at least one on each side of said loading passage, said system providing for transferring water between said charge tanks and said loading passage and also for transferring water between said loading passage and the sea and for transferring water between said charge tanks and the sea.

12. The vessel of claim 11 characterized by trim tanks at the bow end of the vessel and a system for transferring water from the sea thereinto and water from there into the sea.

13. A barge-carrying flotation-loaded waterborne vessel having a hollow interior defining a plurality of vertically disposed tiers of longitudinal barge holds, each with apparatus to supply barge-flotation water thereto, characterized by at least one loading lock at one end of the vessel, a pumping system for supplying water to and removing it from each said lock, a gate for opening each said lock to the sea for flotation loading and unloading of a barge, and a plurality of separate lock gates, each connecting a said lock to one said hold so that the barge can be floated from the lock into its stowage position in the hold.

14. The vessel of claim 13 characterized by having three said tiers with three longitudinal barge holds on each said tier vertically aligned with the holds of the other tiers, and three said locks.

15. The vessel of claim 14 characterized in that the end gates comprise a transom at said stern, four spaced-apart gate posts, one on each side of the transom, extending above said transom, and two others spaced between them to provide three gate openings, a gate slidable vertically in between each successive pair of said gate posts and in each said gate opening, means for enabling said gate to withstand hydraulic pressure exerted from each side thereof when air is on the other side, and opening and closing means for raising and lowering said gate.

16. The vessel of claim 13 characterized in that there is a single lock and a single end gate comprising a stern transom, having a gate opening therethrough between sidewalls, a pair of spaced-apart gate posts extending above said transom in line with the sidewalls of the gate opening, a gate slidable vertically in between said gate posts and in said gate opening, means for enabling said gate to withstand hydraulic pressure exerted from each side thereof when air is on the other side, and an opening and closing device for raising and lowering said gate.

17. The vessel of any of claims 13 to 16 characterized in that each lock gate for an upper hold comprises a pair of gate portions hinged-together about a vertical axis and including apparatus enabling the gate, when closed, to withstand large hydraulic pressures exerted separately against each side thereof, the vessel having a recess to accommodate the opened gate so that opening does not narrow the barge passage, so as to enable folding of the portions together and into the recess, one gate portion being vertically pivotally supported, and a power device for swinging the lock gate to one side about the pivot and into the recess while folding the gate portions together.

18. The vessel of any of claims 13 to 17 characterized in that there is a single lock gate for the lower hold and wherein that said lock gate comprises two separate but meeting laterally slidable members, and recesses in said vessel for receiving the slidable members when that lock gate is opened.

19. The vessel of any of claims 13 to 18 characterized by a series of charge tanks at the stern end of said vessel, one below and some to each side of said lock or locks, said pumping system enabling transfer of water between said lock and said charge tanks.

20. The vessel of any of claims 13 to 19 characterized by trim tanks at the bow end of said vessel and apparatus for transferring water between said trim tanks and the sea.

21. The vessel of any of claims 13 to 20 characterized by barge-moving means in each of said holds and the associated transfer area thereof.

22. A waterborne vessel for carrying very heavy loads on deck, including in combination a hull with rigid supporting and hull-reinforcing structure, a bow, a stern, and sidewalls providing a series of buoyancy compartments, said hull having a hollow interior hold and a strong wellsupported main deck, characterized by a flotation loading system at one end of said hull having a passage with a deck and walls extending up thereabout, special buoyancy and charge tanks adjacent the loading passage comprising an upper tank and a lower tank on each side of the loading passage and also a tank beneath the loading passage deck, and a water circulation system for passing seawater directly into and out from said loading passage and directly into and out from each of said special buoyancy and charge tanks and also directly between said loading passage and each of said special buoyancy and charge tanks.

23. The vessel of claim 22 characterized by additional buoyancy tanks at the opposite end of said vessel, and a pumping system for pumping seawater directly into and out from said additional buoyancy tanks.

24. A method for use in a deepwater port for flotation loading of barges aboard a carrier vessel having buoyancy tanks and two tiers of barge-carrying holds, one tier above the other, each said hold being connected by a normally closed inner gate to a loading passage which is connected to the sea by an outer, normally closed, gate, comprising the steps of: (1) placing water inside each hold of the upper tier and its loading passage at sufficient depth for floating barges into each hold of the upper tier, (2) shipping water into the buoyancy tanks to bring the waterline of the vessel to the level of the water inside the holds of the upper tier, (3) opening the inner gates connecting each hold of the upper tier to its loading passage, (4) opening the outer gate or gates to place each loading passage in communication with the sea, (5) floating barges into each loading passage and thence into the holds of the upper tier until those holds are loaded, (6) closing the inner gates between the holds of the upper tier and their loading passage, (7) closing the outer gate or gates to isolate the loading passage or passages from the sea, (8) drying out said upper tier of holds and placing water inside the holds of the lower tier, (9) replacing water inside said buoyancy tanks with air to raise said vessel to a waterline substantially the same as the water level inside said lower holds, while lowering the water level inside each said loading passage to the level of the water inside the lower holds, (10) opening the inner gates between each lower hold and its loading passage, (11) opening the outer gate or gates, (12) floating barges into each said loading passage and thence into each said lower hold until that hold is loaded, (13) closing those inner gates, (14) closing the outer gate or gates, and (15) drying out said lower holds and the loading passage or passages.

25. The method of claim 24 characterized by including the step, after step (13) and before step (14) of floating at least one barge into the loading passage means and later receiving it there.

26. The method of either of claims 24 or 25, wherein said loading passage includes a shelf at about the level of said upper tier, characterized by including the step after step (6) and before step (7) of loading at least one barge on said shelf and projecting out from beneath said shelf means a retractable support before settling the barge on said shelf.

27. The method of any of claims 24 to 26 characterized by including the step of securing all the barges on the lower tier and holding them down with force sufficient to enable transfer of buoyancy between said barges and said vessel when said lower tier is flooded.

28. A method for use in a shallow-water port for flotation loading of barges aboard a carrier vessel having a plurality of tiers of a plurality of bargecarrying holds , one tier above another , and a loading passage between each hold and an end of the vessel, with a normally closed inner gate between each hold and its loading passage and a normally closed outer gate between each loading passage and the sea, comprising the steps of: (1) placing water inside each loading passage sufficient to float a barge at the waterline of the vessel, (2) placing water inside each upper hold sufficient to float a barge, (3) opening each outer gate to place its loading passage in communication with the sea, (4) floating a barge from the sea into the loading passage, (5) closing the outer gate to isolate the loading passage from the sea, (6) raising the water level in the loading passage to place the barge therein on a level with an upper said hold, (7) opening the inner gate between said loading passage and said upper hold, (8) floating the barge into said upper hold, (9) closing the inner gate between the loading passage and said upper hold, (10) lowering the water level in said loading passage to the vessel's waterline, and (11) repeating steps (2) -(10) until said upper holds are loaded, (12) pumping the upper holds dry, (13) opening the inner gates between each lower hold and its loading passage, (14) opening the outer gate, (15) floating barges via said loading passage into said lower hold until said lower holds are loaded, (16) closing the inner gate between each said lower hold and its loading passage, (17) floating a barge into each loading passage, (18) closing the outer gate, and (19) pumping the lower hold and loading passage dry.

29. The method of claim 28 wherein there is a single said loading passage having a shelf at about the level of said upper tier, characterized by including the steps after step (16) and before step (17) of (a) floating a barge into said loading passage, (b) closing the outer gate, (c) raising the water level in said loading passage above said shelf, (d) locating the barge on shelf means, (e) lowering the water level in said loading passage to said waterline level, and (f) opening said outer gate.

30. The method of claim 29 wherein there is a series of lock charge tanks, one beneath said loading passage or passages and at least one on each side thereof, characterized by including the steps of exchanging the rater in steps (10) and (6) on each repetition, (1) on repetitions also, and in steps (c) and (e) between said loading passage and said lock charge tanks, as appropriate.

31. The method of claim 30 wherein, at the opposite end of the vessel from the loading passage or passages there are lock trim tanks, characterized by including the steps of varying the amount of water in the lock trim tanks from empty to various amounts sufficient to keep the vessel in trim and horizontal at all times during the stated method steps.

32. The method of any of claims 28 to 31 wherein there are two tiers of barge-carrying holds, each tier having a plurality of said holds, and a single loadingpassage between the holds and an end of the ship, with a normally closed inner gate between the loading passage and each of the holds and a normally closed outer gate between the loading passage and. the sea, said loading passage on the lower level being wide enough to accommodate a single barge and having a shelf on the level of the upper tier of holds, the loading passage above the shelf being wider than a plurality of said barges, there also being a transfer bay on the lower tier between the inner gate and the lower holds, wider than a plurality of said barges, comprising replacing the steps (12) to (20) with the following steps: (12) pumping the upper holds dry and placing water in said transfer bay and said lower holds sufficient to float a barge, (13) opening the gate between said transfer bay and said loading passage, (14) opening the outer gate, (15) floating barges via said loading. passage and transfer bay into said lower holds until said all lower holds and the transfer bay are loaded as desired, (16) closing the inner gate between said transfer bay and said loading passage, (17) floating a barge into said loading passage, (18) closing the outer gate, (19) pumping the lower hold and transfer bay dry, (20) raising the water level in said loading passage to lift the barge therein above said shelf means, (21) lowering the water level in said loading passage to the waterline level, while lowering the lifted barge supported on said shelf means, (22) opening said outer gate, (23) floating a barge into said loading passage, (24) closing the outer gate, and (25) pumping the loading passage dry.

33. The method of claim 32 characterized by, after step (6) and before step (8), shifting the barge laterally to align it with a chosen said upper hold.

34. The method of claim 32 comprising at step (15), laterally shifting each barge in said transfer bay between a generally central position to one in line with a selected lower hold.

35. The method of either of claims 33 or 34 characterized in that said shifting involves projecting water jets on the sidewalls of the barge.

36. The method of any of claims 28 to 35 wherein said lower holds lie well below waterline, characterized by, in steps (13) to (15), the steps of: (a) opening the outer gate, (b) floating a barge into said loading passage, (c) closing the outer gate, (d) lowering the level of water in said loading passage to the level of that in said lower holds, (e) opening the lower inner gate, (f) floating the barge into said transfer bay, (g) laterally shifting the barge to place it in lines with a selected lower hold, (h) floating the barge into the selected lower hold, (i) closing the lower inner gate, (j) raising the level of water in the loading passage to the vessel's waterline, (k) repeating steps (a) to (j) until said lower holds are loaded, and (1) floating a barge into said transfer bay..

37. The method of any of claims 32 to 36 characterized by including between steps (20) and (21) the step of projecting out horizontally from beneath said shelf a series of retractable supports for the barge to rest on while resting on the shelf.

38. A method for loading a very heavy and voluminous cargo item onto the deck of a vessel having a series of large capacity buoyancy tanks along its length and also having a gate at one end leading into a flotation- loading hold, comprising the steps of loading the item onto a rolling support on a trimmable barge, trimming the barge to have a fore-and-aft trim angle between 1° and 5°, trimming the vessel at the same angle by admitting water to said flotation-loading hold and to adjacent buoyancy tanks, while keeping air in buoyancy tanks at the opposite end of the vessel, to obtain substantially the same angle of trim as the barge, bringing the gate end of the vessel against the bow of the barge and with its deck at the same height above water, rolling the cargo on said rolling support from the barge to the vessel's deck and to a desired location on the deck, and then retrimming the vessel to horizontal and adjusting its waterline to its desired waterline.

39. A method for loading a very heavy and voluminous cargo item from a pier onto the deck of a vessel having a series of large capacity buoyancy tanks along its length and also having a gate at one end leading into a flotation-loading hold, comprising the steps of placing the item on a self-propelled rollable support,

placing a ramp on the edge of said pier having an upward inclination of 1° to 5°, ballasting and trimming the vessel to place the deck at its gate end at substantially the level of the upper end of the ramp and the vessel at a trim angle substantially the same as that of the ramp, bringing the vessel's gate end against the upper edge of the ramp, and rolling the item on said rollable support up the ramp, into the vessel's deck, and therealong to a desired loca- tion on the deck, and then retrimming and reballasting the vessel to a proper seagoing waterline and trim.

40. A waterborne vessel having a hull with an interior hold, characterized by a stern transom at the stern of the vessel having a gate opening therethrough between sidewalls leading into said interior hold, a pair of spaced-apart gate posts extending above said transom in line with the sidewalls of the gate opening, a gate slidable vertically in between said gate posts and in said gate opening, apparatus enabling said gate to withstand high hydraulic pressures on each side thereof, and apparatus for raising and lowering said gate.

41. A waterborne vessel having a hull with an interior hold, and a gate in said hold dividing the hold into two portions, characterized by a pair of gate portions hinged together about a vertical axis so as to enable folding of the portions together, one said gateportion being vertically pivotally supported, apparatus for swinging said gate to one side about the pivot while folding the gate portions together, and a recess in the hold to accommodate the opened gate so that opening does not narrow the barge passage.

42. A waterborne vessel having a hull with an interior hold and a gate in said hold dividing the hold into two portions, characterized by said gate having two separate but meeting laterally slidable members and by recesses in said vessel's hold for receiving the slidable members.

43. A barge-carrying waterborne vessel having a hull with a hollow interior, characterized by three tiers of longitudinally extending barge holds, in said interior, one above the other, each tier having three such holds, one hold on each side and a central hold in between, the holds of each tier being separated from each other by longitudinal bulkheads, said hull having a stern end with a central engine compartment in line with said central hold of the lowermost said tier and in between the two side holds of the lowermost said tier, a first stern gate at said stern in line with one said side hold of said lowermost tier for flotation loading and unloading thereof, a second stern gate at said stern in line with the other side hold of said lowermost tier for flotation loading and unloading thereof, that said hold having its bulkhead provided with a lateral passage between it and said lower- πost central hold, a first lock gate spaced longitudinally from said first stern gate in said lowermost hold, with a barge lock in between it and said first stern gate, a second lock gate above said first lock gate between said lock and a hold of the intermediate tier of holds, and a third lock gate above said second lock gate between said lock and a hold of the uppermost tier of holds, said intermediate and uppermost tiers of holds each having a passage or passages through its bulkheads at suitable locations for enabling lateral transfer by flotation of barges from one said hold to another.

44. A barge-carrying non-self-propelling waterborne vessel having a hull with a hollow interior, characterized by: three tiers of longitudinally extending barge holds, one above the other in said interior, each tier having three such holds, one hold on each side and a central hold in between, the holds of the lowermost and intermediate tiers being separated from each other by longitudinal bulkheads, said hull having a stern end with a central bearing surface for engagement by the bow of a pushing tugboat, a first stern gate at said stern in line with one said side hold of said lowermost tier for flotation loading and unloading thereof, a second stern gate at said stern in line with the other side hold of said lowermost tier for flotation loading and unloading thereof, that said hold having its bulkhead provided with a lateral passage between it and said lowermost central hold, a first lock gate spaced longitudinally from said first stern gate in said lowermost hold, with a barge lock in between it and said first stern gate second lock gate above said first lock gate between said lock and a hold of the intermediate tier of holds, and third lock gate above said second lock gate between said lock and a hold of the uppermost tier of holds, said intermediate tier of holds having a passage through its bulkheads at suitable locations for enabling lateral transfer by flotation of barges from one said hold to another.

45. The vessel of claim 43 or 44 chararacter- ized by an additional gate spaced longitudinally from said second gate and in line with its said hold and providing between said second and third gates a barge-stowage passage.

46. The vessel of claim 43 or 44 characterized by said lock and said uppermost hold being open on top.

47. The vessel of claim 43 or 44 characterized by a supplementary central hold over said central engine compartment at each of said intermediate and uppermost tiers, each separated from said central hold of its tier, with a passage for transferring a barge laterally thereinto.

48. The vessel of claim 43 characterized by- having a small electric-powered tugboat in said vessel for aiding in moving the barges within said vessel both longitudinally and laterally.

49. A barge-carrying waterborne vessel having a hull with a hollow interior and characterized by three tiers of longitudinally extending barge holds, one above the other, each tier having three such holds, namely, a port hold, a starboard hold, and a central hold, each extending most of the length of said vessel, the holds of each tier being separated from each other by longitudinal bulkheads, the uppermost said tier being generally open at the top and having its bulkheads interrupted to provide passage for lateral transfer of barges from one hold to another, a first gate at said bow in line with said central holds for flotation loading and unloading thereof, a barge lock aft of said bow gate and in line with said central holds, a second gate, at the opposite end of said lock from said first gate and in line with and leading into said lowermost central hold, said lock also providing between said first and second gate a barge-stowage passage, a third gate at the opposite end of said lock from said first gate and in line with and leading into said intermediate central hold, said barge lock being open at its upper end, and a fourth gate above said third gate between said lock and the central hold of the uppermost tier of holds, each said tier of holds having a passage system through its bulkheads at suitable locations for enabling lateral transfer by flotation of barges from each said central hold to its adjacent starboard and port holds.