An improvement in a barge-carrying flotation-loaded waterborne vessel. A hollow interior defines upper and lower longitudinal barge holds arranged in vertical rows of aligned tiers, each hold being flooded during the time it is loaded and unloaded. There is at least one loading lock at one end of the vessel for enabling flotation loading of each vertical row of barge holds; each lock has a pair of side bulkheads and a bottom, and gate means for separating the lock from and opening it to the outside for flotation loading and unloading of one barge at a time. There is also a separate lock gate for each tier of each row for connecting a hold of each row to a lock. In each lock there are sets of barge support panels, each pivotally attached by a horizontal longitudinally extending pivot to one of the side bulkheads, at least one set being disposed on each side of the lock adjacent to and approximately on a level with each upper longitudinal barge hold. Associated with each set of barge support panels is an erection system for swinging panels up from a vertical storage position to a horizontal barge-supporting position. First locking and releasing means secure each panel in its vertical storage position and release each panel for movement to its load-supporting position. Second locking and releasing means secure each panel in its horizontal barge-supporting position and release each panel to return to its vertical storage position.

BACKGROUND OF THE INVENTION 
This invention relates to a barge-carrying water-borne vessel with at least 
two tiers of barge holds and a lock for flotation loading of barges into 
those holds. More particularly, the invention relates to a means for 
employing the otherwise unoccupied space of the lock for stowing a 
plurality of barges during a voyage. The invention also relates to a 
bow-loaded multi-tiered vessel using locks for flotation loading. 
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 onto ocean-going vessels, sent to 
other ports across the sea, unloaded there, and reloaded in many instances 
onto other barges to be shipped up another river system. In recent years, 
however, the costs of loading and unloading cargo have risen higher at an 
ever-increasing rate. Containerizing of cargoes has 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, and the time required for 
transportation. 
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 heavy; cranes or elevators to lift them would be very 
expensive. In fact, large river barges cannot be lifted by cranes or 
elevators. 
Recent inventions such as our U.S. Pat. No. 3,913,512, issued Oct. 21, 
1975, and our co-pending application, Ser. No. 105,414, now abandoned, 
filed Dec. 19, 1979 have proposed flotation loading of barges and other 
cargo-carrying containers into barge-carrying ships. 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 long relative to their beam. The barges used on the 
Mississippi and Rhine rivers, for example, are very long compared to their 
width; the Mississippi barges are more than 60 meters long and more than 
10 meters wide. For a barge-carrying system to be practical, the 
ocean-going, barge-transporting vessel must be able to carry many barges. 
A ship able to accommodate only a single line of barges would, of 
necessity be extraordinarily long and narrow to be profitable. This 
general problem was solved in our U.S. Pat. Nos. 3,978,806, issued Sept. 
7, 1976; and 4,135,468, issued Jan. 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. Pat. No. 4,147,123, which 
issued Apr. 3, 1979. 
A problem that arises as soon as one attempts to load two or more tiers of 
barges in a single vessel, is the problem of draft. A few ports can 
accommodate drafts up to 75 or 80 feet, drafts that exceed those of most 
vessels, so that their depths would accommodate a ship loading two or more 
tiers of barges. However, most ports have depths less than 40 feet. A 
system restricted to voyages between deep-draft ports would not be 
econimically practical. For this reason, the preferred form of these 
barge-carrying vessels has a lock disposed at one end, for hydraulically 
elevating barges to the various tier levels in floatation loading. This 
broadens the range of barges on which the system can operate; not 
requiring any special roller mechanisms for dry loading and unloading. It 
also increases the number of ports which may be serviced. 
The economic feasibility of this mode of transportation depends on being 
able to load and carry the maximum amount of cargo in a minimum of space. 
Each unused or unusable area in the vessel detracts from its 
profitability. It is, therefore, desirable to maximize a vessel's 
efficiency by using as much potential cargo-carrying space as possible. 
To that end, a problem has arisen. The space occupied by the loading lock 
has been generally unusable for the transportation of cargo. At best, it 
had been possible to store and transport one barge on the bottom of a 
lock. Since the lock typically extends from the lowest tier to the upper 
deck of such vessels, space which could otherwise be used to store at 
least one extra barge for each tier of longitudinal barge holds serviced 
by the lock has remained unused. This was primarily because of an 
inability to securely support barges at multiple levels of a loading lock 
without interfering with the operation of the lock when loading. 
One recently proposed system as illustrated in our co-pending application 
Ser. No. 105,414, now abandoned employs horizontal barge support members 
which can be projected our from and retracted into the side bulkheads of a 
loading lock. This solution, however, gives rise to other problems of 
inefficient space use because storage space on the sides of the lock's 
bulkheads is required to receive these sliding supports when they are not 
in use. This reduces the otherwise usable storage space and severely 
limits the number of adjacent, independently operating locks which may be 
disposed together at the end of a vessel. 
Heretofore, no one has proposed a feasible system of this kind. For 
example, the vessel shown in the Vargas U.S. Pat. No. 3,939,790, which 
issued Feb. 24, 1976, involves flotation loading and unloading and 
accommodates up to three tiers of relatively small lighters, especially 
designed to be lifted or hung by their ends, but the vessel cannot support 
full size river barges. Vargas shows a hold having supporting brackets 
which are movable out of the side walls of the dock chamber. The Vargas 
supports are stored flush against the side walls or bulkheads in a recess, 
and swing out along a vertical axis to provide points of support to the 
side edges of barges. The supports are received by sockets in the lash 
type barges which the system is designed for, and requires careful 
placement of the barge. These supports, however, are designed for loads 
which are far lighter than the barges transported in the vessel of the 
present invention. Furthermore, since only points of support are provided, 
and not an extended surface on which to support the barges, a great deal 
of instability is inherent in the use of the system. 
Thus, an important object of the invention is to provide a means and a 
method for supporting a barge at each level within a loading lock. 
Another object is to provide barge support means entirely disposed at all 
times within the lock, and yet not interfering with the loading operation. 
Another object of the invention is to provide a broad support surface for 
supporting a barge at various upper levels in the lock of a barge-carrying 
vessel, the apparatus providing the support surface being readily stored 
in the side bulkheads of the lock, yet easily and automatically erected, 
and not interfering with lock operation. 
Yet another object of the present invention is to provide an efficient and 
simple system for maximizing the usuable barge transporting area of a 
flotation-loading waterborne vessel to include the upper areas of the 
loading locks. 
SUMMARY OF THE INVENTION 
The invention comprises a series of load-supporting panels on each side of 
each deck level of each loading lock for a flotation-loaded and 
flotation-unloaded barge carrier. Each panel has a plurality of 
spaced-apart, parallel support arms comprised of a buoyant section and an 
attachment section, the buoyant sections have a plurality of grate or 
platform sections disposed between adjacent support arms. The sets of 
panels of the invention, preferably four panels per barge, two on each 
side of the lock, are swingingly attached along a horizontal pivoting axis 
to corrugated side bulkheads in the lock chamber. 
The invention provides means for automatically erecting and stowing the 
sets of barge-supporting panels. Such means include buoyancy tanks, which 
are part of the support arms of the panels, having flood valves associated 
with barge-actuated valve controls for flooding and emptying the buoyancy 
tanks. Locking mechanisms, for securely holding the panels in the erect, 
barge-supporting position are also provided. These locking or securing 
means include either a lock pin arrangement or a lock stop arrangement. 
The method of the invention involves, first, loading the main barge holds 
of the vessel and then floating a barge in the lock to the level of the 
uppermost deck, and erecting and securing in place support panels in the 
lock under the barge. In the next step, the water level in the lock is 
lowered, and the barge settles on the panels, and is secured there. If 
there is a plurality of main holds, the invention calls for accommodating 
a barge at each deck level in the same manner. Finally, a barge may also 
be stowed on the lock bottom level. 
Unloading is accomplished by first releasing any barge stowed on the lock 
bottom. Then the next, lowermost, lock-stowed barge is released from being 
secured for transportation. The lock water level is raised to float the 
barge, and then the support panels beneath it are stowed. The lock water 
level is lowered to the vessel's waterline, the barge is floated out, and 
the process repeated for other barges stored thereabove in the lock. Then 
the holds are unloaded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The vessel 30 
(FIG. 1) 
As illustrated in FIG. 1, the invention pertains to a barge-carrying vessel 
30, designed for flotation loading and unloading. The vessel 30 has a 
series of compartmented port, starboard, and bottom buoyancy tanks 31, 32, 
and 33 for raising and lowering the vessel with regard to the vessel's 
waterline. There are also lock trim buoyancy tanks 34 at the bow end of 
the vessel 30, all generally as in our co-pending application Ser. No. 
105,414, filed Dec. 19, 1979, now abandoned. The vessel 30 has a plurality 
of longitudinal barge holds 35 at several deck levels, in each of which 
barges may be carried. In the embodiment illustrated in FIG. 1 there are 
four vertical rows of barge holds: port outboard holds 36, port inboard 
holds 37, starboard inboard holds 38, and starboard outboard holds 39. 
Barges 40 are shown being carried on four deck levels: a first bottommost 
tier 41 above the bottom buoyancy tank 33, a second tier 42 thereabove, a 
third tier 43 above that, and a topmost fourth tier 44 or upper deck, 
which may be open to the sky. The barges 40 are orientated longitudinally 
in the holds 35, parallel with the direction of the vessel 30. Here, there 
are sixteen holds 35, four parallel rows of longitudinal barge holds at 
each of four deck levels. There may be fewer levels or rows in both. 
A number of barge locks are disposed at the stern 45 of the vessel 30 to 
enable flotation loading and unloading. There is preferably one barge lock 
for each longitudinal row of barge holds 35. As shown in FIG. 1 there is a 
port outboard barge lock 46, a port inboard barge lock 47, a starboard 
inboard barge lock 48, and a starboard outboard barge lock 49. Each barge 
lock has a water-tight inner barge lock gate for each of the barge hold 
levels. In the embodiment illustrated at FIG. 1 each of the barge locks 
has a first tier inner gate 51, a second tier inner gate 52, a third tier 
inner gate 53, and a fourth tier inner gate 54. Each of the barge locks 
46, 47, 48, 49 further has a respective water-tight stern gage 56, 57, 58, 
59, each with mechanical, pneumatic, or hydraulic elevating means for 
raising and lowering its stern gate. 
Barges 40 are loaded onto the vessel 30 by first opening one or more of the 
barge lock stern gates 56, 57, 58 or 59. Minimum vessel draft when loading 
and good trim may be obtained by loading simultaneously with two locks on 
opposite sides of the vessel's centerline and by operating them so that 
two locks are filled while two are empty of water. The vessel's 
compartmented buoyancy tanks 31, 32, and 33 are used to adjust the bottom 
level of the barge locks 46, 47, 48, 49 to lie beneath the waterline, by 
at least the draft of a loaded barge 40. The barge is floated into one of 
the locks 46, 47, 48, 49 without interference from the vessel 30. Only one 
tier at a time is flooded with water and loaded (typically beginning with 
the top tier 44 and working down), and it is flooded to a level greater 
than the draft of a typical barge 40, or approximately three meters. The 
barge lock stern gate 56, 57, 58, or 59 is closed, and the barge lock 46, 
47, 48, 49 is filled with water, which may be pumped in by a barge lock 
pump (not shown) to a water level appropriate for the tier 41, 42, 43 or 
44 being loaded. The barge 40 rises in the lock 46, 47, 48 or 49 as the 
water level rises. When the water level is to the deck level desired, the 
matching inner barge lock gate 51, 52, 53, or 54 is opened, and the barge 
40 is floated forward into a hold 35 and floated forward to the position 
in which it is to be stowed during the voyage. Once the barge 40 is fully 
inside its hold, the inner barge lock gate 51, 52, 53, or 54 is closed, 
and the water level in the lock 46, 47, 48 or 49 is lowered back down to 
the waterline. Then the barge lock stern gate 56, 57, 58, or 59 is opened, 
and another barge 40 is loaded into that lock. 
Once the uppermost tier 44 has been loaded to capacity with barges 40, the 
next lower tier 43 is loaded, then the next lowest tier 42 is loaded, and 
finally the lowest tier 41 is loaded. Once the tiers have been loaded, the 
lock is not longer needed as a lock until the barges 40 are unloaded. It 
is desirable to stow another barge 40 for each tier in each lock during 
the voyage, to make complete use of all available cargo space and to 
increase the vessel's efficiency. 
The barge support panels 60 
(FIGS. 2 and 3) 
Barge storage within the locks 46, 47, 48, or 49 is facilitated by a 
plurality of barge support panels 60; a set 61 of four panels 60, as 
illustrated in FIG. 2, is preferably used to support each large barge 40. 
There may be a set 61 at each upper tier 42, 43, and 44, but not at the 
bottom-most tier 41, where the barge 40 can rest on the bottom of the 
lock. For example, in the vessel 30 shown in FIG. 1, each barge lock 46, 
47, 48, and 49 would have three sets 61 of barge support panels 60, one 
set 61 adjacent to the second tier 42, one set 61 adjacent to the third 
tier 43, and a set 61 adjacent to the uppermost tier 44 (see FIG. 9). 
Each panel 60 has a series of support arms 62 spaced apart from each other 
and having a top surface 63 and joined to each other by a series of metal 
gratings 64 flush with the top surface 63. The gratings 64 may be welded 
to the arms 62. The weight of a barge 40 on a set 61 is thus (in this 
example) borne by four panels 60 and, in each panel, directly or 
indirectly by the support arms 62 of each panel 60. The gratings 64 let 
water pass through freely in order to lessen the load during erection of 
the panels 60. In a preferred embodiment there may be eight support arms 
62, each designed to support a load of fifty-two metric tons, and each 
panel 60 may be designed to support four hundred sixteen metric tons, 
since a loaded Mississippi river barge 40 typically weighs one thousand 
six hundred fifty metric tons. 
The support-arm 62 
(FIGS. 3-5 and 7) 
Each support arm 62 (see FIGS. 4 and 5) is preferably an integral member 
comprising a buoyancy tank 65 as a major portion thereof and a pivoted end 
member 66 with a horizontal pivot opening 67 therethrough, about which the 
arm 62 swings from its vertical storage position to its horizontal support 
position. 
Each panel 60 is pivotally attached to the structure of the ship along a 
horizontal axis 69 (see FIG. 3). The side walls of the lock are preferably 
corrugated bulkheads 70 having a series of projections 71 and recesses 72. 
Those corrugated bulkhead projections 71 which are disposed adjacent to a 
panel 60 are preferably truncated and provided with connecting webs 73 set 
back from the normal extremity of the projections 71 by a distance equal 
to the thickness of the grating 64. This enables the grating 64 to lie 
flush against the side bulkheads 70 when the panels 60 are in their 
storage position. For those lock walls which separate one lock from 
another, the corrugations mean that the panels in one lock are slightly 
out of line with those of the next lock, since the projections for one 
lock are the recesses of the other one. 
FIGS. 3, 4, and 7 illustrate one means of attachment of the support arms 62 
relative to the bulkhead 70. In this form of the invention, a pivot pin 75 
extends through and beyond the pivot opening 67 and a pair of pin travel 
blocks 76 and 77 and are secured to the ends of the pin 75, one on each 
side of the end member 66. 
Each travel block 76 and 77 is arranged to travel up and down in a guideway 
78, and a spring 79 urges each block 76, 77 upwardly, as by exerting pull 
on it. Thus, the support arms 62 can swing between a vertical storage 
position (FIG. 8) and a horizontal load-supporting position (FIG. 5) by 
pivoting around their pins 75, the pins 75 themselves being attached 
rigidly to the travel blocks 76 and 77. The weight of the arm 62 tends to 
pull the travel blocks 76 and 77 down, and the weight of the arm 62 is 
considerably greater when the buoyancy tanks 65 are filled with water than 
when they are filled with air. 
The buoyancy tank portions 65 
(FIGS. 4 to 6) 
The buoyancy tank portion 65 of the support arm 62 preferably has a pair of 
check-type flood valves 80 and 81 and a pair of valve actuators 82 and 83. 
the valve actuators 82 and 83 extend upwardly and above the top surface 63 
of the support arm 62, and each of them has a rod or spring stem 84 with a 
contact head 85 at its top. A spring 86 holds the contact head 85 in a 
normally closed or "up" position. The rod 84 is connected by a linkage 87 
to the flood valve 80 or 81, which remains closed when the contact head 85 
is up and which opens when the contact head 85 is pressed down. Each valve 
80 has its respective vent port 88, so that air can enter the buoyancy 
tank 65 at the time when a valve 89 is allowing water to exit from the 
buoyancy tank 65 when the support arm is in a vertical position, as shown 
in FIG. 7A. The vent port 88 is opened and closed by a valve 120, normally 
urged to a closed position by a spring 121 and opened by a ball float 122, 
attached to a crank 123 and therethrough to a wire 124 that passes via a 
pulley wheel 125 to the valve 120, when and only when the buoyancy tank 65 
is flooded does the ball float 122 open the valve 120 and then it holds it 
open until the buoyancy tank 65 is substantially emptied in its vertical 
stowed position. 
The Locking Means for the Panels 60 
(FIGS. 3-5, 7 and 8) 
There are two sets of locking means: one for locking the panels 60 in their 
vertical storage position and the other for locking them in their 
horizontal load-supporting position. 
As shown in FIGS. 3 and 8, at each end of each panel 60 is a panel lock pin 
90. A vertical rod 91 carries at its lower end a panel lock arm 92 having 
a notch 93 for engagement of the lock pin 90, thereby to lock the panel 60 
in its vertical storage position during loading and unloading of the holds 
35. When it is time to use the panels 60 for supporting a barge, the lock 
46, 47, 48 or 49 is filled with water; the valves 80 and 81 prevent the 
entry of water into the buoyancy tanks 65 at this time. The light weight 
of the air-filled buoyancy tanks 65 also enables upward movement of the 
travel blocks 76 and 77 in their guideways 78. 
Each arm 62 has, below its pivot opening 67 and offset therefrom a lock bar 
95. For each lock bar 95 a lock stop 96 is recessed rigidly in the 
bulkhead 70. Both of these members 95 and 96 are preferably rectangular 
parallelepipeds. The springs 79 by their upward pull on the blocks 76 and 
77 tend to raise the arms 62, and the buoyancy tanks 65, when filled with 
air, also tend to raise the arm 62. The resultant upward motion keeps the 
bar 95 above the stop 96 so that they do not engage each other during the 
upward swinging movement nor when the panel 60 finally reaches its 
horizontal position. However, when a barge 40 settles down from above on 
the panels 60, it opens the valves 80 and 81 to admit water (for 
eliminating its buoyancy when the arm 62 is being restored) and soon 
thereafter rests on the panels, so that whether the water drains out of 
the tanks 65 or not, the weight of the barge 40 pushes the arms 62 down 
vertically, carrying the blocks 76 and 77 down and urging the lock bar 95 
into a position just in front of the lock stop 96, so that (being 
rectangular ) the bar 95 and stop 96 engage and prevent downward rotation 
of the arms 62 and of the panel 60. The panel 60 is thus locked in its 
load-supporting position so long as the barge 40 rests thereon. 
When the ship is to be unloaded, the lock is filled with water to a level 
where the barge 40 is floated up above the panel 60. The buoyancy tanks 
65, which have filled with water during the flooding of the lock cause 
their support arms 62 to swing down to a vertical position while the 
springs 79 simultaneously lift the blocks 76 and 77 so that the bar 95 is 
released from the stop 96. The arms 62, then, swing down to their vertical 
position when the water level in the lock is lowered, and the buoyancy 
tanks drain and become lighter, so that the side of the bar 95 comes to 
rest on the top side of the step 96. The lock pin 90 then is engaged in 
the notch 93 of the panel lock arm 92, by control from the vessel's main 
deck through actuation of the vertical rod 91. 
Operation of the Device of FIG. 3-9 
After the holds 35 are fully loaded, a stern gate 56, 57, 58 or 59 is 
opened, and a barge 40 is floated into the corresponding lock 46, 47, 48, 
or 49; the stern gate is then closed. The barge lock 46, 47, 48, or 49 is 
filled with water to a level greater than the draft of a barge 40 above 
the level of the uppermost, vertically stowed set 61 of four panels which 
is to support the barge 40. 
As the barge 40 rises in the lock 46, 47, 48, or 49 to a level above the 
stored panels 60, the control rods 91 are operated to free the panel lock 
pin 90 from their notches 93. The panels 60 float upwardly, as shown at 
the center of FIG. 9, swinging to their horizontal position, shown at the 
upper part of FIG. 9. The lock water level is then lowered, and the barge 
40 settles onto the panels 60, depressing the contact platforms 85, so 
that the valve actuators 82 and 83 open the check-type flood valves 80 and 
81 and admit water to the buoyancy tanks 65. As the weight of the barge 40 
is transferred down on to the support arm 62, it moves the travel blocks 
76 and 77 down, and the lock bar 95 is engaged and locked against the lock 
stop 96, and the barge 40 is now in place. Another barge 40 may now be 
loaded onto the next lowest set 61 of panels 60. This lock loading 
operation may take place one level at a time at each tier 44, 43, 42, from 
the top down, immediately after that tier of holds 35 has been loaded, or 
after all the holds 35 for the entire vessel have been loaded. The same is 
true for unloading but in reverse order of tiers. 
To unload a barge 40 in this embodiment, the lock 46, 47, 48 or 49 is 
flooded to a level at least equal to the draft of a typical barge above 
the lowest set 61 of panels 60, causing the stowed barge 40 to float above 
that set 61 of panels 60. The buoyancy tanks 65 on this set 61 of support 
arms 62 are filled with water as the lock water level rises above them, 
since the valve actuators 82 and 83 are at that time depressed by the 
weight of the barge 40, leaving the check valves 80 and 81 open. 
The water-weighted panels 60 swing them down toward and into the vertical 
stowed position, since the buoyancy tanks 65 are filled with water. The 
deck-controlled rods 91 may then be operated to actuate the locking 
mechanisms 90 and 93, but, preferably, this is actuated automatically, 
thereby securing the panels 60 in their vertical storage positions. As the 
lock water level is lowered with it and also the buoyancy tanks 65 will 
drain of water as air flows in through the vent valves 88, so that the 
arms 62 are ready to be floated up to their horizontal position again when 
needed. The appropriate stern gate 56, 57, 58, or 59 is opened and the 
barge 40 is floated out of its lock 46, 47, 48, or 49. 
A Modified Form of the Support Arm Locking Mechanism CL (FIGS. 10-13) 
In the embodiment of the invention illustrated in FIGS. 10-13 an end 
portion 100 of each support arm has a hinge pin recess 101, and each 
panel-supporting bulkhead projection has a lock pin 102 connected by a rod 
103 to a gang link arm 104 disposed horizontally through the bulkhead 70. 
The gang link arm 104 is in turn connected to a remote-control hydraulic 
ram actuator 105. When the panels 60 are in the horizontal position, the 
hydraulic ram actuator 105 is engaged to move the gang link arm 104, in 
turn moving the lock pins 102 into the lock pin recesses 101 in each 
support arm, thereby locking each panel 60 in a load-supporting position 
for supporting a barge 40. 
A Bow Opening Vessel 
(FIGS. 14-17) 
A vessel 150 differs from the vessel 30 in that flotation loading of the 
vessel is done through its bow 151 rather than through its stern 152. This 
enables use of better hull lines at the stern and thereby improves 
operation and efficiency. 
Bow gates 153 and 154 open outwardly to each side for loading and unloading 
of barges. As in our U.S. Pat. No. 4,135,468, the vessel 150 is provided 
with upwardly swinging collision bulkheads 155 and 156 that are pivoted 
along an axis 157. The two bow gates 153 and 154 and the corresponding 
collision bulkheads 155 and 156 open into a pair of loading locks 160 and 
161, like the locks already described and provided with the same means for 
storing barges in the locks 160 and 161. 
In the vessel 150 there are five tiers 162, 163, 164, 165 and 166 of holds 
for storing the barges. On the lowest tier 162, there are two holds 167 
and 168. On each of the other four tiers 163, 164, 165, and 166 there are 
four holds per tier. Archways and passages enable transfer of barges from 
each inboard hold to an outboard hold as shown in our U.S. Pat. No. 
4,147,123. The top tier 166 may be an open-topped deck. The vessel 150 can 
hold eighty of the large Mississippi River barges, including ten barges 
stored in the locks 160 and 161. 
The preferred embodiment described herein is intended to be purely 
illustrative, and not limiting of the scope of the invention. Other 
embodiments and variations will be apparent to those skilled in the art 
and may be made without departing from the essence and scope of the 
invention as defined in the following claims.