Abstract:
A method of building a levee or an island is disclosed. The method includes dredging material from a surface of a body of water with a dredge assembly mounted to a hull and supporting a hopper with the hull. The hopper is adapted to receive the material. The hopper includes a floor with a portion of the floor moveable to permit movement of the material in the hopper, and depositing at a desired location dredge material from the dredge using a transfer conveyor. The transfer conveyor is mounted on the hull and is shiftable between a first position in which the transfer conveyor receives material

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of U.S. patent application Ser. No. 09/486,280 filed on Feb. 24, 2000. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     Field of the Invention  
         [0003]     The invention relates generally to dredging, and, more particularly, to a multi-purpose vessel and method for recovering, storing and/or transporting, and off-loading material in a dredging operation.  
         [0004]     Due largely to erosion, the waterways of many areas of the world are becoming choked with silt and the like. As the waterways become more and more shallow, certain problems arise. For example, navigation through the waterways becomes difficult or altogether impossible. In addition, the risk of flooding adjoining areas of a waterway increases as the depth of the waterway decreases.  
         [0005]     Over the years, many dredging techniques have been devised. Perhaps the most popular dredging technique involves a vacuuming dredge which sucks silt and the like from the bottom of the waterway through a conduit or a hose. This technique is disadvantageous in several respects. For example, it collects large volumes of water in the dredging process. As a result, the material recovered by this dredging technique is largely a liquid mixture that is difficult to handle and dispose of. By way of another example, the vacuuming technique mentioned above tends to disturb the bed of the waterway in a manner that mixes silt and impurities imbedded in the silt into the water. Some of these impurities may be toxic lead and mercury). Dredging with this old technique can, therefore, pose an environmental hazard. Due to these and other difficulties, dredging a waterway using the vacuuming technique is an expensive, time-consuming and hazardous proposition.  
         [0006]     Recently, Caterpillar® has invented a new dredging assembly. The dredging assembly is a large wheel that rolls along and slices into the bed of a waterway. The wheel is compartmentalized by slicing blades that slice and pick-up segments of the bed of the waterway as the wheel turns in a fashion similar to a cookie cutter slicing cookies from dough. The development of this new dredging technology has made it possible to dredge waterways in a much more efficient, cost-effective manner. Specifically, because the dredging wheel lifts large segments of silt from the waterway bed, the material it recovers is largely solid and undisturbed, is not mixed with much (if any) additional water during dredging, and, thus, can be more efficiently handled than material recovered by the prior art vacuuming system discussed above.  
         [0007]     While the development of the Caterpillar® dredging wheel offers a significant opportunity to recover material from the Waterways of the world and to restore those waterways to navigable depths, it has also given rise to a new set of technological problems from the material handling perspective. Specifically, now that it is possible to quickly dredge large volumes of substantially solid material from a waterway, it is necessary to develop apparatus and systems for handling, transporting and/or disposing of the material recovered by the dredge.  
       SUMMARY OF THE INVENTION  
       [0008]     In accordance with an aspect of the invention, a multi-purpose vessel for use when recovering material from a bottom surface of a body of water comprises a hull, a dredge assembly mounted to the hull, a hopper, and a transfer conveyor. The dredge assembly is adapted to recover the material from the bottom surface and the hopper is supported by the hull and is adapted to receive the material. The transfer conveyor is adapted to receive the material from the dredge assembly, and is shiftable between a first position in which the transfer conveyor is operable to convey the material toward the hopper, and a second position in which the transfer conveyor is operable to convey the material off the vessel.  
         [0009]     In further accordance with a preferred embodiment, the hull may be provided with a propulsion system, and the hopper may include a moveable floor adapted to move the material in the hopper. The moveable floor may include a slat conveyor, such as comprising a plurality of cleats attached to the moveable floor, The moveable floor may include a flexible belt mounted on a plurality of rollers, or the moveable floor may include an ejector blade moveably mounted within the hopper, with the ejector blade being adapted to move the material in the hopper.  
         [0010]     The vessel preferably includes a distribution conveyor mounted to the hull. The distribution conveyor includes a first end and a second end, and a discharge conveyor may be provided having a portion extending into the hopper and being adapted to discharge the material from the hopper to the distribution conveyor adjacent the first end. The distribution conveyor second end is moveable to a desired position to thereby unload the material at a desired location. The distribution conveyor may include an extendable portion, such as by slidably mounting the extendable portion in a housing, and may include a rack and pinion assembly mounted to the housing and engaging the extendable portion for extending and retracting the extendable portion. Still preferably, the distribution conveyor is mounted on a turret assembly, and a rack and pinion assembly may be provided, which is arranged to rotate the distribution conveyor on the turret assembly.  
         [0011]     Preferably, the transfer conveyor is moveably mounted to the hull, such as by mounting the transfer conveyor on a turret assembly. A rack and pinion may be provided which is arranged to rotate the transfer conveyor on the turret assembly.  
         [0012]     The hopper may be generally rectangular, and preferably a discharge auger or other discharge assembly is mounted to the hull and includes a portion extending into the hopper to discharge the material from the hopper. The discharge assembly may include a pair of counter rotating augers, with each of the augers including a portion extending into the hopper.  
         [0013]     The hull may be provided with a propulsion system for moving the hull through the water. The propulsion system may include a tractive element which is adapted to engage the bottom surface of the body of water. Preferably, the tractive element is moveably mounted to the hull and is shiftable between a retracted position in which the tractive element is disposed toward the hull and an extended position in which the tractive element engages the bottom surface. The propulsion system may also include a plurality of positioning jets.  
         [0014]     Preferably, the distribution conveyor is provided with a moveable counterweight. The counterweight is positionable relative to the distribution conveyor so as to counteract the forces applied to the distribution conveyor by the material.  
         [0015]     In accordance with another aspect of the invention, a multi-purpose vessel for use when recovering material from a bottom surface of a body of water comprises a hull, with a dredge assembly being mounted to the hull. The dredge assembly is adapted to recover the material from the bottom surface. A conveyor system is provided, with the conveyor system including a first portion adapted to receive the material from the dredge assembly, a moveable second portion, and a distribution conveyor. The second portion is moveable to a first position in which the second portion is adapted to receive the material from the first portion and to convey the material to a first desired location disposed a first distance away from the hull. The second portion is further moveable to a second position in which the second portion is adapted to convey the material to the distribution conveyor. The distribution conveyor is adapted to convey the material a second distance greater than the first distance away from the hull.  
         [0016]     In accordance with a still further aspect of the invention, a multipurpose vessel for use on a body of water vessel comprises a hull, a dredge assembly mounted to the hull, with the dredge assembly being adapted to recover material from a bottom surface of the body of water, a hopper supported by the hull, with the hopper being adapted to receive the material, and a conveyor system. The conveyor system includes a first portion adapted to receive the material from the dredge assembly, and further includes a moveable second portion adapted to receive the material from the first portion and to convey the material along a plurality of desired paths. A first of the desired paths being away from the hull and a second of the desired paths being toward the hopper.  
         [0017]     In accordance with yet another aspect of the invention, a method of conveying material recovered in a dredging operation to a desired location comprises the steps of positioning a water4iorne vessel having a dredge assembly and a distribution conveyor at a first position in a waterway, recovering the dredged material from the waterway and conveying the material to a first end of the distribution conveyor, positioning a second end of the distribution conveyor at a desired location, and conveying the material along the distribution conveyor to the second end for deposition therefrom as the vessel proceeds along the waterway.  
         [0018]     In accordance with another aspect of the invention, a method of forming a working channel in a silt4aden waterway comprises the steps of moving a water-borne vessel having a dredge assembly and a distribution conveyor through the waterway, recovering the silt material from the waterway and conveying the silt material to a first end of the distribution conveyor, positioning a second end of the distribution conveyor at a desired location, and conveying the material along the distribution conveyor to the second end for deposition therefrom as the vessel proceeds along the waterway.  
         [0019]     In accordance with a further aspect of the invention, a method of forming an emergency levee in a waterway comprises the steps of moving a water-borne vessel having a dredge assembly and a distribution conveyor through the waterway, recovering the material from a bottom surface of the waterway and conveying the silt material to a first end of the distribution conveyor, positioning a second end of the distribution conveyor at a desired levee location, and conveying the material along the distribution conveyor to the second end for deposition therefrom as the vessel proceeds along the waterway.  
         [0020]     In accordance with yet a further aspect of the invention, a method of repairing a breach in a levee comprises the steps of moving a water-borne vessel having a dredge assembly and a distribution conveyor through a waterway adjacent the levee, recovering material from a bottom surface of the waterway and conveying the material to a first end of the distribution conveyor, positioning a second end of the distribution conveyor at a desired location adjacent the breach, and conveying the material along the distribution conveyor to the second end for deposition therefrom as the vessel proceeds along the waterway.  
         [0021]     Other features and advantages are inherent in the disclosed apparatus or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0023]      FIG. 1  is a perspective view of a multi-purpose vessel for use in a dredging operation which has been constnicted in accordance with the teachings of the present invention;  
         [0024]      FIG. 2  is a perspective view of the vessel of  FIG. 1  and illustrating the vessel in one possible state of operation in which the recovered material is being transferred to a nearly full hopper;  
         [0025]      FIG. 3  is a perspective view of the vessel of  FIG. 1  but illustrating the vessel in another possible state of operation in which the recovered material is being offloaded onto an adjacent transport vessel;  
         [0026]      FIG. 4  is a right side elevational view, partly in section, of the vessel illustrated in  FIG. 1 ;  
         [0027]      FIG. 5  is a top plan view of the vessel illustrated in  FIG. 1 ;  
         [0028]      FIG. 6  is an stern end elevational view of the vessel illustrated in  FIG. 1  but illustrating the vessel in yet another possible state of operation in which the recovered material is being offloaded at a desired location; the distribution conveyor is shown in a rotated or slewed position;  
         [0029]      FIG. 7  is a bow end elevational view of the vessel of  FIG. 1  providing an end view of the dredging assembly;  
         [0030]      FIG. 8  is a fragmentary cress-sectional view taken along line  8 - 8  of  FIG. 7  and illustrating the manner of operation of one possible dredge assembly for use on the vessel of FIG.  1 ;  
         [0031]      FIG. 9  is a fragmentary cross-sectional view similar to  FIG. 9  and illustrating recovered material exiting the dredge wheel and being deposited into a collection trough;  
         [0032]      FIG. 10  is a top plan view of the hopper having a moveable floor;  
         [0033]      FIG. 11  is an enlarged, fragmentary side elevational view taken along line  11 - 11  of  FIG. 10  showing the moveable floor and the ejection augers;  
         [0034]      FIG. 12  is an enlarged fragmentary top plan view showing an alternative configuration for the hopper in which the slat conveyor floor of the hopper is supplemented by an ejector blade assembled in accordance with the teachings of the present invention;  
         [0035]      FIG. 13  is an enlarged fragmentary end view taken along line  1343  of  FIG. 12 , partly in cut away, illustrating the ejector blade;  
         [0036]      FIG. 14  is a perspective view of another multi-purpose vessel for use in a dredging operation which has been constructed in accordance with the teachings of the present invention, the vessel is shown in one possible state of operation in which recovered material is being conveyed directly toward a distribution conveyor for deposition therefrom at a desired location;  
         [0037]      FIG. 15  is a perspective view of the vessel of  FIG. 14 , hut shown in a second possible state of operation in which the recovered material is being conveyed to an adjacent transport vessel;  
         [0038]      FIG. 16  is a perspective view of the vessel of  FIG. 14 , but shown in a third possible state of operation in which the recovered material is being directed toward a storage hopper.  
         [0039]      FIG. 17  is a side elevational view of the vessel of  FIG. 14 ;  
         [0040]      FIG. 18  is a top plan view thereof illustrating the manner by which portions of the conveyor system and the distribution conveyor may be rotated or slewed;  
         [0041]      FIG. 19  is stem end elevational view of the vessel illustrating the manner by which the distribution conveyor may be slewed to deposit recovered material at a desired location away from. the vessel;  
         [0042]      FIG. 20  is an enlarged fragmentary cross-sectional view taken along line  20 - 20  of  FIG. 18 ; and  
         [0043]      FIG. 21  is an enlarged fragmentary side elevational view of an alternate retractable tractive propulsion element constructed in accordance with the teachings of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]     The following description of the preferred embodiments is not intended to limit the scope of the invention to the precise forms disclosed, but instead is intended to be illustrative of the principles of the invention so that others may follow its teachings.  
         [0045]     Referring now to  FIGS. 1 through 11  of the drawings, an exemplary water-borne multi-purpose vessel constructed in accordance with the teachings of the present invention is generally referred to by the reference numeral.  30  and is shown afloat on a body of water  32  having a bottom surface  34  (viewable in  FIGS. 4 and 7 - 9 ), which bottom surface may have deposited thereon a layer of silt material  36 . The vessel  30  includes a hull  38  to which is mounted a dredge assembly  40 . The hull  38  is designed with a low draft for operation in shallow water. Preferably, the dredge assembly  40  mounted to the hull  38  is a dredge wheel  42  developed by Caterpillar®, which dredge wheel  42  is shown in greater detail in  FIGS. 7-9 . The Caterpillar® dredge wheel  42  may be used to rapidly dredge large amounts of the material  36  from the bottom surface  34  of a waterway, such as rivers, lakes, etc. A further description of an exemplary dredge wheel  42  will be provided in greater detail below.  
         [0046]     A hopper  44  and a conveyor system  60  are also mounted to the hull. As shown to advantage in  FIGS. 1-3  and  10 , the hopper  44  is preferably rectangular in shape and is preferably substantially centered with respect to the hull  38  and extends substantially along the length thereof. Persons of ordinary skill in the art will readily appreciate that hoppers of other shapes, sizes and locations can be utilized without departing from the scope or spirit of the invention. In any event, the size of the hopper  44  is preferably selected along with the hull dimensions to provide a desired payload capacity. The hull  38  is powered by a propulsion system (not shown) which is controlled by an operator located in a cab  48  in a conventional manner.  
         [0047]     The dredge wheel  42  is located in a well or aperture  50  ( FIGS. 3, 8  and  9 ) which is formed generally centrally relative to the hull  38 . The dredge wheel  42  is supported by hydraulic jacks  43  (See  FIGS. 8 and 9 ) or the like which can be powered to raise or lower the dredge wheel  42  to a desired depth for dredging or transport.  
         [0048]     Referring now to  FIGS. 7-9 , for the purpose of capturing the recovered material  3 $ to be dredged from the bed or bottom surface  34  of the waterway, the dredge wheel  42  is provided with a number of generally evenly spaced blades  52 . The blades  52  divide the outer perimeter of the dredging wheel  42  into a plurality of capture cavities  54 . Two of the blades  52  cooperate to form two, oppositely disposed sides of each capture cavity  54 . The other two opposite sides of the cavities  54  are formed by generally parallel, circular wheel plates  56 . The top and bottom (i.e., the radially outward and radially inward sides, respectively) of each capture cavity  54  are open.  
         [0049]     In operation, as the vessel  30  moves forward (i.e., to the left when viewing  FIGS. 8 and 9 ), the dredging wheel  42  rotates such that a capture cavity  54  digs into the waterway bottom and collects a slab of material  36  to be dredged (See  FIGS. 8 and 9 ). As the wheel  42  continues to rotate, the filled capture cavity  54  rotates between an inner capture plate  55  and an outer capture plate  57  formed at the back of the wheel  42 . The capture plates  55 ,  57  seal the radially inner and outer openings of the capture cavity  54  to ensure the recovered material  36  remains in the cavity  54  as the cavity  54  rotates toward the top of the wheel  42 .  
         [0050]     As the filled capture cavity  54  reaches the top of the wheel  42 , the inner capture plate  55  terminates such that, when the filled cavity  54  reaches the top of the wheel  42 , the dredged material  36  falls out of the capture cavity  54  under the influence of gravity (and, optionally, under the influence of a mechanical assist (not shown)) and into a hopper or trough  58  disposed toward the center of the wheel  42 . As shown in  FIGS. 1-3  and  5 - 7 , the trough  58  is serviced by two, oppositely disposed angers  59  which function independently to discharge the recovered material  36  from the trough  58 . A more detailed description of the structure and function of an exemplary dredge wheel  42  may be found in Satzler, U.S. Pat. No. 5,903,989, Satzler, U.S. Pat. No. 5,907,915, and U.S. patent application Ser. No. 08/834,676, the entire disclosures of which are hereby incorporated by reference herein in their entirety.  
         [0051]     For the purpose of handling the material  36  recovered by the dredge assembly  40 , the vessel  30  is further provided with a conveyor system  60 . The conveyor system  60  may include a transfer conveyor  62 , which is mounted on a turret  64  of conventional design. It will be understood that the vessel  30  is preferably provided with a pair of transfer conveyors  62 , one on each side of the hull  38 . The transfer conveyor  62  may be a rotatable belt conveyor, and includes a first end  63  and a second end  65 . A receiving box  63   a  is provided adjacent the first end  63  in order to contain material  36  deposited thereon. A rack and pinion assembly  68  is provided, which enables the transfer conveyor to be rotated or pivoted between the position shown in  FIG. 2 , in which the second end  65  of the transfer conveyor is disposed over the hopper, and the position shown in  FIG. 3 , in which the second end  65  of the transfer conveyor  62  is disposed over an adjacent transport vessel. As shown in  FIGS. 1-3 , the transfer conveyor  62  is preferably upwardly inclined to facilitate loading into the hopper or the adjacent vessel. Note that as an alternatively, hydraulic cylinders may be employed in place of the rack and pinion assembly  68  in order to pivot the transfer conveyor  62  on the turret. Additional details concerning the structure and function of the adjacent transport vessel can be found in en-pending application Ser. No., ______, attorney docket number 29038/10003 PCT, which is hereby incorporated by reference in its entirety.  
         [0052]     Another conveyor  70  is disposed on the hull  38  generally adjacent to the dredge wheel  42 , and includes a first end  71  having a receiving box  71   a , and a second end  72  disposed generally adjacent to the first end  63  of the transfer conveyor  62 . The receiving box  71  is disposed generally below the auger  59  so as to receive material.  36  ejected thereby. The second end  73  of the conveyor  70  is pivotally mounted to the hull  38  by a pivot  39  ( FIGS. 1-3 ), to accommodate upward and downward movement of the wheel  42  as the cylinders  43  raise and lower the wheel  42  to adjust the dredge assembly for different working depths.  
         [0053]     Each turret  64  permits the corresponding receiving box  63   a  and transfer conveyor  62  to rotate approximately 180°. Persons of ordinary skill in the art will readily appreciate that both the turrets  64  and the belts of the conveyors  62 ,  70  can be driven in many ways without departing 1 mm the scope or spirit of the invention. By way of examples, not limitations, the conveyor belts and/or the turrets can be driven by electrical motors or hydraulic motors.  
         [0054]     Referring now to  FIGS. 10 and 11 , the hopper  44  is provided with a movable floor  74 . The movable floor  74  preferably extends over substantially the entire length and width of the hopper  44  and supports the material recovered in the dredging operation within the hopper  44 . As most easily seen in  FIG. 11 , the movable floor  74  is preferably implemented by a conveyor belt  76  mounted upon a plurality of idler rollers  78  journalled between the side walls of the hopper  44 . The idler rollers  78  are preferably mounted in low friction bearings (not shown) of conventional design and are closely spaced, but do not touch one another to minimize friction during movement of the floor  74 .  
         [0055]     The belt  76 , which is preferably endless, is preferably implemented by commercially available conveyor belting material such as steel or nylon reinforced rubber. As shown in  FIG. 10 , the belt  76  is also preferably provided with steel cleats  80  to reduce, and preferably prevent, slippage between the moving floor  74  and the recovered material the floor supports as the material is being conveyed or moved by the floor  74 .  
         [0056]     The belt  76  is driven by a pair of ejection winches  82 , which are operatively connected to a pair of cables  83  which extend along the top length of the belt  76 , over an end roller  84 , and back along the length of the belt  76  to an attachment point  85  ( FIG. 11 ). A return winch  86  is provided, which also has a cable  87  secured to the attachment point  85 . The arrangement of the winches  82 ,  86  and their associated cables  83 ,  87 , respectively, makes possible a dual mode operation as follows. As material  36  is being deposited in the hopper  44  on the floor  74 , the winches  82  gradually draw in their cables  83  and the winch  86  gradually lets out its cable  87 . Thus, as the hopper  44  is loaded, the attachment point traverses the bottom of the hopper  44  (i.e., toward the left when viewing  FIG. 11 ), to a point adjacent the end roller  84 , at which point the hopper  44  is full of material  36 . When it is desired to empty the hopper  44  (such as with the assistance of an ejection or discharge assembly  88  which will be described in greater detail below), the winches  82  continue to pull the belt  76  via the attachment point  85 , such that the attachment point  85  travels up over the end roller  84 , and traverses the hopper  44  again (i.e., this time to the right when viewing  FIG. 11 ), as the discharge assembly  88  draws the material out of the hopper  44 . When the hopper  44  is empty, the return winch  86  is used to reverse the motion of the belt  76 .  
         [0057]     As an alternative, the hopper  44  may be equipped with an ejector blade  90  as shown in  FIGS. 12 and 13 . The ejector blade  90  is preferably mounted within a pair of guides defined in the sidewalls of the hopper  44  and secured to the belt  76 . The structure and function of the ejector blade  90  is described more fully in the above-mentioned co-pending application Ser. No. ______, attorney docket number 29038110003 PCT, which is hereby incorporated by reference in its entirety. Note that in the present application, and by way of example rather than limitation, the blade  90  may be de-coupled from the flexible belt  16 , such that the above-described dual mode operation is still possible. The blade  90  may then be operable independently to assist in clearing the material  36  from the hopper  44 .  
         [0058]     Referring now to  FIGS. 1-6 , a distribution conveyor  92  is preferably a faxed length conveyor and is mounted to the hull  38  adjacent an end  93  of the hopper  44 . The distribution conveyor  92  is preferably mounted to a turret  94  of conventional design, and is rotatable on the turret  94  by a rack and pinion assembly  95 . The distribution conveyor  92  includes a first end  96  disposed in a receiving box  97 , and further includes a second end  98 . As shown for example in  FIG. 4, 5  or  6 , the second end  98  can be placed at a desired location a substantial distance away from the hull  38 , and can further be rotated or slewed by operation of the turret  94 .  
         [0059]     The discharge assembly  88  preferably includes a pair of counter-rotating augers  100 , each of which is rotated by conventional electric or hydraulic motors as would be known. The augers  100  are disposed in a housing  102  having an ejection chute  104  generally adjacent to the receiving box  97 . A bottom portion  106  of each auger  100  extends into the hopper  44 , such that the material  36  may be extracted therefrom and conveyed through the housing  102  to the ejection chute  104 , from where the material is conveyed to the first end  96  of the distribution conveyor  92  via the receiving box  97 . The distribution conveyor  92  includes a flexible and rotatable belt and suitable drive motors, all of which are of conventional design and which are carried by a suitable support  108  mounted on the turret  94 . The distance the second end  98  is disposed from the vessel  30  may typically be controlled simply by slewing the distribution conveyor  92  on its turret  94 .  
         [0060]     As shown in  FIG. 1 , the distribution conveyor  92  may optionally be extensible, such as by slidably mounting an extensible portion  110  in a suitable housing  111  defined in the support  108 . A rack and pinion assembly  112  may be provided for extending and retracting the extensible portion  110 .  
         [0061]     In order to enhance the maneuverability of the vessel  30 , the vessel  30  is further provided with stern and bow thrusters  114  on each of its sides as can be seen in each of  FIGS. 1-3 . The thrusters  114  are preferably implemented as low power water jets or impellers of conventional design. In other words, they are implemented by hydraulically or electrically driven impellers located in transverse tubes having preferably oval shaped outlet ports  116  to ensure the thrusters create a fan-shaped water stream (as opposed. to a circular water jet which might be less effective than the fan-shaped jet in shallow water). A more detailed description of the thrusters may be found in co-pending application Ser. No. ______, attorney docket number 29038/10003 PCT.  
         [0062]     The vessel  30  is also provided with a rudder (not shown) of conventional design, which enhances the steerability provided by the side thrusters  114 . Suitable engines (not shown) are provided for primary propulsion, preferably twin engines having suitably spaced, high pitch low diameter screws. The engines along with the side thrusters  114 , the rudder and the various other systems of the vessel  30  are preferably aontrolied from a control panel located in the cab  48 .  
         [0063]     While as described above, twin engines  58  are preferred as the primary source of propulsion for the vessel  50 , persons of ordinary skill in the art will appreciate that water jets could be used in place of the engines  58  without departing from the scope or spirit of the invention.  
         [0064]     In operation, the vessel proceeds along under power in a direction generally to the upper left when viewing  FIG. 1 . As described above, the rotating dredge wheel  42  continually deposits recovered material  36  into the trough  58 , from where the material  36  is extracted by the augers  59  and deposited into the receiving box  71   a  of the conveyor  70 . The material is then conveyed from the first end  71  to the second end  73 , from where it is deposited into the receiving box  63   a  of the transfer conveyor  62 .  
         [0065]     The transfer conveyor  62  enables the conveyor system  60  to operate in a number of modes. One such mode is shown in  FIG. 3 , in which an adjacent transport vessel of the type described above is disposed alongside the vessel  30  and secured thereto by a suitable docking pins and capture anus of the type described more fully in the above-mentioned co-pending patent application Ser. No. ______, attorney docket number 29038/10003 PCT. By operation of the rack and pinion assembly  68 , the transfer conveyor  62  maybe rotated on its turret  64  such that the second end  65  is disposed over the hopper of the adjacent vessel. According, the material  36  recovered by the dredge wheel  42  may be deposited along a path directly into the adjacent vessel for transport.  
         [0066]     Another such operational mode is illustrated in  FIG. 1 , wherein the second end  65  of the conveyor  62  is positioned directly over the hopper  44  of the vessel  30 . In this mode, the material may be directed along a path into the hopper  44 . As the material  36  is deposited on the moveable floor  74 , the winches  82  are activated such that the hopper  44  is gradually loaded as the moveable floor  74  carries the material  36  toward the discharge assembly  88 . Further in this operational mode, once the hopper  44  is full it may be emptied by continuing to operate the winches  82 . As the belt  76  proceeds as described above, the material  36  is conveyed toward the augers  100  of the discharge assembly  88 , which augers  100  draw the material  36  from the hopper  44  and convey the material  36  to the receiving box  97  of the distribution conveyor  92  via the discharge chute  104 . The material is then conveyed along the distribution conveyor  92  to the second end  98  thereof, from where the material is deposited at a desired location.  
         [0067]     It will be understood that the vessel  30  may also load an adjacent vessel simultaneously with loading its own hopper  44 , simply by independently positioning the transfer conveyors  62  on both sides of the vessel as required. It will also be understood that the vessel  30  may load the hopper  44  until full, cease dredging operations, and then travel to a designated location to deposit the material  36  (such as at a levee to be constructed, at an island to be constructed, or at a designated truck loading station if it is desired to haul the material  36  away). Other possible modes of operation will become readily apparent to those skilled in the art.  
         [0068]     Referring now to  FIGS. 14 through 21 , a multi-purpose vessel constructed in accordance with the teachings of a second embodiment of the present invention is shown and is referred to by the reference numeral  130 . To the extent possible, those elements that are the same or similar to the elements outlined above with respect to the first embodiment have the same or similar reference numerals, but increased by  100 . The vessel  130  includes a hull  138 , a dredge assembly  140 , such as the same dredge wheel  142  construction, and a conveyor system  160 . A trough  158  is disposed toward the center of the wheel  142 , and is serviced by two, oppositely disposed augers  159  which function independently to discharge the recovered material  136  from the trough  158 .  
         [0069]     The conveyor system  160  includes first and second conveyors  170  and  172 , as well as an intermediate transfer conveyor  162 . The conveyor  170  includes a first end  171 , a second end  173 , and a receiving box  171   a , while the second conveyor includes a receiving box  172   a  at a first end  172   b , and further includes a second end  172   c . The receiving boxes  171   a ,  172   a  work to contain the material  136  received at their respective ends. The conveyor system  160  also includes a transfer conveyor  162 , which is mounted on a turret  164  of conventional design. Again, it will be understood that the vessel  130  is preferably provided with substantially similar conveyor systems  160  on both sides of the hull  138 . The transfer conveyor  162  may be a rotatable belt conveyor, and includes a first end  163  and a second end  165 . A receiving box  163   a  is provided adjacent the first end  163  in order to contain material  136  deposited thereon. A rack and pinion assembly  168  is provided, which enables the transfer conveyor  162  to be rotated or pivoted between the position shown in  FIG. 14 , in which the second end  165  of the transfer conveyor  162  is disposed over the receiving box  172   a  of the conveyor  172 , to the position of Fig. i˜ in which the second end  165  of the transfer conveyor  162  is disposed over the hopper  144 , and to the position of  FIG. 16  in which the second end  165  of the transfer conveyor is disposed over the hopper of an adjacent transport vessel. Again, each turret  164  permits the corresponding receiving box  163   a  and transfer conveyor  162  to rotate approximately 180°.  
         [0070]     The hopper  144  includes a moveable floor  174  of the type described above with respect to the first embodiment. The movable floor  174  preferably extends over substantially the entire length and width of the hopper  144  and supports the material recovered in the dredging operation within the hopper  144 . The movable floor  174  is preferably implemented by an endless conveyor belt  176  mounted upon a. plurality of idler rollers (not shown). As shown in  FIG. 14 , the belt  176  is also preferably provided with steel cleats  180  to reduce, and preferably prevent, slippage between the moving floor  174  and the recovered material the floor supports as the material is being conveyed or moved by the floor  174 . The belt  176  is driven by a pair of ejection winches  182  and a retracting winch  186 , so as to be capable of the dual mode operation described above.  
         [0071]     Referring now to  FIGS. 14-18 , a distribution conveyor  192  is mounted to the hull  138  adjacent an end  193  of the hopper  144 . The distribution conveyor  192  is preferably mounted to a turret  194  of conventional design, and is rotatable on the turret  194  by a rack and pinion assembly  195 . The distribution conveyor  192  includes a first end  196  disposed in a receiving box  197 , and. further includes a second end  198 . As shown to advantage in  FIGS. 17-19 , the second end  198  can be placed at a desired location a substantial distance away from the hull  138 , and can further be rotated or slewed by operation of the turret  194 .  
         [0072]     The discharge assembly  188  preferably includes a pair of counter-rotating augers  200 , each of which is rotated by conventional electric or hydraulic motors as would be known. The augers  200  are disposed in a housing  202  having an ejection chute  104  generally adjacent to the receiving box  197 . A bottom portion  206  of each auger  200  extends into the hopper  144 , such that the material  136  may be extracted therefrom and conveyed through the housing  202  to the ejection chute  204 , from where the material is conveyed to the first end  196  of the distribution conveyor  192  via the receiving box  197 . As can be seen in  FIG. 17 , the housing  202  includes a lower inlet  203 , through which material  136  may be drawn from the hopper  144 , and further includes an upper inlet  205 , through which material  136  may be received from the second end  172   e  of the conveyor  172 . Material entering through either inlet  203  or  205  will be conveyed by the augers  200  to the discharge chute  204 , for deposition onto the first end  96  of the distribution conveyor  192 . The distribution conveyor  192  includes a flexible and rotatable belt and suitable drive motors, all of which are of conventional design and which are carried by a suitable support  208  mounted on the turret  194 . The distance the material  136  is deposited away from the hull  138  may typically be controlled by slewing the distribution conveyor  192  on its turret  194 .  
         [0073]     As shown in  FIG. 17 , the distribution conveyor  192  may optionally be extensible, such as by slidably mounting an extensible portion  210  in a suitable housing  211  defined in the support  208 . A rack and pinion assembly  212  may be provided for extending and retracting the extensible portion  210 .  
         [0074]     The distribution conveyor  192  includes a support  208  which includes an extending cantilevered portion  214 . The cantilevered portion  214  includes a moveable counterweight  216  ( FIGS. 14-16 ) which is slidably mounted in a track  218  defined in the cantilever portion  214 . The counterweight  216  is slidable within the track, such as by a rack and pinion arrangement or a winch and cable assembly (not shown), so as to counteract the significant weight of the material, on the conveyor  192 .  
         [0075]     Referring now to  FIGS. 14, 15 ,  17  and  19 - 21 , a propulsion system  220  having a flexible tractive belt is mounted to the underside of the hull  1 . 38 . Such a propulsion system  220  may be used in place of or in addition to a more traditional propulsion system (not shown) such as water jets or propeller drive systems. The propulsion system  220  includes a flexible, cleated track  222 , and is mounted to a retractable linkage assembly  224  actuated by a hydraulic cylinder  226  ( FIG. 21 ). The linkage assembly  224  permits the track  222  to be raised and lowered between the drive position of  FIG. 21  and the retracted position shown in phantom in  FIG. 21 . The track  222  is preferably driven by hydraulic motors having suitably sealed operating systems. Such a flexible track  222  having a hydraulic drive system is manufactured by Caterpilar®.  
         [0076]     In operation, the vessel  130  proceeds along under power in a direction generally to the upper left when viewing  FIG. 14 . As described above, the rotating dredge wheel  142  continually deposits recovered material  136  into the trough  158 , from where the material  136  is extracted by the augers  159  and deposited into the receiving box  171   a  of the conveyor  170 . The material is then conveyed from the first end  171  to the second end  173 , from where it is deposited into the receiving box  163   a  of the transfer conveyor  162 .  
         [0077]     The transfer conveyor  162  enables the conveyor system  160  to operate in a number of modes. One such mode is shown in  FIG. 16 , in which an adjacent transport vessel of the type described above is disposed alongside the vessel  130  and secured thereto by a suitable docking pins and capture arms of the type described more fully in the above-mentioned co-pending patent application Ser. No. ______, attorney docket number 29038/10003 ItT. By operation of the rack and pinion assembly  168 , the transfer conveyor  162  maybe rotated on its turret  164  such that the second end  165  is disposed over the hopper of the adjacent vessel. Accordingly, the material  136  recovered by the dredge wheel  142  may be deposited along a path directly into the adjacent vessel for transport.  
         [0078]     Another such operational mode is illustrated in  FIG. 15 , wherein the second end  165  of the conveyor  162  is positioned directly over the hopper  144  of the vessel  130 . In this mode, the material may be directed along a path into the hopper  144 . As the material  136  is deposited on the moveable floor  174 , the winches  182  are activated such that the hopper  144  is gradually loaded as the moveable floor  174  carries the material  136  toward the discharge assembly  188 . Further in this operational mode, once the hopper  144  is full it may be emptied by continuing to operate the winches  182 . As the belt  176  proceeds as described above, the material  136  is conveyed toward the augers  200  of the discharge assembly  188 , which augers  200  draw the material  136  from the hopper  144  through the lower inlet  203  and convey the material  136  to the receiving box  197  of the distribution conveyor  192  via the discharge chute  204 . The material  136  is then conveyed along the distribution conveyor  192  to the second end  198  thereof, from where the material is deposited at a desired location.  
         [0079]     It will be understood that the vessel  130  may also load an adjacent vessel simultaneously with loading its own hopper  144 , simply by independently positioning the transfer conveyors  162  on both sides of the vessel as required. it will also be understood that the vessel  130  may load the hopper  1 . 44  until full, cease dredging operations, and then travel to a designated location to deposit the material  136  (such as at a levee to be constructed, at an island to be constructed, or at a designated truck loading station if it is desired to haul the material  136  away).  
         [0080]     Another possible mode of operation is illustrated in  FIGS. 14 and 19 . With the transfer conveyor  162  positioned as shown with the second end  16 . 5  disposed over the receiving box  172   a  of the conveyor  172 , the material  136  may be routed directly and continuously to the distribution conveyor as the vessel  130  operates. As shown in  FIG. 19 , with the distribution conveyor  192  slewed by rotating the conveyor on its turret  194 , the vessel may deposit the material on the riverbank, on a levee, or build an island as the vessel  130  continues through the waterway. in certain circumstances wherein there is not enough room in a channel top operate adjacent transport vessels, the vessel  130  can directly transport the material  136  sideways for deposit until a working channel has been created. Alternatively, the vessel  130  can create a levee as it travels through the waterway, and can even repair a breach in a levee as it travels by slewing, advancing, and/or retracting the conveyor  192  as required to continuously deposit material  136  at a designated location. Accordingly, the vessel  130  can operate quickly to construct a levy using on-site materials, namely, materials dredged from the bottom of a waterway threatening to flood, In view of the large volumes of material that can be recovered and deposited quickly by the vessel  130 , levies can be constructed or repaired in a very short thne frame to address a potentially dangerous situation. Again, other possible modes of operation, including operating in a number of modes simultaneously, will: become readily apparent to those of skill in the art.  
         [0081]     Although certain instantiations of the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto, On the contrary, this patent covers all instantiations of the teachings of the invention fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.