Abstract:
A method for rapid transportation and loading of stacks of cartons aboard vessels is provided which may include the mounting of slings about the stacks of cartons, transporting the cartons to the dock using a flatbed vehicle, hoisting the stacks of cartons off the flatbed vehicle and into the hold, depositing the cargo onto a landing pad, lifting the cargo off the landing pad with a lift truck, preferably a load push type lift truck, and depositing the cargo in the hold at the appropriate location. A sling pallet and a landing pad for use with the method are also disclosed. The method provides the advantages of improving the quality of the product by, inter alia, reducing the risk of thawing or spoilage, reducing costs by eliminating labor, eliminating the need to remove pallets and debris from within the vessel, reducing the likelihood of injury to workers, saving demurrage charges and speeding the transportation to and loading of the vessel. A rotator may be used to facilitate the removal of pallets and the installation of slings about stacks of cartons, and stacks of cartons may be lifted directly out of the rotator and into the hold of a ship by the slings using, for example, the ship&#39;s gear.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a Continuation Application of a CPA of pending U.S. patent application Ser. No. 09/303,792, filed Apr. 30, 1999 (abandoned Sep. 8, 2000, which is a CIP of U.S. patent application Ser. No. 09/093,461, filed Jun. 8, 1998 (U.S. Pat. No. 5,980,198). 
    
    
     BACKGROUND INFORMATION 
     1. Field of the Invention 
     The present invention relates to the field of cargo handling, and in particular, to the rapid transportation and loading of cartons of frozen animal products onto a refrigerated vessel. 
     2. Background of the Invention 
     While there have been significant advances in the methods employed for the loading and unloading of vessels, the loading of refrigerated, cartonized cargo, and in particular, frozen animal products has proved particularly difficult due to several intractable problems. As a result, the transfer of the products from the packers to their loading aboard a vessel is presently carried out by processes that involve high costs and significant expenditure of manual labor, and which include bottlenecks that slow the process, that may result in product degradation or spoilage, and that result in long loading times for the product onto the vessel. It is presently common for the handling of cartons of frozen animal products to proceed as follows. 
     A large volume of animal products such as frozen chicken, turkey, beef, pork and seafood products (including livers, hearts, parts, deboned meat and the like) are frozen and shipped in and from the U.S. in relatively flat boxes. For example, chicken thighs, legs or quarters may be shipped in cartons of about 23.5 inches in length by 16.5 inches in width by 4 to 6.25 inches in height (59.7 cm by 41.9 cm by 10.2 to 15.9 cm). A preferred standardized box size for use with this invention, however, would be 24 inches by 16 inches (61.0 cm by 40.6 cm) with the height of the box varied to hold the particular products to be shipped. A box of such chicken parts may weigh on the order of 35 to 45 pounds (16 to 20 kg). 
     For simplicity, reference will hereafter be made to cartons of chicken parts, as other animal products may be handled in a similar manner. 
     Owing to the size restrictions imposed by standard trucks and trailers, the cartons are normally stacked on 40×48 inch (102×122 cm) pallets in layers of five cartons arranged with two cartons placed on the pallet in an end-to-end relationship beside three cartons placed side to side with their long axes perpendicular to those of the first two cartons. A palletload of cartons generally contains between about 10 to 12 such layers of cartons. 
     The packer sends the fresh chicken parts in such palletloads to a blast freezer/cold storage warehouse. At the warehouse, the cartons are restacked with spacers between the layers thereof. The spacers allow the circulation of air between the layers of cartons. Once the cartons are so stacked, the palletload of cartons are transferred to a blast freezer, which forces air chilled to about −40° F. (−40° C.) between and around the cartons. When the freezing process is completed, the cartons are removed from the blast freezer and placed in a rotator. The load of cartons is then rotated 90 degrees onto its side, the spacers are removed, and the load of cartons is then rotated back to an upright position in which it rests once more on the pallet. In order to facilitate transportation and storage of the stacks of cartons, the stack may be wrapped with a stretchable plastic film to help prevent excessive sliding of the layers of cartons relative to one another. Lift trucks are then used to move the cartons of frozen chicken products and transport them into the cold storage warehouse. 
     When the time comes to load a ship, lift trucks are used to remove the palletloads of cartons of chicken parts from the warehouse, and tie cartons are placed inside dry van trucks or truck trailers for transportation to the dock. These are typically uninsulated and unrefrigerated, and thus can be deleterious to the frozen product contained therein. At the dock, the cartons are removed from the truck trailer and placed on the dock, where they are subsequently lifted into the hold using the ship&#39;s gear, such as by using slings, lifting platforms or flying forks to lift the cartons and pallets. 
     In the hold, lift trucks engage the pallets and transport the pallets with their stacks of cartons to locations near where the cartons will be stowed. Stevedores then manually remove the cartons from the pallets and stack them without pallets for shipping. The pallets are then returned to the square of the hatch and are stacked to be hoisted out of the hold and back onto the dock by the ship&#39;s gear. The square of the hatch is the volume of space extending vertically downward from the open hatch to the floor of the cargo hold. 
     This process is quite inefficient. Delays in bringing a sufficient quantity of product to the dock and in unloading the cartons from the truck can increase the time needed to load the vessel. The space constrictions in the vessel limit the number of workers who can be engaged in stowing of the cartons, and thus may create a backup for product arriving at the dock. Excessive delays in loading which result in the cartons being left on the dock or in the truck can allow the product to begin to thaw, which can result in spoilage or otherwise render the product unmarketable. Delay in loading may also result in increased condensation of moisture on the cartons which can complicate the handling process. As the industry is seeking to use less wax on the cartons and to utilize paper-coated boxes, the damaging effect of condensation and internal thawing on the boxes is increased. 
     The breakage rate for pallets during this process is fairly high. As many as half of the pallets may suffer some breakage, and this can result in splintered wood, which may contain protruding nails, being left at the warehouse, on the dock or in the cargo hold of the vessel. Additional work is thus required to collect the pallets and pallet debris, to extract it from the hold of the ship or remove it from the dock, and to repair or discard the broken pallets. Further, the existence of pallet debris at the warehouse, on the dock, and in particular in the hold of the vessel, presents a risk of injury to workers. 
     Inefficient as this method of handling may be, there are a number of constraints that have made it difficult to improve. The main problems encountered is that the holds of the ship are irregular both in the overhead clearance and in the shape of the floor space. Not only does the overhead clearance of the cargo holds vary from ship to ship, and perhaps within a ship from hold to hold, the internal structure of the vessel and of the cooling system within it can result in overhead clearances that vary depending on the location within the hold. 
     Another difficulty in loading such cargoes is that the cartons are typically stacked to a uniform height after freezing. This is necessary for efficient use of the cold storage warehouse. This uniform height is generally ten or twelve layers of boxes arranged on a lift truck pallet, but it may vary somewhat from this number depending on the size of the cartons. The cartons are unitized by wrapping them with a stretchable plastic film that aids in transportation of the palletloads by fork lift, etc. However, space on refrigerated vessels is at such a premium that the wasted space of such pallets is considered undesirable. Thus, it has been considered necessary to avoid stowing the cartons on the pallets, and thus it has been the practice to stow the cartons in the ship by restacking them without the pallets within the ship. Moreover, since the ceiling height of holds on ships varies, and is seldom equal to the height of the cartons when stacked for warehousing purposes, it has heretofore been considered essential to manually stack the cartons in order to obtain as complete a filling of the vessel as possible. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for transportation of cartons of frozen products from the blast freezer/cold storage warehouse into a refrigerated vessel. The method may be practiced as follows. 
     As mentioned above, in preparing cartons of animal products and the like for freezing, the cartons are restacked on a pallet with spacers between the layers of cartons. The spacers permit the flow of cold air between the layers of the pallets and thus facilitate the rapid freezing of the product. At this stage, as the cartons require restacking with the spacers, a sling pallet may be used under the stack to be frozen. 
     A sling pallet, namely, a pallet with two or more channels in its upper surface, each of which extends from a first side of the pallet to the opposite side may be used in the present method. Preferably, the channels are parallel to one another and are symmetrically disposed with respect to the upper surface of the pallet. Changing to sling pallets at this stage permits the ordinary pallets to be stacked and returned to the producer. 
     Although it is the general practice to use pallets having dimensions of 40×48 inches (102×122 cm) in the frozen chicken parts industry to allow loading thereof into enclosed vans or trailers, the method of the present invention permits the use of 48×48 inch pallets (122×122 cm), which hold six rather than five cartons per layer. If such a layout is to be used, of course, and if restacking of the cartons is performed to accomplish this transformation, the cartons could be restacked on a sling pallet at that time. On the smaller pallet, the first layer of boxes is arranged with two cartons adjacent one side of the pallet in end to end alignment. Three cartons in a side-by-side arrangement are placed adjacent the other edge of the pallet (the two by three stacking pattern). The cartons should be stacked on the pallet such that the channels in the pallet extend longitudinally under the two end-to-end cartons and transversely under the three side-by-side cartons. For the larger pallets, where the cartons are arranged in two rows of three side-by-side cartons, one channel should run under each such row transversely to the long axes of the cartons. The next higher layer would have the same pattern, but would be rotated ninety degrees, and the layer on top of that would be identical in layout and orientation to the first layer (the three by three stacking pattern). This is the preferred configuration. 
     After the cartons are stacked with spacers between layers, the contents of the cartons are frozen in the blast freezer. The pallet and stacks of cartons are then placed in a rotator to facilitate removal of the spacers. It is also possible to replace a standard pallet with a sling pallet at this stage, rather than stacking the cartons with the spacers on the sling pallet as discussed above, although the configuration of the boxes cannot be changed from five boxes per layer to six boxes per layer at this stage without restacking. 
     After removal of the spacers and re-rotation of the palletload of cartons, the cartons may be wrapped with stretchable plastic film and slings may be inserted about the stack of cartons. The cartons may then be transported for storage in the refrigerated warehouse by means of lift trucks or other transportation means. 
     When the time for loading of a vessel comes, the palletloads of cartons are removed from the cold storage warehouse and loaded onto a truck for transportation to the dock. Preferably, the slings are placed on the stacks of cartons before they are loaded onto the truck, although the slings could be installed at the dock. Rather than loading them into uninsulated, enclosed trucks or trailers for transportation to the docks, as in the prior art method, the palletloads of cartons are loaded onto flatbed trucks or the flatbed trailer of a tractor-trailer truck and an insulating blanket of any known type which is adequate to protect the cartons against excessive warming is placed over them to reduce warming and possible melting that could occur in the uninsulated trucks. Hold-down straps may then be fastened over the stacks of cartons and blanket and tightened using the known belt and winch systems. Alternatively, if the blanket is of a sufficiently strong material or construction, the blanket itself could be used as a hold-down for the stacks of cartons and the blanket could be fastened down tightly atop the cartons. This might be accomplished, for example, by affixing straps of webbing in positions corresponding to winches on the trailers which extend beyond the edge of the blanket and pulling these tight with winches. 
     The trucks are then driven to the dock and positioned alongside the ship, where the ship&#39;s gear is used to lift the preslung stacks of cartons by their slings off of the truck and load them directly into the cargo hold. Since the cartons are lifted by the slings, the pallets remain on the truck and can then be transported directly back to the blast freezer/cold storage warehouse for further use. This direct loading of the ship from the flatbed truck eliminates the need for loading the cartons off the truck and onto the dock. This is important, as it reduces the amount of time the cartons are exposed directly to the ambient air and humidity, reducing the likelihood of thawing and of accumulation of condensation. Furthermore, the elimination of the need to unload trucks out onto a dock and thereafter load them into the ship eliminates delays in feeding the cargo into the ship. This is also important to the practice of the present invention since the improved efficiency in stowage provided by the present invention can only be fully utilized if the cargo can be loaded on board with sufficient speed to keep pace with the increased speed of the stowing operation. 
     The ship&#39;s gear deposits the cartons in the hold onto a special landing pad. This is a sling/lift truck pallet that can receive the cartons but which has channels to receive the slings so that the slings may be removed from the stacks of cartons. The landing pad also permits the stacks of cartons to be picked up directly by a load push lift truck owing to the existence of open-top channels into which the blades (or platens) of the lift truck may be inserted. 
     A load push lift truck, has at least two and preferably three blades extending from its lift mechanism. Preferably, the three blades are relatively broad, and have smooth, polished upper surfaces to facilitate the sliding of the cartons thereon. A push plate associated with the lift mechanism which can be extended by means of hydraulic cylinders from a retracted position adjacent the lift mechanism to a position adjacent the ends of the blades is used to extract the blades from under the cargo. Preferably, such a lift truck includes a side-shift mechanism which permits small lateral adjustments in the position of the cargo to facilitate its precise placement. Such load-push lift trucks are known in the art of specialized lift trucks. 
     When a cargo is landed on the landing pad, the slings may be removed from the stack of cartons. The load push lift truck positions the push mechanism in its fully retracted position and slides its blades between the blocks of the landing pad. Thereafter, the entire stack of cartons is transported to its stowage location. If the stack is to be positioned on the floor of the cargo hold, the operator maneuvers the load into position, possibly using the side shift mechanism to position it against an adjacent stack or wall, and activates the load push mechanism while backing the lift truck away from the location or allowing the load push mechanism to push it away from the stack of cartons. Additional layers of cartons can then be manually stacked on top of the cartons to fill the hold from floor to ceiling from stacks of cartons transported to a nearby location by the load push lift truck. 
     Attentively, in order to reduce the amount of lifting required by the stevedores, the lift truck may first position stacks of cartons in areas to be filled. The stevedores then commence manual stacking of layers of cartons on the floor of the vessel by removing some of the layers of cartons from the stacks deposited by the load push lift truck. Once the desired number of layers have been laid down such that a full stack of cartons will fill the remainder of available space to the ceiling, the load push lift truck can then deposit full height stacks of cartons on top of such partial stacks to complete the stowing process at that location. 
     When the loading of the hold is completed except for the area under the square of the hatch, the load push lift truck, removed slings, if any, and landing pad may be removed from the hold. Thereafter, the square of the hatch may be filled by landing stacks of cartons therein using the ship&#39;s gear. In the absence of a landing pad, the slings may not be easily removable from the stacks of cartons so landed. As such, in order to speed the loading of the square of the hatch, the slings may be left in place. Some manual restacking of cartons to fill the square of the hatch may of course be necessary in order to avoid the wasting of space in the cargo hold. 
     A number of operators of cold storage facilities have the practice of moving all of their frozen chicken to the dock in refrigerated trucks. As most of such trucks will not accept a 48×48 inch (122×122 cm) pallet, 40×48 inch (102×122 cm) pallets are commonly used. The use of such refrigerated trucks for transporting the frozen chicken may be used for a variety of reasons. For example, the cold storage warehouse may be located too far from the dock to allow for unrefrigerated transportation. 
     Regardless of the reason, however, the result is that a large amount of the frozen chicken produced is shipped on 40×48 inch (102×122 cm) pallets. As a result, the two by three stacking method is used. These pallets are typically loaded such that the long axis thereof is parallel to the long axis of the truck. The top and bottom boards that make up the upper and lower surfaces of the traditional pallet generally are of 40″ length and run transversely to the long axis of the pallet. It is not possible to convert such a pallet to a sling pallet by removal or repositioning of the top boards. As the channels for a sling pallet must run parallel to the long axis of the 40×48 inch (102×122 cm) pallet in order to be positioned parallel to the long axis of the two end-to-end boxes in the two by three pattern, and as the boards of the more typical 40×48 inch (102×122 cm) pallet run transverse to the long axis, removal of planks would not result in channels through which slings could be extended. Planks could be removed from the bottom of the pallet and, with some clearancing, channels could be made to allow insertion of the forks of a lift truck to permit the pallet to be picked up by a lift truck from any side. 
     This problem may be overcome in the present invention by the use of one or more dockside rotators that are capable of rotating, or tipping, one or more palletloads of frozen chicken onto its side. Preferably the palletload(s) of frozen chicken are rotated by 90° or more, and preferably by about 100°. This permits the pallet to be removed easily. The rotator may have channels in appropriate locations to permit slings to be positioned such that, when the stack of cartons of frozen chicken is rotated back to an upright position, the slings may be connected to a hook or spreader bar lowered by the ship&#39;s gear and the stack of frozen chicken may be lifted, without a pallet, into the hold of the ship. 
     Of course, where the stacks of frozen chicken will be rotated through more than 90°, and even if the stacks of frozen chicken are only rotated 90°, it is preferred to provide means for preventing the stack from sliding too far away from the pallet upon rotation, and to prevent cartons of frozen chicken from falling from the top of the stack. This can be accomplished by providing the rotator with adjustable retaining bars that can be opened and closed, as desired. 
     The rotator mentioned above may be configured to rotate one, two or more stacks of frozen chicken at a time. Preferably, the rotator is operated hydraulically, in which case electric or diesel-powered hydraulic pumps may be used to provide the pressurized hydraulic fluid. The retaining bars may also be opened and closed hydraulically. 
     Calculations based on the speed with which a truck can be unloaded using fork lifts and the cycle time typical of ships&#39; gear, there is adequate time to perform the rotating of the palletloads of frozen chicken, the removal of the pallets, the placement of the slings and the re-rotation of the stack of cartons of frozen chicken to an upright position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a wooden sling pallet according to the present invention. 
     FIG. 2 is a perspective view of a wooden landing pad according to the present invention. 
     FIG. 3 is a perspective view of a flatbed tractor-trailer carrying a plurality of stacks of cartons being unloaded into a vessel. 
     FIG. 4 is a top view showing the two by three stacking pattern on a 40×48 inch (102×122 cm) wooden pallet. 
     FIG. 5 is an end view of a 40×48 inch (102×122 cm) wooden pallet. 
     FIG. 6 is a side view of a wooden pallet with planks removed from the bottom surface, and with clearancing of the longitudinal beams. 
     FIG. 7 is a front view of a pallet rotator. 
     FIG. 8 is a front view of a two-pallet pallet rotator with two palletloads of cartons of frozen chicken aboard and with slings in place, with parts of the slings broken away. 
     FIG. 9 is a side view of a pallet rotator. 
     FIG. 10 is a side view of a support member of a pallet rotator. 
     FIG. 11 is a side view of a rotator with a palletload of cartons of frozen chicken loaded aboard, showing the operation of the rotator. 
     FIG. 12 is a side view of the retaining bar mechanism. 
     FIG. 13 is a rear view of the retaining bar mechanism with parts broken away. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 depicts a wooden sling pallet  11  made in a manner similar to ordinary wooden lift truck pallets. The sling pallet  11  is made by arranging three pieces of nominal 4 by 4 inch (nominal 10.2 by 10.2 cm) lumber  12  arranged in parallel with two such pieces of lumber  12  positioned adjacent the periphery of the pallet  11  and one piece  12  extending along its center line. The upper and lower surfaces  13 ,  14  of the pallet are formed of comparatively flat boards  16  extending transversely to the three pieces of lumber  12 . These boards  16  may be, for example, a nominal one inch (2.54 cm) in thickness, and may be affixed by nails, screws, or other means to the upper and lower sides of the three pieces of lumber  12 . Open-top channels  17  are formed in at least the upper surface of the pallet by adjusting the spacing between the boards  16 . The channels  17  should be of a width greater than that of the slings to be used, and the depth of the channels  17  should likewise be greater than the thickness of the slings such that the slings (including the eye portion) may be inserted therethrough when a stack of cartons is loaded onto the pallet  11 . Of course, sling pallets may be made of any of a variety of materials, such as plastics, metals and fiberglass, and the manufacture of pallets using such materials is known in the art of pallet manufacturing. Likewise, molding, stamping, welding, bonding, forming or other known methods may be used to make the sling pallet. The material and method used to make the pallet, however, is of less importance than the provision of channels therein which can receive slings. 
     In use, slings  31  may be prepositioned in the channels  17  prior to loading a stack of cartons thereon, or may be drawn through the channels after loading of the pallet by means of a rod with a hooked end or the like. Of course, it is also possible to use a standard pallet, to preposition slings on the pallet, and thereafter load the pallet with the cartons. However, the channels provide a convenient means for positioning the slings and provide the ability to add the slings either before or after loading of the pallet. 
     FIG. 2 depicts a wooden landing pad  21  according to the present invention. The landing pad  21  is formed from a bottom sheet  22  of plywood. Blocks of nominal 4 by 4 inch (nominal 10.2 by 10.2 cm) lumber  23  are affixed to the bottom sheet  22  by means of nails, screws, adhesive or other means in a pattern which provides two channels  24  which extend from one edge of the bottom sheet  22  to an opposite edge thereof between the blocks  23 . As with the channels  17  of the sling pallet  11 , these channels  24  should be of sufficient width and depth to allow a sling  31  to be drawn therethrough. 
     As the preferred load push lift truck of the present invention has three blades, a second set of channels  26  is provided to receive the blades of the lift truck. These channels  26  extend transversely between the blocks  23 , and are of a depth sufficient to receive the blades of the load push lift truck. As with the sling pallet  11 , the landing pad  21  may be made of materials other than wood, and by methods other than the use of nails, screws and the like. The important consideration in making a suitable landing pad is the provision of the channels as discussed above. 
     Load push, side shift lift trucks are known in the art of specialty lift trucks. Such lift trucks are discussed, for example, in U.S. Pat. 4,752,179 to Seaberg discusses such a lift truck. A preferred lift truck according to the present invention would include either two or three relatively flat blades (platens) which may conveniently have a width of 4 to 8 inches (10.2 to 20.3 cm), and would include side shift capability. The blades would be smooth and preferably polished, and would have rounded edges. The load push system should be sufficiently powerful to push a full stack of cartons of frozen chicken parts or the like off of the blades and onto another stack of cartons. 
     One preferred embodiment of the present method involves the transportation and stowage of the cartons of frozen products in the following manner. The preferred embodiment will be described with reference to cartons of frozen chicken parts. However, it is applicable to other frozen animal products stored in similar cartons. 
     A standard lift truck is used to remove stacks of cartons  30  of frozen chicken parts stacked on sling pallets  11  from the cold storage warehouse. If slings  31  have not already been provided, hooked rods are used to draw the slings  31  through the channels  17  in the pallets  11 . The palletloads of cartons are then placed on a flatbed truck trailer  32 . Once the trailer  32  is fully loaded, an insulating blanket  33  is used to cover the cartons  30  and is held in place by straps  34  which overlie the blanket  33  and are fastened to the frame of the trailer  32 . Any of a variety of insulating blankets may be used. An R-2 insulating quilted blanket made of two sheets of a quilted water-resistant nylon with 10 ounce polyester insulation therebetween should be sufficient for most applications. Preferably, the nylon outer layers are of a light color to reflect sunlight. Blankets of this type are offered by RefrigiWear, Inc. of Dahlonega, Ga. under the WEATHERGUARD mark, for example. Once the blanket  33  and cartons  30  have been secured in place, the tractor-trailer  32  is then driven to the dock. 
     At the dock, once the vessel is ready to receive the stacks of cartons  30  from the trailer  32 , the straps  34  and insulating blanket  33  are removed, and the ship&#39;s gear  36  (or a shore crane) is used to lift the stacks off the sling pallets and into the hold. Preferably, the blanket  33  is rolled up as the stacks of cartons  30  are lifted from the trailer by the ship&#39;s gear  36 . The insulating blanket  33  is then returned to the warehouse for use on the next load. 
     The ship&#39;s gear  36  deposits the stack of cartons in the ship&#39;s hold  37  on a landing pad  21  situated in the square of the hold. The square of the hold is the volume space extending vertically downward from the open hatch  38 . Once the stack of cartons  30  has been deposited on the landing pad, the slings  31  are released from the ship&#39;s gear  36  and are drawn through the channels  24  in the landing pad  21  to remove them from the stack of cartons. 
     A load push lift truck is then used to lift the stack of cartons off the landing pad  21  and to transport the cartons to the storage location. At this stage, either of two approaches may be taken. The load push lift truck may initially deposit the cartons  30  in their final stowage locations, with a view to stevedores subsequently filling the remaining space atop the stack from a lift-truck-deposited stack nearby, or the lift truck may deposit the stack in a convenient location with a view to the stevedores breaking down the stack into two or more shorter stacks on top of which the load push lift truck may deposit a full stack of cartons  30 , the combined height of the hand-stacked and lift-truck-deposited cartons filling the available vertical space. 
     In order to deposit a stack of cartons  30  on the floor of the cargo hold, the lift truck operator moves the stack into the desired position and lowers the blades of the lift truck to the floor. If necessary, the side shift can be used to position the stack in abutting relation with an adjacent stack or wall. The lift truck operator then simultaneously actuates the load push mechanism and either backs the lift truck away from the location or allows the load push mechanism to push the lift truck back from the stack (assuming the front of the stack is engaged with another stack or with a wall). The process for depositing a stack of cartons  30  on top of another partial or full stack is the same, except the lift truck positions the blades immediately above the full or partial stack on top of which the full stack is to be deposited. 
     For stowage in irregular spaces, such as adjacent a sloping wall, in spaces too small for a full stack to be inserted or the like, the lift truck may deposit a full stack of cartons near such stowage location and the stevedores can stow the cartons in such areas by hand. 
     When substantially all of the cargo hold has been filled, apart from the square of the hatch  38 , the lift truck and landing pad  21  are removed from the hold, and the square of the hatch is filled by depositing stacks of cartons directly into the square of the hatch using the ship&#39;s gear. Some manual stowage of cartons will likely be necessary, of course, as the ceiling height under the closed hatch may not be fillable merely by loading full stacks of cartons one on top of another. 
     Of course, in the absence of the landing pad  21 , most of the slings used to load the stacks of cartons into the square of the hatch may have to be left in the cargo hold. However, this will facilitate the offloading of the vessel, and the cost of the cargo slings is offset by the lower labor and other costs achieved by the practice. 
     It is important that the elements of the aforementioned method be used together for maximum efficiency. At present, using the prior art method of transportation and stowage, there are several critical bottlenecks that prevent the efficient handling of the cargo. The current manual method of stowage is capable of stowing not more than about 20 to 40 metric tons per hour per hatch. At this pace, the unloading process for the trucks, the extracting pallets from the cargo hold and handling thereof and other ship-side activities become extremely hectic. As the present method would permit an increase in the stowage rate to about 70 to 110 metric tons per hour per hatch, the prior art method of using enclosed trucks, unloading the trucks onto the dock, transporting the cartons into the hold together with pallets and the like would not be able to keep pace with the stevedores in the hold, even though the number of stevedores required for the practice of the present method is substantially less than required for the prior art method. 
     Similarly, the use of the present method speeds loading of the cartons onto the trucks and placing thereof under the ship&#39;s gear, so that the transportation of the stacks of cartons from the warehouse to the dock can keep pace with the loading. 
     Not all wooden pallets can conveniently be made into sling pallets by removal and or rearrangement of boards  16  which form the upper surface of the pallet. Referring to FIGS. 4-6, many 40×48 inch (102×122 cm) pallets  11  are made with 40 inch (102 cm) boards  16  forming their upper and lower surfaces. Removal of boards  16  from the upper surface of such a pallet  11  would result in channels which extend transverse to the long (48 inch, 122 cm) axis of the pallet. In order to lift a stack of cartons of frozen chicken which are stacked in the two by three pattern, shown in FIG. 4, with two slings, one sling must run longitudinally under the two end-to-end cartons  41 ,  42  lengthwise to them, and the other sling must run transversely under the three side-by-side cartons  43 ,  44 ,  46 . 
     Various equipment limitations result in the use of pallets as described above. One such limitation is the existence of a large fleet of refrigerated trucks which require the loading of 40×48 inch (102×122 cm) pallets with their long axes parallel to the longitudinal axis of the truck. Such trucks may be used for a variety of reasons to deliver palletloads of stacks of frozen chicken directly to the dock. So-called four-way pallets can be made by removal and/or rearrangement of boards  16  from the lower surface of a pallet  11 , and by cutting through portions of the nominal 4×4 inch lumber  12  to form channels  47 ,  48  which allow for insertion of the blades of a lift truck transversely to the long axis of the nominal 4×4 inch lumber  12 , as shown in FIG. 6 . However, unless 48 inch (122 cm) boards  16  are used for the upper and lower surfaces of the pallet  11 , and unless 40 inch (102 cm) nominal 4×4 inch lumber is used therebetween, removal of boards  16  from the upper surface of the pallet  11  will not produce channels  17  which run parallel to the long axis of the pallet. In any event, the fact remains that such pallets  11  are not always readily available and thus cannot always be substituted for the 40×48 inch (102×122 cm) pallets  11  in which the boards  16  extend transversely to the long axis of the pallet. 
     Where such 40×48 inch (102×122 cm) non-sling pallets  11  are used, the ship loading method of the present invention may still be used according to another preferred embodiment of the invention by use of a rotator  51  as shown in FIGS. 7-13. The rotator  51  of the present invention includes a plurality of L-shaped brackets  52  which are preferably made of steel tubing having a rectangular cross section. Such brackets are comprised of bottom beams  53  and back beams  54  The brackets  52  are adapted for attachment to a square cross section beam  56 , as shown in FIG. 10, by parallel plates  57 ,  58  which are welded to the back beam  54  and extend perpendicularly therefrom. The L-shaped brackets may be mounted to the square beam  56  by bolts  61  which pass through holes adjacent the distal edges of the plates  57 ,  58 . 
     The plates are positioned apart from one another by a distance which is just sufficiently larger than the width of the square beam  56  to permit them to fit on either side of it. Thus, when the plates  57 ,  58  of an L-shaped bracket  52  are positioned on the square beam  56 , and when bolts  61 are extended through the plates and nuts are tightened onto their ends, the plates  57 ,  58  are drawn together, gripping the beam. The location of the L-shaped bracket along the square beam  56  may thus be adjusted by loosening the bolts  61  and sliding the L-shaped brackets  53  laterally along the square beam  56 . Gussets  62 ,  63  may be welded to the plates  57 ,  58  and to the back beam  54  of the L-shaped bracket to provide greater resistance to flexure to the plates  56 ,  57 . As shown in FIGS. 7 and 8, bottom plates  64  may be welded between the bottom beams  53  of pairs of L-shaped brackets  52  to form sling channels  66  therebetween. Preferably, two sling channels  66  are provided for each stack of cartons of frozen chicken  30  which is positioned on the rotator  51 . The rotator  51  shown in FIGS. 7 and 8 is adapted to receive two such stacks of cartons of frozen chicken  30 . 
     The beam  53  is pivotably mounted to a frame  67  such that it is free to rotate about its longitudinal axis. A plurality of L-shaped brackets  52  are spaced along the length of the beam  53 , including both pairs of L-shaped brackets  52  having bottom plates  64  and single L-shaped brackets  52 . As shown in FIG. 9, hydraulic cylinders  68  are attached between the left and rightmost L-shaped brackets  52  such that the L-shaped brackets  52  and beam can be rotated from a first position  69  in which the back beams are vertical to a second position  71  in which they have been tipped past the horizontal. 
     If the stacks of cartons of frozen chicken  30  were to be rotated past 90° without some form of restraint, it is possible that cartons of frozen chicken could fall from the stack  30 , or that the entire stack  30  could slide out of the rotator  51 . In order to prevent this, as best shown in FIG. 9 and 1, a plurality of restraining bars  72  are pivotably mounted to the pairs of back beams  54  which are connected by bottom plates  64  by means of pairs of mounting brackets  73 . The mounting brackets  73 , in turn, are mounted on a plate  74  which extends between the two back beams  54  and which is bolted to the back beams  54  of the L-shaped members by means of bolts extending through the plate  74  and back beams  54 . A plurality of mounting holes is provided on the back beams  54  to which the plate  74  is to be mounted. This permits the height of the restraining bars  72  above the bottom beams  53  to be adjusted according to the height of the stacks of cartons of frozen chicken. 
     An arm  76  depends from each of the restraining bars, and a hydraulic cylinder  77  is mounted between the distal end of the arm  76  and the pairs of mounting brackets  73 , such that the hydraulic cylinder  77  can pivot the restraining bars  72  between a closed position in which they are parallel to the bottom beams  57  of the L-shaped brackets  52  to an open position in which they are parallel to the back beams  54 . 
     The hydraulic cylinders  68 ,  77  are manually controlled by conventional manual hydraulic controls  78  mounted to the frame, one set of controls being for the cylinders  68  that power rotation of the rotator  51  and the other set for controlling the hydraulic cylinders that open and close the restraining bars. The controls could be interlocked in a conventional manner such that the rotator  51  would not operate unless the restraining bars  72  are in their closed position. 
     The rotator  51  may be conveniently powered by a diesel or electric hydraulic power pack (not shown) of conventional design, or by other sources of hydraulic power. Of course, other methods could be used to power the rotator  51 , such as electric ball screws, pneumatic cylinders, and the like, but hydraulic operation is considered the most convenient. 
     In use, where stacks of cartons of frozen chicken  30  are presented along side a ship for loading without being on sling pallets or being preslung, a rotator may be used. To do so, the controls  78  are used to move the restraining bars  72  to their open position. Fork lifts would be used to move the palletloads of stacks of cartons of frozen chicken  30  into position on the rotator  51 . The restraining bars are then closed and held in place by means of the hydraulic cylinders  77 , and the hydraulic cylinder  68  is cycled to rotate the stack of cartons of frozen chicken  30  from a vertical orientation through 90° or more. Preferably, the rotator  51  rotates through about 100°. While it should be possible to remove the pallet manually with rotation of only 90 °, 100° should facilitate this process without causing excessive sliding of the stack of cartons of frozen chicken  30  away from the pallet  11 . 
     At this stage, with the stack of cartons of frozen chicken rotated from vertical to about horizontal, the pallet  11  may be removed, and slings may be positioned in the channels  66 . This accomplished, the rotator  51  can be returned to its upright position. As it rotates back, the stack of cartons will slide down against the bottom beams  53  of the L-shaped brackets. The restraining bars  72  may then be moved to their opened position by the associated hydraulic cylinders  77  and the slings may be affixed to a hook, spreader bar or other device by means of which the ship&#39;s gear can hoist the stack of cartons of frozen chicken, one or more at a time, out of the rotator  51  and into the hold of the ship, to be landed on a landing pad  21 . The remainder of the stowing process is as described above. 
     In addition to allowing the palletless loading of stacks of cartons of frozen chicken  30  as described above, the rotator may be used for removing pallets and slinging such stacks for a variety of other purposes, such as preparing such stacks of cartons of frozen chicken  30  for loading aboard a flatbed truck for transportation to the dock. 
     While the present invention has been described with reference to the preferred embodiments, it will be apparent to those skilled in the art that modifications to the method may be-made within the scope of the invention.