Abstract:
A vessel comprising a hull having a length, a main deck located above and rigidly connected to the hull and at least one beam extending substantially along the length of the hull at a position spaced above the deck, wherein the beam is rigidly connected to and longitudinally reinforces the deck and the hull.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to ship design in general and in particular to a ship hull having increased longitudinal strength by means of a structure external to the hull. 
         [0003]    2. Description of Related Art 
         [0004]    Shipping goods and materials is a common and efficient method of distributing such materials around countries and the globe. In particular for use on rivers and inland waterways barges and similarly designed powered vessels are commonly used. Such shipping requires the use of marine vessels adapted to carry an adequate amount of material to make the shipping process economical. Additionally, the vessels required for such shipping need to be sufficiently strong to support cargo, resist external loads and ensure safety of navigation. 
         [0005]    One measure of hull strength is the hull section modulus which is a measure of geometric stiffness (expressed in length unit to third power, e.g. cu ft or m3). Marine vessels are traditionally required to have a minimum hull section modulus in order to provide adequate longitudinal strength that will prevent the hull from breaking. 
         [0006]    As illustrated in  FIGS. 1 and 2 , a prior art container ship for use in inland waterways is illustrated generally at  10  comprising a hull  12 , a main deck  14  located thereabove with a plurality of containers  8  located above the main deck. Such vessels commonly include a solid deck for reasons of economy of construction. Accordingly, such vessels only receive and transport containers upon the top deck surface. Longitudinal strength in such vessels is commonly achieved by increasing the size and strength of the longitudinal structural members of the vessel such as the bottom shell and the deck as well as introducing longitudinal beams  16  therealong which are used to stiffen them. 
         [0007]    However such approach of adding additional or thicker members for the hull or deck increases the weight of the vessel thereby limiting the cargo which may be carried thereby and increasing both the cost of the vessel to construct and operate. 
         [0008]    An additional means of longitudinally stiffening marine vessels is to increase hull depth, or the height of the deck above the bottom of the hull shell. A disadvantage of such raised deck heights in inland waterway vessels is that any shipping containers which are located thereupon are also raised thereby limiting the number of such containers which may be carried on such a vessel that is intended to pass under bridges and the like. 
       SUMMARY OF THE INVENTION 
       [0009]    According to a first embodiment of the present invention there is disclosed a marine vessel comprising a hull having a length enclosing an interior volume from above by a deck and at least one beam extending substantially along the length of the hull at a position spaced above the deck, wherein the beam is rigidly connected to and longitudinally reinforces the deck and the hull. 
         [0010]    The at least one beam may include a plurality of rigid members extending between the beam and the main deck. The at least one beam and the rigid members may form a truss. The vessel may further include trusses adjacent to each longitudinal side of the hull. The trusses may include at least one bracing beam extending transversely therebetween 
         [0011]    The vessel may further comprise bow and stern bodies extending above the main deck wherein the trusses are rigidly connected to the bow and stern. At least one of the bow and stern bodies may include one or more of personnel accommodation and machinery space. 
         [0012]    Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. 
         [0013]    The hull may include side walls having top edges proximate to the deck. The top edges of the side walls may terminate at the deck. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    In drawings which illustrate embodiments of the invention wherein similar characters of reference denote corresponding parts in each view, 
           [0015]      FIG. 1  is a perspective view of a prior art ship. 
           [0016]      FIG. 2  is a cross sectional view of the prior art ship of  FIG. 1 . 
           [0017]      FIG. 3  is a perspective view of a ship according to a first embodiment of the present invention. 
           [0018]      FIG. 4  is a cross sectional view of the ship of  FIG. 3 . 
           [0019]      FIG. 5  is a perspective view of the ship of  FIG. 3  having a plurality of containers located thereon. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring to  FIGS. 3 through 5 , a vessel for shipping containers  8  according to a first embodiment of the invention is shown generally at  20 . The vessel  20  includes a hull  22  of any conventional shape extending along a central axis  24  between front and rear ends,  26  and  28 , respectively. The vessel  20  also includes a main deck  30  spaced vertically above the hull  22  and attached thereto as is conventionally known. The main deck  30  is substantially horizontal and planar and is continuous to support a plurality of shipping containers  8  thereon as illustrated in  FIG. 5 . As illustrated in  FIG. 4 , the hull  22  may include a side  44  having a top edge  46  terminating at or proximate to the deck  30 . 
         [0021]    The vessel includes a pair of spaced apart horizontal beams  32  extending substantially along the length of the hull  22  at a position parallel to and spaced above the main deck  30 . The beams  32  are connected to the hull  22  or the main deck  30  by a plurality of rigid angled and vertical supports  34  and  36 , respectively. It will be appreciated that the beams  32  and angled and vertical supports  34  and  36  form trusses in conjunction with the main deck or hull so as to provide additional strength to the vessel. The beams  32  may be of any size or shape depending upon the size of the vessel and the strength requirements which they are to contribute to the longitudinal stiffness of the vessel such as by way of non-limiting example, H-section or box-section beams although it will be appreciated that other shapes may be utilized as well. In particular, the beams  32  may be designed to have a maximized section for a given weight. The beams  32  may be formed of any suitable material, such as by way of non-limiting example, steel, other metals, or composite materials. Similarly the angled and vertical supports  34  and  36  may be formed of similar materials and sizes and may be connected to the beams  32  and the hull  22  or the main deck  30  by any convention means such as by way of non-limiting example, welding, fasteners adhesives or a combination thereof. 
         [0022]    The angled and vertical supports  34  and  36  may be secured to either the hull  22  or the main deck  30  and are located proximate to the side edges of the vessel to maximize the space therebetween. As illustrated in  FIG. 3 , the beams  32  may optionally include cross-braces  38  extending transversely across the vessel between the beams  32  so as to provide additional torsional and transverse rigidity to the vessel. The cross-braces  38  may be formed of a similar material as the beams  32  and supports  34  and  36  and may be secured thereto by any conventional means such as by way of non-limiting example, welding, fasteners, adhesives or any combination thereof. 
         [0023]    As illustrated in  FIGS. 3 and 5 , the vessel  20  may optionally include stern and bow bodies,  40  and  42 , respectively extending from the main deck  30  at locations proximate to the front and rear  26  and  28  of the vessel. As illustrated in  FIG. 3 , the bow body is shown in dashed lines to not obstruct the remainder of the vessel  20  although it will be appreciated that this structure is constructed similar to the stern body. It will be appreciated that one or both of the bow and stern bodies may optionally include operator accommodation or machinery therein. As illustrated in  FIGS. 3 and 5 , the beams  32  may terminate at bow and stern bodies so as to incorporate them into the overall strengthening structure of the vessel. 
         [0024]    With reference to  FIG. 5 , in operation a plurality of shipping containers  8  may be located upon the main deck  30  between the beams  32 . The beams provide additional strength to the vessel while permitting a low main deck height. In particular the height of the main deck above the hull (generally indicated at  50  in  FIG. 4 ) can be minimized as much as only the necessary displacement of the vessel may so as dictate to maximize the height above the hull deck available to locate cargo upon. Accordingly the the main deck  30  can be moved as low as the few inches above waterline and the space above deck can accommodate a full 8 tiers of containers, thereby increasing the efficiency of such shipping operations. 
         [0025]    While specific embodiments of the invention have been described and illustrated, such embodiments should be considered illustrative of the invention only and not as limiting the invention as construed in accordance with the accompanying claims.