Abstract:
An inflatable boat including at least one inflatable tube forming first and second pontoons, the first and second pontoons meeting at a front of the boat to form a stem; a floor constructed of a flexible non-inflated fabric material spanning the area between the first and second pontoons and attached to the bottom of the first and second pontoons; and an inflatable keel formed of an inflatable high-pressure drop stitch material and secured to the bottom of the floor.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    Embodiments relate to watercraft, and more particularly, to an external inflatable keel for inflatable boats. 
         [0003]    2. Description of the Related Art 
         [0004]    Small watercraft are used for a number of activities such as fishing, rowing, sailing, rafting, paddling, motoring and recreational boating. Larger and some small watercraft are commonly equipped with a keel, or an underwater extension protruding from the bottom of the watercraft. The keel functions to provide stability and resist sideways movement or drift. 
         [0005]    Inflatable watercraft also may be found without a keel or with an inflatable internal keel positioned between an exterior fabric floor and a rigid or semi-rigid interior floor such as a drop stitch floor or wooden, plastic or aluminum sectional floorboards. 
         [0006]    Watercraft not having a keel tend to slide when turning and do not plane properly at high speeds. In particular, watercraft not having a keel tend to plow with their bow up instead of getting on a plane at twice the speed. Watercraft, such as the inflatable pontoon boat  100  shown in  FIG. 1  having an internal keel  110  demonstrate better performance in turns and will plane at high speeds. However, an inflatable pontoon boat  100  with a conventional internal keel  110  have a greater tendency to tip because the floor  120  tends to bend where the internal keel  110  is located. Also, pontoon boats with internal keels  110  tend to slide over water because of their soft rounded shape. 
         [0007]    In an inflatable kayak without a keel, the kayak will tend to yaw, or move sideways, from the intended course with each stroke of the double-ended paddle. This yaw reduces the efficiency of the kayak, resulting in lower speeds and increasing the fatigue of the paddler. 
         [0008]    Due to these problems and others an inflatable watercraft with an improved keel design is desired. 
       SUMMARY 
       [0009]    Therefore, it is one aspect of the present invention to provide an external inflatable keel for inflatable boats. 
         [0010]    Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
         [0011]    According to an aspect, an inflatable boat includes at least one inflatable tube forming first and second pontoons, the first and second pontoons meeting at a front of the boat to form a stem; a floor constructed of a flexible non-inflated fabric material spanning the area between the first and second pontoons and attached to the bottom of the first and second pontoons; and an inflatable keel formed of an inflatable high-pressure drop stitch material and secured to the bottom of the floor. 
         [0012]    The inflatable boat may further include a floor made of inflatable high-pressure drop stitch material placed on top of the flexible non-inflated fabric floor. 
         [0013]    The inflatable boat may further include rigid floorboards made of wood, plastic or aluminum placed on top of the flexible non-inflated fabric floor. 
         [0014]    In the inflatable boat, the non-inflated fabric floor may be attached to the at least one inflatable tube by gluing. 
         [0015]    In the inflatable boat, the non-inflated fabric floor may be attached to the at least one inflatable tube by welding. 
         [0016]    In the inflatable boat, the at least one inflatable tube may be constructed of polyester fabric and may further include at least one air valve. 
         [0017]    In the inflatable boat, the floor and the inflatable keel may be each made of polyester fabric and the floor may further include an air valve to inflate the inflatable keel. 
         [0018]    In the inflatable boat, the ratio of the length of the inflatable keel to the width of the inflatable keel may be at least 5:1. 
         [0019]    In the inflatable boat, the inflatable boat may not include a skeg. 
         [0020]    In accordance with another aspect, an inflatable kayak includes at least two inflatable tubes forming first and second pontoons, the first and second pontoons meeting at a front of the kayak to form a stem, and the first and second pontoons meeting at a rear of the kayak to form a stern; a floor constructed of a flexible non-inflated fabric material spanning the area between the first and second pontoons and attached to the bottom of the first and second pontoons; and an inflatable keel formed of an inflatable high-pressure drop stitch material and secured to the bottom of the floor by gluing or welding. 
         [0021]    The inflatable kayak may further include a skeg attached to the bottom of the aft end of the non-inflated flexible fabric floor. 
         [0022]    In the inflatable kayak, the non-inflated flexible fabric floor may be attached to the first and second pontoons by gluing or welding. 
         [0023]    In the inflatable kayak, the at least two inflatable tubes may be constructed of polyester fabric and each may further include an air valve. 
         [0024]    In the inflatable kayak, the ratio of the length of the inflatable keel to the width of the inflatable keel may be at least 5:1. 
         [0025]    In accordance with another aspect, an inflatable sailboat includes at least two inflatable tubes forming first and second pontoons, the first and second pontoons being substantially parallel; a frame constructed of rigid material connecting the first and second pontoons; two inflatable keels formed of an inflatable high-pressure drop stitch material and secured to the bottom of each of the first and second pontoons. 
         [0026]    The inflatable sailboat may further include one skeg attached to the bottom of the aft end of each of the first and second pontoons. 
         [0027]    In the inflatable sailboat, the at least two inflatable tubes may be constructed of polyester fabric and each may further include an air valve. 
         [0028]    In the inflatable sailboat, the ratio of the length of each inflatable keel to the width of each inflatable keel may be at least 5:1. 
         [0029]    The inflatable sailboat of may further include a transom made of plastic or wood, the transom being configured to support a rudder and/or a motor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which: 
           [0031]      FIG. 1  is front sectional view of a conventional inflatable pontoon boat; 
           [0032]      FIG. 2  is a bottom perspective view of an inflatable boat in accordance with an embodiment; 
           [0033]      FIG. 3  is front sectional view of an inflatable boat in accordance with an embodiment; 
           [0034]      FIG. 4  is a top view of an inflatable boat in accordance with an embodiment; 
           [0035]      FIG. 5  is a bottom view of an inflatable kayak in accordance with an embodiment; 
           [0036]      FIG. 6  is a rear view of an inflatable kayak in accordance with an embodiment; 
           [0037]      FIG. 7  is a front view of an inflatable kayak in accordance with an embodiment; 
           [0038]      FIG. 8  is a side view of an inflatable kayak in accordance with an embodiment; 
           [0039]      FIG. 9  is a top view of an inflatable kayak in accordance with an embodiment; and 
           [0040]      FIG. 10  is a bottom perspective view of an inflatable sailboat in accordance with an embodiment 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0041]    Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below to explain the present invention by referring to the annexed drawings. 
         [0042]      FIGS. 2-4  show an inflatable boat in accordance with an embodiment of the present invention. Herein, the term high pressure drop stitch material construction refers to upper and lower fabric layers and also a core section made up of an array of threads extending throughout the drop stitch structure. A benefit of this material is that the inflated the walls of the material create rectangular shapes of varying lengths, widths and depths, instead of taking on a rounded “balloon” shape. As shown in  FIG. 2 , the inflatable boat, generally designated by the reference numeral  1 , includes at least one inflatable tube forming pontoons  2  which meet at the front of the boat to form a stem  3 . The inflatable boat further includes a floor  4  made of a flexible non-inflated fabric material, which spans the area between the two pontoons  2  of the inflatable tube and is attached to the bottom of the inflatable tube. An inflatable high-pressure drop stitch keel  5  is attached to the bottom of the floor  4  by means of a gluing or welding. When the high-pressure drop stitch keel  5  is inflated, a rectangular external keel is formed. Because of the drop stitch construction of the inflatable keel  5 , the inflated keel  5  maintains a generally rectangular shape in cross-section instead of a rounded shape. This generally rectangular shape improves the performance and efficiency of the keel  5 . 
         [0043]    The floor  4  is generally attached to the bottom of the inflatable tube  2  by means of gluing or welding but other means for attaching the floor  4  to the bottom of the inflatable pontoons  2  may be used. 
         [0044]    The inflatable pontoons  2  are generally made of 1000 denier polyester fabric but may be made of other stronger or weaker fabric materials. As depicted in  FIG. 4 , the inflatable pontoons  2  further include air valves  13 , preferably one-way air valves to prevent blow back during inflation and fast deflation. 
         [0045]    The non-inflatable flexible fabric floor  4  is generally made of 1000 denier polyester fabric but may be made of other stronger or weaker fabric materials. As depicted in  FIG. 4 , the floor  4  further includes an air valve  14 , preferably a one-way air valve to prevent blow back during inflation and fast deflation, to allow inflation of the inflatable keel. 
         [0046]    In order to allow the inflatable keel  5  to cut through the water and provide additional stability, the inflated keel will be of generally long and narrow dimensions. The ratio of the length of the inflated keel to the width of the inflated keel is generally 6:1, but the exact ratio may be greater or smaller. The inflated keel further provides additional buoyancy. 
         [0047]    In the inflatable boat  1 , above the non-inflated flexible fabric floor is either an additional inflatable floor of high-pressure drop stitch construction, or floorboards made of wood, plastic, or aluminum laid transversely across the non-inflated flexible fabric floor  4  to provide a more rigid floor surface. 
         [0048]    It is another feature of the present invention that the structure of the external inflatable keel  5  provides that the inflatable boat  1  does not require a skeg or rudder. 
         [0049]    In another embodiment of the present invention,  FIGS. 5-9  show an inflatable kayak. As shown in  FIG. 5  the inflatable kayak, generally designated by the reference numeral  6 , includes at least two inflatable pontoons  7  which meet at the front of the kayak  6  to form a stem  8 . The pontoons  7  meet at the rear of the boat to form a stern  9 . The kayak  6  further includes a floor  11  made of a flexible non-inflated fabric material, which spans the area between the pontoons  7  and is attached to the bottom of the inflatable tube  7 . An inflatable high-pressure drop stitch keel  10  is attached to the bottom of the floor  11  by means of gluing or welding. When the high-pressure drop stitch keel  10  is inflated, an external inflatable keel  10  is formed. Because of the drop stitch construction of the inflatable keel  10 , the inflated keel  10  maintains a generally rectangular cross-section instead of a rounded shape. This generally rectangular shape improves the performance and efficiency of the keel  10 . It also improves the floating stability of the boat because it acts as an outside keel on a sailboat. 
         [0050]    As depicted in  FIG. 8 , the kayak  6  may further include a skeg  12  attached to the bottom side of the flexible non-inflated fabric floor  11  under the stern  9 . The skeg  12  in combination with the inflatable keel formed by the keel  10  prevents the kayak  6  from slide slipping and wandering, and further provides for more accurate maneuvering. This combination of inflatable bow keel  10  and skeg  12  provide additional floating stability like the keel or rudder of a sailboat. 
         [0051]    The flexible non-inflated fabric floor  11  is attached to the bottom of the pontoons  7  by means of a gluing or welding but other means for attaching the floor  11  to the bottom of the inflatable tube  7  may be used. 
         [0052]    The pontoons  7  are generally made of 1000 denier polyester fabric but may be made of other stronger or weaker fabric materials. As depicted in  FIG. 9 , the pontoons  7  further include an air valve  15 , preferably a one-way air valve to prevent blow back during inflation and fast deflation. 
         [0053]    The floor  11  and inflatable keel  10  are each generally made of 1000 denier polyester fabric but may be made of other stronger or weaker fabric materials. As depicted in  FIG. 9 , the floor  11  further includes an air valve  16 , preferably a one-way air valve to prevent blow back during inflation and fast deflation, to allow inflation of the inflatable keel  10 . 
         [0054]    In order to allow the inflatable keel to cut through the water and provide additional stability the inflated keel will be of generally long and narrow dimensions. The ratio of the length of the inflated keel to the width of the inflated keel is generally 6:1, but the exact ratio may be greater or smaller. 
         [0055]    In another embodiment of the present invention,  FIG. 10  shows an inflatable sailboat. As shown in  FIG. 10 , the inflatable sailboat, generally designated by reference numeral  17 , includes at least two inflatable pontoons  18 . The inflatable sailboat  17  further includes a frame  19  made of a rigid material, which connects the two pontoons  18 . Inflatable keels  21  made of inflatable high-pressure drop stitch fabric are attached to the bottom of each of the pontoons  18  by means of gluing or welding. When the high-pressure drop stitch fabric is inflated, external inflatable keels  21  are formed. Because of the drop stitch construction of the inflatable keels  21 , the inflated keels  21  maintain a generally rectangular cross-section instead of a rounded cross section. This generally rectangular shape improves the performance and efficiency of the keels  21  and floating stability. 
         [0056]    The inflatable pontoons  18  are generally made of 1000 denier polyester fabric but may be made of other stronger or weaker fabric materials. 
         [0057]    In order to allow the inflatable keels  21  to cut through the water and provide additional stability the inflated keels  21  will be of generally long and narrow dimensions. The ratio of the length of the inflated keel to the width of the inflated keel is generally between 5:1 to 25:1, but the exact ratio may be greater or smaller. 
         [0058]    Although several embodiments of the invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.