Abstract:
A boat hull comprises a central hull having top and bottom portions and first and second side hulls slidably supported from the top portion of the central hull so as to be transversely extendable relative thereto. The bottom portion of the central hull is rotatably connected to the top portion so as to be movable between raised and lowered positions. A method of reconfiguring the boat hull comprises slidably displacing first and second side hulls relative to a central hull and rotatably displacing a bottom portion of the central hull relative to a top portion from a raised position to a lowered position between the first and second side hulls.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates generally to boats and in particular to boats that may be converted into multiple hull configurations. 
     2. Description of Related Art 
     Recreational boats are available with a variety of hull configurations. Each configuration has benefits for different uses and conditions. In particular, shallow multihull boats have great stability, particularly at low speeds and at rest. These boats are desirable for fishing or cruising on calm waters, are well suited for coaching of various watersports due to their low wake, and can also achieve high speeds with relatively low wake. Water skiers prefer low wake to enable carving of turns, thus a shallow multihull boat is desirable for this sport. 
     Deep vee bottomed boat hulls are advantageous at high speeds and in rough water conditions. They can also create a significant amount of wake, which is desirable for wakeboarding. At lower speeds this design has less stability, and is therefore less desirable for low speed or at rest recreational uses, such as fishing, low speed cruising or resting at anchor. 
     Both deep vee bottom and shallow multihull boats have advantages. Rather than utilize multiple boats to meet the needs of all water sport enthusiasts, boats with convertible boat hulls allowing multiple hull profiles are desirable. Previous attempts have been made to allow conversion between two different hull shapes, however such attempts have not been satisfactory. 
     Some previous convertible boat hull attempts have included designs which modify the shape of a single hull, but do not include multiple hulls. Examples of such are U.S. Pat. No. 6,223,674 B1 to Wyman et al. and U.S. Pat. No. 3,559,222 to Walker. 
     Other attempts have included the ability to adjust the configuration of multiple hulls, such as described in U.S. Pat. No. 2012/0024211 A1, Wiltse, but stabilizers remain present in all configurations. Additionally, the movement of the pontoons or stabilizers in such designs is largely vertical and does not affect the overall width of the boat. 
     The configuration illustrated in U.S. Pat. No. 6,619,224 B1, Syfritt, similarly does not significantly affect the overall width of the boat between the two configurations. Additionally, this design includes only one bow. 
     SUMMARY OF THE INVENTION 
     According to a first embodiment of the present invention there is disclosed a boat hull comprising a central hull having top and bottom portions and first and second side hulls slidably supported from the top portion of the central hull so as to be transversely extendable relative thereto. The bottom portion of the central hull is rotatably connected to the top portion so as to be movable between raised and lowered positions. 
     The first and second side hulls may be positioned outside the bottom portion of the central hull at the lowered position. The bottom portion of the central hull may be nested within the first and second side hulls at the raised position. The boat hull may further comprise at least one actuator for extending the first and second side hulls relative to the central hull. 
     The bottom portion of the central hull may be rotatable relative to the top portion about an axis. The axis may be horizontal. The axis may be located proximate to a leading edge of the bottom portion. The bottom portion may have an angular orientation relative to horizontal greater at the lowered position than at the raised position. 
     The boat hull may further comprise an actuator for extending the bottom portion between the raised and lowered positions. The bottom portion may be abuttable against and alignable with the first and second side hulls such that a bottom running surface of the bottom portion is continuous with corresponding bottom running surfaces of the side hulls at the lowered position. The bottom portion of the central hull may be positionable at an intermediate position between the raised and lowered positions. The bottom portion may be abuttable against and alignable with the first and second side hulls at the intermediate position so as to form a continuous bottom running surface therebetween. The boat hull may further comprise a motor and drive assembly supported on the bottom portion of the central hull. 
     According to a further embodiment of the present invention there is disclosed a method of reconfiguring a boat hull comprising providing a central hull having top and bottom portions and providing first and second side hulls slidably supported from the top portion of the central hull so as to be transversely extendable relative thereto. The bottom portion of the central hull is rotatably connected to the top portion so as to be movable between raised and lowered positions. 
     According to a further embodiment of the present invention there is disclosed a method of reconfiguring a boat hull comprising slidably displacing first and second side hulls relative to a central hull and rotatably displacing a bottom portion of the central hull relative to a top portion from a raised position to a lowered position between the first and second side hulls. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In drawings which illustrate embodiments of the invention wherein similar characters of reference denote corresponding parts in each view, 
         FIG. 1  is a diagrammatic perspective view of a marine vessel with a convertible hull. 
         FIG. 2  is a side view of the marine vessel of  FIG. 1 , in a first or shallow hull configuration. 
         FIG. 3  is a side view of the marine vessel of  FIG. 1 , in a third or deep vee hull configuration. 
         FIG. 4  is an aft view of the marine vessel of  FIG. 1 , in the first hull configuration. 
         FIG. 5  is an aft view of the marine vessel of  FIG. 1 , in a second or wide beam shallow hull configuration. 
         FIG. 6  is an aft view of the marine vessel of  FIG. 1 , in a third hull configuration. 
         FIG. 7  is an aft view of the marine vessel of  FIG. 1 , in a fourth or mid-level vee hull configuration. 
         FIG. 8  is a bottom view of the marine vessel of  FIG. 1  in a third hull configuration. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a multihull marine vessel with a convertible hull according to a first embodiment of the invention is shown generally at  10 . As best seen in  FIGS. 4, 5 and 6 , the marine vessel  10  comprises a plurality of hulls, including first and second side hulls  12  and  14 , respectively, and a central hull  16  therebetween. As will be described in more detail below, the first and second side hulls  12  and  14  can be adjusted in lateral position, and the central hull  16  can be adjusted in vertical position, thereby altering the overall hull configuration of the marine vessel  10 . 
     Turning to  FIG. 8 , the marine vessel  10  has fore end indicated at  20 , aft end indicated at  22 , first or port side  24  and second or starboard side  26 . The first and second side hulls  12  and  14 , having first and second side hull keels  32  and  34 , respectively, as shown on  FIGS. 4-7 , are positioned proximate to first and second sides  24  and  26 , respectively, and extend substantially from fore end  20  to aft end  22 . The central hull  16 , having central hull keel  36 , as shown on  FIGS. 4-7 , extends substantially from central hull front end  28  to aft end  22 , and is positioned centrally between first and second side hulls  12  and  14 . The central hull  16  includes a motor and drive assembly  18  therein. As illustrated in  FIGS. 1 and 8 , the central hull front end  28  may be positioned rearwardly of the fore end  20  of the vessel. 
     When in the first or second positions, as shown in  FIGS. 4 and 5 , the exterior of the hull has a generally trimaran shape, with the first and second side hulls  12  and  14  being generally the same shape and size, and the central hull  16  formed in a vee shape therebetween. The central hull  16  extends between first and second sides,  42  and  44 , and includes a central hull top portion  46  and central hull bottom portion  48 , respectively, wherein the central hull bottom portion  48  extends to a central keel  36 . The central hull  16  is shallower than the first and second side hulls throughout its length, from central hull front end  28  to aft end  22 , with the central hull keel  36  substantially parallel to the first and second side hull keels  32  and  34 . The central hull keel  36  extends substantially from the central hull keel front end  29  to aft end  22 . As illustrated, the bottom surface of the central hull bottom portion  48  is formed of first and second central running surfaces,  43  and  45 , respectively, extending from the keel  36  as is commonly known. The first and second central running surfaces  43  and  45  are angled relative to horizontal at a deadrise angle, as is commonly known. 
     As best shown on  FIGS. 5 and 6 , the first side hull has lower portion  13 , upper portion  17  and a first side hull actuating cavity  21  therebetween. Similarly, the second side hull has lower portion  15 , upper portion  19  and a second side hull actuating cavity  23  therebetween. The lower portions  13  and  15  of the first and second side hulls,  12  and  14 , respectively, are essentially oblique prisms in shape at the aft end of the vessel, although it may be appreciated that they may be another shape throughout the remainder of the length. The first side hull  12  lower portion  13  has outside surface  50 , first outside running surface  52 , inside lower side surface  54 , inside lower top surface  56 , inside upper side surface  58  and inside upper bottom surface  60 . The inside lower top surface  56  and inside upper side surface  58  form a cavity  66  sized to receive the central hull bottom portion  48  therein. The second side hull  14  lower portion  15  has outside surface  70 , second outside running surface  72 , inside lower side surface  74 , inside lower top surface  76 , inside upper side surface  78  and inside upper bottom surface  80 . The inside lower top surface  76  and inside upper side surface  78  form a cavity  86  sized to receive the central hull bottom portion  48  therein. The first and second side hulls,  12  and  14 , are identical in shape, mirrored along centreline  200 . 
     In the first position, as shown on  FIG. 4 , the top of the bottom portion  48  of the central hull first and second sides,  42  and  44 , are arranged proximate to each other with the central hull bottom portion  48  nested within the cavities  66  and  86 , respectively. In this position, the marine vessel  10  has a narrow beam width  108 . The first position is beneficial for transporting the marine vessel  10  on a trailer outside of the water. 
     Turning to  FIGS. 4, 5 and 6 , the floor  102  is formed with the central hull top portion  46  and is positioned within the first and second side hull actuating cavities  21  and  23 . The floor  102  comprises a box shape with actuators enclosed therein lengthwise extending substantially from central hull keel front end  29  to floor rear end  106 , and having a width close to a narrow beam width  108  of the marine vessel  10 , extending from first side  24  to second side  26  as shown in the first position in  FIG. 4 . As best seen in  FIGS. 2 and 3 , two front lateral actuators, first side front lateral actuator  90  and second side front lateral actuator  92  (not shown), are located at the front of the floor  102 , proximate to central hull keel front end  29 . Two rear lateral actuators, first side rear lateral actuator  94  and second side rear lateral actuator  96 , are located at the rear of the floor  102  proximate to the floor rear end  106 . The first side front and rear lateral actuators  90  and  94  are fixed at their first ends to the first side hull  12  and extend from first side  24  to a fixed upright wall  104  within the floor  102  at the centreline  200 , to which the second ends of the lateral actuators  90  and  94  are fixed. The second side front and rear lateral actuators  92  and  96  are fixed at their first ends to the second side hull  14  and extend from the second side  26  to a fixed upright wall  104  within the floor  102  at centreline  200 , to which the second ends of the lateral actuators  92  and  96  are fixed. The lateral actuators  90 ,  92 ,  94  and  96  may be selected to be linear actuators such as, by way of non-limiting example, hydraulic, pneumatic or mechanical screw jack, although it will be appreciated that other actuator types may be useful, as well. 
     To convert from the first shallow hull position, as shown in  FIG. 4 , to the second shallow hull position, as shown in  FIG. 5 , the lateral actuators  90 ,  92 ,  94  and  96  are extended simultaneously. As the lateral actuators  90 ,  92 ,  94 , and  96  extend, the first and second side hulls  12  and  14  slide laterally outwards, increasing the beam width until it reaches a maximum beam width  110 . The floor  102  slides substantially out of the first and second side hull actuating cavities  21  and  23 , exposing most of the top of the floor surface. A small portion on each side of the floor remains within the actuating cavities,  21  and  23 , below the upper portions  17  and  19  of the first and second side hulls  12  and  14 . 
       FIGS. 3 and 6  illustrate the third or deep vee hull configuration of the marine vessel  10 . As best seen in  FIGS. 2 and 3 , a pivot hinge  112  pivotally connects the central hull top portion  46  to the bottom portion  48  at a location proximate to the central hull keel front end  29 . As illustrated in  FIG. 2 , a vertical actuator  98  extends from the compressed first position, and  FIG. 3  shows the vertical actuator  98  in the extended second position. The vertical actuator  98  is located proximate to the floor rear end  106  and the upper end is fixed to the floor  102  by any known means, such as, by way of non-limiting example, to a bracket attached by, such as, by way of non-limiting example, weld, bolts or rivets, although other attachment methods may be useful, as well. The lower end of the vertical actuator  98  is fixed to the central hull  16 . Although one vertical actuator  98  is illustrated in the present embodiment of the invention, it may be appreciated that additional vertical actuators may be useful, as well, so as to permit placement proximate to each side of the central hull bottom portion  48 . The vertical actuator  98  may be such as, by way of non-limiting example, hydraulic, pneumatic or mechanical screw jack, but other actuator types may be useful, as well. 
     To convert from the second shallow hull position, as illustrated in  FIGS. 2 and 5 , to the third deep vee hull configuration, as illustrated in  FIGS. 3 and 6 , the vertical actuator  98  is extended, pivoting the central hull on the pivot hinge  112  and pushing the central hull keel  36  at the rear end of the central hull  16  proximate to the aft end  22  down past the first and second side hull keels  32  and  34 , such that the aft end  22  of the vessel forms a single deep vee configuration. The central hull bottom portion  48  and the first and second side hulls  24  and  26  may be slidably interlocked to each other by any commonly known means, such as, by way of non-limiting example, tongue and groove connector slides or the like. A cavity  99  is formed above the top of the central hull bottom portion  48  when the vessel is in the third deep vee configuration. The cavity  99  may be fitted with an expandable bladder as are commonly known which may be filled with water to weigh down the aft end of the vessel, increasing the aft depth and therefore producing a larger wake. In this configuration, the marine vessel  10  will produce a significant amount of wake, which is beneficial for high wake watersports, such as, by way of non-limiting example, wakeboarding or wake surfing. 
     Turning now to  FIG. 7 , a fourth or mid-level vee hull configuration is shown. This intermediate position between the second or wide beam shallow hull configuration and the third or wide beam deep vee hull configuration is achieved by extending the vertical actuator  98  only part way. This position maintains a generally trimaran hull shape with central hull keel  36  below the first and second side hull keels  32  and  34 , yet not as deep as in the third configuration, as shown in  FIG. 6 . In this configuration, the marine vessel  10  will produce a moderate amount of wake, while still able to achieve high speeds. 
     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.