Abstract:
A watercraft comprises a hull which is bouyant in water, and a propulsion system coupled to the hull for for propelling the hull in the water. The propulsion system comprises a propulsion disc and at least one drive input coupled to the propulsion disc. The propulsion disc is rotatable by the drive input about an axis of rotation and comprises a cavitation-reducing ring and a plurality of paddles extending radially outwards from the cavitation-reducing ring, The cavitation-reducing ring is configured to reduce cavitation in the water during rotation of the propulsion disc.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent application claims the benefit of the filing date of U.S. patent application Ser. No. 60/851,321, entitled “Turbo Boat”, filed Oct. 13, 2006, and U.S. patent application Ser. No. 60/851,322, entitled “Stingray Boat”, filed Oct. 13, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention described herein relates to a self-propelled watercraft. In particular, the invention relates to a pedal-powered watercraft. 
       BACKGROUND OF THE INVENTION 
       [0003]    Conventional pedal-powered watercraft are typically implemented as a kayak or a catamaran, and comprises a human-powered propulsion system. The propulsion system comprises a paddlewheel which is supported on a rotatable crankshaft. The paddlewheel creates cavitation in the water as the paddlewheel is rotated. As a result, the transfer of input pedal energy to watercraft movement is inefficient. 
       SUMMARY OF THE INVENTION 
       [0004]    The invention relates to a watercraft propulsion system that includes an inertial cavitation reduction mechanism. 
         [0005]    In accordance with one aspect of the invention, there is provided a propulsion system that comprises a propulsion disc and a plurality of paddles. The propulsion disc has a central axis and comprising a cavitation-reducing ring. The paddles extend radially outwards from the cavitation-reducing ring. The cavitation-reducing ring is configured to reduce cavitation in water during rotation of the propulsion disc about the central axis. 
         [0006]    In accordance with another aspect of the invention, there is provided a watercraft that comprises a hull which is bouyant in water, and a propulsion system coupled to the hull for propelling the hull in the water. The propulsion system comprises a propulsion disc and at least one drive input coupled to the propulsion disc. The propulsion disc is rotatable by the drive input about an axis of rotation and comprises a cavitation-reducing ring and a plurality of paddles extending radially outwards from the cavitation-reducing ring, The cavitation-reducing ring is configured to reduce cavitation in the water during rotation of the propulsion disc. 
         [0007]    In one implementation, the propulsion disc has a pair of opposing sides, and comprises at least one aperture disposed radially outwards from the axis of rotation and extending axially between the opposing sides. The cavitation-reducing ring is disposed radially outwards from the at least one aperture, and comprises a pair of cylindrical walls each extending axially outwards from a respective one of the opposing sides. 
         [0008]    Further, the propulsion disc also comprises a support ring that is disposed around a circumference of the disc. Each paddle includes an outer end and extends radially outwards from the cavitation-reducing ring and terminates at the respective outer end. The support ring is coupled to the paddles at the outer ends thereof. 
         [0009]    The drive input may comprise comprises a pedal provided on a crankshaft, and the propulsion disc may comprise a keyed centre that is configured for receiving the crankshaft therein. The keyed centre is concident with the axis of rotation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]    The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0011]      FIG. 1  is a perspective view of the watercraft, according to the invention; 
           [0012]      FIG. 2  is a perspective view of the hull of the watercraft shown in  FIG. 1 ; 
           [0013]      FIG. 3  is a perspective view of the propulsion disc of the watercraft; 
           [0014]      FIG. 4  is a side elevation of the propulsion disc when the watercraft is deployed in water; 
           [0015]      FIG. 5  is an end view of the propulsion system; 
           [0016]      FIG. 6  is an exploded schematic view of the propulsion system; 
           [0017]      FIG. 7  is a top perspective view of one of the seats of the watercraft; 
           [0018]      FIG. 8  is an exploded view of the seat shown in  FIG. 7 ; 
           [0019]      FIG. 9  is a side elevation of the seat; 
           [0020]      FIG. 10  is a bottom perspective view of the seat; 
           [0021]      FIG. 11  is a perspective view of the bimini top of the watercraft; 
           [0022]      FIG. 12  is a schematic view of a bimini mount when the bimini top is in the closed/inclined position; 
           [0023]      FIG. 13  is a schematic view of the bimini mount when the bimini top is in the closed/down position; 
           [0024]      FIG. 14  is a perspective view of the bimini mount when the bimini top is in the open position; 
           [0025]      FIG. 15  is a perspective view of the bimini mount without the bimini top; 
           [0026]      FIG. 16  is a perspective view of the hull, depicting the storage locations of the propulsion discs; 
           [0027]      FIG. 17  is a magnified view of the bow of the hull; 
           [0028]      FIG. 18  is a magnified top view of the seat back attachment mechanism of the seat shown in  FIGS. 7 and 8 ; 
           [0029]      FIG. 19  is a magnified bottom view of the seat back attachment mechanism; 
           [0030]      FIG. 20  depicts the propulsion discs proximate the hull mounting locations thereof; 
           [0031]      FIG. 21  is a bottom perspective view of the watercraft; 
           [0032]      FIG. 22  is a top perspective view of the watercraft; 
           [0033]      FIG. 23  is a perspective view of one variation of the propulsion disc shown in  FIG. 3 ; and 
           [0034]      FIG. 24  is a magnified view of the propulsion disc shown in  FIG. 23   
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0035]    As shown in  FIGS. 1 and 16 , the watercraft, according to the invention, is hydrodynamically-stable, and comprises a low profile catamaran hull  1 , and a hood  2 . 
         [0036]    Preferably, the watercraft uses a dual independent drive system that allows for the left and right peddlers to pedal independently of each other and at their own pace. The dual independent drive system comprises a pair of turbo propulsion discs  4  and a pair of crankshafts  5 . Each crankshaft  5  is supported by a pair of crankshaft bearings  32 ,  33 , and is secured at one end to a corresponding propulsion disc  4 .  FIG. 5  depicts the left and right propulsion discs  4  and the left and right crankshafts  5 , and associated crankshaft bearings  32 ,  33 . 
         [0037]      FIG. 6  depicts one of the crankshafts  5  prior to being installed into the corresponding propulsion disc  4 .  FIG. 6  also reveals the design of the crankshaft bearings  32 ,  33 , and the location of the crankshaft bearings  32 ,  33  relative to the crankshafts  5 . As shown in  FIG. 2 , the hull  1  includes recesses  23 ,  24  that are formed into the top surface of the hull  1  and retain the crankshaft bearings  32 ,  33  therein. The crankshaft bearings  32 ,  33  are open ended or substantially U-shaped in design to allow the propulsion disc  4   s  and the crankshafts  5  to be quickly and easy installed into the hull  1  from the top of the hull  1 .  FIG. 21  depicts the propulsion disc  4   s  and the crankshafts  5  installed into the hull  1 . 
         [0038]    Preferably the crankshaft bearings  32 ,  33  are tapered inwardly adjacent their open end to thereby retain the crankshafts  5  within the crankshaft bearings  32 ,  33 . Further, preferably the crankshaft bearings  32 ,  33  are dimensioned relative to the recesses  23 ,  24  such that, when the crankshaft bearings  32 ,  33  are inserted into the recesses  23 ,  24 , and the crankshafts  5  are installed into the crankshaft bearings  32 ,  33 , the crankshafts  5  urge the crankshaft bearings  32 ,  33  slightly outwards to thereby retain the crankshaft bearings  32 ,  33  in the recesses  23 ,  24 . 
         [0039]    The propulsion disc  4  is best shown in  FIGS. 3 and 4 . As shown, each propulsion disc  4  includes a ring  27  disposed around the centre of the propulsion disc  4 , and a series of paddles  26  extending outwards from the ring  27 . Each propulsion disc  4  also includes a plurality of apertures or through-holes  29  that extend axially between the opposing sides of the disc  4 . As shown in  FIG. 4 , the ring  27  is disposed radially outwards from the inner series of apertures, and reduces cavitation and turbulence in the water when the propulsion disc  4  is being rotated about its centre of rotation, thereby creating more propulsion power. The propulsion disc  4  also includes an outer ring  28  surrounding the paddles  26  that allows the propulsion disc  4  to be used as a wheel to move the turbo boat around on land, or between land and water. Further, the propulsion disc  4  includes a keyed centre  30  which is disposed at the centre of rotation, and is configured to receive one of the crankshafts  5  therein. 
         [0040]    One variation of the propulsion disc is shown in  FIGS. 23 and 24 . The propulsion disc depicted therein includes a plurality of paddle extensions  26   a . As shown, each paddle extension  26   a  slides over the outer end of one of the paddles  26  and snaps onto the outer ring  28 , thereby locking the paddle extension into place. Preferably, the paddle extensions  26   a  are fabricated from soft PVC, thereby imparting resilient properties to the paddle extension. As a result, the paddle extensions  26   a , when attached to the paddles  26 , increase the efficiency and propulsion ability of the propulsion disc. Although the propulsion disc is shown comprising a paddle extension for each paddle  26 , the propulsion disc may be fitted with fewer paddle extensions  26   a , depending upon the desired efficiency of the propulsion disc. 
         [0041]      FIG. 17  is a magnified view of the hood  2 , and the front portion of the hull  1 . As shown in  FIGS. 1 ,  16  and  17 , the two-component hull and hood design constitutes a change in traditional thinking of the forms of pedal boats from bulky designs to a low profile sleek design with the propulsion disc  4  positioned to the front center of the hull  1  at mid level of the hull  1 . This two-component design, in conjunction with the design of the crankshaft bearings  32 ,  33 , allows the propulsion disc  4 , crankshafts  5  and the crankshaft bearings  33  to be easy installed into the hull  1  from the upper surface of the hull  1 . 
         [0042]    As shown in  FIGS. 16 and 17 , the hood  2  includes a pair of hinge pins  51  disposed on opposite sides of the hood  2 . The hinge pins  51  are received in corresponding channels  55  formed in the top surface of the hull  1 , thereby allowing the hood  2  to be quickly installed into the low profile sleek hull  1 . The channels  55  also allow the hood  2  to be rotated rearwardly about the hinge pins  51 , into a retracted position ( FIG. 20 ), to thereby facilitate installation and removal of the propulsion discs  4  and the crankshafts  5 . 
         [0043]    The hood  2  also includes a tongue  53  at the rear portion thereof, and a pair of lock lips  52  disposed on opposite sides of the hood  2 . When the hood  2  is rotated from the retracted position into the closed position ( FIG. 22 ), the lock lips  52  engage the crankshafts  5  at the uppermost portion of the crankshaft bearings  32 ,  33 . The tongue  53  also frictionally engages the hull  1 , thereby causing the lock lips  52  to lock the crankshafts  5  into the crankshaft bearings  32 ,  33 . 
         [0044]    As shown in  FIG. 2 , the hull  1  includes a wet self-cleaning and bailing hole  16 . When the turbo boat is placed in the water, a thin layer of water is allowed on the floor of the hull  2  (through the bailing hole  16 ). When the boat is lifted out of the water, this thin layer of water drains out through the bailing hole  16 , thereby washing the upper surface of the hull  2  as it exits through the bailing hole  16 . There is also a plug (not shown) to seal the bailing hole  16 . 
         [0045]    As shown in  FIGS. 1 ,  2  and  16 , the hull  2  includes a cavity molded into the upper surface thereof for store the propulsion disc  4  when not in use. This feature reduces transportation costs in mass production movement. 
         [0046]    As shown in  FIG. 1 , preferably the turbo boat includes a pair of rearwardly facing chairs  3 . The turbo boat also includes a pair of frontwardly facing chairs  3  (not shown). As shown in  FIGS. 7 to 10 , each chair  3  comprises a seat  40  and a backrest  34 . Preferably, the backrest  34  has three ( 3 ) integrally molded arms extending downwards from the lower end of the backrest  34 . As shown in  FIGS. 8 and 18 , each arm includes a locking pin  36  disposed at the end of the arm, and a pivot pin  35  disposed between the locking pin  36  and the lower end of the backrest  34 . 
         [0047]    As show in  FIGS. 18 and 19 , the seat  40  has three ( 3 ) key-type holes  54  extending through the seat  40 , adjacent the rear portion of the seat  40 . The key-holes  54  are dimensioned to receive a respective one of the backrest arms therein. Further, each key-hole  54  includes a pair channels  56  that extend laterally outwards from the centre of the key-hole  54  to receive and support a respective one of the pivot pins  35 . 
         [0048]    Further, as shown in  FIG. 19 , the seat  40  includes a series of integrally-molded shallow channels  39  formed on the underside of the seat  40 . When the backrest arms are inserted into the key-holes  54  of the seat  40 , the pivot pins  35  are received within a pair of channels  56 , thereby supporting the weight of the occupant&#39;s back. The locking pins  36  are also received within one of the shallow channels  39 . 
         [0049]    As shown in  FIG. 9 , by rotating the backrest  34  forwards about the pivot pins  36 , the locking pins  36  can be positioned within any one of the shallow channels  39 , to thereby allow the user to adjust the angle of the backrest  34  as desired. As a result, the chair  3  can be configured in various positions to allow for various sizes of occupants. 
         [0050]    The bimini assembly  43  is depicted in  FIG. 1  and  FIGS. 11 to 15 . As shown, the bimini assembly  43  comprises a pair of support rods  41 , a bimini top  44  secured to the support rods  41 , and a bimini mount  45  supporting and securing the support rods  41 . As shown in  FIGS. 14 and 15 , the bimini mount  45  includes a pair of mounting holes  48  for securing the bimini mount  45  to the hull  1 , and a pair of rod clamps, each terminating in a pair of opposed unlocking fingers  46 ,  47 . Each rod clamp is configured to receive and retain one of the support rods  41  therein. Each support rod  41  is also pivotally secured to the bimini mount  45  preferably via a respective aluminum pin  50  that extends through the respective rod clamp and support rod  41 . This configuration of the bimini mount  45  allows the bimini top  44  to be deployed in one of the following three ( 3 ) positions: open ( FIGS. 11 and 14 ), closed/inclined ( FIG. 12 ) and closed/down ( FIG. 13 ) to thereby shield the boat occupants from the sun, as desired.