Abstract:
A system for steering a watercraft propelled by a water jet includes a control lever supported to pivot rightward and leftward about a first axis, a nozzle supported on the watercraft to pivot rightward and leftward and through which water is discharged from the watercraft, first and second cables, and a steering module interconnected by the cables to the control lever and connected to the nozzle, supported to pivot laterally about a second axis and to pivot the nozzle laterally in response to pivoting of the control lever about the first axis.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to a boat propelled by a water jet. In particular, the invention pertains to a kayak-like watercraft that is steered and maneuvered by directing a nozzle through which the water jet is discharged. 
         [0003]    2. Description of the Prior Art 
         [0004]    A jet-boat is a boat propelled by a jet of water ejected from the back of the craft. Unlike a powerboat or motorboat that uses a propeller in the water behind the boat, a jet-boat draws the water from under the boat into a pump-jet inside the boat, then expels the injected water through a nozzle at the stern. 
         [0005]    Jet-boats are steered and maneuvered by directing the nozzle and water jet laterally from the longitudinal axis of the craft, such that the water jet both propels and steers the craft. Jet boats can be reversed and brought to a stop within a short distance from full speed using the jet. 
         [0006]    A conventional screw impeller accelerates a large volume of water by a small amount, similar to the way an airplane&#39;s propeller accelerates a large volume of air by a small amount. In a jet-boat, pumping a small volume of water, accelerating it by a large amount, and expelling the water above the water line delivers thrust that propels the craft. Acceleration of the water is achieved by the impeller driven by a small ICE onboard the craft. 
       SUMMARY OF THE INVENTION 
       [0007]    A system for steering a watercraft propelled by a water jet includes a control lever supported to pivot rightward and leftward about a first axis, a nozzle supported on the watercraft to pivot rightward and leftward and through which water is discharged from the watercraft, first and second cables, and a steering module interconnected by the cables to the control lever and connected to the nozzle, supported to pivot laterally about a second axis and to pivot the nozzle laterally in response to pivoting of the control lever about the first axis. 
         [0008]    The rider sits on the upper deck of the boat&#39;s hull with legs extended along the deck and straddling the control lever. The control lever is simple and intuitive to operate and is conveniently located within easy reach of the rider. The control lever can be stowed away when the craft is being stored or transported. 
         [0009]    An accelerator for adjusting engine speed and starting and stopping the engine are located on the control lever. The craft is steered and maneuvered by pivoting the control lever rightward and leftward, thereby causing the nozzle to pivot and direct the water jet in a direction that causes the watercraft to turn in the direction that the lever is pivoted. 
         [0010]    The control lever and its interconnection to the nozzle are direct and reliable, has few moving parts, is of low cost, and can be installed and assembled easily. 
         [0011]    The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: 
           [0013]      FIG. 1  is a cross-sectional side view of an engine-powered kayak showing the water induction system and engine; 
           [0014]      FIG. 2  is schematic top view of the steering system; 
           [0015]      FIG. 3  is a side view partially in cross section showing the control lever and a forward steering module; 
           [0016]      FIG. 4  is a top view, partially in cross section, of the control level shown in  FIG. 3 ; 
           [0017]      FIG. 5  is a side cross sectional view showing the rear steering module and nozzle aligned with the longitudinal axis of the craft; and 
           [0018]      FIG. 6  is an end cross sectional view showing the rear steering module and nozzle disposed as shown in  FIG. 5 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    Referring now to  FIG. 1 , a kayak  10  includes a sealed hull portion  12  covered with a seamless molded plastic skin, the hull being formed with a recess  14  on its upper surface  15 , in which recess the rider sits facing forward with legs straddling a manually-operated control lever  16  (called a joystick) and feet supported on foot rests. The volume of hull  12  between its upper deck  15  and its bottom surface  17  is filled with a core material  20  that reinforces, strengthens and stiffens the hull. The core  20  may be expandable, cellular molded foam or a hollow, hexangular honeycomb whose walls are of Kevlar or a similar synthetic material. Alternatively, the core may be formed of machined foam. The hull portion  12  is sealed, thereby preventing entry of water from waves or spray and making it possible to roll the kayak upright again following a tip over without it filling with water. 
         [0020]    A seat back  22 , secured to the upper surface of the hull  12  supports the seated rider. The core-reinforced portion of the hull  12  is closed by a partition or bulkhead  24 , located at the forward end of an engine compartment  26 , which contains an engine  28 , water intake duct  30 , bladed impeller  32  that forces water from the intake duct, and a nozzle  34 , whose angular position about a vertical axis can be varied leftward and rightward to steer the kayak  10 . Water inducted through duct  30  flows through the impeller and exits through the nozzle  34 . The engine compartment  26  is covered with a cowling  36  formed with an air inlet passageway  38 . Cowling  36  is secured by latches to the upper surface of the hull, thereby sealing the engine compartment against entry of water when the cowling is latched to the hull. Preferably, engine  28  has a single cylinder and piston, low displacement and operates at high efficiency on a four stroke cycle. 
         [0021]    The intake duct  30 , which may be a component separate from the hull  12  or formed integrally with the hull, is of molded plastic having an intake opening  44  in the bottom of the hull, through which water is inducted and flows toward the outlet of nozzle  34 . A driveshaft  46 , secured to the crankshaft  47  of engine  28  drives the bladed impeller  32  in rotation, thereby drawing water into the intake duct  30  and forcing it through the impeller and out the nozzle  34 . A water jet, which propels and steers the kayak  10 , rises from the outlet of nozzle  34  into the air above the water surface. 
         [0022]    The rider pivots the joystick  16  leftward and rightward about axis  48  to steer the craft  10 . The joystick  16  carries a button  50 , which is depressed to start engine  28 , a button  52  that stops the engine, and an engine throttle in the form of a trigger  64  located on the underside of the joystick, by which the engine throttle is opened and closed to control engine speed and the speed of the kayak  10 . 
         [0023]    The rider also pivots the joystick  16  upward and downward about axis  49  to locate its hand grip in a comfortable position during use and in a downward position when the craft  10  is stored or being transported. 
         [0024]    As control lever  16  pivots rightward and leftward about axis  48 , cables  54 ,  56  transmit movement of the lever  16  to the nozzle  34 , which pivots leftward and rightward, respectively, in response to movement of the lever, thereby steering and maneuvering the kayak  10  by redirecting the water jet exiting the nozzle rightward and leftward relative to the longitudinal axis of the craft. Cables  54 ,  56  may be similar to the type used manually to actuate the brakes of a bike. 
         [0025]      FIGS. 2 and 3  show that the hand grip  66  of control lever  16  carries a extension  68 , which is attached by a bolt fitted into a central hole  70  and engaged with a support  72 , which supports lever  16 . Support  72  is secured to a bracket  74 , which is fixed at bolt holes  75  to the surface of the upper deck  15  of the hull  12 . Support  72  provides the axis  49 , about which control lever  16  pivots upward and downward. Support  72  also pivots about axis  48  as the rider applies lateral force to control lever  16  to steer the kayak  10 . 
         [0026]    A forward rotary disc  76 , seated in a recess  78  formed in support  72 ,  5  pivots about axis  48  in response to pivoting of lever  16 . One end of cable  56  enters a laterally passageway  80 , formed in support  72 , and is secured at  82  to the rotary disc  76 . One end of cable  54  enters a laterally passageway  84 , formed in support  72 , and is secured at  86  to the rotary disc  76 . Cables  54 ,  56  are preferably constructed of twisted strands of steel encased in a plastic tube, which supports the  10  cables against compression instability when a compressive force is applied to the steel strands. 
         [0027]    When control lever  66  pivots clockwise as seen in  FIGS. 2 and 4 , tension force is applied to cable  54  and compression force is applied to cable  56  as rotary disc  76  rotates about axis  48 . When control lever  66  pivots counterclockwise as seen in  FIGS. 2 and 4 , tension force is applied to cable  56  and compression force is applied to cable  54  as disc  76  rotates about axis  48 . 
         [0028]      FIGS. 5 and 6  show a steering control module  90  connected to the opposite ends of cables  54 ,  56  for directing nozzle  34  laterally in response to movement of the control lever  16 . A support  92  is secured to a bracket  94 , which is fixed at bolt holes  95  to the surface of the upper deck  15  of the hull  12 . A cover  95  closes the upper surface of support  92 . 
         [0029]    A rear rotary disc  96 , seated in a recess  98  formed in support  92 , pivots about a vertical axis  100  in response to pivoting of lever  16 . The opposite end of cable  56  from the end that is attached to forward disc  76  enters a laterally passageway  102 , formed in support  92 , and is secured at  104  to the rear disc  96 . The opposite end of cable  54  from the end that attaches to disc  76  enters a laterally passageway  106 , formed in support  72 , and is secured at  108  to the rear rotary disc  76 . 
         [0030]    A pin  110  is fitted into holes aligned with axis  100  and formed in cover  95 , support  92 , disc  96  and bracket  94 . The lower end of pin  110  is formed with a lateral hole that is engaged by a lateral pin  114 . Pin  110  is formed with a shoulder  126 , which is fitted in a hole  128  in disc  96 , thereby fixing pin  110  and disc  96  mutually for rotation as a unit about axis  100 . 
         [0031]    An angle bracket  116  includes a vertical leg  118  having a hole that is engaged by pin  114 , and a horizontal leg  120  secured by two screws  122 ,  123  to the upper surface  124  of nozzle  34 . A transverse pin  130 , such as a cotter pin, passes through pin  114  and prevents inadvertent disconnection of bracket  116  from pin  110 . 
         [0032]    When control lever  16  pivots clockwise about first axis  48 , as seen in  FIGS. 2 and 4 , tension force applied to cable  54  is transmitted to rear disc  96 , thereby causing disc  96 , pin  110  and pin  114  to rotate counterclockwise about axis  100 . As pin  114  rotates, bracket  116  rotates counterclockwise forcing nozzle  34  to turn counterclockwise about axis  110 , thereby directing the water jet exiting the nozzle  34  rightward causing the kayak to turn rightward, i.e., in the same direction as the control lever  16  is pivoted by the rider. Nozzle  34  is supported at  132  for rotation about an axis  134 , which may be aligned with axis  100  or eccentric of axis  100 . 
         [0033]    When control lever  66  pivots counterclockwise about first axis  48 , as shown in  FIGS. 2 and 4 , tension force applied to cable  56  is transmitted to rear disc  96  causing disc  96 , pin  110  and pin  114  to rotate clockwise about axis  100 . As pin  114  rotates clockwise, bracket  116  rotates clockwise forcing nozzle  34  to turn clockwise, thereby directing the water jet exiting the nozzle  34  to the left and causing the kayak to turn to the left, i.e., in the same direction as the control lever  16  is pivoted by the rider. 
         [0034]    Preferably pin  114  and bracket  116  are made from stainless steel, and support  92  is made from ABS reinforced with  20  percent fiber glass by volume. 
         [0035]    Cables  54 ,  56  may be replaced by any suitable connectors able to transmit movement of the control lever  16  to the rear disc  96  including, but not limited to connecting rods, ropes and wires. 
         [0036]    In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.