Abstract:
A small, light weight watercraft that can be used and enjoyed in substantially the same manner as a conventional kayak, but one that includes a novel auxiliary power system for propelling the watercraft through the water. The auxiliary power system comprises a four-stroke, overhead-valve, single-cylinder engine that is of the character typically used to drive the cutting line head of a conventional line trimmer device. In one form of the invention, the speed of the engine can be controlled by a hand-operated throttle mounted on the kayak paddle. The conventional kayak has been modified by installing at the stem of the kayak an elongated, tubular-shaped duct having a water inlet port and by mounting within the hull of the kayak the engine system that includes a drive shaft that extends through the hull and into the tubular shaped duct to impart rotation to a propeller that is mounted on the drive shaft for controlled rotation within the tubular shaped duct.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates in general to small, motor powered watercraft. More particularly the invention concerns a specially modified, kayak-like watercraft having a gasoline powered engine mounted within the hull of the kayak. The motor has an elongated drive shaft that is adapted to drive a propeller that is rotatably disposed within a uniquely configured, tubular housing that is mounted within the stem of the watercraft and has a water inlet port in communication with the body of water through which the watercraft is propelled.  
           [0003]    2. Discussion of the Prior Art  
           [0004]    A number of different types of small, motor powered watercraft, such as kayaks have been suggested in the past. One such watercraft is described in U.S. Pat. No. 5,481,997 issued to Arndt and entitled Water Jet Propelled kayak. The Arndt watercraft comprises a kayak having a kayak-style hull with one or more cockpits and an inboard power device that accelerates water and directs it out a steerable stem nozzle. The stem nozzle laterally redirects the accelerated water from the impeller over an angular range centered on a long axis of the hull.  
           [0005]    Kayaks are well known in prior art and generally consist of a small double-ended watercraft having a displacement hull sometimes formed from a moldable plastic material. Typically, kayaks are propelled a manually by double ended paddle which is adequate for many purposes. However, when the kayak is going upstream or when the kayak is used for ocean sport, auxiliary power is beneficial.  
           [0006]    A common type of auxiliary power plant found in small prior art watercraft is the so-called water jet drive. Such a drive is found in the previously discussed Arndt watercraft and is also discussed U.S. Pat. No. 3, 823,684 issued to Baggs. For example, the Arndt power plant comprises an impeller that receives water via a water intake and accelerates the water and urges it through an impeller duct to a funneling jet nozzle. The water is further accelerated as it is funneled by the jet nozzle to the stem nozzle, which is the searing nozzle. The Baggs power plant is somewhat similar and construction and includes a duct which is generally cylindrically shaped at the termination point of a drive shaft. A propeller is affixed to the end of the drive shaft and has a minimal tip to duct wall clearance. The duct is reduced in area aft of the propeller by approximately one-half the propeller disc area so as to accelerate the water as it is funneled into the nozzle-like reduced duct area.  
           [0007]    The watercraft apparatus of present invention, which constitutes an improvement over the prior art, includes a unique power plant that can be quickly and easily installed within a conventional kayak. The power plant comprises a conventional four stroke, overhead valve, single cylinder engine having an elongated drive shaft. In the preferred form of the invention the power plant is of the character typically used to drive the cutting line head of a line trimmer type device that has become very popular for cutting grass, weeds, brush and the like. In the preferred form of the present invention, the drive shaft of the line trimmer has been modified to drive a propeller that is housed within a tubular shaped duct of uniform cross-section. The tubular shaped duct is mounted at the stern of the kayak and includes a strategically located water inlet port through which water is drawn by the propeller. In one form of the apparatus of the invention the speed of the engine is controlled by a hand-operated throttle that is mounted on the kayak paddle making the kayak ideal for use in the ocean. The engine is cooled by novel cooling means that is of a simple, but effective construction.  
           [0008]    Unlike many of the prior art small powered watercraft, the watercraft of present invention is of a simple, easy to use, lightweight construction making it ideal for many different types of water sports. As will be better understood from the description that follows, most conventional prior art, commercially available kayaks can be readily modified to embody the novel power plant, cooling means and throttle control means of the present invention. Being a lightweight construction, the watercraft of the present invention can be easily transported on the roof of the car or in the back of a pickup truck. Additionally, the modified kayak of the present invention can easily be carried over dry land to and from the body of water where the kayak is to be used.  
         SUMMARY OF THE INVENTION  
         [0009]    It is an object of the present invention is to provide a small, light weight watercraft that can be used and enjoyed in substantially the same manner as a conventional kayak, but one that includes a novel auxiliary power system for propelling the watercraft through the water.  
           [0010]    Another object of the invention is to provide a water craft of the aforementioned character that is of a simple construction, is easy use and one that can be easily transported without the need of a boat trailer.  
           [0011]    Another object of the invention is to provide a watercraft of the character described in the preceding paragraphs in which the auxiliary power system comprises a four-stroke, overhead-valve, single-cylinder engine that is of the character typically used to drive the cutting line head of a conventional line trimmer device.  
           [0012]    Another object of the invention is to provide watercraft of the character described in the preceding paragraph in which the speed of the engine can be controlled by a hand-operated throttle mounted on the kayak paddle.  
           [0013]    Another object of the invention is to provide a watercraft in the nature of a conventional kayak that has been modified by installing at the stern of the kayak an elongated, tubular-shaped duct having a water inlet port and by mounting within the hull of the kayak an engine of the character previously described that has a drive shaft that extends through the hull and into the tubular shaped duct to impart rotation to a propeller that is mounted on the drive shaft for controlled rotation within the tubular shaped duct.  
           [0014]    Another object of the invention is to provide the watercraft of the character described in the preceding paragraphs that can be manufactured inexpensively and is easily maneuverable making it ideally suited for use in a number of environments including lakes, rivers and oceans. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a side elevational view of one form of the powered watercraft of the invention shown here as a modified kayak-type apparatus.  
         [0016]    [0016]FIG. 2 is a top plan view of the apparatus shown in FIG. 1.  
         [0017]    [0017]FIGS. 3A and 3B, when considered together, comprise an enlarged view taken along lines  3 - 3  of FIG. 1 and partly broken away to show internal construction.  
         [0018]    [0018]FIGS. 4A and 4B, when considered together, comprise a view taken along lines  4 - 4  of FIGS. 3A and 3B.  
         [0019]    [0019]FIG. 5 is an enlarged, cross-sectional view taken along lines  5 - 5  of FIG. 4A.  
         [0020]    [0020]FIG. 6 is an enlarged, fragmentary, cross-sectional view of a portion of the drive means of the invention showing the construction of the bearing that supports the drive shaft and one form of universal joint of the apparatus.  
         [0021]    [0021]FIG. 7 is a view taken along lines  7 - 7  of FIG. 6.  
         [0022]    [0022]FIG. 8 is a cross-sectional view taken along lines  8 - 8  of FIG. 4A.  
         [0023]    [0023]FIG. 9 is a generally perspective, fragmentary view of the float device shown in FIG. 8.  
         [0024]    [0024]FIG. 10 is a view taken along lines  10 - 10  of FIG. 8.  
         [0025]    [0025]FIG. 11 is a view similar to FIG. 8, but showing the float device in an inverted, vent-opening closure position.  
         [0026]    [0026]FIG. 12 is an enlarged, fragmentary view, partly broken away to show internal construction of one form of the manifold cooling device of the invention.  
         [0027]    [0027]FIG. 13 is a view taken along lines  13 - 13  of FIG. 10.  
         [0028]    [0028]FIG. 14 is a view taken along lines  14 - 14  of FIG. 13 partly broken away to show internal construction.  
         [0029]    [0029]FIG. 15 is a view taken along lines  15 - 15  of FIG. 12.  
         [0030]    [0030]FIG. 16 is a generally schematic view illustrating the throttle operating means of the invention controlling the speed of the engine component. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0031]    Referring to the drawings and particularly to FIGS. 1, 2,  3 A,  3 B,  4 A, and  4 B, one form of the powered watercraft of the invention is there illustrated. In this form of the invention, the watercraft comprises a modified, readily commercially available type of kayak. As best seen in FIGS. 1 and 2, the modified kayak here includes a hull  20 , having a stern portion  20   a  and a forward portion  20   b . Formed in hull  20  is an operator cockpit  22  and a spaced-apart top accessible compartment  24 . Also formed in the forward portion of hull  20  is a storage compartment  26 .  
         [0032]    As shown in FIGS. 3A and 4A, a motor  30  is mounted within top accessible compartment  24  by transversely spaced apart mounting brackets  32  that are secured to hull  20  by suitable connectors  34 . While motor  30  can take several forms, it is here shown as a gasoline powered, four-stroke, over-head valve, single-cylinder engine of the character used in commercially available line trimmers to rotatably drive the cutting line head that houses the cutting line used to cut grass, weeds and the like. Connected to the engine is an elongated, rearwardly extending drive shaft  36  (FIG. 4A). Various types of two or four stroke engines could be used for the present application, but an engine used in a line trimmer device, Model No. UNK 422 NNA manufactured and sold by Honda has proven quite satisfactory.  
         [0033]    As illustrated in FIG. 4A, the conventional kayak has been modified by cutting away a portion of the underside of the stern area of the kayak and securely mounting, within the cut-away portion, a tubular member  40 . Tubular member  40 , which can be constructed from any suitable, rigid plastic material is generally circular in cross section throughout its length and has a first open end  40   a  and a second end  40   b . Disposed intermediate ends  40   a  and  40   b  is a propeller compartment  40   c  that houses a uniquely configured, five vane propeller  42  (see FIG. 5). Also disposed intermediate ends  40   a  and  40   b  of the tubular member is an inlet port  44  that is in communication with the body of water being traversed by the watercraft. In operation, water from the body of water is drawn into tubular member  40 , through the inlet port  44  in the manner illustrated by the arrows  45  in FIG. 4A.  
         [0034]    Fixedly mounted within second end  40   b  of tubular member  40  is a support  48 . Support  48  is generally disk shaped and, in a manner presently to be described, carries a bearing means for rotatably supporting the drive shaft  36  that extends through and is supported by support  48 . Turning particularly to FIG. 6, the bearing means of the present form of the invention can be seen to comprise a conventional bearing assembly  50  that is interconnected with support  48  by suitable threaded connectors  51  in the manner shown in FIG. 6. Bearing assembly  50  comprises an outer housing  54  within which is mounted a pair of longitudinally spaced-apart conventional bearings  56  that function to rotatably support the rear portion  36   a  of drive shaft  36 . As illustrated in FIG. 6, the rear portion  36   a  of the drive shaft is coupled with the forward portion  36   b  of the drive shaft by means of a conventional universal joint generally designated in the drawings by the numeral  56 . As best seen in FIG. 3A, forward portion  36   b  of the drive shaft is operably interconnected with and controllably rotated by motor  30 . With the construction shown in the drawings, rear portion  36   a  of the drive shaft is cantilevered into tubular member in the manner best seen in FIG. 3 a . Mounted at the rearward extremity of drive shaft portion  36   a  is the previously identified propeller  42 , which propeller rotates within support  40  in a manner to cause the water that is drawn into tubular member  36  through inlet  44  to be expelled forcibly from the tubular member in the direction indicated by the arrows  57  in FIG. 4A. It is this expelled water that propels the watercraft through the body of water.  
         [0035]    An important feature of the powered watercraft of the present invention is cooling means that is carried by hull  20  for cooling motor  30 . In the present form of the invention, this important cooling means comprises an exhaust manifold cooler  60  that is connected to one side of the motor  30  in the manner best seen in FIG. 20. The cooling means of the invention also comprises an oil pan cooler  62  that is connected to the oil pan of the motor in the manner illustrated in FIGS. 12 and 15. Considering first the oil pan cooler, it is to be noted that hull  20  includes a first water inlet  64  that is formed in the bottom wall of the hull  20  and is in communication with the body of water “W” through which the watercraft is propelled (FIG. 4B). One end  66   a  of a first conduit  66  is sealably connected to water inlet  64  and a second, opposite end  66   b  is connected to the oil pan cooler  62  in the manner shown in FIG. 12. As the watercraft moves through the water, water will flow through first conduit  66  and into the cooling chamber  67  of the oil cooler unit  62  to provide the cooling fluid for cooling the oil pan (FIGS. 12 and 15). After flowing through the oil pan cooling chamber, the water will flow into an exhaust conduit  68 . Conduit  68  has one end  68   a  connected to the oil pan cooler and an opposite end  68   b  connected to support  48  in the manner best seen in FIG. 4A. In operation, it is apparent that as the watercraft moves through the water, water will flow into inlet  64  through first conduit  66  into the cooling chamber of the oil pan cooling unit  62  and then outwardly through conduit  68  to an outlet port  70  formed in support  48 . Water flowing through outlet port  70  will flow into tubular support  40  and will then flow outwardly of the tubular support due to the urging of propeller  42 .  
         [0036]    The exhaust manifold cooler  60  of the cooling means comprises a second conduit  72  that has a first end  72   a  that is connected to a second water inlet  74  that is formed in the bottom wall of the hull  20  and is also in communication with the body of water “W” through which the watercraft is propelled (FIG. 4B). At its opposite end  72   b  conduit  72  is connected to the cooling chamber  73  of the exhaust manifold in the manner shown in FIG. 12. As the watercraft moves through the water, water will flow through second conduit  72  and into the cooling chamber of the exhaust manifold cooler unit  60  to provide the cooling fluid for cooling the exhaust manifold. After flowing through the cooling chamber of the exhaust manifold cooling unit, the water will flow into an exhaust conduit  76 . Conduit  76  has one end  76   a  connected to the exhaust manifold cooler and an opposite end  76   b  connected to support  48  in the manner best seen in FIG. 3A. In operation, it is apparent that as the watercraft moves through the water, water will flow into inlet  74  through second conduit  72  into exhaust manifold cooling unit  60  and then outwardly through conduit  76  to an outlet port  80  formed in support  48 . Water flowing through outlet port  80  will also flow into tubular support  40  and will then flow outwardly of the tubular support due to the urging of propeller  42 .  
         [0037]    Referring particularly to FIGS. 12 and 13, it is to be noted that the motor exhaust enters the manifold exhaust cooling unit through an inlet  80 . The exhaust gas is then passed through a passageway  81  formed in the exhaust manifold cooling unit and exits the cooling unit via an outlet  82 . From outlet  82 , the now cooled exhaust gases flow into an exhaust conduit  84  that carries the exhaust gases to the exterior of the kayak (see also FIG. 14). It is obvious that as the gases flow through passageway  81 , they will be cooled as a result of the cooling of the exhaust manifold by the water flowing through chamber  73 .  
         [0038]    Another important feature of the apparatus of the present invention is the novel throttle means for controlling the speed of the engine. As shown in FIGS. 3B and 16, this novel throttle means comprises a first, hand-operated throttle mechanism  88  that is mounted on kayak paddle  91  in the manner shown in the drawings. Throttle mechanism  88  includes a pivotally movable hand-operated lever  90  which is connected to a throttle cable that extends telescopically through a cable sheath  92 . The throttle cable is interconnected with the carburetor of the motor  30  in a conventional manner as schematically shown in FIG. 16. As indicated in FIGS. 3B and 16, the cable sheath  92  that surrounds the throttle cable is interconnected with a tether  94 , one end  94   a  of which is connected to paddle  90  (FIG. 3B). At its opposite end, the tether is fixedly connected to the kayak hull. Tether  94  performs the important function of limiting the extent of travel of the paddle  91  away from the kayak hull so as to preclude accidental stretching or kinking of the cable sheath  92  that is connected to the tether by connectors generally designated in the drawings by the numeral  96 . Tether  94  is long enough so that the paddle can be used in a normal fashion, but prevents the paddle from being extended away from the kayak a distance that would likely cause damage to the throttle system including the cable sheath and the throttle cable telescopically carried therewithin. The throttle control mounted on the paddle is particularly useful when the kayak is being used for ocean sports. For example, when the kayak is traversing ocean waves, the operator can controllably increase the speed of the engine and, accordingly, the speed of the kayak by simply operating the hand lever  90  that is conveniently mounted on the paddle and, in this way, provide additional power to the watercraft to smoothly traverse the ocean waves. The throttle means of the invention operates in a manner such that a pivotal movement of the handle  90  results in a telescopic movement of the throttle cable within the protective cable sheath and the concomitant movement of the throttle control carried by the carburetor “C” of the motor  30  (FIG. 16).  
         [0039]    Also forming a part of the throttle means of the present invention is a second fixedly mounted throttle unit generally designated in the drawings by the numeral  100 . Throttle unit  100  is mounted on one side of the kayak hull in the manner shown in FIG. 3B and is operated in a conventional manner by a push/pull control mechanism  102  that is interconnected with a throttle cable, which, in turn, is interconnected with the throttle control carried by the carburetor (FIG. 16). With this novel construction, the speed of the motor can be controlled either through the hand-operated throttle control that is connected to the paddle  91 , or in the alternative, by the throttle unit  100  that is fixedly mounted on the hull of the kayak.  
         [0040]    As depicted in FIG. 16, the carburetor “C” of the motor  30  is appropriately interconnected via supply lines  103  with a gasoline tank  104  that is mounted within the hull of the kayak in the manner shown in FIGS. 3B and 4B. With the arrangement shown in the drawings, gasoline tank  104  can be conveniently filled through a capped fill port  106  that is accessible from the top of the kayak hull in the manner indicated in FIGS. 3B and 4B. Fill port  106  is appropriately interconnected with the gasoline tank by a fill tube  105 .  
         [0041]    Yet another unique aspect of the apparatus of the present invention resides in the fact that the starter pull rope  108  that is used to start the motor  30  in a conventional manner is readily accessible from the top of the kayak hull in the manner indicated in FIG. 3A. More particularly, as indicated schematically in FIG. 16, the pull rope  108  extends through an aperture  110  formed in the kayak hull so that when the handle portion  108   a  of the pull rope mechanism is pulled outwardly from the exterior of the kayak hull, the motor  30  can be started in a conventional manner.  
         [0042]    Another important feature of the watercraft of the present invention resides in the novel closure means of the device for closing the top accessible compartment  24  that houses motor  30 . In the present form of the invention, this closure means comprises an oval shaped cover member  110  that sealably closes the top open compartment  24  in the manner indicated in FIGS. 2 and 4A. Member  110  is preferably formed of a yieldable plastic material and includes a peripheral portion  110   a  (FIG. 4B) that can be secured into sealing engagement with the peripheral opening of the top accessible compartment  24  in a manner to provide a watertight seal.  
         [0043]    Also forming a part of the closure means of the present form of the invention is a tubular member  114  that extends through and is sealably connected to cover member  110  by an appropriate sealing ring  116  that is sealably connected to and circumscribes tubular member  114  (FIG. 8). Tubular member  114  has an upper portion  114   a  that, in normal operation, extends above cover  110  and a lower portion  114   b  that extends below cover member  110 . Formed in upper portion  1   14   a  of support  114  is an air inlet opening  118  that normally permits air to flow from atmosphere into the lower portion of tubular member  114   b  in the manner indicated by the arrows  119  in FIG. 8. Air flowing from atmosphere into tubular support  114  will then flow freely into the engine compartment. Formed within the lower portion of member  114  is a multiplicity of spaced-apart vent openings  122 .  
         [0044]    A unique aspect of the closure means resides in the provision of plug means for closing air inlet opening  118  in the event that the kayak is accidentally inverted. This plug means here comprises a buoyant plug  124  that is normally maintained in the upper position illustrated in FIG. 8 by biasing means shown here as a coil spring  126 . One end of coil spring  126  is connected to a cross bar  128  that extends transversely of member  114  and the other end is affixed to buoyant plug  124  by means of connector element  129  (FIG. 9) so as to continuously urge the plug into the uppermost position shown in FIG. 8. However, should the kayak be accidentally inverted, moving the closure means into the position shown in FIG. 11, water will, of course, flow into tubular member  114  causing the buoyant plug  124  to move upwardly in the direction of the arrow  129  of FIG. 11 against the urging of spring  126 . Upon the plug reaching the position shown in FIG. 11, the plug sealably close inlet opening  118  thereby preventing water from flowing into the engine compartment and into the hull of the kayak while the kayak is in the inverted position.  
         [0045]    A similarly configured, second closing means is mounted within hull  30  forwardly of the tubular member  114  in the manner shown in FIG. 4B. This second closure means functions to close an opening  130  formed in the kayak hull intermediate the operator compartment  22  and top accessible compartment  24 . This second closure means is of similar construction and operation to the closure means previously described and includes a buoyant plug that, in the event the kayak is inverted, will function to seal an air inlet opening  132  formed in a tubular member  134 . More particularly, the construction of the second closure member is such that if the kayak is inverted in the manner shown in FIG. 11, the buoyant plug that is telescopically movable within member  134  will be moved into a sealing position such as that shown in FIG. 11 to seal opening  132  against the flow of water into the interior of the kayak hull.  
         [0046]    It is apparent that the first and second closure means of the invention permit the adequate flow of air into and out of the interior of the hull during normal operation and, at the same time, prevent water from flowing into the interior of the hull in the event that the kayak is accidentally inverted.  
         [0047]    In operation of the watercraft of the invention, motor  30  can be conveniently started from the exterior of the watercraft by pulling on the pull rope handle  108   a  which is readily accessible from the top of the kayak hull. With the motor running, the operator can be comfortably positioned on a seat  136  that is mounted within the operator&#39;s cockpit  22  in the manner shown in FIG. 4B. When seated within the cockpit, the operator can conveniently grasp the paddle  91  with both hands and then by gripping the throttle handle  90  with the right hand can precisely control the speed of the engine while at the same time propelling the kayak through the water by use of the paddle  91 . Direction of the kayak can be controlled in a conventional manner by foot pedals mounted within the operator&#39;s cockpit that are interconnected with a conventional rudder assembly that is generally designated in the drawings by the numeral  140 . As previously mentioned, when the watercraft is used for ocean sport, the throttle mounted on the paddle is extremely useful in adding power to the watercraft to enable it to smoothly ride over ocean waves and through strong ocean currents.  
         [0048]    Having now described the invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difficulty in making changes and modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.