Abstract: A tail cone assembly for a watercraft jet pump includes a tail cone body with a shuttle recess, a self-actuated shuttle biased into the shuttle recess, and a pump back pressure inlet orifice through the tail cone body and into the shuttle recess. The shuttle may have a rear portion with an outer conical surface of at least two different conical slopes that are positioned to determine two discrete stages of jet pump discharge area. The shuttle recess may include a side wall with a grit exhaust groove therein. The grit groove and inlet orifice may both be positioned at gravitational low points within the assembly. The assembly may further include a grit screening device associated with the inlet orifice that restricts grit having a size greater than or equal to a shuttle clearance from entering the inlet orifice.

Abstract: A water jet pump is provided which reduces cavitation and thereby allows an improvement in pump efficiency. In a water jet pump in which an impeller driven for rotation and is provided in a cylindrical housing, an edge portion of the outer circumferential surface of the impeller that opposes the inner surface of the housing is formed with a radius of curvature. This structure reduces a variation in the pressure of a water stream passing between the outer circumferential surface of the impeller and the inner surface of the housing toward the impeller front surface side, thereby reducing the occurrence of cavitation and improving the pump efficiency.

Abstract: Sound and bubble producing apparatus formed by a channeled member having an air inlet and outlet immersible in a body of water, with said outlet accompanied by structure that casuse air bubbles and sound to be emitted from said outlet when immersed the body of water.

Abstract: A vessel hull that does not create bow, stern, or transverse waves when moving through the water having an exterior surface that has a substantially constant cross-section along the length of the hull, and an interior surface that substantially encloses a flow channel for the length of the hull, the interior surface forming a converging-diverging diffuser. One standing half wave is contained within the hull, and no waves are generated outside the hull. The hull operates most efficiently at higher speeds, and has broad applications, including icebreaker, hybrid displacement and waveless hull, and other hull types.

Abstract: A thrust bearing assembly is described that includes a self-aligning thrust bearing used in fluid thrust assemblies where the thrust may become unevenly distributed, e.g. in a water jet propulsion unit. The thrust bearing is designed to be lubricated by water and to be self-aligning against uneven thrust forces applied to it. The self-alignment is achieved by the design of the bearing, which is in the form of an annular multi-layer plate. The bearing plate comprises a metallic central core layer, an interface layer of marine bearing material on one side of the core and a flexible backing layer on the other side of the core. The backing layer supports the thrust flange against a support face and is formed of a high resilience polymer material capable of being deformed under thrust action sufficiently to align the thrust bearing to correct for uneven thrust.

Abstract: Force balance and moment balance associated with thrust of air and water craft equipped with thrust generators are preset in view of non-linear characteristics and dynamic characteristics of thrust generators. A performance index for minimizing thrusts generated by the thrust generators is defined. Using the balance as restricting condition, propeller thrusts of the thrust generators and rudder angles and changing speeds of rudders that minimize the performance index are calculated.

Abstract: An integrated propulsion and guidance system for a vehicle includes an engine coupled to an impeller via a driveshaft to produce propulsive force. The impeller includes a hub and a plurality of blades, wherein one or more of the blades is pivotably mounted to the hub. A control system provides a control signal to the impeller to adjust the blade pitch of the pivotable impeller blades as the blades rotate about the hub. The change in blade pitch produces a torque on the driveshaft that can be used to control the heading of the vehicle. By varying the magnitude and phase of the control signal provided to the impeller, the torque can be applied in a multitude of distinct reference planes, thereby allowing the orientation of the vehicle to be adjusted through action of the impeller.

Abstract: Rotary vanes having inducer-joined axial-flow vane portions, mixed-flow vane portions collisionlessly connected to the axial-flow vane portions, and centrifugal vane portions collisionlessly connected to the mixed-flow vane portions are wound around an outer peripheral surface of a hub that is continuously curved. The hub is configured with a moderate slope region and a steep slope region. The axial-flow vane portions and the mixed-flow vane portions are wound around the moderate slope region, and the centrifugal vane portions being wound around the steep slope region.

Abstract: To provide an engine control unit for facilitating steering control. In particular, the invention relates to a controller of a boat propelled by jetting water pressurized and accelerated by a water jet pump. If a throttle angle of an engine for driving the water jet pump is a predetermined value or less and a steering angle by a steering handlebar of the jet propulsion boat is a predetermined value or more, a throttle valve of the engine is operated in an opened direction and advance angle control is made over the normal ignition timing of the engine.

Abstract: A personal watercraft with a steering nozzle for determining the jet direction of jet water is movably disposed on the rear side of a water jet propeller, a connection portion is provided at an upper portion of the steering nozzle, and a reverse bucket has a recessed portion for obviating the interference with the connection portion.

Abstract: A jet-propulsion personal watercraft having improved features over conventional personal watercraft. The personal watercraft includes a hull including primarily an upper hull releasably secured to a lower hull. A gasket is disposed between the upper and lower hulls to seal the interior of the hull. A DC motor is powered by at least one battery and turns a water pump. The batteries are connected in series with a power controller. A gearing mechanism is provided for adjusting the rotational velocity of the motor to achieve the required rotational velocity of the pump. A forced air system is provided to force heat and battery acid fumes from within the hull when the motor is operating. A light circuit includes a switch, a front light and a rear light.

Abstract: A propulsion aggregate for boats of planing type is disclosed. The aggregate (10) comprises at least one inboard engine (5) disposed in a supporting frame (6), at least one first drive shaft (1) having a propeller (3), which shaft (1) extends through the boat hull (11) at the stern section of the boat, at least one rudder (12), and a second drive shaft (2) that extends through the stern section of the boat and drives a water turbine (4). The first drive shaft (1) is in direct connection with the power take-off (7) of the engine (5) via a releasable coupling (8) and said first drive shaft (1) is in operation during forward propulsion above a certain speed only, and the second drive shaft (2) is connected to the power take-off (7?) of the engine (5) and is arranged at a higher level than the propeller (3) and said second drive shaft (2) is in operation at forward propulsion at low speeds and at reverse motion.

Abstract: The present invention provides a jet pump assembly that includes a rotatable shaft adapted to be operationally coupled to a power source. An impeller is operationally connected to the rotatable shaft. A housing surrounds at least a portion of the rotatable shaft operationally coupled to the impeller. In addition, a single bearing is disposed between the housing and the rotatable shaft, permitting rotation of the rotatable shaft therein. The bearing has at least an inner race operationally coupled to the rotatable shaft and an outer race operationally coupled to the housing. The bearing also includes at least two sets of rolling components disposed, side-by-side between the inner and outer races, permitting rotation of the inner and outer races with respect to one another.

Abstract: The present invention relates to a jet propulsion unit (1) for propulsion of a waterborne craft comprising at least one impeller pump (3) with a pump housing (4) in which an impeller shaft (22) or ajournal (21) connected to said impeller shaft (22) is is rotatably journalled in bearings, and an impeller (7) blades (24), the impeller (7) being fixed to said impeller shaft (22) or journal (21) so as to follow the rotation of the impeller shaft (22), the impeller blades (24) being arranged at the impeller ( ) with a play of the blades (25) between each impeller blade (24) and the inside (15) of the pump housing (4). According to the invention the jet propulsion unit (1) also comprises an axially adjustable thrust bearing (27) arranged to cooperate with the impeller shaft (22) for adjusting said play (25).

Abstract: A watercraft, equipped with a jet propulsion system with improved efficiency of operation is disclosed. Structures are disposed within a water passage of the jet propulsion system at a position upstream of the jet propulsion unit that modulate the amount of water that is allowed to pass through the water passage. The structures can be a flexible fluid filled bag, an adjustable ride plate, and an additional water passage. Each of the structures allow a greater amount of water into the water passage during acceleration than during constant speed travel of the watercraft.

Abstract: A jet pump for a personal watercraft is designed to prevent water from contacting an impeller shaft therein. The apparatus includes a stator 31 with a channel 18 formed therein. An impeller 32 and an impeller shaft 35 are rotatably disposed in the stator 31, and are connected to one another by a threaded connection therebetween. A collar 40 is integrally formed with the impeller 32, and a water-resistant seal 37 is provided between the collar 40 and the stator. The impeller shaft 35 is constructed so that a drive shaft 22 is connectable to the front thereof by a spline fit. A shock-absorbing member 50 is provided for placement between the impeller shaft and the drive shaft, and the shock-absorbing member includes structure adapted to allow air or grease to pass toward the drive shaft side thereof, when the impeller is screwed on to the impeller shaft.

Abstract: A method and apparatus is disclosed for producing propulsion underwater with minimal acoustical emission. In basic concept, the method comprises the expulsion and sucking of liquid into and out of a liquid port of a watercraft in a manner generating compression and expansion waves adjacent the liquid port. Such expansion and compression waves generate a positive net thrust on the watercraft in a direction opposite that of their expulsion. Also disclosed is a method and apparatus for reducing the drag caused by hull skin friction by actively increasing the momentum of the liquid stream boundary layer adjacent a watercraft via the expulsion of fluid (liquid or gas) from ports in the hull of such a watercraft.

Abstract: Variable venturi for use in jet propulsion systems of watercraft include discharge openings with selectively variable discharge areas that enable a venturi controller to selectively maximize top speed, acceleration, and/or fuel efficiency. The variable venturi may include a plurality of circumferentially-spaced, squeezable, flexible sections that selectively move radially inwardly to alter the discharge area. Alternatively, the variable venturi may include a flexible venturi with a variably-shaped flexible discharge opening. Alternatively, the variable venturi may include a main rear discharge opening and a plurality of additional discharge openings with selectively openable valves, whereby selective opening of the valves effectively increases the discharge area. Alternatively, the variable venturi may have a movable end flap that selectively varies the discharge area.

Abstract: An impeller for a jet propulsion device includes at least one fluid channel formed on each impeller blade. During impeller rotation, a fluid back-flow is generated through the fluid channels. The back-flow advantageously sweeps cavitation bubbles away from the impeller blades and inhibit their implosion on the blade surfaces and/or inner housing surface which lies adjacent the blade tips. This desirably reduces erosion and provides a long-life and efficient propulsion device.

Abstract: Presented is an efficient propulsion system for boats that operates, with the boat going forward at high speeds, with its fluid accelerating rotor operating on an air and water mixture. The rotor is disposed, as seen in vertical transverse planes of the boat, at least in its majority to sides of hulls of the boat. The lower periphery of the rotor is proximal a keel of the boat when the boat is moving forward at high speed thereby insuring a shallow draft situation. When the boat is going in reverse, the rotor is supplied only with water so that it can act to pressurize the water in its discharge. The pressurized water from the rotor discharge is then reversed by one or more reversing buckets. An inlet flow adjusting system, inlet flow directing vanes, and air fences are options. This efficient new propulsion system for boats may be applied to all manner of boats including monohulls and multi-hulls.

Abstract: The device according to the invention relates to a device for detecting a risk of aquaplaning which arises during the driving mode of a vehicle. The device contains for this purpose first means which determine a first propulsion variable which describes the propulsion of the vehicle which is to be expected on the basis of the operating state of the engine and/or of the drive train. In addition the device contains second means which determine a second propulsion variable which describes the propulsion occurring during the driving mode of the vehicle and which arises due to the longitudinal acceleration acting on the vehicle. The presence of the risk of aquaplaning is inferred as a function of a deviation between the first propulsion variable and the second propulsion variable.

Abstract: A method and apparatus is disclosed for producing propulsion underwater with minimal acoustical emission. In basic concept, the method comprises the expulsion and sucking of liquid into and out of a liquid port of a watercraft in a manner generating compression and expansion waves adjacent the liquid port. Such expansion and compression waves generate a positive net thrust on the watercraft in a direction opposite that of their expulsion. A reciprocating member and an actuator are also disclosed for generating the forces and energy necessary to create the expansion and compression waves.

Abstract: A blow-by gas ventilation system particularly suited for use with a small watercraft includes a oil separation chamber preferably disposed within a plenum chamber defined by an air intake box. An inlet tube permits blow-by gases to move from the crankcase chamber of the engine to the oil separation chamber. An outlet allows blow-by gases to move from the oil separation chamber to the plenum chamber. Desirably, an outlet tube connects the outlet to an opening in an intake port of the induction system to discharge blow-by gases into the intake port. The oil separation chamber may be defined by a cover member, along with a portion of the interior surface of the air intake box.

Abstract: The instant invention presents enhancements to waterjet propulsors used for propelling marine vehicles including a way to bleed off aerated boundary layer water from the inlet of the waterjet propulsor, air fences to further help in preventing aerated boundary layer water from entering the inlet of the waterjet propulsor, and a way to preclude water from entering the waterjet's water inlet when the waterjet is not operating and the marine vehicle is moving forward at high speed.

Abstract: The invention is directed to a thick stator vane that effects continuous acceleration of the water stream within the jet pump, a non-uniform spacing of stator vanes or impeller blades to reduce noise output of the jet pump during operation, and a coupling structure positioned between the impeller and engine that prevents transfer of axial thrust to the engine caused by jet pump failure.

Abstract: An outboard motor which includes a driving motor, a switching device, an impeller and a blade casing. The switching device switches rotation of a drive shaft of the driving motor between normal and reverse directions. The impeller is rotated with a driven shaft connected to the switching device. The blade casing includes a first duct member and a second duct member. The first duct member has first opening through which water is sucked from the outside when the impeller is rotated in the normal direction. The second duct member connected to the first duct member encloses the impeller, and has a second opening through which water is sucked from the outside when the impeller is rotated in the reverse direction.

Abstract: An aquatic toy comprises a hollow, buoyant body having a discharge port formed therein. At least one electrically driven pump is disposed in the body in fluid communication with the discharge port. An electrical power source is also disposed in the body. At least one proximity switch is disposed in the body and connected to the pump and the electrical power source. The proximity switch causes a control circuit between the electrical power source and the pump to close in response to the application of a magnetic field to the proximity switch.

Abstract: An amphibious vehicle which on land looks remarkably like a conventional automobile. The wheels may be raised when the vehicle is in the water. The engine is placed in the stern, directly over the jet and transaxle, which provides room for four passengers. The vehicle has plates which slide under the wheels for use in water, and the plates do not extend up over the sides of the wheel wells.

Abstract: The hydrojet boat submerged propulsions system is low noise and has good output.

Abstract: To provide a jet propulsion boat in which cooling water is prevented from flowing into the footrest deck or from splashing toward the footrest deck and wherein the occupant can easily recognize the cooling water. A jet propulsion boat includes a vessel body constructed of a lower hull including a ship bottom and an upper hull superimposed thereon. A saddle-riding type seat is provided at the center of the upper surface of the upper hull with footrest decks provided on the left and right of the saddle-riding type seat. An engine and an exhaust system are provided in the interior of the vessel body. The jet propulsion boat includes cooling flow paths for forcing the engine and the exhaust system to be cooled by cooling water. The cooling water discharge ports from the cooling flow paths is provided on the rear surface of the vessel body, except for the portion immediately behind the saddle-riding type seat.

Abstract: The invention comprises a propulsion system for ships comprising an impeller (13, 14), a stator shell (1), and a impeller housing (3) for achieving a waterjet, a shaft (11, 12) for the propulsion of the impeller (13), and a bearing arrangement for the shaft (11, 12) in the stator shell (1), and preferably a sealing (15) of the shaft (11, 12) in the impeller housing (3), wherein said bearing arrangement comprises at least one sliding bearing unit (25; 26) intended to carry axial load, and which sliding bearing preferably is water lubricated.

Abstract: The invention is directed to a thick stator vane that effects continuous acceleration of the water stream within the jet pump, a non-uniform spacing of stator vanes or impeller blades to reduce noise output of the jet pump during operation, and a coupling structure positioned between the impeller and engine that prevents transfer of axial thrust to the engine caused by jet pump failure.

Abstract: A watercraft includes a shell, a ride plate, an internal combustion engine, and a jet pump. The shell defines a tunnel that extends forwardly from the transom and is defined laterally by the shell. The tunnel is open at its bottom The ride plate mounts to the shell under the tunnel. The engine and jet pump are supported by the ride plate and disposed in the tunnel. The engine drives the jet pump. The engine is cooled by water that continuously flows past the ride plate. The engine, jet pump, and ride plate are installed from below or the behind the shell.

Abstract: An axial-flow outboard water jet propulsion unit is designed so that it does not extend below the bottom of the boat hull, but rather is disposed directly behind the hull transom. This is achieved by arranging the impeller shaft generally perpendicular to a generally vertical drive shaft, and by installing the impeller in a flow-through duct which, although placed directly behind the transom, has an inlet for taking in water located directly below the impeller shaft. The duct does not extend to a depth lower than the lowest point of the hull bottom. The impeller shaft penetrates the duct wall, while the impeller itself is rotatable inside the duct. The impeller impels water rearward toward a convergent exit nozzle of the duct, sucking in water through the duct intake. The aft opening of the exit nozzle forms the duct discharge outlet.

Abstract: A watercraft is fitted with any one or combination of a retractable rudder fin and filter systems and improved jet drive systems. A retractable rudder-fin and filter system includes an extendable/retractable blade and a mechanism for extending the blade a variable amount from below a watercraft upon sufficient reduction or cutting-off of power from the drive system. An improved jet drive system is powered by an engine that is supported within a take-out jet structure. The take-out jet structure has an inner housing in which the engine block and jet pump are supported for operation, an outer housing fixed or unitary with the watercraft hull and a suspension structure for suspending the inner housing within the outer housing. The suspension structure has tubing that is pressurized with a gas or fluid. The engine may have a camshaft sprocket or pulley that is configured to be directly connected to drive the impeller or rotor at half-speed drive relative to the engine crankshaft.

Abstract: A modified boat hull, providing for dual, non-ventilating aft thruster tunnels. Each tunnel includes a generally tubular section which fluidly communicates with the transom outlet orifice, and a converging transition section which communicates at the extreme opposite end with a water inlet orifice which is positioned within an enhanced, vertical strake surface. The vertical strake surface is located beneath the chine of the boat, as well as beneath the water line. The modified hull also includes an inboard offset for the vertical strake surface, and a chine step to enhance hydrodynamic performance of the hull when attempting to achieve or exceed plane speed.

Abstract: An aquatic toy comprises a hollow, buoyant body having a discharge port formed therein. At least one electrically driven pump is disposed in the body in fluid communication with the discharge port. An electrical power source is also disposed in the body. At least one proximity switch is disposed in the body and connected to the pump and the electrical power source. The proximity switch causes a control circuit between the electrical power source and the pump to close in response to the application of a magnetic field to the proximity switch.

Abstract: A propulsion system component or accessory specifically used for boats which utilize either an inboard-outboard motor, or an outboard motor. A cylindrical shroud very closely surrounds the peripheral sides of a propeller situated inside, while leaving exposed the front and rear surface areas of the propeller. The shroud closely surrounds the peripheral circumference of the propeller blades by 360 degrees. This unique aspect of the shroud minimizes slippage and maximizes fluid displacement. The shroud is installed symmetrically as to ensure uniform distance between the shroud and all propeller blades. The front of the shroud is considered the leading edge, and the rear of the shroud is considered the trailing edge. The leading edge of the shroud allows unrestricted laminar flow to the propeller from the front. The trailing edge of the shroud directs propeller wash from the rear of the propeller, out through the trailing edge of the shroud.

Abstract: A propulsion system for ships having an impeller (13, 14), a stator shell (1), and an impeller housing (3) for achieving a water jet, a shaft (11, 12) for the propulsion of the impeller (13), and a bearing arrangement for the shaft (11, 12) in the stator shell (1), and preferably a sealing (15) of the shaft (11, 12) in the impeller housing (3), wherein the shaft (11, 12) consists of a light weight shaft, which has considerably lower bending rigidity than a homogenous, conventional steel shaft, and the driving force is transmitted via at least one non-flexible coupling (11B, 12A) and via the bearing arrangement which is rigid as to bending and handles the axial load, to the stator shell (1), such that a high power density is achieved.

Abstract: An underwater propulsion system and method are more efficient and reduce vortex wake effects. A submersible has a cylindrically-shaped hull, a nose portion connected forward and a sinusoidal-shaped tapered portion aft coaxially symmetrically disposed around a longitudinally extending axis. The tapered portion has a leading end the same diameter as the hull, a symmetrical apex at its trailing end on the longitudinal axis, and symmetrical rounded laterally extending contours and rounded longitudinally extending contours. An internal pump creates volumes of pressurized water from ambient water for equal-distantly-spaced-apart jets extend through the tapered portion in a circumferential row extending around the tapered portion. The jets point in an asymptotical relationship with respect to a down slope surface of the tapered portion and emit jetted water that creates a spinning toroidal vortex of swirling jetted water along the down slope of the tapered portion.

Abstract: A water intake and transmission system for simultaneously driving dual jet units of a jet boat. According to a preferred embodiment, the water intake includes dual channels to allow the uptake of dedicated streams of water. Mounted to the intake is a housing having first and second jet units encased therein wherein each jet unit receives a dedicated stream of water from a respective channel of the water intake. A transmission is operatively coupled to each respective jet unit and is further connected to the driveshaft of the boat engine, preferably via gears, belt-drives, and/or chain drives, that is operative to simultaneously drive both jet units from a single driveshaft.

Abstract: An electrical component mounting structure for a personal watercraft which simplifies a waterproof treatment of the electrical components. The structure includes an exhaust outlet of the exhaust pipe formed on one side of the body of the personal watercraft in a lateral direction. In this personal watercraft, a plurality of electrical components is disposed in the body so as to be offset on the one side from a central portion in the lateral direction. In other words, none of these electrical components is disposed in the vicinity of a wall surface on the other side of the body. The electrical components are preferably disposed in the body at an intermediate portion in the vertical direction, and at least one of a plurality of the electrical components is preferably mounted to a side wall constituting the one side of the body.

Abstract: Aquatic propulsion apparatus formed by a channeled outlet member; a channeled inlet member extending into the outlet member; with pressure applied in the channel of the outlet member surrounding the channel of the inlet member, which extends into the outlet member; the apparatus for powering a watercraft, having an interior and a bottom surface, has the inlet member as a tube extending from the interior through the bottom surface, with the outlet member surrounding the inlet member below the bottom surface, where a source of pressure is applied.

Abstract: A method and apparatus is disclosed for producing propulsion underwater with minimal acoustical emission. In basic concept, the method comprises the expulsion and sucking of liquid into and out of a liquid port of a watercraft in a manner generating compression and expansion waves adjacent the liquid port. Such expansion and compression waves generate a positive net thrust on the watercraft in a direction opposite that of their expulsion. Also disclosed is a method and apparatus for reducing the drag caused by hull skin friction by actively increasing the momentum of the liquid stream boundary layer adjacent a watercraft via the expulsion of fluid (liquid or gas) from ports in the hull of such a watercraft.

Abstract: A method and apparatus is disclosed for producing propulsion underwater with minimal acoustical emission. In basic concept, the method comprises the expulsion and sucking of liquid into and out of a liquid port of a watercraft in a manner generating compression and expansion waves adjacent the liquid port. Such expansion and compression waves generate a positive net thrust on the watercraft in a direction opposite that of their expulsion. A reciprocating member and an actuator are also disclosed for generating the forces and energy necessary to create the expansion and compression waves.

Abstract: Variable venturis for use in jet propulsion systems of watercraft include discharge openings with selectively variable discharge areas that enable a venturi controller to selectively maximize top speed, acceleration, and/or fuel efficiency. The variable venturi may include a plurality of circumferentially-spaced, squeezable, flexible sections that selectively move radially inwardly to alter the discharge area. Alternatively, the variable venturi may include a flexible venturi with a variably-shaped flexible discharge opening. Alternatively, the variable venturi may include a main rear discharge opening and a plurality of additional discharge openings with selectively openable valves, whereby selective opening of the valves effectively increases the discharge area. Alternatively, the variable venturi may have a movable end flap that selectively varies the discharge area.

Abstract: A floating steerable spa chair (10) is provided. The floating, steerable spa chair (10) includes an upper hollow frame (12) having at least one air inlet (16) and a plurality of air outlets (18) formed therein. The spa chair (10) further includes a lower hollow frame (14) having a water inlet (20) and first and second valves (22, 24) formed therein. The lower hollow frame (14) has a plurality of spa jets (26, 28) and plurality of propulsion jets (46) formed thereon. First valve (22) selectively controls water flow to spa jets (26, 28) and second valve (24) selectively controls water flow to propulsion jets (46), allowing a user (60) to control speed and steering of the spa chair (10) when the chair (10) is being propelled through water. Jets (26, 28, 46) are in communication with air outlets (18), allowing the water projected through the jets (26, 28, 46) to be aerated.

Abstract: A method and an apparatus for braking a jet-propelled boat. The method comprises the steps of deploying a reverse gate and then opening a throttle of an engine in response to actuation of a brake pedal. The system comprises an engine having a throttle, a water jet propulsion system, a reverse gate, a brake pedal, and a mechanical system for deploying the reverse gate and then opening the throttle in response to the brake pedal being actuated by the boat operator. The reverse gate is deployed when the brake pedal is moved from a first position to a second position and the throttle is opened as the brake pedal is moved from the second position to a third position.

Abstract: A jet pump for a personal watercraft is designed to prevent water from contacting an impeller shaft therein. The apparatus includes a stator 31 with a channel 18 formed therein. An impeller 32 and an impeller shaft 35 are rotatably disposed in the stator 31, and are connected to one another by a threaded connection therebetween. A collar 40 is integrally formed with the impeller 32, and a water-resistant seal 37 is provided between the collar 40 and the stator. The impeller shaft 35 is constructed so that a drive shaft 22 is connectable to the front thereof by a spline fit. A shock-absorbing member 50 is provided for placement between the impeller shaft and the drive shaft, and the shock-absorbing member includes structure adapted to allow air or grease to pass toward the drive shaft side thereof, when the impeller is screwed on to the impeller shaft.

Abstract: A jet propulsion boat having a longitudinally disposed tunnel comprises a drive unit for powering a screw propeller, and a pressure chamber with a constricting passage for housing the propeller. The pressure chamber has an upper half section integral with the boat hull, and a lower half section detachably mounted to the upper half section with bolts. A steering wheel assembly with a steering wheel and a steering post is supported in a vertical orientation on a top surface of the drive unit for manipulating a rudder, which is disposed at the stern behind the exhaust opening of the pressure chamber. The rudder is manipulated by means of bevel gears and a transmission shaft. The drive unit may be detachably mounted on the hull for ease in transportation.