Abstract: An outboard motor assembly for use as external propulsion for a watercraft includes a drive assembly, a shaft assembly, and an impeller-jet assembly coupled to the shaft assembly. The impeller-jet assembly includes an inlet stator, an exit stator, an impeller, and an external housing surrounding the stators and impeller. The inlet stator contains a plurality of blades, forcing the flow of water into an optimum direction for the impeller. The exit stator also contains a plurality of blades, which are configured to direct the flow from the impeller, removing the twist and resulting in a more efficient flow of water. The exit stator is tapered such that each blade is thicker at the trailing edge than at the leading edge, to create a circular array of separate nozzles with gaps between them.

Abstract: Presented is a way to reduce the wave drag of high speed ships by ingesting wave energy into water propulsors disposed at the bow and/or on the sides of the main hull of the ship. A forward secondary bow disposed at a lower portion of the main bow of the ship is an optimum location to have bow water propulsor water inlets. Performance of the water propulsors can be enhanced by using Coanda effect water energizers at the inlets to the water propulsors. Water propulsor discharge is preferably into an air layer on the underside of the ship's main hull.

Abstract: A propulsion or pumping device which includes two counter-rotating shafts (3, 4) each carrying at least one impeller (7, 8), wherein each impeller (7, 8) can deflect by a predetermined amount in directions substantially perpendicular t to the longitudinal axis of the shaft (3, 4) on which the impeller (7, 8) is mounted.

Abstract: A fouling removal system for use in a water-jet drive system is described. The fouling removal system includes a cutter arm assembly and an optional cutter stud. The cutter arm assembly includes a pivotable cutting blade located adjacent to the intake grate and arranged to sever any debris, such as seaweed and eel grass, clogging the intake grate. The cutter arm assembly may be tied into existing watercraft hydraulic systems to use a hydraulic cylinder to cause movement of the cutting blade across the surface of the intake grate. The optional cutter stud is located adjacent to the impeller within the water-jet drive system housing. The cutter stud acts to sever debris associated with the impeller blades, which, if left on the blades, would reduce the efficiency of the impeller. The present fouling system is capable of removing debris from the intake grate and impeller of a water-jet drive while a watercraft is stationary or is operating at any speed, including full speed.

Abstract: A top side of a deck can have a generally flat shape. A pedestal-like operator's seat base can be disposed slightly rearwardly from a central part of the deck. On an upper part of the operator's seat base, an operator's seat, a passenger's seat and a handlebar can be provided. A cowl can form a front face of the operator's seat base and can have an air inlet for introducing ambient air therethrough into an engine room. The air inlet can be provided with a water separating structure for separating ambient water from the ambient air to prevent any entry of the water into the engine room. A handrail can be provided on an upper part of the operator's seat base. Rails can be provided in a front part of a peripheral edge of the deck. A container including a containing recess and a lid can be provided in a front part of the top side of the deck.

Abstract: A jet-propelled watercraft capable of maintaining a propulsion force required for a turn made at the same time as closing of a throttle valve. The jet-propelled watercraft has an auxiliary intake valve and an ECU. The auxiliary intake valve in an intake pipe opens/closes an auxiliary intake passage to bypass a throttle valve. The ECU performs control such that an opening of the auxiliary intake valve in a state where the rotation speed of the engine is not lower than a threshold value is larger than the opening of the auxiliary intake valve in a state where the engine is idling. When in a state where the rotation speed is not lower than the threshold value, it is detected that the throttle valve is completely closed and that a steering mechanism has been turned by a prescribed angle or more, a current opening of the auxiliary intake valve is maintained.

Abstract: A seal pressure vent system for a waterjet propulsion apparatus including a water intake section and a pumping unit. The pumping unit is designed such that in operation the seal pressure vent system provides a fluidic path for the flow of high pressure water away from a lip seal assembly toward a near ambient pressure region. The seal vent system includes a plurality of fluid passageways formed in a stator structure in conjunction with a water barrier ring, a tail cone including an extended flange, or a modified stator web structure.

Abstract: The present disclosure relates to a jet pump tail cone insert for a jet pump. The jet pump tail cone insert comprises a cap, a body and an end member. The end member has a plurality of projections configured to matingly receive a plurality of forks of the body. When connected together, the body and the end member have a plurality of receivers configured to receive stator vanes of a bearing hub of the jet pump. The body and the end member are configured to be proximate the stator vanes. The cap is configured to matingly couple to the body. The jet pump tail cone insert encompasses a portion of the bearing hub of the jet pump. The jet pump tail cone insert occupies space proximate the bearing hub within the pump, thereby increasing a flow rate of water through the jet pump.

Abstract: The present invention relates to a watercraft with an improved waterjet propulsion system. The present invention further relates to a waterjet propulsion system with an improved steering nozzle design. The watercraft preferably is either what is known as a jet ski, a boat or a ship. A watercraft can be propelled by the thrust produced by a high-speed waterjet discharged from a nozzle located at the rear of the watercraft. A device that enables this type of propulsion is called a waterjet propulsor or a propulsor. Larger watercraft, such as a boat or a ship may often have two or more waterjet propulsors. The improved steering nozzle design incorporates a groove(s) or a channel(s) that is formed or machined into the steering nozzle wall thickness and does not exceed the thickness of the wall. The groove(s) or channel(s) begins at a point between the steering nozzle inlet and exit and ends at a point near or at the exit of the steering nozzle.

Abstract: A corvette ship-type equipment system includes standard-equipment segments, such as an energy generator, an energy distributor, a drive and an automation segment, and a hull which is adapted to the size and specific requirements on the corvette ship-type equipment system. In order to construct standard equipment-segments for a corvette ship-type equipment system which is technically and constructively simple and economical in terms of cost, at least one of the standard-equipment segments, such as the energy generator and/or the energy distributor and/or the drive and/or the automation segment is constructed from standard units or components which correspond to the requirements of the corvette ship-type equipment system and which are arranged in the hull of the boat and which can be built into the hull of the boat according to the different boat or ship-type equipment systems.

Abstract: The invention relates to a high-speed, sea-going ship comprising a double hull and a water-jet drive, the latter consisting of at least one pump assembly for generating the water-jet and at least one drive motor for the pump assembly. According to the invention, the pump assembly and its drive motor are located outside the stern area of the ship by using, in part, the space in the double hull.

Abstract: Stand alone decoupling clutch (10) is used in drive shafts, eg of watercraft. Clutch (10) is separate from any gearbox, etc, does not change the direction of rotation of the drive shaft, and has a single clutch area which allows slippage at any speed or torque. Electronic control system (44) controls slippage of the clutch (10) providing for low speed operation, high energy launches, driveline protection, etc. Slip speed is controlled sensing input shaft speed (38) and the output propeller speed (40) and altering hydraulic pressure accordingly on a clutch-compressing piston by opening direct-acting, high flow, electro-hydraulic solenoids (36).

Abstract: A motorized watercraft with a hull of the craft on which a user lies prone, at least partially, or stands up, with a flow channel extending in the hull of the craft with an electric motor-driven water screw. The electric motor and the batteries, as well as the control device for the electric motor and the water screw are housed, at least partially, in the flow channel in the hull of the craft. A clear increase in efficiency can be attained in connection with the motorized watercraft if a flow stator is arranged in the flow channel of the water screw, upstream, or preferably downstream, in the flow direction, which at least partially straightens the rotating water flow generated in the flow channel.

Abstract: A personal flying water jet apparatus consisting of two autonomous units: one is a towing inflatable tube (12A) (and so on) equipped with water jet nozzles (18) directed downward and mounted on both sides by means of brackets (20); the other is an inlet port (24) fixed on a tow line (16A) and connected with the nozzles (18) by mean of lay flat discharge hose (22). While the tube is being towed, the kinetic head appears and pressurized water is discharged at the nozzles (18) making a thrust, so the rider (10) will fly.

Abstract: A preload system for bearings in a waterjet propulsion apparatus, the apparatus including a water intake section and a pumping unit including a bearing cartridge. The bearing cartridge is designed such that during operation a preload system provides tailoring between radial and axial thermal growths of a plurality of bearing components that comprise the bearing cartridge and such that an initial ambient temperature preload condition can be maintained or reduced during normal water mode operation conditions. The preload system includes a plurality of spacers that when positioned relative to the bearing components of the bearing cartridge prevent relative motion between the bearing components during land mode operation and maintain or reduce the initial ambient room temperature preload condition during normal water mode operation.

Abstract: An integrated motor support and transmission apparatus for a marine propulsion system having a motor and marine drive with a drive shaft, comprising: an output shaft; a support housing attached to a marine vessel and having an upper end and a lower end, the upper end supporting the motor and the lower end substantially aligning the output shaft with the marine drive; and a transmission connecting the motor to the output shaft, whereby the motor, transmission, and output shaft can be installed in the marine vessel in a single operation.

Abstract: A seal pressure vent system for a waterjet propulsion apparatus including a water intake section and a pumping unit. The pumping unit is designed such that in operation the seal pressure vent system provides a fluidic path for the flow of high pressure water away from a lip seal assembly toward a near ambient pressure region. The seal vent system includes a plurality of fluid passageways formed in a stator structure in conjunction with a water barrier ring, a tail cone including an extended flange, or a modified stator web structure.

Abstract: Personal watercraft systems and watercraft power systems are described. The personal watercraft power systems include a housing for supporting a water jet pump and engine system. The housing is constructed to support the power system and removably engage a watercraft. An engine and a centrifugal pump are enclosed in the housing and operatively connected by an endless drive, such as a belt. A crankshaft of the engine is generally aligned and offset for a pump shaft of the centrifugal pump. An impeller is connected to the pump shaft and is constructed in rotate in a plane generally aligned, and preferably offset from, a plane of a water surface. The orientation of the engine and the centrifugal pump provides a watercraft power system that has a reduced profile and is particularly applicable for watercraft constructed to support an operator in a prone position.

Abstract: A propulsion system for a watercraft includes a concavity formed in a hull of the watercraft. The concavity has a minimum depth at its leading end and a maximum depth at its trailing end. An impeller is mounted in the trailing end of the concavity and a stator trails the impeller. A nozzle having a radius only slightly less than a radius of the impeller is disposed in trailing relation to the stator. An elongate drive shaft extends from an engine mounted fore of the concavity to the impeller. An intake grate is disposed in a mouth of the concavity. Water flowing through the intake grate flows through the concavity in a laminar flow and encounters no obstacles other than the elongate drive shaft before encountering the impeller.

Abstract: Jet pump mounting structure of a small-sized boat including a front face of a thrust plate attached to a rear face of a front wall of a pump case, and a jet pump attached to a rear face of the thrust plate. The jet pump is arranged in the pump case. The front wall is formed at an up grade toward the rear of the hull, the front face of the thrust plate is formed at an up grade so that the front face is parallel to the front wall, and the rear face of the thrust plate is formed in parallel with a plane perpendicular to the axis of the jet pump.

Abstract: An outboard motor assembly for use as external propulsion for a watercraft includes a drive assembly, a shaft assembly, and a impeller-jet assembly coupled to the shaft assembly. The impeller-jet assembly includes an inlet stator, an exit stator, a impeller, and an external housing surrounding the stators and impeller. The inlet stator contains a plurality of blades, forcing the flow of water into an optimum direction for the impeller. The exit stator also contains a plurality of blades, which are configured to direct the flow from the impeller, removing the twist and resulting in a more efficient flow of water. The exit stator is tapered to create a more efficient flow of water. The center portion of the impeller contains a hub with an exhaust vent. In the alternative, a duct can be positioned adjacent to the outlet stator such that air is directed into the flow from the outlet.

Abstract: The present invention provides a personal propulsion device including a body unit having a center of gravity, where the body unit includes a thrust assembly providing a main conduit in fluid communication with at least two thrust nozzles, with the thrust nozzles being located above the center of gravity of the body unit. The thrust nozzles are independently pivotable about a transverse axis located above the center of gravity, and may be independently controlled by a single common linkage. The present invention may further include a base unit having an engine and a pump, which provides pressurized fluid to the body unit through a delivery conduit in fluid communication with both the base unit and the thrust assembly.

Abstract: A waterjet-propelled marine vessel having a hull with a transom and a bottom, a jet pump, and an intake duct, the improvement comprising: (1) the transom and bottom having a common opening for intake duct installation and (2) the intake duct having an intake duct upper part and an intake duct lower part, whereby the intake duct upper part closes the common opening and the intake duct lower part fits into the intake duct upper part to form the intake duct.

Abstract: A mounting portion of a water jet pump of a personal watercraft is disclosed. The mounting portion typically includes a tubular pump casing configured to accommodate the impeller, and a pump bracket configured to fasten the pump casing to the body of the watercraft. The pump casing is configured to be mountable to the pump bracket in such a manner that an internal fitting portion of the pump casing is internally fitted to a casing receiving portion of the pump bracket from rearward with a ring-shaped seal element fitted into a groove provided on the pump casing, and an outer peripheral surface of the internal fitting portion and an inner peripheral surface of the casing receiving portion are sealed by the seal element.

Abstract: A propulsion unit for a boat has a cooling water intake structure through which entry of cooling water is obstructed when the boat is towed while the impeller is not turned, and through which sufficient cooling water enters when the impeller is turned. The propulsion unit includes an impeller, plural stationary blades provided on the downstream side of the impeller, and a cooling water intake structure. The intake structure is disposed between adjacent first and second stationary blades, on the side of the first stationary blade relative to a bisecting line between the two stationary blades. Hydraulic pressure on the side of the first stationary blade, relative to the bisecting line, is lowered by guide action of the impeller, and hydraulic pressure on the side of the second stationary blade relative to the bisecting line is raised, respectively, when the boat is towed while the impeller is stopped.

Abstract: A variable marine jet propulsion system incorporates a motor, a variable-pitch propeller pump in a spherical housing, a variable housing and a variable inlet duct, and a microcontroller. The pump, the nozzle and the inlet are controlled by the microcontroller, which is programmed to control the pump as a continuously variable power transmission for maintaining efficient motor operation, the nozzle for maintaining efficient pump operation, and the inlet for maintaining efficient recovery of the total dynamic head of the incoming water. The spherical pump housing maintains close fits to the propeller vane tips for more efficient operation at all pitches, including zero and reverse pitches. Zero pitch results in no effective pumping action, effectively a true neutral in fluid power transmission. Reverse pitch in combination with the large variable nozzle provides reverse flow and consequently reverse thrust, which eliminates the need for the “backing bucket”.

Abstract: A pod propulsion system comprises a housing defining a fluid duct and an annular drum rotatably mounted to the housing within the fluid duct. The annular drum has a drum interior and a cylindrical outer surface. The system further comprises a rotor mounted to the drum for rotation therewith, the rotor and the drum having a common axis of rotation. A bearing assembly mounted to the housing comprises a first bearing comprising a first plurality of bearing pads disposed circumferentially around the drum. Each pad has a pad bearing surface adapted to contact a first drum portion in a predetermined manner and is pivotably mounted to the housing so as to maintain contact of the pad bearing surface with the first drum portion in the predetermined manner when an orientation of the drum portion relative to the housing changes.

Abstract: A highly efficient watercraft propulsion system that operates continually submerged and relies on a non-circular variable area pump discharge opening which is configured, positioned and oriented so as to maximize the hydraulic reaction between the high velocity water jet stream and the surrounding body of water and is driven by a positive displacement pump.

Abstract: A propulsion system for a jet- or rocket-propelled vehicle in which the resulting jet exhaust nozzle profile is a 3D spiral. The propulsion system can be applied to any jet- or rocket-propelled vehicle, including aircraft and watercraft.

Abstract: A marine waterjet propulsion system having an impeller with an impeller hub, a diffusor with a diffusor hub, and a motor driving the impeller, the motor being placed inside at least one of said impeller and diffusor hubs. In one preferred embodiment of the propulsion system, the motor is an electric motor.

Abstract: A water jet propeller for preventing an impeller from being exposed when the water jet propeller is disassembled. The water jet propeller includes a stator disposed at a rear-end portion of an impeller housing, and an impeller is disposed inside the impeller housing. The water jet propeller expels a water jet by rotating the impeller. The impeller of the water jet propeller is rotatably mounted to the stator, being disposed inside the impeller housing. The impeller housing, the stator, and a nozzle are connected integrally with each other using a connection bolt. The impeller housing and the stator are connected integrally with each other using a lock bolt.

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 outboard jet drive marine system for a boat includes a housing, the housing has front and rear sides, and a top and bottom. The housing is adapted to be affixed behind a hull of a boat. An engine is disposed within the housing. A jet drive unit is releasably mounted to a housing extending from the rear of the housing and is operatively coupled to the engine in the housing. The jet drive unit includes a jet unit housing and drive shaft disposed within and supported by the jet unit housing. The jet unit housing is detachably received by the housing.

Abstract: A mounting structure for mounting a jet propulsion pump in a body of a personal watercraft includes, a front mounting portion of the pump being mounted to a rear portion, in a planing direction of the watercraft body, and a ride plate mounted to the watercraft body, so as to be located beneath the pump, wherein the ride plate is mounted to watercraft body in at least two positions in the planing direction of the watercraft body. Further, an elastic member is disposed between the ride plate and the pump, such that a rear portion of the pump is supported by the ride plate through the elastic member.

Abstract: A boat propulsion system includes a plurality of positive displacement pumps which having high discharge head and having inlets and outlets therein and a controlling panel having circuits, wherein the pumps are mounted on a bottom of a boat and driven by a motive power. By means of different positions of the outlets in each pump or different power transmission of each pump and cooperating with using the controlling panel, the boat can therefore move toward desired directions and enhancing power transmission by the pumps are drawn uniform flow when the boat is moved.

Abstract: A compact operational retro-fit drive plant, for installation in the base of the bow or stern of various types of marine vehicle, in particular of displacement types, which serves for maneuvering and traveling at cruising speed on normal and particularly flat stretches of water. The drive plant includes a simple and economically produced water jet drive (1), having a propeller pump (8), for various types of engine and installations, which generates an efficient and completely controllable propeller thrust with optimized propeller approach flow and flat water capability. The propeller shaft (11) of the water jet drive (1) is arranged on the pressure side of the propeller pump (8) in a conventional 90 DEG elbow tube (6), the rotational axis (9) of the propeller is neither vertical nor horizontal, but has an inclination angle alpha of 20 DEG to 50 DEG, preferably between 25 DEG and 40 DEG relative to the baseplate (20) as a horizontal base.

Abstract: In an underwater vehicle, hydrogen and oxygen are fed into a combustion chamber of a combustor of the underwater vehicle to initiate a combustion reaction, which generates high-pressure steam. The high-pressure steam can be cooled with the injection of seawater, and can be condensed into high-pressure water by the addition of sufficient seawater. High-pressure water is then ejected out of the combustor, generating thrust for the underwater vehicle. Sensors that measure the combustor pressure and the external pressure could be used to adjust the combustor pressure, allowing for constant velocity as the depth of the underwater vehicle changes. Alternatively, the sensors could adjust the area of an exit nozzle of the combustor. Stored water can be converted back into hydrogen and oxygen by using electrical power external to the system. After regeneration of the water into hydrogen and oxygen, the propulsion system would be ready for operation again.

Abstract: A water jet propulsion watercraft that allows accurate speed detection of a speed detection unit to be achieved. A water jet propulsion watercraft includes a hull bottom plate with left and right guide grooves for guiding water rearwardly of the hull. The left and right guide grooves are disposed in a fore-and-aft direction at an area excluding at least a front portion of the hull bottom plate. Further, the hull bottom plate includes a flat surface formed at the front portion of the left and right guide grooves and on a surface facing the water. The flat surface is provided with an opening for guiding water to a speed detection unit.

Abstract: A multistage axial-flow pumping or marine propulsion device having fixed or variable pitch stators between rotors. Stator vanes are designed to lower internal fluid speed without sacrificing total pressure as working fluid travels toward the discharge nozzle. A variable pitch stator controls the amount of energy, i.e., torque, imparted to the working fluid at successive rotor sections. A variable inlet guide vane provides throttling of mass flow rate independently of rotor speed. An exit guide vane provides flow straightening and pressure maintenance at the discharge nozzle. A variable area throat at the discharge nozzle controls the exit velocity of the water jet according to boat speed and/or desired propulsive efficiency. Advantageously, the device enables a shipmaster to set performance characteristics of a vessel at any desired speed, loading, horsepower setting, or operating characteristic of the power plant.

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 outboard waterjet propulsion system for a marine vessel having a bottom and a transom with a top edge, the propulsion system comprising: an intake duct with grid bars; a motor; an impeller with an impeller hub and driven by the motor; a steering deflector; and a diffusor with a diffusor hub rigidly attached to the intake duct and supporting the steering deflector. The propulsion system is positioned outboard of the vessel against the transom, and vessel steering is achieved by articulation of the steering deflector.

Abstract: The invention relates to a propulsion system for a fast seagoing ship, especially a naval ship, which comprises a propulsion system driven by at least one water jet produced by a pump assembly with an outlet nozzle for water, and a propeller jet produced by at least one propeller. The water jet carries along gases that are introduced downstream of the pump assembly, especially exhaust gases of at least one drive device which especially comprises a power generation device and a generator. The water jet is generated in at least one water jet drive by means of a pump that is, e.g., driven by an electric motor and whose drive power is generated by e.g. a generator assembly.

Abstract: To provide a jet propulsion boat that enables preventing the occurrence of cavitation. In a jet propulsion boat that jets water pressurized and accelerated by a water jet pump from a rear jet nozzle and is propelled by its reaction, a turbocharger is provided to an engine for driving the water jet pump and in case the rate of the rise of engine speed is a predetermined value or more, delay control is applied to the rise of the boost pressure of the turbocharger.

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 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: A water jet propulsion boat includes a pump chamber provided at a rear portion of a boat body of the boat. Further, a water jet pump is disposed in the pump chamber and a ride plate closes a bottom of the pump chamber. The ride plate includes a base fixable to the boat body. A setting plate detachably fixed to the base, and forms part of a bottom surface of the rear portion of the boat body.

Abstract: A trim operating wire is disclosed wherein the length of the pull wire connecting between the push-pull converter and the trim operating lever can be made short, and the push wire can be made long. As a result, even where the pull wire, which is thin and highly flexible, is disposed in the state of being bent at several portions thereof, the sliding resistance of an inner wire of the pull wire is small, and operability is enhanced.

Abstract: A ride plate positioning mechanism for a personal watercraft can reduce the burden on an operator during assembly, and can also raise manufacturing productivity. In a ride plate positioning mechanism 30 of a personal watercraft 10, a portion of a bottom wall 15a of a stern 15, that is located below a water jet propeller 17, is formed from a ride plate 31 removable from a craft body 11. Further, a pair of left and right positioning projections 32, 32 are formed integrally on the ride plate 31, while a pair of left and right tab stops 33, 33 corresponding to the positioning projections 32 are provided on the craft body 11 side.

Abstract: A marine propulsion system places an in-line engine at a tilted angle relative to a vertical plane in order to reduce the maximum height requirement space of an engine compartment in a marine vessel. The crankshaft axis of the in-line engine can be located on a vertical vessel symmetry plane or can be offset from it. The crankshaft of the inline engine can be disposed parallel to the vessel symmetry plane, within the vessel symmetry plane, or perpendicular to the vessel symmetry plane.

Abstract: An outboard jet drive boat apparatus has a boat hull (11) having a transom (12) and having a removably attached outboard jet drive (10) attached to the transom (12). The outboard jet drive (10) includes a housing (13) sealed against the intrusion of water and has an engine mounting platform (14) therein having an engine (16) mounted thereon on flexible engine mounts (15). The housing (13) has a sealable entrance through the top thereof and is removably attached to the transom of the hull (11). A jet drive unit (17) is attached in the housing (13) below the engine supporting platform (14) and extending generally parallel to the engine (16) and extending from the front of the housing (13) out the rear of the housing. The jet drive unit (17) is operatively attached to the overhead engine (16) through a clutch mechanism.