Abstract: A pump jet assembly includes universal components, such as a rotor, shroud and stator, that can accommodate all marine drives within a given range and adapter components, that accommodate the difference between the universal components and a particular marine drive within the range. A pump jet adapter system includes both the universal components and a plurality of adapter components, and is made by assessing a variation in parameters for the range of marine drives and determining rotor parameters to allow use of a universal rotor for all the range of marine drives. Parameters for adapter components are determined to correspond to different marine drives within the range.

Abstract: A system and method of starting a water jet propulsion system for a ship in which the propulsion system includes a stator shell adapted to be mounted to the hull and having a nozzle ending in an outlet with a cross-sectional outlet area, an impeller housing attached to the stator shell and having an upstream inlet, and an impeller rotatably mounted in the impeller housing for receiving water from the inlet and discharging it through the nozzle of the stator shell so as to create a water jet upon rotation of the impeller. The method includes reducing the outlet area by partly closing the nozzle during a start up phase of the water jet propulsion system, wherein there is provided a back flow hindering arrangement arranged to hinder air to enter into the impeller housing via the nozzle.

Abstract: Clean energy powered surfboard having various advantages that make for easy to learn, easy to use, safer, exciting, high performance, environmentally friendly surfing on any ocean wave in the world. The various embodiments include novel motor, turbine, or electric motor generator surfboards comprising hydrogen or electric-powered motors, which can be switch-activated and which drive jet pumps. Energy can be stored as compressed gas, including air and hydrogen. Energy can be stored in novel capacitors that are incorporated in the body of the surfboard. Energy can be generated by solar or water power while surfing or by passing waves, for example, while waiting for a big wave. An output jet provides thrust to catch a wave, to return to the wave breaks, or to avoid a hazard. A novel fin output jet increases stability and maximizes thrust. Self-contained, self-recharging embodiments are low cost, lightweight, safer, and good for the environment.

Abstract: In recreational boats, multiple drive units, e.g., multiple outboard motors, Z-drives, or jet drives, are often provided to propel the boat, at least one of the drive units having a propulsion reversal function for executing a reverse propulsion. To facilitate execution of a turning maneuver with a boat in an extremely tight space, and to ensure that even an unskilled person is able to reliably execute such a turning maneuver, it is provided that the drive units be activated automatically for executing the turn on the spot as a function of a command for turning. The command may be made via a switch, which is operated by the driver of the boat. One drive unit is then operated automatically in propulsion reversal mode, and the other drive unit is operated in propulsion mode. The power of the drive units is then controlled in such a way that the instantaneous efficiency of the drive units operated during turning is taken into account.

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 within the bearing hub thereby increasing a flow rate of water through the jet pump.

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 water-jet pump includes a cylindrical housing and an impeller. The impeller is disposed in the cylindrical housing and is configured to be rotated in a rotating direction. The impeller includes a shaft body and plural blades. The plural blades are provided on an outer circumference of the shaft body. A front portion of one of the plural blades overlaps a rear portion of another of the plural blades adjacent to one of the plural blades when viewed in an axial direction of the shaft body. When viewed in the axial direction, at least a part of a rear edge of the rear portion is formed obliquely with respect to a radial direction of the impeller towards the rotating direction. A cutaway portion is formed in each of the plural blades between at least a part of the rear edge and the outer circumference.

Abstract: A water propulsion unit having an intake housing, a pump housing and an outlet with two spaced apart counter rotating impellers being located in the pump housing. The impeller blades on one impeller have an opposite pitch to the blades of the second impeller. The impellers are configured so that one of the impellers will impart less energy to the water as it passes the blades of the impeller than the second impeller.

Abstract: The invention relates to a ship propulsion system (S) having a pump jet (P) comprising a pump housing (G) and a drive motor, wherein the drive motor is a solenoid motor (M) integrated into the pump housing (G).

Abstract: A water jet propulsion watercraft includes a hull, an engine, a jet propulsion device, an exhaust channel, and an engine control unit. The engine includes a combustion chamber arranged to combust fuel therein, an exhaust port arranged to discharge exhaust gas after the combustion of the fuel in the combustion chamber, an exhaust valve arranged to open and close the exhaust port, an intake port arranged to pass air and the fuel into the combustion chamber, and an intake valve arranged to open and close the intake port. The jet propulsion device is arranged to be driven by the engine and to draw in water from around the hull and then jet the water. The exhaust channel is connected to the exhaust port of the engine and provides a channel through which the exhaust gas, discharged from the exhaust port, flows. The engine control unit is arranged to control the engine such that at least one location in a path leading from the exhaust channel to the intake port is blocked when the engine is stopped.

Abstract: A watercraft has a hull and a deck disposed above the hull. A ride plate is mounted below a rear portion of the hull. A jet pump assembly includes a jet pump disposed at least in part between the ride plate and the hull. A front wall is formed at least in part by the hull and disposed forwardly of the jet pump. The jet pump assembly is mounted on a top surface of the ride plate via a plurality of resilient mounts At least one sealing member forms a seal between the portion of the jet pump and the portion of the front wall. The jet pump is mounted to the watercraft only via a plurality of mounting points. The jet pump is resiliently mounted to the watercraft via each of the plurality of mounting points.

Abstract: The present invention's methodology for designing a fluid propulsion intake configuration of a marine vessel considers the integral geometry of the inlet together with a portion of the hull, with respect to which the inlet's entrance opening is flush. The inventive methodology typically includes definition of an inlet reference line (an “axial” description, straight and/or curved, of the inlet), cross-planes (each of which perpendicularly intersects the inlet reference line), a footprint (a planar outline of the inlet's entrance opening), an inlet shaping line (a projection of the footprint onto the hull portion), inlet flow lines (angularly spaced about the circumference of the inlet shaping line, each connecting the cross-planes), two fairing reference curves (one at the inlet's entrance opening and the other on the hull portion, thereby demarcating a fairing therebetween that is consistent with the inlet flow lines), and a lip nose (at the inlet's entrance opening).

Abstract: A system and related methods for manned and/or unmanned marine transportation involving equipping a vessel capable with a linear pump for propelling the vessel through or substantially over a body of water.

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 method of controlling a watercraft comprises actuating a lever, controlling a speed of rotation of an engine to be at or below a reverse gate actuation speed in response to the actuation of the lever, moving the reverse gate in response to the actuation of the lever without further driver intervention once the speed of rotation of the engine is at or below the reverse gate actuation speed, and controlling the speed of rotation of the engine in order to decelerate the watercraft in response to the actuation of the lever and the reverse gate moving without further driver intervention. A watercraft and a method of controlling the watercraft based at least in part on an angle of a helm assembly are also disclosed.

Abstract: A variable rating impeller (10) for the pump of a waterjet unit that is rotatably driven by an engine to generate a high velocity jet stream. The impeller (10) having a hub (12) mountable to a rotating shaft through which an input power is transmitted by the engine, and a plurality of blades (18) spaced about the periphery of the hub. The blades (18) have a primary profile that defines the primary rating of the impeller, and a trailing portion (28) of each blade has resilient flexibility relative to the primary profile such that the trailing portion will progressively flex under hydrodynamic load to alter the profile of the blades to progressively lower the rating of the impeller (10) with increase in engine speed.

Abstract: A water jet propulsion watercraft includes, a main engine body, a rotor chamber provided at a rear portion of the main engine body, a crankshaft arranged such that a rear end portion of the crankshaft is disposed in the rotor chamber, the rear end portion having a first connection portion, an output shaft having a second connection portion at a front end of the output shaft, the second connection portion arranged to be connected to the first connection portion of the crankshaft such that the output shaft rotates together with the crankshaft about a rotational center axis of the crankshaft, a rotor unit housed in the rotor chamber and fixed to the output shaft, a fastening member arranged to fasten the first connection portion and the second connection portion, a drive shaft connected to a rear end portion of the output shaft and arranged to be rotated together with the output shaft, and a jet propulsion unit, having an impeller that is coupled to the drive shaft and arranged to suck in and jet out water.

Abstract: A water jet propulsion watercraft includes a main engine body, a rotor chamber disposed at a rear portion of the main engine body, a crankshaft disposed so as to extend penetratingly through the rotor chamber such that a rear end portion thereof protrudes to an outer side of the rotor chamber, a rotor unit coupled to the crankshaft inside the rotor chamber, a drive shaft connected to the rear end portion of the crankshaft and rotated together with the crankshaft, and a jet propulsion unit, having an impeller that is coupled to the drive shaft, and arranged to suck in and jet out water. The crankshaft includes a flange portion that is integral with the crankshaft inside the rotor chamber. The rotor unit is fixed to the flange portion.

Abstract: A watercraft has a hull, a deck, an engine, a steering assembly, a jet pump, a venturi, a steering nozzle, and a reverse gate pivotable between a fully stowed position and a fully lowered position. The reverse gate includes a reverse gate body having inner and outer arcuate surfaces, and reverse gate upper and lower edges. First and second side walls are connected to the sides of the reverse gate body. At least one deflector is connected to at least one of the outer arcuate surface, the first side wall, and the second side wall. The at least one deflector is spaced from the outer arcuate surface. A deflector trailing edge is disposed upwardly and rearwardly from a deflector leading edge at least when the reverse gate is in the fully lowered position. Water deflecting surfaces and turning deflectors connected to a reverse gate are also disclosed.

Abstract: Disclosed is a device for transporting and transferring containers. Said device is embodied as a floating and automotive object which is equipped with at least one crane. The crane comprises at least one vertical element, a slewing ring, and a boom. The crane is arranged in the area of a transversal axis that extends perpendicular to the longitudinal axis of the object. Furthermore, the crane is disposed laterally offset relative to the longitudinal axis while a deck house encompassing a pilot house is placed laterally next to the crane.

Abstract: A multiple-cylinder engine for a planing water vehicle includes an operation control device which changes the number of deactivated cylinders step by step in response to an engine speed when the engine speed exceeds a preset speed. The operation control device can have a plurality of cylinder deactivation order maps used for instructing an increment order of cylinders which are deactivated step by step when the engine speed exceeds the preset speed. The operation control device can exchange one of the cylinder deactivation order maps which is currently used for another one of the maps in accordance with an operation state of the engine.

Abstract: A personal flying water jet apparatus consisting of two towing connected units: one is a floating platform, mainly an inflatable Ski 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 (16) and connected with nozzles (18) by mean of a hose (22). While the tube is being towed, the kinetic head appears and pressurized water is discharged at the nozzles (18) producing a thrust, so the rider (10) will fly. An additional version of the apparatus is: the nozzle (18) can be fixed on the rider's (10) back, so this lifting assembly performs like a Backpack, but the floating platform can be made in the shape of a life jacket (12B).

Abstract: A boat includes a connection structure that connects couplings via a transfer shaft on a rear end portion of a crankshaft extending rearward from an engine. The crankshaft and the transfer shaft are connected by screwing an external thread and a front internal thread, and the transfer shaft and the couplings are connected by screwing an external thread and an internal thread. There are provided an inner bolt that strengthens the connection between the external thread and the front internal thread, an end bolt that strengthens the connection between the transfer shaft and the couplings, and an outer nut that strengthens the connection between the crankshaft and the transfer shaft. The boat can prevent movement between the crankshaft and an intermediate member and between the intermediate member and a coupling both in a rotational direction and in an axial direction without causing an increase of processing time or processing cost.

Abstract: An electrical linear motor for propelling a marine vessel comprises a thruster assembly disposed within a guide tube. Permanent magnets are attached to the thruster assembly and placed in close proximity to electrical coil windings, which are positioned outside of and parallel to the guide tube. Electrical current energizing the coil windings creates an electromagnetic field, which interacts with the magnetic field of the magnets to cause reciprocating linear motion of the thruster assembly with the guide tube. During the non-propelling back stroke, a check valve on the thruster assembly is in open position to allow free passage of water. The check valve is moved to a closed position during the working stroke of the thruster assembly, allowing the thruster assembly to propel the marine vessel.

Abstract: One embodiment of the invention comprises a method for controlling a marine vessel having a first steerable propulsor, a corresponding first reversing device, a second steerable propulsor and a corresponding second reversing device. The method comprises receiving a first vessel control signal corresponding to a rotational movement and no translational movement command, generating at least a first actuator control signal and a second actuator control signal in response to the first vessel control signal, coupling the first actuator control signal to and controlling the first steerable propulsor and the second steerable propulsor, and coupling the second actuator control signal to and controlling the first reversing device and the second reversing device. The method creates rotational forces on the marine vessel with substantially no translational forces on the marine vessel.

Abstract: A system for driving a water induction and discharge system of a watercraft propelled by a water jet includes a water impeller, an engine including a driven shaft and a first chamber for containing engine oil, a second chamber for containing engine oil, a pinion secured to the driven shaft and located in the second chamber, a gear located in the second chamber, engaged with the pinion and driveably connected to the water impeller, and a dam located in the second chamber for limiting oil flow across the dam into the oil contained in the second chamber.

Abstract: A watercraft has a hull and a deck disposed above the hull. A ride plate is mounted below a rear portion of the hull. A jet pump assembly includes a jet pump disposed at least in part between the ride plate and the hull. A front wall is formed at least in part by the hull and disposed forwardly of the jet pump. The jet pump assembly is mounted on a top surface of the ride plate via a plurality of resilient mounts At least one sealing member forms a seal between the portion of the jet pump and the portion of the front wall. The jet pump is mounted to the watercraft only via a plurality of mounting points. The jet pump is resiliently mounted to the watercraft via each of the plurality of mounting points.

Abstract: To provide a small watercraft capable of suppressing vibration and noise of a vessel body, a jet pump is mounted to a hull via a thrust plate. A dynamic damper is disposed as an adjunct at a plate mounting portion that attaches the thrust plate to the hull. More specifically, the thrust plate is first mounted to the hull. Then, with a flange portion of the jet pump pressed up against a rear surface of the thrust plate, a second bolt is screwed in toward the thrust plate from an outward side of the hull. The jet pump is thereby attached to the rear surface of the thrust plate.

Abstract: A watercraft (1) includes at least two oar handles (3a, 3b) which are designated to be actuated by a passenger of the watercraft in order to propel the same. A considerably expanded functionality is achieved in such a way that the oar handles (3a, 3b) are connected to a control unit which controls at least one power-actuated driving motor (6a, 6b; 7; 16a, 16b; 26a, 26b) of the watercraft depending on the actuation of the oar handles (3a, 3b).

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 sports apparatus configured to support a rider upon the water surface is disclosed and may comprise either a compartment in the top surface configured to accept personal articles and a watertight cover to prevent damage and loss of personal articles or a propulsion source. The sports apparatus can have a V-shaped hull to add stability when used in the waves. The propulsion source is powered by either a combustion or electric motor that is controlled by a user interface on the board.

Abstract: The three-way valve allows fluid flow to be selectively directed to a run outlet, a bypass outlet or both at the same time. The three-way valve includes a flow diffuser with a primary valve seat positioned opposite a bypass valve seat. Choke points and flow restrictions, strategically positioned in the flow diffuser create a substantially flat velocity profile downstream of the bypass outlet. Larger versions of this three-way valve may be used in Vertical Takeoff and Landing (“VTOL”) aircraft. Other versions may be used in ships and other watercraft.

Abstract: A water-jet pump includes a cylindrical housing and an impeller. The impeller is disposed in the cylindrical housing and is configured to be rotated in a rotating direction. The impeller includes a shaft body and plural blades. The plural blades are provided on an outer circumference of the shaft body. A front portion of one of the plural blades overlaps a rear portion of another of the plural blades adjacent to one of the plural blades when viewed in an axial direction of the shaft body. When viewed in the axial direction, at least a part of a rear edge of the rear portion is formed obliquely with respect to a radial direction of the impeller towards the rotating direction. A cutaway portion is formed in each of the plural blades between at least a part of the rear edge and the outer circumference.

Abstract: A system for driving a water induction and discharge system of a watercraft propelled by a water jet includes a water impeller, an engine including a driven shaft and a first chamber for containing engine oil, a second chamber for containing engine oil, a pinion secured to the driven shaft and located in the second chamber, a gear located in the second chamber, engaged with the pinion and driveably connected to the water impeller, and a dam located in the second chamber for limiting oil flow across the dam into the oil contained in the second chamber.

Abstract: To provide a water jet propeller that enables an efficient flow of water from a water flow duct to an impeller housing even if an inner periphery of the impeller housing has an inside diameter smaller than the inside diameter of a rear end portion of the water flow duct. A water jet propeller has a stator disposed at a rear end portion of an impeller housing. An impeller is disposed inside the impeller housing. The water jet propeller expels a water jet by rotating the impeller. The water jet propeller further has the impeller disposed so as to circumvent a front end portion of an inner periphery of the impeller housing. The impeller housing includes a liner disposed over a region facing the impeller and representing the inner periphery of the impeller housing, except for the front end portion. The front end portion is formed to have an inside diameter that gradually increases forwardly.

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 water jet propulsion apparatus having an engine producing an exhaust gas, a pump driven by the engine, a nozzle in fluid communication with the pump, and an exhaust passageway communicating between the engine and the nozzle is disclosed. The exhaust passageway is connected the nozzle at a point in the nozzle where the water flow velocity is being increased, and prior to the water being expanded. By mixing the exhaust with the water while the water flow velocity is being increased, the result is a decrease the density of the mixture and an increase the total mass flow rate, thus resulting in increased thrust.

Abstract: A watercraft propelled by a water jet includes an sealed hull portion including an upper deck and a bottom surface, an engine compartment located behind the sealed hull portion and containing a propulsion and steering system including an engine, a bladed impeller driven by the engine for inducting water and forcing the inducted water away from the craft through a directionally displaceable nozzle, and a control lever located on the upper deck including an engine throttle control and a steering control for adjusting the directionally displacement of the nozzle.

Abstract: A water jet propulsion boat is constructed such that a fuel pressure detection device is free from a detection error or breakdown and a restart ability of an engine is protected against malfunction. A fuel tank is provided in a boat body of the water jet propulsion boat through vibration absorbing members. A fuel pump unit including a fuel pump is provided in the fuel tank. A fuel pressure sensor is provided in the fuel pump unit. An electric control device stops the fuel pump if the value detected by the fuel pressure sensor is out of the normal value range. Additionally, an electric control device stops operation of the fuel pump if the fall sensor detects the overturning of the boat body and if the detected value of the fuel pressure sensor is out of the normal value range. A regulator and a filter are provided to the fuel pump unit.

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 highly efficient watercraft propulsion system that relies on a positive displacement pump to generate a water jet. The pump is fully submerged at all times and its inlet is positioned so as to cause water to be forced into the pump as the watercraft moves through the water. The pump is preferably combined with a variable area pump opening which is configured, positioned and oriented so as to maximize the hydraulic reaction between the water jet stream and the surrounding body of water.

Abstract: A small planing boat can include a multi-cylinder engine, and a propulsion unit driven by the engine, such as a jet pump, for propelling a hull by drawing up and jetting out water. The engine can be configured to change the number of deactivated cylinders in a phased manner corresponding to an engine speed when the engine speed becomes a prescribed speed or more, and can include memory devices for storing a plurality of cylinder deactivation sequence schedules for determining sequences of cylinders that are deactivated and increasing the number of deactivated cylinders in a phased manner. An operation control device configured to deactivate the cylinders of the engine in a phased manner in accordance with the cylinder deactivation sequence schedules stored in the memory devices. The operation control device shifts the cylinder deactivation sequence schedules to be read out from the memory devices to another cylinder deactivation sequence schedule corresponding to an operational state of the engine.

Abstract: The present invention relates to a novel and non-obvious propulsion system for watercraft, especially, but not limited to, watercraft less than about 50 feet in length. Propulsion system of the present invention provides a system that is less prone to being impeded by debris, water plants and the like; less likely to cause motor stalling or motor over heating if said propulsion system does become clogged or impeded and is designed to provide increased thrust resulting in, for example, more efficient operation.

Abstract: A water propulsion unit having an intake housing, a pump housing and an outlet with two spaced apart counter rotating impellers being located in the pump housing. The impeller blades on one impeller have an opposite pitch to the blades of the second impeller. The impellers are configured so that one of the impellers will impart less energy to the water as it passes the blades of the impeller than the second impeller.

Abstract: A directional nozzle for the jet output that is attached to a control cable system. This cable turns the directional nozzle, which causes the trust of the jet output to turn the boat. Thus, the boat can be steered without having to turn the entire motor. Two different mechanisms are disclosed that enable the steering. The first is a tiller system that operates much like the traditional tiller on an outboard motor. However, unlike those tillers, this tiller operates the directional nozzle and does not turn the entire motor. The second mechanism is a bicycle handlebar system that is placed forward of the motor, much like a traditional wheel. The handlebar system, when combined with the directional nozzle system, produces faster steering response without the effort required to turn the wheel to make large sweeping turns.

Abstract: A foil shaped lifting body is attached by means of a strut to the underwater body of a vessel in such a manner as to cause a standing wave to be developed when the vessel is in operation in order that the standing wave will induct water into machinery intakes. The technology of this invention is particularly applicable to the operation of waterjet marine propulsion systems.

Abstract: A jet pump of a personal watercraft of the present invention includes a pump casing 10 provided with a fairing vane part including a plurality of fairing vanes 12, and the front portion of each of the fairing vanes 12 has two attack angles which are an attack angle ? of the fairing vane and the front end attack angle ? which is larger than the attack angle ?. Thereby, the attack angle of the fairing vane is adapted to the water jet flow so that reduction of pump efficiency is suppressed.

Abstract: The present invention relates to a novel and non-obvious propulsion system for watercraft, especially, but not limited to, watercraft less than about 50 feet in length propulsion system of the present invention provides a system that is less prone to being impeded by debris, water plants and the like; less likely to cause motor stalling or motor over heating if said propulsion system does become clogged or impeded and is designed to provide increased thrust resulting in, for example, more efficient operation.

Abstract: A water propulsion unit having an intake housing, a pump housing and an outlet with two spaced apart counter rotating impellers being located in the pump housing. The impeller blades on one impeller have an opposite pitch to the blades of the second impeller. The impellers are configured so that one of the impellers will impart less energy to the water as it passes the blades of the impeller than the second impeller.

Abstract: A system and related methods for manned and/or unmanned marine transportation involving equipping a vessel capable with a linear pump for propelling the vessel through or substantially over a body of water.