Abstract: A watercraft has first and second jet propulsion units. The first jet propulsion unit includes a first inlet, a first outlet, a second outlet, and a first valve. The second jet propulsion unit includes a second inlet, a third outlet, a fourth outlet, and a second valve. The watercraft also includes first and second discharge ports disposed on opposite sides of a longitudinal centerline, a first pipe fluidly communicating the first discharge port with the second outlet, a second pipe fluidly communicating the second discharge port with the second outlet, third and a fourth discharge ports disposed on opposite sides of the longitudinal centerline, a third pipe fluidly communicating the third discharge port with the fourth outlet, and a fourth pipe fluidly communicating the fourth discharge port with the fourth outlet.

Abstract: A system for controlling a marine vessel having first and second waterjets, corresponding first and second steering nozzles and corresponding first and second reversing buckets. The system comprises a speed control device for providing a first vessel control signal that corresponds to a speed to be provided to the marine vessel, a processor configured to receive the first vessel control signal and that is configured to provide at least one first actuator control signal coupled to the first and second waterjets, and at least one second actuator control signal coupled to the first and second steering nozzles and the first and second reversing buckets. The system any of improves upon turns provided by conventional waterjet propulsion systems, improves upon slowing down or stopping marine vessels as is done by conventional waterjet propulsion systems, and improves upon the controllability of the waterjet propulsed marine vessel at low vessel speeds.

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 jet boat comprising an engine-balance system, the engine-balance system comprising a first impeller and a second impeller, wherein water can be driven out of the first impeller for forward motion and water can be selectively driven out of the second impeller, regulated by a balance detecting device, wherein water from the second impeller can provide balance to the jet boat.

Abstract: A self-contained hydraulic thruster for vessel. A power pack is mounted on a forward end of a base, and a helm platform is mounted on an aft end of the base at a substantial height above the base. A reservoir in communication with the power pack is mounted on the helm platform, thus facilitating hydraulic fluid flow from the reservoir to the power pack, and also rendering the hydraulic system self-priming. At least one lower unit is tiltably mounted to the base aft end, laterally offset from the helm platform. Due to the lateral offset between the lower unit(s) and the helm platform, interference between the lower unit(s) and the helm platform is avoided when the lower unit(s) is retracted and tilted up for transportation, storage, or maintenance.

Abstract: A dynamic or aerodynamic fin comprising at least two parallel arranged fin sections. At least one fin section comprises a rotational axis for installing the fin section by a rotation shaft. An end stop is provided for stopping the rotational movement of the fin section to define an extreme position. In the extreme position the fin sections provide a substantially cambered shape to the fin. The dynamic fin is improved in that it comprises a pair of coupling elements. A first fin section is coupled to a second adjacent fin section by a pair of a first and second coupling elements. The first coupling element is complementary to the second coupling element. The first coupling element is part of, preferably integral, with the first fin section and the second coupling element is part of, preferably integral, with the second fin section.

Abstract: A self-contained hydraulic thruster for vessel. The hydraulic thruster incorporates a lower unit housing tiltably attached to a lower unit mounting tube attached to a base, a tube whose upper end is attached through the lower unit housing, and a shaft slidably disposed within the tube. A substantial length of tube extends downwards from the lower unit housing, thus providing support for the shaft. An actuator is disclosed which extends and retracts the shaft relative to the tube. A steering clamp is releasably attached to an end of the shaft which protrudes through the top of the lower unit housing. A steering clamp key traveling in a shaft keyway, or a shaft key in combination with a steering clamp keyway, help maintain constant the angular orientation between the steering clamp and the shaft. A steering gear meshing with a steering assembly, or an actuator driving a tie rod, provide steering.

Abstract: A thruster mounted to the transom of a boat and aligned to provide a lateral thrust for maneuvering the boat at low speeds. The thruster comprises a central housing having a propeller therein, and two extension members extending oppositely outwardly from end openings of the housing. The extension members each have a lower perimeter portion located below the water line of the boat and arranged to prevent ambient air from being entrained into the water that goes through the central thruster section.

Abstract: A system and apparatus for providing integrated boat thrusters which eliminates interfering with the integrity of the hull, and undesirable drilling and cutting of the hull to accommodate separate glass tubes or pipes that are conventionally used to form thruster tunnels. The instant system provides integrally molded thruster tunnel sections within the hull, and unique keystone inserts which are complementary to the molded thruster tunnel sections and complete the water flow chambers through the hull about the propellers. Separate tubes are not utilized. Thruster motors and mounting mechanisms are securely fastened in flat planes enhancing strength, performance and maintenance of the assemblies. In a preferred embodiment, the keystone insert is generally wedge shaped to provide a secure fit and bond within the molded tunnel section having angled walls.

Abstract: Status indicators for use with a watercraft propulsion system are described. An example indicator includes a light operatively coupled to a propulsion system of a watercraft, wherein an operation of the light indicates a status of a thruster system of the propulsion system.

Abstract: A system for controlling a marine vessel having first and second steering nozzles and corresponding first and second reversing buckets, comprises a processor configured to receive a first vessel control signal including at least a component corresponding to a translational thrust command in a port direction, and that is configured to provide a set of actuator control signals coupled to and control the first and second reversing buckets. The processor is configured to provide the set of actuator control signals so as to maintain the first reversing bucket substantially in a first discrete position and the second reversing bucket substantially in a second discrete position as long as the first vessel control signal includes a component corresponding to a translational thrust command in the port direction.

Abstract: A self-contained hydraulic thruster for vessel. The hydraulic thruster incorporates an elevated helm platform mounted to a base having reinforced base feet, and a hydraulic fluid reservoir mounted on the helm platform. The elevation of the hydraulic fluid reservoir facilitates flow of hydraulic fluid to a hydraulic power pack mounted on the base. A lower unit mounting tube is attached to the base, and at least one lower unit is mounted at an end of the lower unit mounting tube, laterally offset from the helm platform, so that when the lower unit is retracted and tilted up, it lies on one side of the platform, and the platform doesn't interfere with retraction and tilting of the lower unit. Lower units are pivotably mounted in lower unit housings with lower unit bushings, and steering is provided by a steering motor through an overhung load adaptor to a drive gear.

Abstract: A thruster unit for generating side thrust for improved maneuverability of a marine vessel employs a peripherally-driven propeller situated below the waterline and remotely powered by a motor situated above the waterline via a flexible drive member. The propeller is supported by a rolling element bearing disposed circumferentially around the outer perimeter of the propeller providing both axial and radial support. The lower portion disposed for submerged operation has a substantially thin cross section with a narrow thickness aligned transversely to the vessel to operate hydro-dynamically while the vessel is underway. This makes it possible for the present invention to remain in the operating position indefinitely even while the vessel is in motion without risking a structural damage.

Abstract: A steering shaft is rotatably supported on a body by a housing, and a slide portion having a handlebar attachment portion at the top is attached to the steering shaft. The rotational movement of a handlebar around the central axis of the steering shaft is regulated by a rotation regulating mechanism, while the axial translation of the handlebar is allowed. The steering shaft is provided with a plurality of grooves. A lock mechanism provided in the slide portion inserts a locking bar into any one of the grooves to regulate the axial translation of the slide portion. Owing to the shape of a link portion and a cam groove constituting the lock mechanism, the locking bar is not pulled, out of the groove by operations other than a release operation using a release lever.

Abstract: Steering device for boats comprising a through channel passing through the hull of a boat from side to side under the water line, inside which channel there is provided at least a propeller operated by a motor, wherein said motor is housed inside said channel and the propeller is mounted directly on the axle of said motor or by means of a drive placed between said axle of the motor and said propeller.

Abstract: A steering system for a waterjet propelled marine vessel is disclosed that incorporates an intelligent control system interfacing a manually steerable control device with a number integrated propulsion systems. The propulsion systems can be controlled by the control system in isolation or in combination with one another in order to propel and steer the marine vessel.

Abstract: A steering system for a marine vessel includes one or more steering devices operable to turn a marine vessel; a steering input device arranged to generate a desired turn rate signal; a rate sensor arranged to generate a turn rate signal indicative of vessel turn rate; and a control system configured to receive the vessel and desired turn rate signals and to control the steering device(s) to turn the marine vessel so as to minimise any difference between the signals.

Abstract: A steering unit for a small watercraft, which can positively prevent jolting of a steering shaft relative to a bearing section for allowing smooth rotation of the steering shaft, and makes for improving the installing characteristic of the steering shaft and a collar into the bearing section. A steering shaft is rotatably supported with respect to a watercraft body through a cylindrical bearing section in which the steering shaft is inserted. A plurality of ribs are provided around an inner surface of the cylindrical bearing section and extend in an axial direction of the steering shaft. The steering shaft is rotatably supported by the bearing section with a collar, formed from an elastic material, being provided interposedly between the ribs and an outer surface of the steering shaft. The cylindrical bearing section includes at least three or more ribs are provided.

Abstract: A method for controlling a marine vessel having a first steering nozzle, a reversing deflector and at least one of a bow thruster and a second steering nozzle is disclosed. The method comprises any of the acts of inducing a net transverse thrust to the marine vessel in response to a transverse thrust component signal, without substantially inducing any forward-reverse thrust or rotational thrust to the marine vessel, or inducing a net forward-reverse thrust to the marine vessel in response to a forward-reverse thrust component signal without substantially inducing any transverse thrust or rotational thrust to the marine vessel, or inducing a net rotational thrust to the marine vessel in response to the rotational thrust component signal without substantially inducing any forward-reverse thrust or transverse thrust to the marine vessel.

Abstract: The present invention relates to a method and an auxiliary device in connection with disassembly and/or assembly of a tunnel thruster unit by use of the auxiliary device (1) to guide the thruster unit (2) and its movement during disassembly/assembly inside the tunnel (4), the thruster unit (2) thereafter being led away through the tunnel (4), said auxiliary device (1) being removably fixed at the thruster unit (2) before final disassembly, such that the auxiliary device (1) controls the movement during disassembly/assembly, mainly by compressive forces.

Abstract: This application concerns a method and system using a hydrodynamical effect for producing a potential over a body. The force obtained this way is useful for the propulsion and maneuvering of ships, submarines, aeroplanes, and airships. A body immersed in a fluid at rest is subject to equal pressures on all sides. A stream close to one side of the body will reduce the local pressure and produce a potential over the body. This is currently done by moving the body in the fluid, cf. aeroplane wings. The potential may be produced by setting up a stream or streams over one side of the body. Bodies attached to aeroplanes by hinges are useful for their lift, propulsion and maneuvering, and will make them independent of velocity for lift and maneuvering. The same will be the case for submarines. Airships and seagoing vessels may be designed so as to have their propulsive bodies integrated in their form.

Abstract: A thruster unit for generating side thrust for improved maneuverability of a marine vessel employs a peripherally-driven propeller situated below the waterline and remotely powered by a motor situated above the waterline via a flexible drive member. The propeller is supported by a rolling element bearing disposed circumferentially around the outer perimeter of the propeller providing both axial and radial support. The lower portion disposed for submerged operation has a substantially thin cross section with a narrow thickness aligned transversely to the vessel to operate hydro-dynamically while the vessel is underway. This makes it possible for the present invention to remain in the operating position indefinitely even while the vessel is in motion without risking a structural damage.

Abstract: A bow thruster includes a pump connected to an inlet opening in a bottom of the boat hull, lines extending from the pump to opposing side outlet openings in the hull below the water line, and a control (normally closed) valve for selectively controlling water flow through each line. A bow thruster control includes on-off switches for operating the inlet pump and simultaneously directing water from pump toward a selected one of the lines to steer a bow of the hull. The bow thruster can be used on V-hulls, flat-bottom hulls for river boats, pontoons, and other watercraft.

Abstract: A radial vane fluid motor or pump has an open ended tubular rotor having a cylindrical outer surface rotatably mounted in a tubular stator having its inner surface contoured to provide successive portions of increased and decreased spacing relative to the rotor body. A plurality of elongated movable vane assemblies are mounted on and project outwardly from the rotor surface to continuously contact the stator surface. Bearings support the rotor within the stator, and seals are provided for sealing the space between the rotor and stator. Pressure inlets and exhaust ports are provided in the stator to permit the flow of pressure fluid into or out of the device. Mounting the vanes on the cylindrical rotor surface enables production cost reduction and simplifies maintenance. A conventional propeller mounted in the cylindrical rotor provides an improved shrouded propellor propulsion system for marine vessels.

Abstract: A system and method of use for a marine vehicle to compensate for the effects of forward velocity of the vehicle and ambient currents of a water medium on lateral thrust from a lateral tunnel in the vehicle. A thruster in the tunnel has a variable pitch propeller rotated by a motor at a maintained constant speed to produce lateral thrust of flowing water through the tunnel. A power supply provides input power to the motor, and voltage and amp meters provide signals representative of the power. A computer generates pitch control signals from the representative signals, and a pitch actuator connected to the propeller and the computer is responsive to the pitch control signals to change the blade pitch of the propeller in order to maintain the lateral thrust at a predetermined level.

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 method for controlling a marine vessel having a first steering nozzle, a reversing deflector and at least one of a bow thruster and a second steering nozzle is disclosed. The method comprises the acts of inducing a net translational force to the marine vessel, corresponding to a first vessel control signal comprising only a translational thrust command and a zero rotational thrust command, so that substantially no net rotational force is induced to the marine vessel, and inducing a net force to the marine vessel, substantially in a direction of a combination of the translational thrust command and the rotational thrust command for all combinations of the rotational and translational thrust commands.

Abstract: A portable bow thruster for use on the bow of a boat in a body of water having a water line. The bow thruster includes a blower assembly for producing an air flow to provide thrust, an exhaust air duct for expelling the air flow from the blower assembly, pivoting means for pivoting the bow thruster in the clockwise and counterclockwise directions, support means for supporting the blower assembly, and a mounting assembly for mounting the bow thruster to the bow of the boat.

Abstract: A device for enhancing the maneuverability of motorboats and motoryachts includes a high velocity water jet pump (HVWJP) attached to the main engine through an electromagnetic clutch. High velocity water flows from the HVWJP's outlet to bow and stern side nozzles, through solenoid valves, individually controlled from the cockpit. The benefits of the device are that turns and lateral movements will be easier and faster, and extra power for fire fighting and emergency bilge water pumping are also available. Further, if the yacht, while speeding, strikes a rock or other submerged obiect and the propellers and shafts are destroyed, the crew will use the U section pipe to connect the NVWJP's outlet to an auxiliary propulsion pipe, demonstrate to the tug's skipper that his yacht is not a dead ship on the water, and legally claim and pay the towage fee, instead of the far more expensive salvage fee.

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 watercraft steer-by-wire control system comprising: an input device; at least one transducer in operable communication with the input device; a rudder control system in operable communication with the input device and configured to control a rudder of a watercraft; and a bow thruster control system in operable communication with the at least one transducer and configured to control a bow thruster of the watercraft. A method for the maneuvering if a watercraft. The method comprises: applying a force in a first degree of freedom of an input device; measuring the movement of the input device in the first degree of freedom; converting the movement into a signal proportional to the amount of movement; and transmitting the signal to a bow thruster control system.

Abstract: A retractable thruster for a surface or submersible vessel, having thruster a propulsion assembly with a rigid structure secured to a cylindrical turbine. The rigid structure contains a motor suitable for rotating at lease one propeller inside the turbine via at least one rotary shaft positioned between the motor and the propeller. The thruster preferably further has a plate for closing the hull placed beneath the turbine and secured thereto, the propulsion assembly being displaceable between a retracted position in which it is at rest inside the hull and a deployed position for providing propulsion in which the propeller is immersed beneath the hull. The propulsion assembly is movable between the retracted and deployed positions by the propulsion assembly moving in a uniformly circular direction about an axis of rotation situated substantially no higher than the level of the hull.

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: The hull of a submerged sea craft adjacent its stern end is provided with auxiliary facilities for controlled maneuvering operations under low speed conditions, including steering, stopping and negative thrust backing performed independently of main propulsion of the craft. The auxiliary maneuvering control facilities include a curved channel pipe connected to two angularly related sub-channel pipe sections for selectively controlled outflow of fluid which is pressurized by a maneuvering control pump within the curved channel pipe before outflow through exit openings in the hull in different directions, as negative angle thrust jets and as steering control jets perpendicular to the hull centerline. By use of a sub-channel flow diverting flapper and gate valves at the inlet and exit outlet openings in the hull, all of the maneuvering operations may be performed under selective control.

Abstract: The boat control system of the invention is a propulsion system for controlling the direction of passage of a vessel underway at low speeds. Six thruster nozzles are installed around the hull so that, used individually or in combinations, the boat can be maneuvered forward, backward, laterally or turned on its axis. The impeller pumps are operated by a water cooled reversible DC electric motor which allows the thruster apparatus to operate for long periods.

Abstract: A system and method providing a portable, floatable vessel for controlling the absolute position and relative position and the motion of a floating craft using a small water plane area, high vertical drag coefficient and dynamic positioning is disclosed. The methodology employs a portable, floatable vessel that includes: a bridge structure, a lifting bridle connected to the bridge structure, a control center, first and second struts connected to the bridge structure, and first and second docking arms connected to the struts. The first and second struts are connected to first and second machinery pods with first and second azimuth thrusters for self-propulsion, motion control, and other operations while in water. Docking arms include drag dishes for stabilization and arm pods for buoyancy control of the docking arms. The docking brackets can firmly grip and stabilize the floating craft to minimize roll, pitch, yaw, and other motions of the craft during cargo transfer.

Abstract: A control system and apparatus for controlling waterjet-driven marine vessels is disclosed. Some aspects allow for generation of a plurality of actuator control signals from a single vessel control signal, such as those provided by vessel control apparatus. A control stick embodiment provides a control apparatus that comprises a shaft moveable in at least one degree of freedom to provide the vessel control signals. Some aspects allow for an intuitive direct movement of the vessel in correspondence to movements of the control apparatus. Yet other aspects allow for locking out on or more degrees of freedom while other degrees of freedom and not locked out.

Abstract: A boat has installed therein a primary propulsion system to produce a thrust at least in the longitudinal direction, manual controls for controlling the primary propulsion system, a transverse propulsion system for producing a transverse thrust, and a joystick control for controlling the primary and transverse propulsion systems for navigation at slow speed or in docking manoeuvres. An electronic control unit controls the propulsion systems and receives information on the instantaneous speed of the boat and on the instantaneous distance between the boat and an obstacle such as the coast, the bottom or floating or half-submerged bodies. The electronic unit is so arranged that when the boat is located at a distance from an obstacle less than a predetermined distance it controls the propulsion systems to reduce the speed of the boat to below a predetermined limit, disables the manual controls of the primary propulsion system and enables the joystick control.

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 thrust drive unit for generating side thrust for improved maneuverability of a marine vessel employs a peripherally-driven propeller situated below the waterline and remotely powered by a motor situated well above the waterline via a drive belt. The propeller is supported by the two ends of the coaxial shaft by a pair of supports which are mounted on either side of the casing and are angularly adjustable with respect thereto about the thrust axis to a position which is least resistance-generating for a particular installation of the thrust drive unit on a vessel. The lower portion disposed for submerged operation has a substantially blade-like cross section with a narrow thickness aligned transversely to the longitudinal axis of the vessel. The cross section of the submerged portion is streamline shaped to help further minimize the resistance.

Abstract: The stern hull portion of a sea craft through which main exit flow channels extend to projecting jet propulsion nozzles, is provided with facilities for controlled maneuvering of the sea craft, including steering, stopping, negative thrust backing and docking without substantial hydrodynamic loading and with facilitated installation. Such maneuvering control facilities include a secondary flow channel extending from each of the main exit flow channels having two angularly related subchannel branches for pressurized water outflow through gated openings in the hull from which propulsion jets emerge under maneuvering control. Either control of a subchannel diverting flapper, or by use of selective closure gates and a flow diverting flap within the main exit flow channel, maneuvering may be effected in response to inflow through inlet openings in the hull of water that is pressurized before supply to the main exit flow channels.

Abstract: An elongated fluid dynamic water jet type of propulsion body receives an inflow of fluid through inlet openings for entry into a jet propulsor from which an outlet jet emerges for passage through an internal transition passage to an exit end between two pairs of horizontal flaps hinged to the body at the exit end for angular displacement about parallel spaced horizontal axes from horizontal neutral positions. Four pair of flaps are pivotally mounted within the transition passage for angular displacement about parallel spaced vertical axes from neutral positions. Actuators inside of the propulsion body connected to the flaps are selectively controlled to impart in-phase angular displacement to all of the flaps about their horizontal and vertical axes from the neutral positions for directional steering by angular deflection of the jet exit outflow from the exit end of the body.

Abstract: An apparatus for aiding in steering and maneuvering a boat that includes a thruster that applies a force transverse to the longitudinal axis of the boat. The operation of the thruster is under control of a remote radio frequency transmitter which permits an operator of the boat to operate the thrusters without being on the bridge of the boat. A switching circuit that includes relays and solenoids associated with a solenoid valve operates with the remote frequency transmitter and receiver to energize a thruster on the boat.

Abstract: A fast military surface craft, particularly a frigate or a corvette, includes at least two electric rudder propeller drives, whereby the electric ruder propeller drive is placed at a cruising speed. The electric energy for the rudder propeller of the electric rudder propeller drives is generated by way of fuel cell units distributed in a de-centralized manner in the ship. At least two, preferably electric, hydrojets are provided with underwater hydrojet exit nozzles to enable the craft to travel at high speeds, whereby the electric energy of the hydrojets is produced, by generators.

Abstract: The integrated and self contained diesel hydraulic thruster system integral has a dynamic positioning control system for dynamic positioning of any waterborne vessel having a hull with at least two sides and a deck connecting the sides, at least two removably mounted azimuthing thrusters, at least two self-contained diesel hydraulic power units removably secured to the deck, one for each thruster, at least one dynamic positioning computer connected to each of the self contained diesel hydraulic power units, at least one motion reference sensor connected to the dynamic positioning computer to correct reference position signals for motion of the vessel, at least one heading sensor, and at least one sensor that is either a position reference sensor connected to the dynamic positioning computer, an environmental sensor connected to the dynamic positioning computer, or a combination thereof.

Abstract: A propelling machine (2) is configured curved- tubular, on a ship bottom (1b), with a front casing (12) having a suction inlet (11) opening fore to water, an impeller casing (10) having an impeller (17) inscribed thereto, and a rear casing (14) having a delivery outlet (13) opening aft to water, and the impeller (17) is forward and reverse rotatable.

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: 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 for propelling a surface vehicle through the water comprised of a submerged portion, including both a stern propulsion unit and a bow propulsion unit. Either unit may be a pumpjet, the bow unit may include a counter-rotating nose hub having attached spirally wound, twin centrifugal propeller blades. The foremost bow propeller is dedicated to stealth and the next-in-line bow propeller is dedicated to supercavitation. Specially-designed vortex loops that connect the pressure side to the intake side of a propulsion unit may be included in the blades, shroud or hub areas. Further, slightly diverged jet exhaust and variable special surface texturing reduce surface friction drag on the vehicle body. The submarine propulsion system is used to power a surface vessel, supported by two or more hydrofoils which combine a submerged midcraft foil with a wave-piercing variety. The surface craft has the capability of submerging and maneuvering.

Abstract: In order to provide an internal combustion engine control unit for a jet propulsion type watercraft which can control an internal combustion engine so that a rider can perform risk avoidance safely, a controller 300 is provided, which increases the rotation speed of the internal combustion engine when the throttle open degree detected by a throttle open degree detector 22 which detects the throttle operation by the rider is a predetermined value or lower, and it is judged that the hull 1 is running based on the rotation speed of the engine 2 detected by the rotation speed detector 24, and when a steering handle angle detector 21 detects that the rider performs the risk avoidance operation.