Abstract: A propulsor is described in which rotation of the frustum of a right circular cylinder generates thrust. Variants of this basic geometrical shape are also described that enable multiple means for propelling fluid past the propulsor.

Abstract: A remote-control unit for control a marine vessel is provided with a thruster actuator and engine actuators. When the marine vessel lacks a thruster, the thruster actuator, when operated, causes the remote-control unit to transmit engine control signals to each of at least two engines to achieve a virtual thruster effect by the marine vessel.

Abstract: An inspection device for use in a fluid container having at least an opening includes a housing sized to fit through the opening. The housing has at least two fluid flow channels extending therethrough, each having an inlet and an outlet, and a pump maintained in the housing within each fluid flow channel. The pumps are selectively controlled to maneuver the housing within the fluid container. The inspection device continues with a method of in-situ inspection of a container having at least one opening to receive a fluid, that includes up-loading a virtual model of the container into a computer, inserting the device into the container, generating a position signal by the device and receiving the position signal on a computer. A virtual image of the device in the virtual model of the container is generated to determine an actual position of the device within the container.

Abstract: An artificial downwelling system, for example, can include one or more free-floating, self-propelled, or anchored wave-inertia pumps. In one embodiment, the wave-inertia pumps may be deployed on the oceanic side of an upwelling front. For example, the wave-inertia pump may pump warm surface water to deeper cold layers (e.g., below a sheared pycnocline of upwelling water) to disrupt the coastal upwelling. In some embodiments, a productivity of the artificial downwelling system can be controlled through remote telemetry, telecommand, and/or electromechanical tools. The artificial downwelling system may, for example, be powered by wave energy, and can be controlled using a telemechanical system powered by wind energy, and/or solar panel energy backed by electrical batteries.

Abstract: A stowable propulsion device for a marine vessel having a deck. A base is configured to be coupled to the marine vessel below the deck. A propulsor is configured to propel the marine vessel in water. An arm couples the propulsor to the base such that moving the arm moves the propulsor into and between a stowed position located proximate to the marine vessel and a deployed position located relatively distal from the marine vessel as compared to the stowed position, and such that moving the arm rotates the propulsor about the arm. An actuator comprises a first link movably coupled to the base and a second link that movably couples the first link to the arm. An actuator moves the actuator linkage to thereby move the propulsor into and between the stowed position and the deployed position.

Abstract: A thruster system for improved steering and maneuverability of a marine vessel when operating at relatively low, or wakeless speeds, such as in the vicinity of docks, swimmers or other obstacles, or when trailering, beaching or mooring. The thruster system has a modularized design adapted to independently control separate motor/propeller units located at various positions on the vessel's hull. Each propeller of the modular thruster motor system has its own relatively small, electric motor and mounting bracket, permitting each motor to be separately mounted to a location on the hull of the marine vessel apart from other thruster motors. The thruster system is further enhanced by an electrical control system for controlling each modular thruster motor system of the thruster system. In some embodiments, a charging system is provided that permits each electrical control system to be separately charged from the marine vessel's main battery.

Abstract: A pontoon boat including a thruster system is disclosed.

Abstract: A bracket for mounting a thruster to a boat includes a horizontal portion, a vertical portion that provides a vertical surface that matches an angle of the vessel transom, generally. The horizontal portion includes an enclosure. The vertical portion forms a transom-facing surface in a plane that is generally at a right angle relative to a horizontal plane, within a small range of angles. The transom-facing surface can angled to match the angle of the transom of a boat to which the thruster bracket is mounted. A thruster is mounted to the thruster bracket on a rotatable thruster mount that allows the thruster to be rotated in a generally horizontal plane relative to the bracket and the vessel to facilitate low speed maneuvering.

Abstract: According to an example aspect of the present invention, there is provided a manoeuvring system comprising at least one unit comprising a channel having a longitudinal axis and comprising at least one water intake opening, at least one water nozzle arranged within the channel and configured to guide a water flow through the at least one water intake opening at an angle relative to the longitudinal axis and in a plane perpendicular or substantially perpendicular to the Earth's normal, at least one piping connected to the channel at a first end and connected to the at least one water nozzle at a second end, and at least one pump arranged between the first end and the second end and configured to control a water flow through the at least one water nozzle.

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: The invention is a jet propulsor using gas or liquid of the environment as an operating medium (OM). The propulsor comprises eight nozzles arranged centrally symmetrically and a channel system (CS). The CS comprises eight active channels (AC) with pressure units therein to control a flow head of the OM, four intermediate channels (IC) and a central channel (CC). Each of the AC is connected by one end to one of the nozzles. All AC are pairwise connected to each other by other ends, forming four connecting nodes of the AC (ACCN). Connected to each of the ACCN by one end is one of the IC pairwise interconnected by other ends and forming two connecting nodes of the IC (ICCN). The CC is connected to the ICCN. The technical result is the reduction of unproductive energy loss in the flows of the OM in the CS and increasing its efficacy.

Abstract: Methods, systems, and apparatus for predicting electromechanical actuator health and remaining life include a method storing a reliability model coupled to a controlled actuator system comprising a motive force system coupled to a driven mechanical system. The motive force system is associated with motive force parameters. The driven mechanical system is associated with driven mechanical parameters. The reliability model represents a probability of failure of the controlled actuator system over time based on motive force parameters and driven mechanical parameters. Operational parameters of the controlled actuator system, received over time from a sensor system coupled to the controlled actuator system, include one of the motive force parameters or driven mechanical parameters. The operational parameters represent a degradation of the controlled actuator system over time. The reliability model is updated to represent a revised probability of failure.

Abstract: A pontoon boat including a thruster system is disclosed.

Abstract: An integrated thruster and ballast system in accordance with some examples herein may include a conduit disposed within a hull of the boat. The conduit includes a first opening in fluid communication with a body of water, a second opening in selective fluid communication with the body of water, and an outlet disposed within the boat. The integrated thruster and ballast system includes a ballast tank in selective fluid communication with the conduit via the outlet, a thruster disposed within the conduit and configured to move water through the conduit, a first valve disposed in the conduit and configured to selectively divide or establish the fluid communication between the conduit and the ballast tank; and a second valve disposed in the conduit and configured to selectively divide or establish the fluid communication between the second opening and the body of water.

Abstract: Aspects of the present disclosure relate generally to apparatus for semi-submersibles, including hulls of semi-submersibles. In one implementation, a hull for a semi-submersible includes a pontoon having one or more sides, and a plurality of columns extending upwards from the pontoon and configured to support a topsides. Each one of the plurality of columns has a cross section that is in a plane perpendicular to an axial centerline of the respective one of the plurality of columns. The cross section includes a first portion being rectangular in shape and a second portion being triangular in shape and having an apex that extends inboard from the first portion.

Abstract: A boat comprises a hull, a primary steering mechanism carried by the hull, a control station located on the hull, a helm located at the control station, and a thruster system carried by the hull. The primary steering mechanism, such as a rudder, is operable via the helm with a helm input being derived from operation of the primary steering mechanism thereby. The thruster system includes at least one thruster mounted to the hull, distinct from the primary steering mechanism, and a controller. The controller receives the helm input and is configured with program instructions to operate the at least one thruster responsive to the helm input to supplement a corresponding movement of the hull. The controller can also automatically operate the thruster responsive to direction, speed and ballast inputs.

Abstract: A propulsion system coupled to a vehicle. The system includes a convex surface, a diffusing structure coupled to the convex surface, and at least one conduit coupled to the convex surface. The conduit is configured to introduce to the convex surface a primary fluid produced by the vehicle. The system further includes an intake structure coupled to the convex surface and configured to introduce to the diffusing structure a secondary fluid accessible to the vehicle. The diffusing structure comprises a terminal end configured to provide egress from the system for the introduced primary fluid and secondary fluid.

Abstract: A boat comprises a hull, a primary steering mechanism carried by the hull, a control station located on the hull, a helm located at the control station, and a thruster system carried by the hull. The primary steering mechanism, such as a rudder, is operable via the helm with a helm input being derived from operation of the primary steering mechanism thereby. The thruster system includes at least one thruster mounted to the hull, distinct from the primary steering mechanism, and a controller. The controller receives the helm input and is configured with program instructions to operate the at least one thruster responsive to the helm input to supplement a corresponding movement of the hull. The controller can also automatically operate the thruster responsive to direction, speed and ballast inputs.

Abstract: Combination of marine vessel and outboard motor, wherein at least one outboard motor is attached in a predetermined position to the transom of the marine vessel, the motor being mounted so as to translate according to a path with at least one motion component having an orientation parallel to the direction of the transverse axis of the hull and/or parallel to the transom of said hull and alternatively towards one or the other side of the hull.

Abstract: In at least one embodiment the present invention provides an improved mounting and actuation device having a mounting body defining a stowage cavity and an actuation arm operable for movement from a first stowed position to a second actuated position, the actuation arm operably connected to the mounting body at a first proximal end and having a second distal end having a mounting surface adapted to receive an accessory wherein the actuation arm is received in the stowage cavity in the first stowed position.

Abstract: A jet boat basically includes a hull, a first jet propulsion unit, a second jet propulsion unit, and a steering unit. The first jet propulsion unit is provided to the hull. The first jet propulsion unit has a first steering deflector with a first propulsion axis. The first steering deflector is movable with respect to the hull. The second jet propulsion unit is provided to the hull. The second jet propulsion unit has a second steering deflector with a second propulsion axis. The second steering deflector is movable with respect to the hull. The steering unit is operatively coupled to the first and second jet propulsion units. The first and second steering deflectors are oriented such that the first and second propulsion axes are non-parallel to a longitudinal center axis of the hull while the steering unit is in a straight steering position.

Abstract: Autonomous underwater vehicles are described that are stackable with other like autonomous underwater vehicles on a suitable launch platform, such as within a vertical missile launch tube of a submarine, waiting to be deployed into the water. The underwater vehicles can be deployed or launched individually, in groups, or all together into the water. While stacked together, the stacked autonomous underwater vehicles can connect to one another or to external structure of the launch platform. In addition, the underwater vehicles can be positively buoyant or can be made to have controllable buoyancy to allow the underwater vehicles to float up and out of the launch platform during deployment without an external deployment force.

Abstract: A jet propulsion boat includes a propulsion device configured to generate a jet of water, a first discharge portion provided in a rear portion of a boat body, including a first discharge port from which the jet of water is discharged, a second discharge portion including a second discharge port from which the jet of water is discharged, configured to be rotatable so as to change the discharge direction of the second discharge port, and a jet path configured to connect the propulsion device to the first discharge portion and the second discharge portion.

Abstract: A thruster assembly is provided for a marine vessel, the assembly having a propeller unit (14), a motor (10) and a drive shaft (12) linking the motor (10) with the propeller unit (14) to drive the propeller unit (14). The drive shaft (12) is foldable and defines a drive path between the motor (10) and the propeller unit (14). A housing (2) locates the propeller unit (14) in a storage configuration. The motor (10) is fixed with respect to the housing (2), the housing (2) being adapted to be fixed with respect to an opening in a hull (8) of the marine vessel. An actuator (22) is operable to move the propeller unit (14) from the storage configuration to a deployment configuration in a direction from inboard to outboard, the propeller unit (14) being extended from the hull (8) for use in the deployment configuration. The propeller unit (14) is supported by a support assembly (36) which is pivotable relative to the housing (2) about a pivot axis (A).

Abstract: An offshore structure for use with an OTEC system includes a submerged spar having a lower portion having a cold water intake. The cold water intake includes a domed terminus in fluid communication with a cold water pipe. A dry machinery space adjacent the cold water intake includes one or more cold water supply pumps and one or more cold water pipe lifting and retention winches having a lifting cable connected to the cold water pipe.

Abstract: A boat includes a hull, a deck, an engine disposed between the hull and the deck, and a jet propulsion unit including a jet nozzle configured to jet water therefrom. The jet nozzle includes a hole to which a water passage is connected and is configured to supply pressurized water from the jet nozzle to a water intake opening located in an interior of the hull. The water intake opening is connected to an interior water passage disposed in the interior of the hull and between the hull and the deck. The interior water passage is connected to a deck hose used to wash the boat.

Abstract: An autonomous underwater vehicle (AUV) for recording seismic signals during a marine seismic survey. The AUV includes a body having a flush shape; an intake water element located on the body and configured to take in water; at least one propulsion nozzle located on the body and configured to eject the water from the intake water element for actuating the AUV; at least one guidance nozzle located on the body and configured to eject water to change a traveling direction of the AUV; and a seismic payload located on the body of the AUV and configured to record seismic signals.

Abstract: A turbine arrangement for a bi-directional reversing flow is provided. The turbine arrangement may include a rotor rotatably mounted to rotate about an axis of the turbine arrangement, and the rotor may have a plurality of rotor blades disposed circumferentially thereabout. A first set of guide vanes may be circumferentially disposed about the axis for directing the bi-directional reversing flow to and from the rotor blades via a first flow passaged defined by a first duct. A second set of guide vanes may be axially spaced from the first set of guide vanes and circumferentially disposed about the axis for directing the bi-directional reversing flow to and from the rotor blades via a second flow passage defined by a second duct. The guide vanes may be disposed at a greater radius than the rotor blades, such that the guide vanes are radially offset from the rotor blades.

Abstract: A jet boat includes a hull, a jet propulsion nozzle mounted to a rear of the hull, and an articulating keel attached at the rear of the hull. The articulating keel is connected to the jet propulsion nozzle via a connecting portion such that when the jet propulsion nozzle is turned, at least a portion of the articulating keel is turned with the jet propulsion nozzle. The jet propulsion nozzle turns about a first pivot axis extending vertically or substantially vertically, and the articulating keel turns about a second pivot axis extending vertically or substantially vertically. The first pivot axis of the jet propulsion nozzle is coaxial with the second pivot axis of the articulating keel.

Abstract: A method for disassembling and/or assembling an underwater section of a retractable thruster unit of a swimming vessel. A supporting cradle is detachably fixed to the underwater section from below, and the thruster unit is lifted so that the underwater section is at least partly brought inside the well formed in the bottom of the vessel. Lifting wires of an auxiliary lift are connected to the supporting cradle for supporting the thruster unit. Water is drained from the well, and the lower gear is disengaged and the intermediate section and the lower gear are sealed. After that water is let to ingress into the well and the underwater section is lowered down by the auxiliary lift to dock bottom or sea bed, from where the underwater section is picked up with a crane.

Abstract: A propulsion assembly of a ship or floating platform includes a housing within a hull or platform. The housing is watertight except for an opening external to the hull. A stationary motor is arranged in the hull external to the housing. A thruster is external to the hull to generate thrust on the ship or floating platform. A telescopic driving shaft passes sealingly through a housing wall to connect the motor and the thruster and to transmit movement from the motor to the thruster. The thruster retracts within the housing through the opening. A separate submersible movable hatch is disconnectable from the thruster and the housing and passes externally to the hull, and seals the opening to form a watertight closed chamber. A fluid evacuation device evacuates fluid within the closed chamber so the thruster, when retracted in the housing and closed by the hatch, forms the closed chamber.

Abstract: An autonomous underwater vehicle (AUV) records seismic signals during a marine seismic survey. The AUV includes a communication device configured to acoustically receive location information from plural transducers of a vessel, wherein each transducer of the vessel transmits its own geographical location; a navigation system configured to receive the location information from the communication device and to calculate current and target positions of the AUV; a propulsion system configured to drive the AUV from the current position to the target position; and a seismic sensor for recording seismic data after reaching a final target position.

Abstract: A vessel with auxiliary steering includes a vessel hull with a bow/stern centerline and a port and starboard side. The vessel has (i) a main propulsion unit including at least one propeller and at least one main rudder, and (ii) a secondary propulsion unit including at least one directional water jet thruster on each of the port and starboard side of the vessel hull. The water jet thrusters are configured to direct water outwardly and perpendicularly to the centerline of the hull, and a control system coordinates the direction of the main rudder and the flow direction of at least one water jet thruster.

Abstract: Marine tunnel thruster includes a duct, within which at least a propeller is fitted that is operatively connected to a rotational drive system. The duct is composed of three sections, which include a first central section and two end sections. The first central section has a specific length and a specific diameter, while the two end sections have a specific length and a specific diameter greater than the diameter of the central section.

Abstract: A position of a target ship alongside is displayed in animation on a display unit 17 by the computer 11 based on any one of the positional information on the target ship alongside, which is transmitted from an automatic identification system (AIS) of a target ship alongside and is obtained by an AIS communication unit 13, positional information on the target ship alongside, which is obtained by the GNSS communication unit 14 from a global navigation satellite system, and positional information on the target ship alongside, which is manually inputted via an operation unit 18. Therefore, the latest position of the target ship alongside can be always displayed in animation.

Abstract: A floating vessel having a hull, at least one thruster tube, at least one water moving device and at least one power supply in the thruster tube. At least one appendage partially surrounds the thruster tube and encircles the thruster tube from 30 percent to 40. A plurality of supports secures the at least one appendage to the hull. At least one fairing plate is installed between a tangent of the appendage and the hull for following a circumference of the thruster tube and encircling the thruster tube from 30 percent to 40 percent, wherein the fairing plate is configured to transition water flow from the hull over the appendage and into the thruster tube to reduce water turbulent flow across an opening of the thruster tube.

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 to the second reversing device. The method creates rotational forces on the marine vessel with substantially no translational forces on the marine vessel.

Abstract: A lateral thruster for a vessel with a housing (1), at least one electric motor (2, 2?) fitted in the housing (1) and at least one transverse propeller (13) acting transversely with respect to a longitudinal axis (3) of the vessel (5) is additionally provided with at least one longitudinal propeller (21) acting in a direction of the longitudinal axis (3) of the vessel (5).

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 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 to 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: In a thruster for a vessel including a hull, the thruster comprises at least one tunnel element and at least one thruster unit. The tunnel element includes at least a part of a through tunnel in the hull when arranged in the hull. The at least one thruster unit and the at least one tunnel element include cooperating fastening devices for detachably fixing the at least one thruster unit in the at least one tunnel element such that the at least one thruster unit is configured to be passed through the tunnel and mounted to the at least one tunnel element, or demounted from the at least one tunnel element and passed out of the tunnel. A method for mounting and demounting a thruster in a tunnel element includes a tunnel element arranged in the vessel of a hull.

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 to the second reversing device. The method creates rotational forces on the marine vessel with substantially no translational forces on the marine vessel.

Abstract: An auxiliary appendage attachable to the steerable nozzle of an existing water craft. A first and second rudder blade attach to steerable nozzle. The first rudder blade includes a torsion spring providing a downward torsion force. A detent attached to steerable nozzle prevents rudder blades from hyper-extending in the direction of the downward torsion force. Rudder blades are connected by a deflection bar. Deflection bar is angled towards rudder blades. Rudder blades pivot between a downward position to an upward position based on the forces created thereon from both the torsion spring and the movement of the water over the appendage.

Abstract: A system and method protect a thruster assembly disposed with a pontoon of a semi-submersible drilling vessel during dry tow transport. A cover may be positioned over the thruster assembly and secured with the pontoon. A thruster cover support structure may be disposed with the pontoon. The thruster cover support structure may be a frame positioned around the pontoon for removable attachment with the thruster cover. The thruster cover support structure may be a bracket, ring or flange fixedly attached with the pontoon. The thruster cover may be removably disposed with the bracket, ring or flange, such as by bolting or welding. A spacer barge may be positioned below the pontoon between thruster assemblies for lifting the semi-submersible drilling vessel before placement of the spacer barge and semi-submersible vessel on the dry tow transporting vessel. The thruster assemblies may be elevated and in some embodiments positioned directly over the dry tow transporting vessel.

Abstract: The thruster pod that is made of a pump plate; a valve plate affixed to the pump plate, and a diaphragm mounted between the pump plate and the valve plate. The pump plate has juxtaposed pressure cavity and outlet cavity, and a partition separating the pressure cavity from the outlet cavity. The pressure cavity communicates with a source of water under pressure and the outlet cavity communicates with an outlet port. The valve plate has a control chamber facing the juxtaposed pressure and outlet cavities. The diaphragm is mounted between the juxtaposed pressure and outlet cavities and the control chamber for movement between a first position and a second position upon a change in pressure in the control chamber. A control valve is mounted in the valve plate for selectively changing a pressure in the control chamber and operating a diaphragm valve.

Abstract: A steering device for a surfboard includes a steering unit, a driving unit and a transmitting unit. The steering unit is operable for controlling a movement of the surfboard. The driving unit includes a base seat secured to a board body of the surfboard, a rotatable linking member disposed in the base seat, and a drive arm mounted with a handle. The drive arm is rotatable and substantially untwistable, is connected to the linking member, and extends outwardly of the base seat. Rotation of the drive arm drives the linking member to rotate, thereby driving operation of the steering unit via the transmitting unit.

Abstract: A tunnel thruster system for a vessel. The tunnel thruster system includes a thruster propulsion mechanism including a drive unit driving a transmission and propeller assembly located within a thruster tunnel. The thruster tunnel comprising a propeller section, first and second tapered tunnel sections interconnected with one another by the propeller section, the propeller section and the first and the second tapered tunnel sections oriented substantially transversely to a keel of the vessel and accommodating the transmission and propeller assembly. Each tapered tunnel section extends from the propeller section to a tunnel opening through a hull of the vessel. Diameters of the first and the second tapered tunnel sections corresponding to a diameter of the propeller section at the propeller section and taper outward toward a larger diameter at each of the corresponding tunnel openings through the hull of the vessel.

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 boat configured for rotating in response to passenger inputs such as rotation of a wheel or pumping a hand pump. The boat includes a hull with an upper portion for receiving at least one passenger and a lower portion comprising a bottom contact surface. Further, the boat includes a rider interface, provided on the upper portion of the hull, that is configured for receiving physical input from the passenger. The boat also includes a torque producing assembly with a boat-to-water interface provided on the lower portion below a waterline region and above bottom contact surface. The boat-to-water interface applies a force to water adjacent to the lower portion of the hull in response to the received physical input, whereby the boat rotates due to a resistive force applied by the water in response to the applied force.

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.