It is difficult to move forward/backward a water jet propulsion boat at very low speed through use of right and left operation elements each provided on a handle. In order to move the boat forward/backward at very low speed through a simple operation, under a state in which neutral operations have been carried out, an operation state of an engine is maintained in an idling state, and a movement position of a jet flow adjustment member including a deflector and a reverse bucket is controlled so as to adjust a difference between a thrust generated by a forward jet flow component and a thrust generated by a backward jet flow component of a jet flow divided into a forward jet flow and a backward jet flow by the jet flow adjustment member, based on an operation on a third operation element provided independently of the right and left operation elements.

It is difficult to move forward/backward a water jet propulsion boat at very low speed through use of right and left operation elements each provided on a handle. In order to move the boat forward/backward at very low speed through a simple operation, under a state in which neutral operations have been carried out, an operation state of an engine is maintained in an idling state, and a movement position of a jet flow adjustment member including a deflector and a reverse bucket is controlled so as to adjust a difference between a thrust generated by a forward jet flow component and a thrust generated by a backward jet flow component of a jet flow divided into a forward jet flow and a backward jet flow by the jet flow adjustment member, based on an operation on a third operation element provided independently of the right and left operation elements.

Current waterjet technology uses hydraulic actuators that are linked to a hydraulic system aboard the vessel. Hydraulic actuators have a significant number of problems including, but not limited to, significant size and weight, poor efficiency, an excessive number of components, excessive heat generation, slop in the feedback system, overshooting of cylinders, limited ramping ability, frequent maintenance, environmental concerns, and difficulty in interfacing with control systems. In an effort to reduce, and in some cases eliminate, these issues, this invention discloses an apparatus and method of controlling a waterjet that uses electric actuators and motor controllers that are integrated on the jet. The use of multiple electric actuators also allows for redundancy, which makes the system more reliable. The system also allows a user to have direct actuator control and bypass the automatic settings for control system backup.

Current waterjet technology uses hydraulic actuators that are linked to a hydraulic system aboard the vessel. Hydraulic actuators have a significant number of problems including, but not limited to, significant size and weight, poor efficiency, an excessive number of components, excessive heat generation, slop in the feedback system, overshooting of cylinders, limited ramping ability, frequent maintenance, environmental concerns, and difficulty in interfacing with control systems. In an effort to reduce, and in some cases eliminate, these issues, this invention discloses an apparatus and method of controlling a waterjet that uses electric actuators and motor controllers that are integrated on the jet. The use of multiple electric actuators also allows for redundancy, which makes the system more reliable. The system also allows a user to have direct actuator control and bypass the automatic settings for control system backup.

A jet pump includes a propulsion system including an impeller coupled to a rotatable shaft configured to receive torque from an engine and an exhaust system including an exhaust flow path configured to direct exhaust from the engine to an exterior of the watercraft, wherein the exhaust system is integrated with the propulsion system. In another embodiment, a jet pump includes a propulsion system including a water intake configured to take in water from a body of water, the water intake including an intake grate and an intake base, and an exhaust system including an exhaust flow path configured to direct exhaust from the engine to an exterior of the watercraft, wherein the intake base of the water intake is configured to be coupled to an exterior surface of a hull of the watercraft.

A jet pump includes a propulsion system including an impeller coupled to a rotatable shaft configured to receive torque from an engine and an exhaust system including an exhaust flow path configured to direct exhaust from the engine to an exterior of the watercraft, wherein the exhaust system is integrated with the propulsion system. In another embodiment, a jet pump includes a propulsion system including a water intake configured to take in water from a body of water, the water intake including an intake grate and an intake base, and an exhaust system including an exhaust flow path configured to direct exhaust from the engine to an exterior of the watercraft, wherein the intake base of the water intake is configured to be coupled to an exterior surface of a hull of the watercraft.

A jet propulsion device is mounted to a vessel body and connected to a drive shaft. A bearing rotatably supports the drive shaft. A bulkhead is disposed inside the vessel body and below a deck. The bulkhead supports the bearing and includes a gap disposed between the drive shaft and the deck. The drive shaft and the gap overlap as seen in a vertical direction.

A jet propulsion device includes an impeller housing, an impeller, a sleeve, a first ring-shaped elastic body, and a second ring-shaped elastic body. The first ring-shaped elastic body is disposed between the impeller housing and the sleeve, and is located between a first end and a middle of the sleeve in an axial direction of the sleeve. The second ring-shaped elastic body is disposed between the impeller housing and the sleeve, and is located between a second end and the middle of the sleeve in the axial direction of the sleeve.

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.

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.