An intake plenum is for a marine engine, the marine engine having first and second throttle devices for controlling flow of intake air to the marine engine. The intake plenum has an airbox providing an expansion volume, first and second inlets that convey the intake air in parallel to the expansion volume, first and second outlets that convey the intake air in parallel from the expansion volume to the first and second throttle devices, and first and second Helmholtz-style attenuator devices located at the first and second outlets, respectively. Together the first and second inlets, expansion volume, and first and second Helmholtz-style attenuator devices are configured to attenuate different frequencies of sound emanating from the marine engine via the first and second outlets.

An outboard motor includes: a driveshaft housing configured to accommodate a driveshaft; and a gear case bulging laterally below the driveshaft housing and configured to accommodate a gear device, wherein an inside of the driveshaft housing communicates with an inside of the gear case, an introduction port for introducing lubricating oil into the gear case is opened on the driveshaft housing, and a confirmation port for causing the lubricating oil introduced into the gear case to flow out is opened on a front end side of the gear case.

A vessel speed control system includes a lever operator on which an operation is performed to increase or decrease a propulsion speed of the vessel, a transition operator on which a transition operation is performed to transition a normal operation mode to a speed control mode, and a controller configured or programmed to perform a control to prevent transition to the speed control mode even when the transition operation is performed on the transition operator during a restriction period of time including at least an acceleration/deceleration period of time during which a rotation speed of an engine or the propulsion speed of the vessel is changed by the lever operator in the normal operation mode.

A vessel speed control system includes a lever operator on which an operation is performed to increase or decrease a propulsion speed of the vessel, a transition operator on which a transition operation is performed to transition a normal operation mode to a speed control mode, and a controller configured or programmed to perform a control to prevent transition to the speed control mode even when the transition operation is performed on the transition operator during a restriction period of time including at least an acceleration/deceleration period of time during which a rotation speed of an engine or the propulsion speed of the vessel is changed by the lever operator in the normal operation mode.

A system for controlling a marine vessel has a sonar depth finder which displays a chart, stored in memory, for a body of water. The chart includes an underwater feature contour that defines a boundary of an underwater feature. The sonar depth finder includes a processor to create or update the topographical chart based on sonar data from a sonar transducer assembly. The sonar data includes information on the underwater feature. The processor can display and store the topographical chart. The user may select from the underwater feature contours on the depth finder display. The depth finder can generate a route for the marine vessel that includes a path along the selected underwater feature contours. A vessel control device, in communication with the depth finder, may receive transmissions, from the depth finder, which include the generated route. The vessel control device can automatically direct the marine vessel along the route.

There are included: a motor contained in a top cover; a vertical shaft that is rotationally driven by the motor, the vertical shaft being contained in an extension casing; and a propeller that is rotationally driven by the vertical shaft, the propeller being provided at a gear casing, wherein a heat exchanging part is provided inside a front portion of the gear casing, and inside the heat exchanging part, there are formed an inflow-side oil channel and an outflow-side oil channel that cooling oil for cooling the motor flows through.

The trolling motor for an overboard person comprises a trolling motor and a wrist worn device. The trolling motor may be a battery-operated propulsion device that is operable to propel and steer a water craft. The wrist worn device may be worn by a person on the water craft. A control unit within the trolling motor may communicate wirelessly with the wrist worn device and may be cognizant of a relative position of the wrist worn device with respect to the water craft. If the person falls overboard, a separation distance between the wrist worn device and the control unit may increase. Upon a determination that the separation distance has exceeded a predetermined distance threshold, the control unit may direct the trolling motor to energize, deenergize, or reverse direction such that the trolling motor may move the water craft closer to the person.

A control system for a marine propulsion device includes a propeller driven by either an engine or a motor. The control system includes a first memory to store first information to identify whether the control system has shut down normally or abnormally even during a reset period of the control system, a second memory to store second information indicating control states of the engine and the motor even during the reset period of the control system, and a controller configured or programmed to start controlling the engine and the motor, based on the second information stored in the second memory, when the first information stored in the first memory indicates an abnormal shutdown of the control system at a startup of the control system.

A control system for a marine propulsion device includes a propeller driven by either an engine or a motor. The control system includes a first memory to store first information to identify whether the control system has shut down normally or abnormally even during a reset period of the control system, a second memory to store second information indicating control states of the engine and the motor even during the reset period of the control system, and a controller configured or programmed to start controlling the engine and the motor, based on the second information stored in the second memory, when the first information stored in the first memory indicates an abnormal shutdown of the control system at a startup of the control system.

A method for maintaining a marine vessel propelled by a marine propulsion device in a selected position includes determining a current global position of the marine vessel and receiving a signal command to maintain the current global position. The current global position is stored as a target global position in response to receiving the signal command. A subsequent global position of the marine vessel is determined and a position error difference between the subsequent global position and the target global position is determined. The method includes determining marine vessel movements required to minimize the position error difference, and causing the marine propulsion device to produce a thrust having a magnitude, a direction, and an angle calculated to result in achievement of the required marine vessel movements. At least one of timing and frequency of discontinuity of thrust production is controlled while the position error difference is minimized.