Abstract: A navigation control system includes an obstacle detector on a hull to detect a distance from a hull to an obstacle on a water surface and a position of the obstacle, a thruster on the hull to generate a propulsive force, a steering to steer the thruster to right and left sides of the hull, and a controller configured or programmed to perform a control to determine an obstacle avoidance route based on a route function including at least an indicator of a lateral acceleration that acts on the hull during steering of the thruster when the obstacle is detected by the obstacle detector.

Abstract: A marine propulsion system includes a controller configured or programmed to perform a marine vessel traveling direction control such that a traveling direction of a marine vessel is changed to a predetermined angle equal to or greater than a first angle with respect to a traveling direction of waves toward the marine vessel when the traveling direction of the marine vessel is less than the first angle with respect to the traveling direction of the waves toward the marine vessel.

Abstract: A marine vessel maneuvering system includes a controller configured or programmed to perform a water entry determination control to determine whether or not water behind a hull that rises above a water surface due to deceleration of the hull may enter the hull when the hull is decelerating.

Abstract: In a boat including a hull, when the hull is moved laterally based on an output from the outboard motor, the hull rolls, which may cause discomfort to a user or passengers. To compensate for this, a lateral movement control method for the boat including the hull and the outboard motor includes generating a propulsion force to laterally move the hull with the output of the outboard motor, and executing a roll reduction process to reduce a roll angle of the hull at a time of laterally moving the hull.

Abstract: An apparatus for judging presence or absence of an abnormality of a marine vessel includes a controller configured or programmed to function as an estimating unit to estimate a marine vessel speed and a pitch angle of a hull of the marine vessel based on a propulsion force of a marine vessel propulsion device and an attitude of the marine vessel propulsion device and a judging unit, and a measuring unit to measure an actual marine vessel speed and an actual pitch angle. The judging unit judges the presence or absence of the abnormality based on at least one of a comparison result between the estimated marine vessel speed estimated by the estimating unit and the actual marine vessel speed measured by the measuring unit or a comparison result between the estimated pitch angle estimated by the estimating unit and the actual pitch angle measured by the measuring unit.

Abstract: A marine vessel includes a hull, left and right propulsion devices attached to a stern of the hull, left and right drive units to change a rotation angle of the left and right propulsion devices about left and right tilt shafts, and to set an angle at which a position of a lower portion of the left and right propulsion devices becomes highest as a maximum rotation angle, left and right lift mechanisms to change a vertical position of the left and right propulsion devices with respect to the hull, and a controller configured or programmed to function as a judging unit to judge whether or not a displacement in a roll direction of the hull has occurred, and a control unit to control the left and right drive units and the left and right lift mechanisms.