A method for maintaining a marine vessel at a global position and/or heading includes receiving measurements related to vessel attitude and estimating water roughness conditions based on the measurements. A difference between the vessel's actual global position and the target global position and/or a difference between the vessel's actual heading and the target heading are determined. The method includes calculating a desired linear velocity based on the position difference and/or a desired rotational velocity based on the heading difference. The vessel's actual linear velocity and/or actual rotational velocity are filtered based on the roughness conditions. The method includes determining a difference between the desired linear velocity and the filtered actual linear velocity and/or a difference between the desired rotational velocity and the filtered actual rotational velocity. The method also includes calculating vessel movements that will minimize the linear velocity difference and/or rotational velocity difference and carrying out the calculated movements.

A method for reducing the swinging of a ship anchored or moored to a buoy, by the suitable activation of the bow thruster and the stern thruster of the ship in accordance with the signals obtained by at least one of the following sensors: a) gyroscope, b) magnetometer, c) anemometer, d) GPS, e) inertial navigation system, f) a device measuring the angle between the longitudinal axis of the ship and the vertical plane through the anchor chain of the ship, is described.

A system for maintaining a marine vessel in a body of water at a selected position and orientation includes a global positioning system that determines a global position and heading of the vessel and a proximity sensor that determines a relative position and bearing of the vessel with respect to an object near the vessel. A controller operable in a station keeping mode is in signal communication with the GPS and the proximity sensor. The controller chooses between using global position and heading data from the GPS and relative position and bearing data from the proximity sensor to determine if the vessel has moved from the selected position and orientation. The controller calculates thrust commands required to return the vessel to the selected position and orientation and outputs the thrust commands to a marine propulsion system, which uses the thrust commands to reposition the vessel.

A method for controlling movement of a marine vessel includes controlling a propulsion device to automatically maneuver the vessel along a track including a series of waypoints, and determining whether the next waypoint is a stopover waypoint at or near which the vessel is to electronically anchor. If the next waypoint is the stopover waypoint, a control module calculates a distance between the vessel and the stopover waypoint. In response to the calculated distance being less than or equal to a threshold distance, the propulsion device's thrust is decreased. In response to sensing that the vessel thereafter slows to a first threshold speed, the vessel's speed is further reduced. In response to sensing that the vessel thereafter slows to a second, lower threshold speed or passes the stopover waypoint, the propulsion device is controlled to maintain the vessel at an anchor point that is at or near the stopover waypoint.

In a vessel steering system including three or more propulsion devices, unintentional turning of a vessel is prevented when the vessel moves in an oblique direction. When a tilt direction of a joystick is an oblique direction between a longitudinal direction and a lateral direction, a controller is configured or programmed to correct at least one steering angle of a left propulsion device, a right propulsion device, and a central propulsion device so that a resultant force of propulsive forces of the left propulsion device, the right propulsion device, and the central propulsion device acts in a direction passing through a center of gravity of the vessel.

A marine propulsion system for a marine vessel includes a first marine propulsion device rotatable with respect to the marine vessel about at least one of a first steering axis and a first tilt-trim axis and a second marine propulsion device rotatable with respect to the marine vessel about at least one of a second steering axis and a second tilt-trim axis. A first control module controls operation of the first marine propulsion device, and a second control module controls operation of the second marine propulsion device. In response to one of the first and second marine propulsion devices being commanded to rotate about at least one of its respective first or second steering axis and its respective first or second tilt-trim axis, the respective first or second control module of the other of the first and second marine propulsion devices is turned ON.

A method for maintaining a marine vessel at a target position in a body of water, the method being carried out by a processing system and including: estimating at least one roughness condition of the body of water based on measurements related to an attitude of the marine vessel; calculating a desired linear velocity based on a difference between an actual position of the marine vessel and the target position; filtering an actual linear velocity of the marine vessel based on the roughness conditions; and operating a propulsion system of the marine vessel to move the marine vessel to minimize a difference between the desired linear velocity and the filtered actual linear velocity. A method for maintaining a marine vessel at a target heading in a body of water is also disclosed.

A method of controlling a propulsion system on a marine vessel includes receiving proximity measurements describing locations of one or more objects with respect to the marine vessel, receiving a command vector instructing magnitude and direction for propulsion of the marine vessel with respect to a point of navigation for the marine vessel, and then determining a funnel boundary based on the command vector. When an object is determined to be within the funnel boundary, a propulsion adjustment command is calculated to move the marine vessel such that the object is no longer in the funnel boundary. At least one propulsion device is then controlled based on the propulsion adjustment command.

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.

A method of controlling a plurality of marine drives on a multi-hull marine vessel includes determining, based on steering information, that the multi-hull marine vessel is entering a turn and then receiving a running trim position for each marine drive. A trim position of at least a portion of the plurality of marine drives is then adjusted from each respective running trim position so as to induce roll of the multi-hull marine vessel during the turn.