An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.

The invention relates to a floating vessel comprising a hull, at least one seat, and two outriggers arranged laterally to the hull and connected directly or indirectly to the hull, wherein a drive unit, separately controllable in its drive output, and comprising a respective at least one propeller driven by a motor, in particular an electric motor, is assigned to each outrigger. A helm of the floating vessel is thereby connected to a proportional transducer, and a control signal from the proportional transducer is supplied to a control unit which directly or indirectly controls the motors in accordance with the control signal from the proportional transducer. Thus, a precisely controllable and yet easily disassemblable floating vessel is provided.

The invention relates to a floating vessel comprising a hull, at least one seat, and two outriggers arranged laterally to the hull and connected directly or indirectly to the hull, wherein a drive unit, separately controllable in its drive output, and comprising a respective at least one propeller driven by a motor, in particular an electric motor, is assigned to each outrigger. A helm of the floating vessel is thereby connected to a proportional transducer, and a control signal from the proportional transducer is supplied to a control unit which directly or indirectly controls the motors in accordance with the control signal from the proportional transducer. Thus, a precisely controllable and yet easily disassemblable floating vessel is provided.

The present disclosure relates to a propulsion control system (30) for controlling a marine vessel (10) comprising at least four propulsion units (20, 22, 24, 26). The marine vessel (10) comprises a longitudinal centre line (L) and a transversal line (T). The transversal line (T) extends in a direction perpendicular to the longitudinal centre line (L) and also extends through the steering axis of the aftmost of the propulsion units. The marine vessel (10) comprises four quadrants (I, II, III, IV) defined by the longitudinal centre line (L) and the transversal line (T) wherein a first (I) and a second (II) quadrant are located on the same side of said longitudinal centre line (L). When a combined sway and yaw motion is desired, the thrust of one propulsion unit is directed towards the second (I) quadrant, and the thrust of the other propulsion units is directed towards the first (II) quadrant.

The present disclosure relates to a propulsion control system (30) for controlling a marine vessel (10) comprising at least four propulsion units (20, 22, 24, 26). The marine vessel (10) comprises a longitudinal centre line (L) and a transversal line (T). The transversal line (T) extends in a direction perpendicular to the longitudinal centre line (L) and also extends through the steering axis of the aftmost of the propulsion units. The marine vessel (10) comprises four quadrants (I, II, III, IV) defined by the longitudinal centre line (L) and the transversal line (T) wherein a first (I) and a second (II) quadrant are located on the same side of said longitudinal centre line (L). When a combined sway and yaw motion is desired, the thrust of one propulsion unit is directed towards the second (I) quadrant, and the thrust of the other propulsion units is directed towards the first (II) quadrant.

An icebreaking vessel (10) with icebreaking reamers (23a, 23b) at each side and, in connection with the reamers, propellers (24a, 24b) for the propulsion of the vessel. The icebreaking vessel can be formed by attaching a detachable icebreaking bow section (31) equipped with reamers and propellers in connection with them to any such ship (30) which is not an actual icebreaker and which has corresponding joint members for attaching the detachable bow section to the ship.

A controller for a watercraft controls first and second marine propulsion devices to start moving the watercraft by setting a first default angle, a second default angle, and a default thrust ratio as a first target rudder angle, a second target rudder angle, and a target thrust ratio respectively when a desired motion of the watercraft is straight sideways movement. The controller determines at least one of a first correcting angle, a second correcting angle, and a correcting thrust ratio to reduce an error between the straight sideways movement of the watercraft and an actual motion of the watercraft. The controller corrects the first target rudder angle, the second target rudder angle, and the target thrust ratio with the first correcting angle, the second correcting angle, and the correcting thrust ratio, respectively. The controller repeatedly detects the error and repeatedly updates the correcting angles and the correcting thrust ratio.

A controller for a watercraft controls first and second marine propulsion devices to start moving the watercraft by setting a first default angle, a second default angle, and a default thrust ratio as a first target rudder angle, a second target rudder angle, and a target thrust ratio respectively when a desired motion of the watercraft is straight sideways movement. The controller determines at least one of a first correcting angle, a second correcting angle, and a correcting thrust ratio to reduce an error between the straight sideways movement of the watercraft and an actual motion of the watercraft. The controller corrects the first target rudder angle, the second target rudder angle, and the target thrust ratio with the first correcting angle, the second correcting angle, and the correcting thrust ratio, respectively. The controller repeatedly detects the error and repeatedly updates the correcting angles and the correcting thrust ratio.

Disclosed is a method of decreasing pressure fluctuation induced on a surface of a hull due to propeller cavitation by using real-time vibration information and adjusting rotation angles of two propellers of a twin-propeller ship.

Disclosed is a method of decreasing pressure fluctuation induced on a surface of a hull due to propeller cavitation by using real-time vibration information and adjusting rotation angles of two propellers of a twin-propeller ship.