A marine propulsion system having a steering axis that allows pivoting of propellers along a first vertical axis directly beneath a gear box located inside the hull of a boat. A lower gear box can be placed within a vented or non-vented tunnel eliminating the need for a rudder and providing directional control of the boat by the orientation of the lower gear box. Surface piercing propellers and/or counter-rotating propellers may be used with the propellers pivoted around the vertical axis of the gear box. The offset steering axis allows pivoting around the first vertical axis wherein a secondary axis is moved with minimal drag providing superior maneuverability at both high and low speeds.

The invention relates to a propulsion system (30) intended to be integrated into a boat (1) and comprising a vertical guide device (31) comprising a member for fixing the vertical guide device (31) to the hull of said boat (1); an electric thruster (32) comprising a gyration box (33), said gyration box (33) being vertically movably mounted on the vertical guide device (31) to be able to adopt an emerged position and a submerged position; a drive system (34) capable of causing a vertical movement of the gyration box (33) of the electric thruster (32) along the guide device (31); a control unit (35) capable of receiving a movement instruction and arranged, in response to said instruction, to control the drive system (34) to cause movement of the gyration box (33) toward the emerged position or toward the submerged position.

A marine vessel includes a hull, a propulsion system, a control unit and a motion sensor system. The propulsion system comprises a first drive unit and a second drive unit separated by a longitudinal midship line of the hull, where each drive unit is arranged to generate thrust in a controllable thrust elevation angle and in a controllable thrust azimuth angle, where at least the thrust elevation angles are individually controllable The control unit is arranged to estimate a pitch motion and a roll motion of the hull based on input from the motion sensor system. The control unit is arranged to suppress pitch motion and roll motion by the hull by controlling the thrust elevation angles and the thrust azimuth angles of the first and second drive units.

The invention relates to a method for determining the direction and the amplitude of a force applied to a system (IO) comprising a stationary portion (13) and a mobile portion (12) which can deform when exposed to said force. Mechanical deformations applied to the mobile portion when exposed to said force are measured by measuring a distance between the stationary portion and the mobile portion in the direction of application of the force, and the distance measurements are processed in order to determine the amplitude and the direction of the force.

A marine propulsion system having a steering axis that allows pivoting of propellers along a first vertical axis directly beneath a gear box located inside the hull of a boat. A lower gear box can be placed within a vented or non-vented tunnel eliminating the need for a rudder and providing directional control of the boat by the orientation of the lower gear box. Surface piercing propellers and/or counter-rotating propellers may be used with the propellers pivoted around the vertical axis of the gear box. The offset steering axis allows pivoting around the first vertical axis wherein a secondary axis is moved with minimal drag providing superior maneuverability at both high and low speeds.

An arrangement including a gearwheel connected to the propulsion unit, a steering electric motor operatively connected to the gearwheel and controlled by a drive, a force transmission arrangement including a clutch between the gearwheel and the steering electric motor, and a measurement unit for measuring rotational motion positioned at each side of the clutch. The steering electric motor is arranged to rotate the gearwheel and thereby also the propulsion unit. A difference in the output signals of the two measuring units indicating slipping of the clutch is detected. The steering electric motor is controlled to at least reduce the difference in the output signals when the difference exceeds a predetermined threshold.

A propeller position changing device which is capable of changing position according to cruise conditions of a vessel of a floating type.

A propeller position changing device which is capable of changing position according to cruise conditions of a vessel of a floating type.

A propulsion assembly of a ship or floating platform includes a housing within a hull or platform. The housing is watertight except for an opening external to the hull. A stationary motor is arranged in the hull external to the housing. A thruster is external to the hull to generate thrust on the ship or floating platform. A telescopic driving shaft passes sealingly through a housing wall to connect the motor and the thruster and to transmit movement from the motor to the thruster. The thruster retracts within the housing through the opening. A separate submersible movable hatch is disconnectable from the thruster and the housing and passes externally to the hull, and seals the opening to form a watertight closed chamber. A fluid evacuation device evacuates fluid within the closed chamber so the thruster, when retracted in the housing and closed by the hatch, forms the closed chamber.

A marine propeller propulsion unit has a double-pinion planetary gear for driving a front and a rear propeller by means of an input shaft. A sun gear is adapted to be connected to the input shaft, a ring gear is adapted to be connected to the front propeller, and a planet carrier is adapted to be connected to the rear propeller.