Abstract: A lateral thrust rudder for a ship includes a cross-channel extending transversely through the ship from one side thereof to the other side and a water conveying mechanism such as a propeller is provided in the cross-channel. A guide vane is pivotally mounted on a horizontal axle at each end of the cross-channel and extends inwardly into the cross-channel. The lower part of each end of the channel is rounded so it flares outwardly. Normally the guide vanes are controlled solely by water flow through the cross-channel but, where necessary, a drive mechanism can be provided for the vanes.