User-operable control for propulsion systems

A method of controlling a propulsion system for an aquatic vessel, wherein the propulsion system includes a plurality of Magnus-type rotors that are operable to rotate about corresponding substantially upright axes, a drive arrangement for rotating the plurality of Magnus-type rotors, and a control arrangement for receiving one or more measured apparent wind speeds and for controlling the drive arrangement for varying rates of rotations of the plurality of Magnus-type rotors as functions of the one or more measured apparent wind speeds and a direction of travel of the aquatic vessel, wherein the method includes:

• using a user-operable control of the control arrangement for adjusting propulsion provided by the plurality of Magnus-type rotors, wherein the user-operable control is implemented as a single throttle control that enables a user to control and/or allocate a total propulsion power demand from the plurality of Magnus-type rotors;
• operating the control arrangement to control the drive arrangement to vary a drive applied to rotate one or more Magnus-type rotors from the plurality of Magnus-type rotors;
• operating the control arrangement to optimize the drive for the one or more Magnus-type rotors depending on a control input provided by the user via the single throttle control;
• and
• operating the drive arrangement to apply the drive to rotate the one or more Magnus-type rotors to render the one or more Magnus-type rotors at least partially invisible to the one or more apparent wind speeds by adjusting their respective rates of rotations, such that their surface-to-flow velocity ratio is adjusted in a range of 0.3 to 1.5.