Autopilot system for marine vessels

An autopilot system for automatically steering a marine vessel, the marine vessel comprising two electric motors respectively connected to a port side propulsor and to a starboard side propulsor, a port side rudder and a starboard side rudder and a rudder steering mechanism, a navigation system for determining the vessel position with respect to an intended course, wherein the autopilot system is configured to operate according to one or more autopilot modes, comprising at least a motor steering autopilot mode wherein the autopilot system automatically controls the rudder steering mechanism in order to lock the rudders at a fixed angle at which the rudders cause the least resistance, and based on a feedback from the navigation system to independently and dynamically adjust power supply to each of the port side propulsor and of the starboard side propulsor by independently and dynamically regulating electric power supply to the respective electric motors order to maintain the vessel on course, thereby reducing power consumption at a certain vessel velocity or increasing vessel velocity at a certain power consumption in the motor steering autopilot mode, while preserving the option to use the rudder steering mechanism for direction control at least in manual mode or other situations.