Systems and methods for automatically controlling attitude of a marine vessel with trim devices

A trim control system automatically controls trim angle of a marine propulsion device with respect to a vessel. A memory stores trim base profiles, each defining a unique relationship between vessel speed and trim angle. An input device allows selection of a base profile to specify an aggressiveness of trim angle versus vessel speed, and then optionally to further refine the aggressiveness. A controller then determines a setpoint trim angle based on a measured vessel speed. If the user has not chosen to refine the aggressiveness, the controller determines the setpoint trim angle from the selected base profile. However, if the user has chosen to refine the aggressiveness, the controller determines the setpoint trim angle from a trim sub-profile, which defines a variant of the relationship between vessel speed and trim angle defined by the selected base profile. The control system positions the propulsion device at the setpoint trim angle.