Propulsion system of boat

A propulsion system of a boat, the propulsion system comprising:

• at least one propulsion device provided on a hull, the at least one propulsion device including a drive source and a propulsor that generates thrust with dynamic power transmitted from the drive source;
• and
• a controller including at least a processor and a memory, the controller being configured to control the thrust of the propulsion device, wherein
• the controller is capable of conducting
• intermittent control of intermittently changing the thrust of the at least one propulsion device, based on a condition for changing a boat speed, and
• turning control of causing the propulsion device to generate the thrust toward a course of the hull, based on an instruction value to be input into a steering angle inputter, when the steering angle inputter is operated during the intermittent control.