WATERCRAFT

A watercraft includes a hull, an engine to generate power to propel the hull, an engine speed sensor to detect the rotation speed of the engine, and an ON/OFF sensor to be turned on and off according to a vertical acceleration of the hull. The watercraft further includes a controller configured or programmed to determine, based on at least one of a detection value of the ON/OFF sensor and a detection value of the engine speed sensor, whether or not a water surface is smooth.