A parent-child type boat having an electric power generating device, such as a fuel cell. The boat includes a parent boat and at least one child boat which is smaller than the parent boat. The parent boat is equipped with a generating device. The child boat is equipped with a battery and an electric propulsion device. When the child boat is docked with the parent boat and electrically connected thereto, power can be supplied to at least one of the battery and the electric propulsion device of the child boat from the generating device of the parent boat.