A processor includes a front end, a cache, and a cache controller. The master transmission apparatus includes blocking unit, conversion unit and transmission unit. A correcting device can be configured to obtain the difference between actual steering unit angles of the outboard motors, to correct the target steering angles based on the difference, and to obtain a target steering angle of each of the outboard motors. In addition, this method results in a rapid speed of the process. The oil contains tocopherol antioxidant and \u03b1-lipoic acid as regenerator for the antioxidant.