Traditional passenger ships sailing on rivers and lakes. With large passenger capacity and frequent docking, small quantities of groceries and mail are mostly loaded and unloaded at the floating dock through the gangway. The main structure is relatively thin. If the flow rate of the leg is less than 3 meters per second, the double bottom may not be set. Generally, there are two decks, and the freeboard is low. The safety requirements are lower than those of seagoing ships because of the convenience of the route section.