Transport Ships are a unit type in Rise of Nations. They are considered 'meta units', as they cannot be built directly, but instead are created automatically when needed. However, a nation needs to develop File:Science Research Icon.png Science 1 (Written Word) and own at least one Dock before land units are allowed to embark on transport ships. As a nation progresses through the ages, transport vessels are upgraded automatically to newer models, thereby slightly increasing their hit points. There are three different transport ships: