From Henry VII's categories to Pepys's ratings

English ship classification can be traced back to Henry VII's division of ships, galleys, pinnaces, and row barges. Later administrators spoke of royal ships, great ships, middling ships, and small ships. Attempts to classify vessels by crew size were unreliable because a transport might carry many soldiers while a fighting ship carried many guns, and few vessels carried both in the same proportions. Pepys needed a system that could answer Parliament when members treated one large ship as interchangeable with several small ones. His ratings supplied a shared administrative vocabulary for explaining why different warships required different levels of money, weapons, and manpower. The system solved a centuries-old measurement problem for naval administration.