A tall ship is a modern term for a traditionally-rigged sailing vessel. Tall ship rigs include schooners (Pride of Baltimore was and Pride of Baltimore II is a topsail schooner), barques, barquentines, brigantines, and brigs. Tall ships can be categorized by the number of masts, the shape of the ship, and the cut of the sails; or by class (size).
Categorized by Type
Schooner: A vessel with two or more masts, with the foremast shorter than the mainmast. A schooner usually has fore-and-aft rigged sails, but may also have square-rigged sails. The typical schooner has only two masts, but can have up to seven. Pride of Baltimore was and Pride of Baltimore II is a topsail schooner.
Categorized by Class
Class A: Square-rigged vessels, including barques, barquentines, brigs, brigantines, and all other vessels more than 131 feet in length overall.
Class B: Traditionally-rigged vessels (defined as those vessels whose sail plan has a predominance of gaff sails) with an overall length of less than 131 feet and a minimum waterline length of 30 feet. Some of these include gaff-rigged sloops, schooners, and yawls. Pride of Baltimore II is in class B.
Class C: Modern-rigged ships with an overall length of less than 131 feet and a waterline length of at least 30 feet. Bermudan-rigged sloops, ketches, and schooners belong to this class.
Class D: Like class C, modern-rigged vessels such as schooners, ketches, and Bermudan-rigged sloops, with an overall length of less than 131 feet and a waterline length of at least 30 feet. The difference is that class D vessels carry spinnaker like sails.