A two-masted sailing ship with square rigging on both masts is called a brig. Brigs were both naval and merchant (mercantile) vessels. As merchantmen, they often followed coastal trading routes. However, ocean voyages were not uncommon, and some were even used for whaling and sealing. Naval brigs carried 10–20 guns on a single deck. In the 18th and 19th centuries, they served as couriers for battle fl eets and as training vessels for cadets. Brigs of the early US Navy won distinction on the Great Lakes in the War of 1812. Because square rigging required a large crew, merchant brigs became uneconomical, and in the 19th century they began to give way to vessels such as the schooner and the bark.