Two-masted sailing ship with square rigging on both masts. Brigs were both naval and mercantile vessels. As merchantmen, they often followed coastal trading routes, but 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–19th century, they served as couriers for battle fleets and as training vessels for cadets. Brigs of the early U.S. 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.