The term 'brown-water navy or 'riverine navy refers in its broadest sense to any naval force capable of military operations in littoral zone waters. The term originated in the United States Navy during the American Civil War, when it referred to Union forces patrolling the muddy Mississippi River, and has since been used to describe the small gunboats and patrol boats commonly used in rivers, along with the larger "mother ships" that supported them. These mother ships include converted World War II-era mechanized landing craft and tank landing ships, among other vessels. Brown-water navies are contrasted with seaworthy blue-water navies, which can independently conduct operations in the open ocean. Green-water navies, which can operate in brackish estuaries and littoral coasts, are the bridge between brown-water navies and blue-water navies. History Napoleonic Wars After losing its blue-water fleet in the Battle of Copenhagen in 1807, the kingdom of Denmark-Norway quickly built a brown-water navy. The partial successes of the resulting Gunboat War were undone by land invasion. Mexican–American War During the Mexican–American War, Commodore Matthew C. Perry decided to invade the Mexican towns along the Gulf Coast near Tabasco. In October 1846 Perry was in command of USS Mississippi, USS Vixen, USRC McLane, USS Reefer, USS Bonito, USS Nonata and USRC Forward with a 253-man landing force. After capturing the port of Frontera on the Tabasco River, the ships under Perry's command crossed the bar at the mouth of the river and traveled up river to the town of Tabasco. After several days of bombardment of Tabasco, Perry's ships captured several Mexican ships on the river and brought them back to Frontera. Some were commissioned into U.S. Navy service and others were burned. The city of Tampico was poorly defended and offered a base for operations for the conquest of the state of Tamaulipas. For these reasons Tampico became the next target for seizure by American naval forces. Commodore David Conner directed that it be attacked in late October 1846 and those plans were captured by General Antonio López de Santa Anna. Santa Anna directed that Tampico be almost abandoned and his forces be moved up river to Pánuco. This move was completed by 28 October. The bar at the mouth of the Pánuco River was only eight feet and hindered the movement of American ships up the river. The wife of the former American consul at Tampico sent word to