Riachuelo was a battleship project for the Brazilian Navy developed between 1913 and 1914. It was designed to be the most powerful warship of its time; it was a Brazilian response to the Chilean projects Almirante Latorre and Almirante Cochrane and to the Argentine projects Rivadavia and Moreno, during the naval arms race in South America. The construction would be carried out by the British construction company Armstrong Whitworth and Vickers, under the codename Project 781, a project chosen among several other plans offered to the Brazilian authorities. The battleship would be 188.98 meters long and have at least eight 381-millimeter guns, displacing up to 30,500 nautical tons.