Design multi-barrelled cannon

Design multi-barrelled cannon is an upgrade in Cossacks 3, available at the Academy.

Background
In addition to conventional single-barrelled cannon, new experimental gun models were created in the 18th century. Inventors attempted to build multi-barrelled artillery systems to provide a greater rate of fire. These multi-barrelled cannon became the predecessors of modern machine-guns and automatic cannon.

Effect

 * Design multi-barrelled cannon