At the beginning of the Civil War, the Confederate Navy was a very small collection of nearly anything that would float -- mostly small, unmilitary vessels and a few captured Union ships; there was not one real warship in the fleet. The North had men-of-war and a large fleet of merchant ships that could be armed quickly. As a result, the North was soon able to blockade the Southern coast and capture port after port. But the South fought back ingeniously, sending agents to England and France to have the finest warships built, innovating such modern weapons as the torpedo, the submarine, and the armored warship -- all of which changed the nature of naval warfare.