in the outbreak of the War of 1812.it was the United States that wanted to impose a blockade. President Lincoln very quickly declared a blockade against the main Confederate ports. To be a legal blockade (under the terms of an international treaty that the United States had not signed!), This blockade simply had to present a risk to shipping trying to enter those ports. This was fortunate for the Union, as when war broke out the United States navy was just as small as the army, and its ships were scattered around the world. Of those ships in American waters, ten were destroyed (or partially destroyed) to prevent them falling into Confederate hands when Virginian seceded, taking the Norfolk naval base with it.diplomats spent much of their time attempting to convince European powers, especially Great Britain, to declare the blockade illegal. Their hope was that British industries dependence on Southern cotton would force the hands of the British government. In 1861 they were so convinced of the power of King Cotton that the south imposed a cotton embargo, voluntarily cutting off its own best supply of money! , the determined Confederate attempts to get Britain to declare against the blockade played a part in convincing her that the blockade was indeed effective. If it had been as leaky as the Confederates were claiming, then why make so much fuss? Great Britain was perfectly happy to declare the Union blockade legal - the inconvenience to British trade was more than balanced by the invaluable precedent thus created.blockade of 1861 was indeed very leaky. Estimates suggest that only one in ten ships attempting to trade with the South was captured in the first year of the war. However, as the war progressed and the Union navy increased in size, the blockade became increasingly effective. By 1864 one in three ships were being captured, although even that ratio still left a good chance of profit for the owner of a blockade runner.claims to the contrary then and since, the blockade was effective. The number of ships entering southern ports was reduced by two thirds. Many of those ships were custom built blockade runners, capable of carrying much smaller cargos that their pre-war equivalents, so the actual amount of cargo carried must have been even smaller. The outgoing figures for cotton exports support this idea. In the three years before the war, ten million bales of cotton were exported from the south. In the three wartime years after the South lifted its own cotton embargo only half a million bales got out. While some of this was probably due to the disruption of the South s poor transport network and the capture by the Union of ports such as New Orleans, it does demonstrate the effectiveness of the blockade . course the best way to close a Southern port was to capture it. The United States Navy retained command of the seas around the Confedera...
