Blockades

Blockades. A blockade in its most common form—the naval blockade—is intended to prevent the passage of ships in and out of an enemy's harbors. It can be defensive, focusing on the enemy's warships; offensive, focusing on his commercial and military supply ships; or it can be both. A blockade can restrain just traffic flying the enemy's flag, or it can halt neutral shipping as well. It can halt the passage of only specified items, or it can halt all. It can last for only a few weeks, or for years. The idea of blockade is the antithesis of the idea of freedom of the seas.

By the time of the French and Indian War (1754–63), the blockade had become one of Britain's major instruments of war. But when the American Revolutionary War began (1775), the Royal Navy was too weak to blockade distant colonial ports. The entry of France and Spain into the war worsened the British position. In 1781, a brief blockade of Chesapeake Bay by a French fleet played an important role in bringing about the surrender of a British army at the Battle of Yorktown, and as a result, the end of the war.

After an arduous campaign in the southern states, Gen. Charles Cornwallis moved his army to Yorktown, Virginia, on the Chesapeake, where the British fleet could resupply and reinforce it easily or, if necessary, evacuate it entirely. As the colonial and French armies under George Washington and count de Rochambeau marched south from New York and Newport to strengthen the small force besieging Cornwallis, ships bearing the French artillery and supplies sailed in convoy from Newport toward the same destination. The British fleet under Adm. Thomas Graves departed New York in order to intercept the French ships as they approached the Chesapeake. The French ships Graves found, however, were those of Adm. count de Grasse's fighting fleet recently arrived from the Caribbean. They had Cornwallis under blockade. In a long but not very bloody fight, de Grasse repulsed Graves and sent him back to New York. The convoy from Newport arrived safely, the allied armies besieged Cornwallis closely, and de Grasse forestalled any British attempt to rescue the trapped army. His situation hopeless, Cornwallis surrendered. The war petered out, and the colonies gained their collective independence. By itself de Grasse's blockade would not have led to that result, but in combination with the effective work of the allied armies, it served perfectly.

The next American experience with blockade, during the War of 1812, was grim. By this time the British Fleet had long regained its strength and more, and it had had nearly twenty years of experience in blockading enemy ports in the wars of the French Revolution and Napoleon. Most of the famous American frigate victories in this war took place in the early months, before the British could deploy forces sufficient to lock the ships of the small U.S. Navy into whatever port they happened to be. As the blockade grew tighter and extended further, American foreign trade dried up. So did American domestic trade, most of which went by water. Farmers could not sell their crops; merchants lost their businesses, employees their jobs. Moreover, without tariffs on imports, the government had little money. In addition, the U.S. invasion of Canada had failed; British warships sailed the Chesapeake; and British troops had burned Washington. Despite American successes on Lakes Erie and Champlain, and spectacular raids by American privateers upon British shipping, the American people were ready for peace. So were the British, who had been at war almost without a break since 1793. In December 1814, the opponents signed a treaty of peace.

Soon after the outbreak of the Civil War President Abraham Lincoln, knowing that the Southern states manufactured little, ordered the U.S. Navy to blockade the Southern ports so as to prevent them from importing arms and other goods from Europe. This the navy attempted, first by using armed commercial steamers and then by adding new ships built for the task. The blockaders drove sailing ships, mostly neutral, out of the trade with the South. But those ships were replaced by swift steamers, again mostly neutral, which sailed from Bermuda and the Bahamas mainly toward Charleston, South Carolina, and Wilmington, North Carolina. By war's end in 1865, the blockaders had driven ashore, sunk, or captured three‐quarters of the 300 blockade‐running steamers. But the latter kept the Southern armies supplied with arms until early in 1865, when Northern forces took Charleston from inland and seized the sea approaches to Wilmington. That spring, Gen. Robert E. Lee surrendered, but not for lack of arms. It is easy to quantify the effort expended on the blockade, but difficult to judge its contribution to the North's eventual success.

Early in the twentieth century, developments in naval mines, torpedo craft, and coast artillery made it plain to the Royal Navy that close blockade was no longer possible. Hence, when World War I broke out in 1914, the Grand Fleet took station at Scapa Flow, north of Scotland, whence, in conjunction with forces in the Channel, it kept the German High Seas Fleet locked uselessly in the North Sea. Protected by the Grand Fleet, old warships and armed merchant cruisers as well as minefields effectively carried out a commercial blockade against both belligerent and neutral merchant ships trying to enter not only Germany's ports but also those of its neighbors.

The Germans responded with a counterblockade against shipping attempting entry into or exit from Allied ports, especially those of Britain. Their instrument was the submarine, a small warship that could sail surprising distances, could hide under the water when attacking or in danger, and that carried the most deadly of naval weapons: torpedoes and mines. By the spring of 1917, when—partly as a result of the brutality of the submarine campaign—the United States joined in the war against Germany, that campaign was driving Britain, the last strong combatant among the Allies, to defeat. The Allied decision to convoy merchant ships rather than to let them continue sailing singly, combined with the arrival of enough U.S. destroyers to make convoy possible, defeated the submarines. The sailing of 2 million American troops to France made possible by this success gave the Allies the edge in strength to halt and then reverse the German offensives in 1918, and that in turn led directly to the end of the war.

The Allies were more vulnerable to blockade than the Germans, but although the submarines were beaten, the Allied blockaders kept their stranglehold on Germany's economy months after the war had ended.

By its nature the submarine, unable to rescue its victims, brought a new savagery to a hitherto not very bloody form of war. Aircraft, soon to join in the war at sea, suffered from the same shortcoming and the savagery worsened.

So far as blockade and counterblockade went, World War II in the Atlantic and Mediterranean followed the pattern of the preceding war. The chief difference was that both sides were better prepared than before to resist the other's blockade. In the Mediterranean and the narrow seas of Europe, aircraft took a leading part in the conduct of blockade. In the Pacific War, the Japanese made no particular effort either to attack enemy shipping or to protect their own. In contrast, the Americans, led by their submarines, destroyed Japanese shipping. This meant that the empire's troops often perished when being moved to where they were needed. For lack of fuel, Japan's pilots could not be trained adequately, and toward the end, its fighting ships could not sail. The blockade was the primary contributor to the defeat of Japan.

In more recent conflicts, blockades have again played significant roles. But in the long struggle against North Vietnam (1965–73), because of an implied (or inferred) threat of Soviet retaliation, the United States imposed no blockade on North Vietnam during the first seven years U.S. combat forces were engaged in that war. As a result, three‐quarters of the arms, ammunition, and fuel that the North used in the Vietnam War entered by sea in ships from the Soviet Union. Finally, in 1972, the United States mined the approaches to North Vietnam's harbors, and the traffic stopped. This, combined with hard fighting on the ground and in the air that used up the North's arms stocks, particularly its surface‐to‐air missiles, led to a peace agreement between that country and the United States that permitted the withdrawal of U.S. forces. These events illustrate both the value of blockade under the conditions of that war and the ease by which an interested and more clever government was able to forestall for years the imposition of a blockade on the Soviet Union's client state.

In itself, blockade is not often likely to achieve much. Used wisely and unremittingly against a foe dependent on sea traffic, however, and in tandem with vigorous action elsewhere, it can be a highly effective instrument of war.
[See also Submarine Warfare.]

Bibliography

Sir Julian S. Corbett , Some Principles of Maritime Strategy, 1911; repr. 1972.
S. W. Roskill , White Ensign: The British Navy at War, 1939–1945, 1960.
G. J. Marcus , The Age of Nelson: The Royal Navy, 1793–1815, 1971.
Clay Blair , Silent Victory: The U.S. Submarine War Against Japan, 1976.
Paul M. Kennedy , The Rise and Fall of British Naval Mastery, 1976.
Stephen R. Wise , Lifeline of the Confederacy: Blockade Running During the Civil War, 1988.
John B. Hattendorf, ed., Mahan on Naval Strategy: Selections from the Writings of Rear Admiral Alfred Thayer Mahan, 1991.
Frank Uhlig, Jr. , How Navies Fight: The U.S. Navy and Its Allies, 1993.
Paul G. Halpern , A Naval History of World War I, 1994.

Frank Uhlig, Jr.