APRIL 19, 1861 -- President Abraham Lincoln proclaimed a Union Navy blockade of the Confederacy days after the Civil War began at Fort Sumter.
The first victory for the U.S. Navy during the early phases of the blockade occurred on April 24, 1861, when the sloop USS Cumberland and a small flotilla of support ships began seizing Confederate ships and privateers in the vicinity of Fort Monroe off the Virginia coastline.
Within the next two weeks, Flag Officer Garrett J. Pendergrast had captured 16 enemy vessels, serving early notice to the Confederate War Department that the blockade would be effective if extended.
The blockade would last until the war’s end as the Union Navy maintained a strenuous effort on the Atlantic and Gulf Coast of the Confederate States of America designed to prevent the passage of trade goods, supplies, and arms to and from the Confederacy.
His strategy, part of the Anaconda Plan (so-named because it was meant to suffocate the South) of General Winfield Scott, required the closure of 3,500 miles of Confederate coastline and 12 major ports, including New Orleans and Mobile, Ala., the top two cotton-exporting ports prior to the outbreak of the war, as well as the Atlantic ports of Richmond, Charleston, Savannah, and Wilmington, N.C.
The Union commissioned 500 ships, which destroyed or captured about 1,500 blockade runners over the course of the war; nonetheless, five out of six ships evading the blockade were successful.
Ships that tried to evade the blockade were mostly newly built, high-speed ships with small cargo capacity. They were operated by the British (using Royal Navy officers on leave) and ran between Confederate-controlled ports and the neutral ports of Havana, Cuba; Nassau, Bahamas, and Bermuda, where British suppliers had set up supply bases.
The blockade runners carried only a small fraction of the usual cargo. Thus, Confederate cotton exports were reduced 95% from 10 million bales in the three years prior to the war to just 500,000 bales during the blockade period.
The Union blockade was a powerful weapon that eventually ruined the Southern economy, at the cost of very few lives.
The blockade severely reduced cotton exports and choked off munitions imports. The measure of the blockade’s success was not the few ships that slipped through, but the thousands that never tried it.
Ordinary freighters stopped calling at Southern ports. The interdiction of coastal traffic meant that long-distance travel depended on the rickety railroad system, which never overcame the devastating impact of the blockade.
The blockade caused other hardships as well, especially the maldistribution of food. Throughout the war, the South produced enough food for civilians and soldiers, but it had growing difficulty in moving surpluses to areas of scarcity and famine.
Robert E. Lee’s army, at the end of the supply line, nearly always was short of supplies as the war progressed into its final two years.
Occasional bread riots in Richmond and other cities showed that patriotism was not sufficient to satisfy the demands of housewives.
Land routes remained open for cattle drovers, but after the Federals seized control of the Mississippi River in summer 1863, it became impossible to ship horses, cattle and swine from Texas and Arkansas to the eastern Confederacy. The blockade was a triumph of the U.S. Navy and a major factor in winning the war.
The Confederacy constructed torpedo boats, tending to be small, fast steam launches equipped with spar torpedoes, to attack the blockading fleet. Some torpedo boats were refitted steam launches; others, such as the David class, were purpose-built.
The torpedo boats tried to attack under cover of night by ramming the spar torpedo into the hull of the blockading ship, then backing off and detonating the explosive.
The torpedo boats were not very effective and were easily countered by simple measures such as hanging chains over the sides of ships to foul the screws of the torpedo boats, or encircling the ships with wooden booms to trap the torpedoes at a distance.
One historically notable naval action was the attack of the H.L. Hunley, a hand-powered submarine launched from Charleston against Union blockade ships.
On the night of Feb. 17, 1864, the Hunley attacked the USS Housatonic. The Housatonic sank with the loss of five crew; the Hunley also sank, taking her crew of nine to the bottom.