Lincoln's naval stranglehold on 3,500 miles of Southern coastline slowly choked the Confederacy of weapons, food, and the cotton revenues keeping it alive.
When Lincoln proclaimed the blockade on April 19, 1861, the Union Navy had only 42 active ships to patrol 3,500 miles of Confederate coastline with 12 major ports — an almost laughably impossible task that would require building an entirely new fleet from scratch.
By the war's end, the Union had commissioned over 500 ships and grown its navy to 671 vessels — the largest navy in the world at the time. Cotton exports from the South collapsed by 95%, from 10 million bales in pre-war years to just 500,000 bales over the entire blockade period.
Despite all the effort, five out of six blockade-running attempts actually succeeded — but the fast, shallow-draft ships built to evade Union patrols could only carry small, high-value cargoes. The Confederacy got luxury goods and some weapons, but never the bulk supplies it desperately needed.
The economic ripples reached across the Atlantic. Britain imported nearly 80% of its cotton from the American South, and the 'Lancashire Cotton Famine' threw hundreds of thousands of British mill workers into unemployment — yet Britain never intervened on the Confederacy's behalf.
Blockade running was extraordinarily lucrative for those willing to risk it. A single successful voyage could earn the equivalent of a million dollars, and ordinary Union sailors who captured a runner earned prize money exceeding a year's pay from a single capture.
The Confederate submarine H.L. Hunley became the first sub in history to sink an enemy warship when it attacked the USS Housatonic in 1864 — but the Hunley itself sank immediately after, taking all eight crew members with it, a grim symbol of Confederate ingenuity running out of time.