The Confederate Blockade Runner Robert E. Lee
It was not just the blockade that caused the problem. There were lots of other causes: disruptions to every form of transportation, the loss of income from exports, the simple fact that the men were off fighting, and could not be home to tend the farm and bring in the crops. But the Union naval blockade was the largest cause of the shortages.
Union Navy Secretary Gideon Welles found more and more ships -- purpose-built or converted from other uses -- and assigned them to blockade duty. As the war wore on, more and more ports were sealed off altogether, or captured outright, allowing the Union to focus its attention on those that were still open. Meantime, the Union navy's blockading tactics improved. Smaller ships stayed close to shore on picket duty [a picket is a forward lookout, watching at the edges for trouble]. When they spotted a blockade runner coming out, they would fire rockets, alerting more powerful ships that patrolled further out so they would have more time to position themselves to intercept.
The Union navy that enforced the blockade was something between the cop on the beat and the jailer watching over the prisoners. Garrison duty [standing guard] is always a difficult and often demoralizing assignment for soldiers and sailors.Men who have joined the armed forces expecting action and fighting instead find that their job is to watch someone else to make sure he can do nothing. Blockade patrol duty was, for the most part, deadly dull. One officer wrote to his mother, and told her that if she wanted to get an idea of it, she should "go on the roof on a hot summer day, talk to a half dozen degenerates, descend to the basement, drink tepid water full of iron rust, climb to the roof again, and repeat the process at intervals until [you are] fagged out, then go to bed with everything shut tight."
Union crews and officers could at least hope for a chase, and a capture, with a big prize payment. Following long-standing tradition, the captain, officers and crew divided up half the value of any prize they captured, the other half going to the government. The prize money meant that blockading fleets had more than incentive enough to do their jobs, and they did it with ever-increasing efficiency.
In the early days, nearly every effort to run the blockade was successful. Incoming and outgoing ships managed to evade the Union navy patrols. But by mid-1863, the odds of a trip ending in the ship being seized, or even sunk, were growing ever better. By 1865, the odds of a successful voyage were perhaps no better than one in ten. There could be no buyers for the cotton the South urgently needed to sell, and no way to get the manufactured goods she urgently needed to buy -- unless the blockade could be evaded, or the blockading ships were destroyed, or forced to withdraw.