many of the substitutes were immigrant irish, who where offered a "job' that paid $500--they didn't realize the job was to get put on the front line of a battlefield.

the substitute issue was also part of the reason for the "draft riots" in NY (and other cities too) since new immigrants were sometimes 'drafted' to serve right on the dock as they got off the boat, but middle class and others could by there way out, with $500.

in the civil war, the north had the advantage-- New Orleans used to be the second largest port in the US, very close to NY in shipping.(and a major place for immigration)

the blockcade of the port was successful, and the south was unable to block NY or other Northern ports. so the North continued trade with europe. the south was unable to sell its cotton, and use the money to by guns, gunpowder and salt, and they also lost out on having boatload of immigrants to draft! For most of the war, the south tried to get France as an ally, since the french were eager to have US cotton for their mills.

After the war, Railroads, (and RR bridges over the Mississippi,) further reduced trade, so by the 1870's, New Orleans was not even one of the top 10 ports of in US.

the Mississippi is the worlds third largest river. It, and its tributaries, drain almost 50% of US, and yet its main port is not one of the top ten in US!