It would seem to be a matter of economic law that you serve your best customer in the most cost effective manner possible. So if your best customer is the southern consumer then it makes no sense to send them their goods via New York or Boston where all you are doing is adding to their costs. It would seem that economic law would mandate that those goods would go to Charleston or Mobile or New Orleans. Yet that wasn't done. Didn't they understand economic law in those days?
And if you send those goods to Charleston to avoid the tariff in New York then what do you do with them? What good will those goods to the customers up North sitting in Charleston? How will Charleston be a way of accessing the North American continent? Seems to me that the stuff will just sit there and rot, which seems to me to be a violation of economic law, too. Because if you're suggesting that those goods will be sent to Northern states then that makes no sense at all. Why ship goods to Charleston, pay the confederate tariff, tranship them to the North, and pay the Northern tariff as well plus all those additional shipping costs? That makes no sense at all.
Perhaps, though such a conclusion assumes what those costs happen to be. Without knowing them though, it is impossible for you to say for sure.
And if you send those goods to Charleston to avoid the tariff in New York then what do you do with them?
Ship them around the continent internally. That means ship them by rail to North Carolina and so forth. Or ship them up the mississippi from New Orleans and so forth. It's a lot harder to collect tariffs on goods travelling over land than by sea at the port of entry.
How will Charleston be a way of accessing the North American continent?
Well, the last time I checked, Charleston was not located in Argentina, nor France, nor Nigeria, nor Japan. It was located on the coast of South Carolina, which is on the North American continent.
Seems to me that the stuff will just sit there and rot
Why would it have any reason to sit there? If buyers up north knew they could get goods without a tariff by going to Charleston, economic law dictates they would go to Charleston. If they knew they could get the same at New Orleans, they'd go to New Orleans.
Because if you're suggesting that those goods will be sent to Northern states then that makes no sense at all. Why ship goods to Charleston, pay the confederate tariff, tranship them to the North, and pay the Northern tariff as well plus all those additional shipping costs?
Because that would not be done. Unless Lincoln established inland customs houses all up the Mississippi and at every road and railway across the border from Virginia and Arkansas, goods could enter the south, paying only the low southern tariff, then be transfered up north by inland means without any further taxation. I suppose it would technically be "illegal" to do so, but without a mechanism to enforce the northern tariff, it simply won't be collected.