Jackson was literally a bad @$$, and he would not hesitate to act when he thought it necessary.
In a fight between all the presidents in their prime, Jackson wins.
“Now, therefore, I, Andrew Jackson, President of the United States of America, do hereby declare and proclaim that such evidence has been received by me, and that by the operation of the act of Congress passed on the 29th day of May, 1830, the ports of the United States are from the date of this proclamation open to British vessels coming from the said British possessions, and their cargoes, upon the terms set forth in the said act. The act entitled “An act concerning navigation,” passed on the 18th day of April, 1818, the act supplementary thereto, passed the 15th day of May, 1820, and the act entitled “An act to regulate the commercial intercourse between the United States and certain British ports,” passed the 1st day of March, 1923, are absolutely repealed, and British vessels and their cargoes are admitted to an entry in the ports of the United States from the islands, provinces, and colonies of Great Britain on or near the North American continent and north or east of the United States.”
Oops, your “Navigation Act of 1817” was repealed thirty years before secession. So there was nothing stopping Southerners from building or buying their own ships and dealing directly with British buyers.