Answer:
By cutting of ports and land access to trade and supplies by taking control along the Atlantic ocean and the Gulf of Mexico.
Step-by-step explanation:
Ports of Mobile and New Orleans, for example, were blocked. Supplies were turned away and no ships were allowed out without being challenged by the navy. Along the Atlantic coast at least one port needed to be taken by force to ensure a supply of coal to the navy’s ships. The successful Union victories secured Port Royal and Fernandina.