This was the start of the Union effort to enforce it’s blockade of the South. It was a systematic effort on the part of the Union to deny the Confederacy access to the sea. It was important to keep supplies out of the Confederacy especially arms. But it was also important to keep cotton in the South. Cotton was the Confederacy's way of paying for the supplies it needed. And if the cotton couldn't get out then no supplies.
A little about the battle:
In the 1860s Hatteras Inlet, between Hatteras and Ocracoke islands, was the most traveled and most vulnerable inlet on the Outer Banks. After North Carolina joined the Confederacy in 1861, soldiers and slaves constructed Forts Clark and Hatteras, at the southern end of Hatteras Island in an effort to control access into Pamlico Sound.
The taking of Hatteras Inlet was an early priority for Union forces. On August 28, 1861, seven Federal ships opened fire on Fort Clark. The great Union ships with their long guns remained far out to sea, well beyond the range of the Confederates’ feeble artillery. By midday the poorly equipped Confederate troops at Fort Clark abandoned their stations and fled to Fort Hatteras. A small contingent of Union soldiers landed and took Fort Clark.
At dawn Union ships began bombardment of Fort Hatteras. After hours of intense shelling, the Confederate commander surrendered the fort and its 700 men.
The taking of Hatteras Inlet was a morale boost for the Union and marked its first victory in the war. This victory was so important that news was dispatched to the White House, where President Abraham Lincoln, roused from bed in the middle of the night to receive the news, danced a jig in his nightshirt.
With the breakthrough at Hatteras Inlet, nearly all of the Confederate-held East Coast between Wilmington, N.C., and Norfolk, Va., would begin to crumble. Pamlico Sound and its major cities of New Bern and Washington, N.C., were the first step, but the Union had its sights on bigger prey.