In the decade preceding the war, Delaware led the United States in shipbuilding. During that time it built 35 iron-hulled ships, more than Philadelphia, New Jersey, Baltimore and Boston.
With the coming of the Civil War, the U.S. Navy was still using wooden-huller warships. And very few of them were steamships.
Once it was learned that the Confederates were building the ironclad CSS Virginia, the U.S. Navy rushed to build its own ironclad steamer, the Monitor. After the clash between the two ships it became well apparent that a new age of naval architecture was here and the federal government rushed to build more ironclad steamers.
To meet the new demand, they established shipyards at Chester, Pennsylvania, and Camden, New Jersey. And, they began transforming Wilmington-built ships into the many blockaders they were going to need to seal the Confederacy's coast. They were also converted into troopships and supply vessels.