Black Americans provided equally valuable intelligence to the Union Navy. Mary Louvestre, a freed slave, worked in Norfolk as a housekeeper for an engineer who was involved in the refitting and transformation of the USS "Merrimack" into the "Virginia", the first Confederate ironclad warship. Overhearing the engineer talking about the importance of his project, she recognized the danger this new type of ship represented to the Union navy blockading Norfolk. She stole a set of plans for the ship which the engineer had brought home and fled North. After a dangerous trip, she arrived in Washington, DC and arranged a meeting with officials at the Department of the Navy.