Sunday, 14 April 1861. The U.S. Navy’s engineer-in- chief, 38-year old Benjamin Franklin Isherwood, arrived at Portsmouth, Virginia, as talk of secession hung over the Tidewater region. First seeking Robert Danby, the Gosport Navy Yard’s chief engineer, a Delaware native with whom he had corresponded as to the state of affairs there, Isherwood then called upon Captain Charles S. McCauley, the yard commandant. Isherwood presented his orders to prepare the inactive steam frigate Merrimack to be moved to Philadelphia. McCauley told Isherwood to take whatever measures he deemed appropriate for expediting the work.
Isherwood found the Merrimack’s engines in what he called a “wretched” state—but not irreparable for temporary duty. He thereupon directed the foremen of the boilermakers and machinists to employ as many men as could work, and begin the next morning. Starting as scheduled they toiled “day and night without an hour’s intermission” in three eight-hour shifts, with Isherwood and Danby alternating 12-hour watches to supervise.