APRIL 20TH, 1861: The USS Constitution, Lt. George Rodgers, moored in the Severn River off Annapolis, was towed into the Chesapeake Bay by steamer Maryland with general Butler's troops on board. This action, preceded that the resolute measures by the Naval Academy staff and midshipmen, prevented Confederates from sizing the already historic "Old Ironsides."
** USS Anacostia, Lt. Thomas S. Fillebrown, was ordered to patrol off Kettle Bottom Shoals, Virginia, to prevent the obstruction of the channel at that point; the crew was augmented by 20 Marines from the Washington Navy Yard.
** Cornelius Vanderbilt offered the government the fast steamer Vanderbilt. Eventually the Navy acquired many private ships by charter or purchase to strengthen the blockade.
** U.S. coast survey schooner Twilight, Andrew C. Mitchell, was seized in Aransas, Texas.