USS Merrimack (1855)
USS Merrimack was the lead of a six ship class of steam frigates, built in Boston, Massachusetts. Commissioned 20 February, 1856, she conducted her shakedown cruise in the Caribbean and Europe, before decommissioning for upkeep. Merrimack reactivated in September, 1857, and departed the following month for the Pacific, where she served as fleet flagship until November, 1859. Merrimack decommissioned again upon reaching Norfolk, Virginia, and was still there when hostilities broke out that led to the United States Civil War. When Virginia seceded, the US Navy planned to move Merrimack to Philadelphia, but the channel was deliberately blocked by scuttled small boats to prevent her escape. Merrimack was burned on 20 April, 1861, as the Union forces evacuated the Norfolk Navy Yard. She only burned to the waterline, however, and the hulk was later raised and refitted into the ironclad ram, CSS Virginia.