The castemate ironclad CSS Arkansas was a one ship wrecking crew on the Mississippi River. The ironclad interfered with Union plans to take Vicksburg and complete their control of the Mississippi River. Thus, the U.S. Navy made several attempts to eliminate the ironclad. While the attempts succeeded in damaging Arkansas, the ironclad remained a "fleet-in-being." Even if she was only one ship, she was still a threat to any Union offensive in the West.
Isaac Brown, commanding officer
of CSS Arkansas
Arkansas' gallant commanding officer, Issac Brown, decided the ship needed a break to regroup. Brown barely slept or ate during the month of July. Worse, he fell ill to the "swamp fever" epidemic that swept both Union and Confederate camps and ships during the months of July and August. Because of this, he was granted four days of shore leave. Before he left, Brown gave strict orders to his executive officer Lieutenant Henry K. Stevens to repair and refit Arkansas and not to let anyone move the ship until he returned from liberty.
Unfortunately for Stevens, senior Confederate leadership had other plans. Confederate General Earl Van Dorn, whose skill set as a general were highly suspect, demanded Stevens immediately prepare Arkansas for battle. Van Dorn planned to use the ironclad in a counter-attack against Union lines at Baton Rouge. Stevens refused and recited Brown's orders to not move the ship. The decision was referred to Flag Officer William Lynch, a man whose two greatest claims to fame were getting his squadron destroyed at Roanoke Island in early 1862 and claiming to have scientific proof of the existence of the lost Biblical cites of Sodom and Gomorrah (read more about that here). Lynch agreed with Van Dorn. Now being faced down by two flag officers, Stevens' will broke and agreed to make Arkansas ready.
Stevens wrote to Brown about the situation. Despite running a high fever and barely being able to walk, Brown jumped out of bed and took two trains to get to Vicksburg. He was too late. Arkansas already left four hours after he got there.
As Arkansas approached Baton Rouge, the ship's engines began to fail. Upon seeing Arkansas head south, Essex followed in hot pursuit and opened fire. Arkansas' engines eventually gave out. Unable to maneuver and bring any guns to bear on Essex, Stevens ordered the ship beached so that she could be scuttled.
With Essex bearing down her, Stevens set Arkansas on fire. Brown was able to get transportation south just in time to see his ship explode. Brown later stated that he did not blame his executive officer for what happened. He squarely placed blame on Lynch and Van Dorn for not being very smart with their side's limited resources. (Read Brown's entire account in Battle and Leaders here) The explosion destroyed the Confederacy's last major warship on the Mississippi River.