This is what I Thought.
Therefore the USS Merrimack ceased to exist as a naval vessel April 1861. What emerged from that salvage wreakage became the CSS Virginia. But it was not the rebirth of the Merrimack. The referring to the CSS Virginia as the "Merrimack" and the battle that insued as the "Monitor and the Merrimack" really does a discredit to the genius of naval engineering that was even able to raise what remained of that hull let alone build a new vessal around it and produce the CSS Virginia from that wreakage and made it the foremost naval fighing ship of its time.
The one mistake (in My Opinion) the Virginia's Commanders made was that they should have ignored the USS Monitor and engaged the other ships. I do not believe that the Monitor could have seriously damaged the Virginia without recieveing equal damage. That was proven in the Battle result as it was. The advantages that the Monitor had over the Virginia was manuverability and shallower draft. Those are only advantages so long as the Virginia engaged with the Monitor.