Roanoke was originally a steam frigate of the same class as USS Merrimack and USS Minnesota. Shortly after the Battle of Hampton Roads, John Lenthall, the Navy's chief designer, got the idea that if the Confederacy could convert a ship like Merrimack into an ironclad, the U.S. Navy could do the same. With the Secretary's approval, Lenthall sent shipyards and ironworks in New York City plans to convert Roanoke into an ironclad monitor-type warship with three turrets. Lenthall's design called for the turrets to be armored with single iron plates that were each 22 feet long, 4 1/2-inches thick, and weighed four tons. Each turret housed either XV-inch Dahlghrens or a 150-pounder Parrott Rifle. If that was not enough firepower, Lenthall wanted a "huge axe" on the bow of the ship in order to ram.
While she was a marvel of engineering, the brains at Scientific American magazine were skeptical of Lenthall's design. "If she makes nine knots, we shall be agreeably disappointed," they wrote. "As the Roanoke will sit very low in the water, we hope that proper arrangements will be made for ventilation on the main deck. The defects of the Galena and Monitor, so clearly pointed out in the Scientific American of last week, by an intelligent correspondent, will be reproduced in the Roanoke. [This will render] her very deficient as a 'sea boat,' unless this advice is heeded."
|Photo of Roanoke as an ironclad.|
First, she lacked speed. Scientific American was hoping for nine knots. Captain Sanders, however, reported to Secretary Welles that the ship would not go more than five knots. He concluded that he could "not consider the Roanoke adapted to fighting a battle at sea, on account of her rolling render her guns unserviceable and exposing her to shot below her iron plating." All Sanders could recommend was that the ship serve as a coastal defense vessel. Once she arrived in Hampton Roads, Welles did just that and ordered the ship to remain in the region for the rest of the war. The Navy would not try to build a three-turreted warship again until the 1890s.