The U.S. Navy's Three Headed Monster-USS Roanoke

One perceived flaw in the design of the original USS Monitor was its lack of firepower. With only two XI-inch guns, many in the U.S. Navy felt the need to upgrade the design. Many engineers felt this could be solved by putting a bigger gun in the turret, or by adding a second turret. USS Monitor's original designer, John Ericsson, was not in favor of a second turret as he saw no need for it.  He also believed the turrets would get in the way of the line of fire.

USS Roanoke as a Merrimack-class steam frigate, 1855

John Lenthall, the Navy's long time chief of the Bureau of Construction and Repair, decided that two turrets were insufficient. Shortly after the Battle of Hampton Roads, Lenthall got the idea in his head 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 each twenty-two feet long, 4 1/2-inches thick, and weighing 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.

USS Roanoke underway in smooth seas as imagine by an artist.

The Common Council of New York City saw the ship and lobbied the Navy hard to assign the vessel as a harbor defense ship for New York harbor. As it usually did to local government requests, the Navy rejected the idea and pencil the ship in for fort suppression duty off of the coast of Charleston.

The conversion was a remarkable feat of American engineering. Iron forges in four different states provided the huge plates to the Novelty Iron Works in New York City. Each plate then had to be heated and bent to correct curvature. In all, workers placed 1,000 additional tons of armor.

 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."

The advice was not taken. The Navy charged forward and Roanoke put to sea as the most powerful warship in the world. Sent to Hampton Roads, her captain quickly discovered what Scientific American writers predicted. Monitor-type ships in general did not have very good sea-keeping traits to begin with, and Roanoke had the worst of them all.

USS Roanoke tied up as she spent most of her career.

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. Welles agreed, but did not assign the ship to New York City. Once the ship arrived in Hampton Roads, she remained there for the rest of the war.