The Stevens Battery was an early design for a type of ironclad, proposed for use by the United States Navy before the American Civil War.

Americans remembered the British invasion of the United States by sea during the War of 1812 and, to avoid its recurrence, President John Tyler and Secretary of the Navy Abel P. Upshur called for a large increase in the size of the U.S. Navy in order to defend the coast.

An Act of Congress authorizing Upshur to contract for the construction of a shot- and shell-proof steamer, to be built principally of iron, on the Stevens plan was approved on April 14, 1842.

She was intended to serve as a fast, powerful, heavily armored, mobile battery, reinforcing the coastal fortifications of New York City.

Experiments by John Ericsson with his 12-inch (305-mm) wrought iron gun Oregon, which could fire a 225-pound (102-kilogram) shell 5 miles (8.0 kilometers), soon proved that 4.5-inch (114-millimeter) armor was insufficient.

She was to be proof against 125-pound (56.7-kilogram) shells, with armor made up of 6.75-inch (171-millimeter) iron plates sloping upwards from 1-foot (0.30 m) below the waterline to the main deck and running along the entire side of the ship from stem to stern.

She was to be the first ship equipped with fan-driven ventilation, to increase crew comfort by extracting fumes and hot air from below decks.

The Stevens brothers made significant progress on the newly designed ship between January 1854 and September 1855, but then work slowed again.

That year, Edwin Stevens and his brother John C. Stevens offered to pay for completion of the ship themselves if the Navy would agree to pay for the ship if it was completed and proved successful, but a Navy board rejected the offer, finding deficiencies in the project.

Hoping to prove his point, he purchased an iron-hulled steamer and modified her greatly into a warship that would demonstrate to the U.S. Navy some of the principles he had in mind for the Stevens Battery, including high maneuverability, a respectable top speed, a semisubmersible capability, and a large gun on the main deck capable of a high rate of fire and loaded from below the deck by gun crews protected by armor.

Her armor protected the gun crew from the explosion as Stevens intended, but the Navy was not won over by the design, and Naugatuck soon went back to the Revenue-Marine.

New Jersey Governor Theodore F. Randolph appointed an oversight commission, and Major General George B. McClellan, the commander of the Army of the Potomac early in the Civil War, became engineer-in-chief.

Her machinery was removed and replaced by ten large-diameter boilers and two Maudsley and Field vertical overhead-crosshead steam engines which were to give the Stevens Battery a top speed of 15 knots (28 km/h).