In this environment, Robert L. Stevens and Edwin Augustus Stevens, the sons of Colonel John Stevens of Hoboken, New Jersey, proposed to the Department of the Navy on August 13, 1841 the construction of a revolutionary steam-powered ironclad vessel of high speed, with screw propellers and all machinery below the water line. Congress passed and President Tyler signed the Stevens Battery Act the same year to authorize funding for the construction of the ship, and the U.S. Navy's Board of Commissioners approved the Stevens brothers' specific proposal for the ship in January 1842. 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. The ship, which became known as the "Stevens Battery," was to be the first such ship ever to be built under government authorization. She was intended to serve as a fast, powerful, heavily armored, mobile battery, reinforcing the coastal fortifications of New York City.