and remained in the area giving support to General McClellan's forces on land until she was ordered to join the Union Navy blockaders off North Carolina in December. On her way there, she foundered while under tow during a storm off Cape Hatteras on the last day of the year. Monitors wreck was discovered in 1973 and has been partially salvaged. Her guns, gun turret, engine, and other relics are on display at the Mariners' Museum in Newport News, Virginia, a few miles from the site of her most important military action. Conception While the concept of ships protected by armor existed before the advent of the ironclad Monitor, the need for iron plating on ship arose only after the explosive shell-firing Paixhans gun was introduced to naval warfare in the 1820s. The use of heavy iron plating on the sides of warships was not practical until steam propulsion matured enough to carry its great weight. Developments in gun technology had progressed by the 1840s so that no practical thickness of wood could withstand the power of a shell. In response, the United States began construction in 1854 of a steam-powered ironclad warship, Stevens Battery, but work was delayed and the designer, Robert Stevens, died in 1856, stalling further work. Since there was no pressing need for such a ship at the time, there was little demand to continue work on the unfinished vessel. It was France that introduced the first operational armored ships as well as the first shell guns and rifled cannons. Experience during the Crimean War of 1854–1855 showed that armored ships could withstand repeated hits without significant damage when French ironclad floating batteries defeated Russian coastal fortifications during the Battle of Kinburn. Ericsson claimed to have sent the French Emperor Napoléon III a proposal for a monitor-type design, with a gun turret, in September 1854, but no record of any such submission could be found in the archives of the French Ministry of the Navy (Ministre de la Marine) when they were searched by naval historian James Phinney Baxter III. The French followed those ships with the first ocean-going ironclad, the armored frigate in 1859, and the British responded with . The Union Navy's attitude towards ironclads changed quickly when it was learned that the Confederates were converting the captured to an ironclad at the naval shipyard in Norfolk, Virginia. Subsequently, the urgency of Monitors completion