 To confront the forms of combat that came about, the federal government developed a new type of warship, the monitor, based on the original, USS "Monitor".The U.S. Navy took over a class of armored river gunboats created for the U.S. Army, but designed by naval personnel, the Eads gunboats.So-called double-enders were produced to maneuver in the confined waters of the rivers and harbors.