The first picture is a typical Union gunboat on the Mississippi River. There were seven of these type built and they were named after cities along the Mississippi. In 1964 the USS Cairo was found in the Yazoo River and raised in 1965. It was given to Vicksburg National Battlefield in 1972. The ship was sunk by a Confederate water mine on December 12, 1862 and sunk in 36 feet of water. It was the first warship in history to be sunk by an electrically detonated mine. These gunboats were huge, sporting thirteen guns.