American Queen is said to be the largest river steamboat ever built. The ship was built in 1995 and is a six-deck recreation of a classic Mississippi riverboat, built by McDermott Shipyard for the Delta Queen Steamboat Company. Although the American Queen's stern paddlewheel is indeed powered by a genuine steam plant, her secondary propulsion, in case of an emergency and for maneuverability around tight areas where the paddle wheel can not navigate, comes from a set of diesel-electric propellers known as Z-drives on either side of the sternwheel. She has 222 state rooms for a capacity of 436 guests and a crew of 160. She is 418 feet (127 m) long and 89 feet (27 m) wide.