What is Rudder?
[[Image:Maler der Grabkammer des Menna 013.jpg|thumb|Stern-mounted steering oar of an Egyptian riverboat depicted in the Tomb of Menna (c. 1422-1411 BC)]] [[Image:Eastern Han pottery boat.JPG|thumb|right|An [[Han Dynasty|Eastern Han]] (25&ndash;220 AD) Chinese pottery boat fit for riverine and maritime sea travel, with an anchor at the bow, a steering rudder at the stern, roofed compartments with windows and doors, and miniature sailors]] [[Image:Rudder of a Roman Boat (RG Museum Koeln, Germany).JPG|thumb|Stern-mounted steering oar of a Roman boat, 1st century AD (RG-Museum, Cologne)]] A '''rudder''' is used to steer [[ship]]s, [[boat]]s, [[submarine]]s, [[aircraft]], [[hovercraft]] or other [[vehicle]]s that move through air or water. ==History of the rudder== [[Oar]]s mounted on the side of ships for steering are documented from the 3rd millennium BC in [[Persia]] and [[Ancient Egypt]] in artwork, wooden models, and even parts of actual boats of that times. An early example of an oar mounted on the [[stern]] is found in the Egyptian tomb of Menna (1422-1411 BC).<ref>William F. Edgerton 1927. Ancient Egyptian Steering Gear. ''American Journal of Semitic Languages and Literatures'' '''43''', (4), 255.</ref> Stern-mounted oars were also quite common in [[Roman Empire|Roman]] river navigation as proved from [[relief]]s more than a millennium later. A depiction of a sternpost-mounted rudder can be seen on a pottery model of a Chinese [[junk (ship)|junk]] dating from the 1st century AD during the [[Han Dynasty]], predating their appearance in the West by a thousand years.<ref>Tom, K.S. 198). ''Echoes from Old China: Life, Legends, and Lore of the Middle Kingdom''. Honolulu: The Hawaii Chinese History Center of the University of Hawaii Press. {{ISBN|0-8248-1285-9}}. Page 103&ndash;104.</ref><ref>Needham, Joseph. (1986). ''Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics''. Taipei: Caves Books Ltd. Pages 627&ndash;628.</ref> The technology of stern-