As the name suggests, rag boat racing is a form of drag racing which takes place on water rather than land. As in drag racing, contests take place between two vehicles over a straight quarter mile (1320 feet) course but unlike drag racing on land the boats begin from a short rolling start rather than a standing start. Many classes are present on race day with the the premier category of drag boat racing being the Top Fuel Hydroplane class which is a water based equivalent to Top Fuel Dragsters capable of covering a quarter mile (1320 feet) of water in less than five seconds with a terminal speed of around 250 mph (400 km/h). There are numerous other categories of drag boats based on various engine configurations (marine and automotive) and hull designs such as Top Alcohol Flatbottoms. The biggest event on the drag boat calendar is the IHBA World Finals which takes place at Firebird Raceway Phoenix, Arizona.