Campbell, an English automobile and speedboat racer, set many speed records for motorcycles, airplanes, automobiles, and motorboats. In 1931, he was knighted for his accomplishments. Four years later, driving his famed automobile Bluebird at Bonneville Flats, Utah, Campbell set his final land speed record, becoming the first person to drive an automobile faster than 300 mph (483 km/h). He later turned to speedboat racing and set a new record in 1939, when his boat reached what speed? Discuss