The World Water Speed Record is the fastest speed achieved by a vehicle on water. This record is officially recognized by the Union Internationale Motonautique (UIM), which sets the rules and regulations for water speed records. The record is typically measured over a specific distance, often one kilometer or one mile, and must be completed in both directions to account for any environmental factors. The current record was set by Ken Warby in 1978, when he reached a speed of 511.11 km/h (317.60 mph) in his boat, the Spirit of Australia. Since then, various teams and individuals have attempted to break this record, showcasing advancements in engineering and technology in the pursuit of speed on water.