A distinction is made between three types of boards : There are twin tips ( also Bidies or short TT called ) , Mutant boards and directional boards , which are also called wave boards . Raceboards distinguished by their really large volume ( greater than or Doors TT ) as well as by the long fins on the underside of the board . A Foilboard ( also hydrofoil ) is a board with a sword-like extension below the actual board .
