The Bora-class, Soviet designation Project 1239 Sivuch, hoverborne guided-missile corvette of the Russian Navy, also bears the NATO class name "Dergach", is one of the few types of military surface effect ship built solely for marine combat purposes, rather than troop landing or transport. The first vessel produced under this designation was MRK-27, which was later renamed Bora. It is one of the largest combat sea vehicles with catamaran design.