Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Udaloy I class are a series of anti-submarine destroyers built for the Soviet Navy - The Russian designation is Project 1155 Fregat (Frigate bird). Twelve ships were built between 1980 and 1991, while a thirteenth ship built to a modifed design as the Udaloy II class followed in 1999. Eight ships are in service with the Russian Navy. The Project 1155 dates to the 1970s when it was concluded that it was too costly to build large-displacement, multi-role combatants. The concept of a specialized surface ship was developed by Soviet designers. Two different types of warships were laid down which were designed by the Severnoye Design Bureau: Project 956 destroyer and Project 1155 large antisubmarine ship.