By the mid-1960s, the firepower and armor protection of the PT-76, the only floating tank that saw service in the Soviet Armed Forces, was no longer sufficient. Therefore, a project for a floating tank with more powerful armament and armor was developed. The vehicle was to be equipped with an 85 or 100 mm autoloader gun, which would reduce the number of crew members to three and increase the rate of fire. It existed only in blueprints.