 On 24 July 2009, work commenced on a second submarine, named "Kazan".On 26 July, the Russian navy command announced that starting in 2011, one multipurpose submarine would be laid down every year, although not necessarily of this class.An August 2009 report from the U.S. Office of Naval Intelligence estimated the Yasen-class submarines to be the quietest, or least detectable, of contemporaneous Russian and Chinese nuclear submarines, but said they were still not as quiet as contemporary U.S. Navy submarines (i.e.