The Borei class (or Borei; Russian named after Boreas, the North wind) is a type of nuclear-powered ballistic missile submarine produced and operated by Russia. It is intended to replace the Delta III and Typhoon class in the Russian Navy.
Work on the first unit of the Borei class (officially designated Project 935) started in 1996. A new submarine-launched ballistic missile was developed in parallel, called the R-39UTTH "Bark". However, the work on this missile was abandoned, and a new missile called the Bulava-30 was designed. The submarine needed to be redesigned to accommodate the new missile, and the project name was changed to Project 955. The vessels are being built at the Northern Machinebuilding Enterprise (Sevmash) in Severodvinsk, and were designed by Marine Equipment Design Bureau (Rubin). Because of the failure of several Bulava test launches, some experts have suggested that the Borei submarine could instead be armed with R-29RMU Sineva missiles. The Sineva is already in active duty on the Delta IV class submarine.
The Borei is claimed to represent the state of the art in submarine design, incorporating characteristics that make it superior to any submarine currently in service, such as the ability to cruise silently and be less detectable to sonar. Advances include a compact and integrated hydrodynamically efficient hull for reduced broadband noise and the first ever use of pump-jet propulsion on a Russian nuclear submarine. Costing some $890 million USD, Borei is approximately 170 metres (560 ft) long, 13 metres (43 ft) in diameter, and has a maximum submerged speed of at least 46 kilometres per hour (25 kn; 29 mph). Smaller than the Typhoon-class, the Borei was initially slated to carry the same number of missiles (20) but has been forced to sacrifice 4 missiles due to the increase in mass of the 45-ton Bulava SLBM (a modified version of the Topol-M ICBM) over the proposed R-39UTTH "Bark".
The launch of the first submarine of the class, the Yury Dolgorukiy, was scheduled for 2002 but was delayed because of budget constraints. The vessel was eventually rolled out of its construction hall on 15 April 2007 in a ceremony attended by many senior military and industrial personnel.The Yuriy Dolgorukiy was the first strategic missile submarine to be launched in the seventeen years since the end of the Soviet era; in fact, it was the first Russian (rather than Soviet) vessel. Currently, there are two more Borei class submarines under construction, named Alexander Nevsky and Vladimir Monomakh. The planned contingent of twelve strategic submarines is expected to be commissioned within the next decade (five "Project 955" are planned for purchase through 2015).
Although the Yuriy Dolgorukiy was officially rolled out of its construction hall on 15 April 2007 the submarine was not put into the water until February 2008. By December 2008 it had yet to be armed with Bulava missiles and is therefore not fully operational, although ready for trials at sea on 24 October 2008. On November 21 2008 the reactor on the Yuriy Dolgorukiy was activated and on 19 June 2009 begin its sea trials in the White Sea after having some minor problems with its nuclear reactor.