Russian submarine B-585 Sankt Peterburg

B-585 Sankt Peterburg (Б-585 «Санкт-Петербург»; named after Saint Petersburg) is the lead boat of the Lada-class submarine of the Russian Navy. The Lada class is the fourth-generation of diesel-electric submarines designed and constructed in the former Soviet Union and Russia to replace the Kilo-class submarine. Construction of the boat started in December 1997, and she was launched in October 2004. After undergoing a series of sea trials, Sankt Peterburg was commissioned in May 2010. However, the Russian Navy decided not to accept the Lada class after it was discovered that the boat's propulsion and sonar systems were inadequate. As a result, Sankt Peterburg is the only operational boat of the class, with construction of two of her sister boats having been halted.

Background and construction
Sankt Peterburg is first boat of Rubin Design Bureau's Lada class, of which a total of eight were expected to be procured by the Russian Navy. A less capable version, the Amur class, is marketed for export. Designed during the 1990s, the Lada class is intended to be the successor to the larger Kilo class. The Kilo class is considered to be one of the quietest diesel classes in operations, giving rise to the nickname "Black Hole". Among the expected capabilities improvements of the Lada class over its predecessor were the incorporation of improved anechoic coating (to minimize sonar contact), extended cruise range, and the upgrade to newer weapons for anti-submarine and anti-ship operations. Lada-class boats can also conduct reconnaissance and defend naval facilities and sea lanes.

Amid a severe shortage of funds experienced during the 1990s following the dissolution of the Soviet Union, the keel of Sankt Peterburg was laid down on 26 December 1997, in Saint Petersburg by Admiralty Shipyard. The company specialises in submarine construction, having built more than 300 boats, including the Victor-class and Alfa-class nuclear-powered submarines. By 2006, two more of Sankt Peterburg's sister boats, Kronshtadt and Sevastopol had had their keels laid down. Sankt Peterburg was launched on 28 October 2004, to coincide with the 300th anniversary of Sankt Peterburg's founding, before undergoing several sea trials, to validate her systems, until 2009.

As of 25 February 2008, Sankt Peterburg was part of the 13th Brigade of Ships Under Repair and Construction (military unit number 22875), Leningrad Naval Base.

Operational history
On 6 May 2010, Sankt Peterburg was commissioned into the Russian Navy, signalling the official start of her operational service. The boat thereafter underwent combat training with the Baltic Fleet and participated in a naval parade and an exercise. At the same time, she continued sea trials until late 2011.

Despite having been commissioned, in November 2011 the Russian Navy decided that the Lada class would not be accepted into service, as Sankt Peterburg has fallen far short of requirements during trials. According to Izvestia, the main drawback was the propulsion unit's inability to produce half of the expected power, along with the inefficiency of the sonar system. With the construction of the other two Lada-class submarines being halted, the Russian Navy ordered additional Improved Kilo-class submarines. The decision to reject the Lada class was confirmed in February 2012 by Russian Navy Commander-in-Chief Admiral Vladimir Vysotsky, who stated, "The Russian Navy does not need the Lada in its current form." Sankt Peterburg would remain an experimental prototype.