Russia has nearly completed sea trials for the second and third (of six) new Type 636.3 Varshavyanka class of diesel-electric submarines. The first of these subs (the Novorossiysk) entered service in late 2014 and is to be stationed in Crimea. The other three are under construction as are six of the older Kilo models for Vietnam. The 636.3 boats are basically a much upgraded version of the Kilo class subs. The Varshavyanka have stealthy features and a top underwater speed of 36 kilometers an hour. The crew of 52 can stay at sea for up to 45 days at a time. Armament consists of 18 torpedoes or missiles plus eight surface-to-air missiles.
The six new 636.3 boats will give Russia 25 Kilos with another seven retired but in reserve (can be restored to active duty). In addition nearly 40 have been exported (delivered or under construction) All are the same displacement (about 2,300 tons) and size (70-74 meters/227-240 feet) and all have six 533mm torpedo tubes. All Kilos are very similar to the world-standard diesel submarine, the 1,800-ton German Type 209. The Kilo is a formidable attack submarine and has been continually upgraded with better mechanical and electronic systems since first introduced in the early 1980s.