The B-274 Petropavlovsk-Kamchatsky submarine’s conventional diesel-electric propulsion system makes it “unlike anything in US Navy service,” and has both its benefits and drawbacks, Forbes defence contributor H I Sutton has explained.
“For comparison the last time the US Navy commissioned a non-nuclear submarine was in the 1950s,” the journalist writes.
One of the main benefits of nuclear submarines is their virtually unlimited range, which makes patrols of a month or more a regular occurrence, compared to weeks at sea for most diesel-electrics.
“Nuclear submarines are also faster and have more surplus energy which can be used to power massive sonar arrays. In open water this makes them much more deadly because they can hear the enemy further away and then move faster to get into position, or get out of trouble,” Sutton notes.
But conventional subs like the Varshavyanka have their own advantages, the analyst adds. Diesel-electric subs’ most obvious strength is their smaller size, which makes them cheaper to build, requires a smaller crew, and can make them the perfect deep sea hunters. Conventional subs “can turn off almost all systems and sit silently on the sea floor, making them extremely difficult to detect,” Sutton suggests.
Given their smaller size, the vessels can also operate in shallower waters, approaching closer to shores, transporting diver saboteurs, or laying mines in narrow channels.
Moreover, unlike US naval doctrine, which requires warships to be able to deploy at any of the hundreds of US military bases dotting the globe, Russia’s requirements are less ambitious, with most of its attack subs expected to patrol closer to their home bases in the Black and Baltic Seas, the North Sea and even the Pacific, in a wartime scenario.
Russia’s Project 636 Varshavyanka-class subs, an updated and modernised variant of the Soviet Project 877 Paltus class vessel, carry the NATO reporting name ‘Improved Kilo’, and are nicknamed ‘black holes’ by the US Navy for their sonar-evading capabilities.
With a complement of 52 crewmembers, the subs have a top speed of 20 knots while submerged, a submerged cruising range of 400 nautical miles (or 6,000-7,500 nautical miles using snorkel), and an endurance of 45 days. The vessels are armed with 18 torpedoes, 24 mines, and eight surface-to-air missiles, with the Rostov-on-Don, Petropavlovsk-Kamchatsky and the new vessels currently under construction in Russian shipyards also fitted with Kalibr/Club land-attack cruise missiles. The vessels are seen by Russian naval strategists as a prospective standoff weapon, capable of detecting and striking an enemy sub or surface warship before they are spotted or targeted themselves.
In addition to Russia, which has 22 Project 877 subs, seven Project 636.3 vessels and at least six more Project 636.3 subs under construction, operators of older and less advanced Kilo-class subs include China, India, Vietnam, Iran, Algeria, Poland, and Romania. Venezuela and the Philippines have also expressed an interest in the vessels.