On December 26th, the Admiralty Shipyard in St. Petersburg floated out the new Project 636.3 Kilo-class diesel-electric submarine “Volkhov.” The Admiralty shipyard is scheduled to build 6 submarines in this class for the Pacific Fleet in total, having already built 6 for the Black Sea Fleet. All Project 636.3 submarines are equipped with 533-milimetre torpedo-tubes, which can launch both heavy torpedoes and the Kalibr-PL cruise missile, the existence of which first came into the public domain in 2016 when submarines from the Black Sea Fleet launched strikes against targets in Syria from positions in the Mediterranean.

Proposals to build Project 636.3 submarines for the Baltic fleet are also being considered, with plans expected to be finalized in 2020 and implemented in 2021.

With a strong hull, the Project 636.3 submarine has an operational depth of 240 metres, and can dive to a maximum depth of 300 metres. They have an operational range of 12,000 kilometres, and can remain at sea for 45 days. Their standard crews will be 52 men.

In recent decades, the tactical debate concerning submarine-design has oscillated between nuclear-powered submarines and air independent propulsion (AIP) submarines. While the latter are far less expensive than nuclear powered submarines, they usually do not have quite the same stealth-capability or maximum speed. The primary limiting factor concerning a submarine’s stealth-capability is its power-supply. While a nuclear sub can remain submerged for months, most AIP submarines must surface every couple of weeks to recharge their batteries. The improved design of AIP submarines has, in recent decades, narrowed the performance-gap, however.

The Russian 636.3 improved Kilo-class submarine employs neither of these technologies. A traditional shortcoming of diesel submarines was that they could maintain silent propulsion (by switching from diesel to electric propulsion) for only a few hours. The design of the improved 636.3 kilo-class improves the stealth-capability of traditional diesel-sub design by coating the submarine’s hull with an anechoic (echo-reducing) material, and by reducing vibrations produced by the diesel engine by isolating the propulsion-plant on a rubber base. These innovations make the Project 636.3 submarine one of the most silent currently existent submarines, at a fraction of the cost of a nuclear powered sub.

In order to see the logic behind the adoption of this design, we need to consider cost and the relationship between overall military expenditure and tactical doctrine.

An American Virginia-class nuclear submarine costs about $2.6 billion dollars.

Most contemporary AIP-submarines cost about half a billion dollars.

These 12 new 636.3 improved Kilo-class submarines will cost the Russian Navy only $250 million each.

Why build one super-sub for close to $3 billion when you can build 12 pretty good subs, technically capable of fulfilling their designated tactical role, for a quarter of a billion dollars each?

In the grand scheme of your overall naval tactical doctrine, the latter option makes a lot more sense.

This echoes a time-honoured wisdom in the philosophy of both the Soviet Union’s and Russia’s military-industrial complex – “The best is the enemy of good enough.”

Why build rifles within the AR-15 or M-16 platforms when you can build 3 times more AK-47’s or AK-74’s for the same cost? Their overall performance in an actual theatre of war (weighing up accuracy, reliability, ballistic performance of their respective cartridges, etc) is largely comparable.

So why waste money on tactically superfluous super-tech?

A piece of military hardware has to be only capable of fulfilling its designated tactical role. Military hardware should always be designed to be mission-specific.

So what is the designated tactical role of the improved 636.3 Kilo-class sub?

Insofar as this sub can remain at sea for only 45 days (whereas many nuclear submarines can remain submerged for 90 days or longer), we can surmise that the Project 636.3 submarine’s designated tactical role is not primarily to pose Russia’s nuclear deterrent. While its 533-milimetre launch-tubes can fire the Kalibr-PL cruise missile, and this missile can carry a nuclear payload, the Project 636.3 sub’s primary tactical role will be actual naval warfare, hunting other submarines or enemy surface-vessels.

That’s why it makes a lot more sense to build more of them, and to build them more cheaply.

As a compliment to this within Russia’s overall tactical doctrine, Russia’s nuclear deterrent will primarily be posed by the new (4th generation) Yasen-M nuclear-powered submarine, the first of which (named the “Kazan”) was unveiled on December 25th at the Sevmash shipyard in Severodvinsk, and will enter service following sea-trials in 2020. In a previous article, I argued that the deployment of NATO’s Aegis Ashore missile defence system made submarines more tactically important than ever. In addressing this issue, the Russian Defence Ministry has adopted quite a rational and cost-effective approach to what is sometimes, in the context of military procurement, referred to as a “high-low mix,” wherein each new design features the technical characteristics (and therefore the cost-parameters) which enable it to fulfill its designated tactical role.