Russian Cruiser Fires Odd Torpedo Tube-Launched Anti-Sub Missile During Arctic Exercise
The weapon gives any surface ship with torpedo tubes, as well as submarines, a stand-off anti-submarine capability.
Russia recently concluded a series of drills in the Barents Sea, situated above the Arctic Circle, which had occurred in an area that overlapped in part with where NATO forces were conducting the alliance's largest exercise in decades. The Kremlin had caused something of a stir by alerting civilian pilots and mariners in the area that it would be firing unspecified missiles. Now we know that these launches included the use of an unusual torpedo tube-launched anti-submarine missile system known as the RPK-6 Vodopad, or Waterfall.
On Nov. 15, 2018, the Russian Ministry of Defense released a video showing Kirov-class nuclear battlecruiser Pyotr Velikiy, or Peter the Great, firing multiple Soviet-era RPK-6s, which NATO also refers to as the SS-N-16 Stallion. An unnamed nuclear-powered submarine was also reportedly involved in this specific drill.
The exercise offered both vessels the opportunity to try to seek out and conduct simulated attacks on each other, according to the video’s caption. Unfortunately, it doesn’t say whether Pyotr Velikiy or the submarine scored the most “kills” against the other.
The battlecruiser has a number of options for engaging underwater threats, including 254mm and 305mm anti-submarine rocket launchers that can send volleys of depth charges or anti-torpedo decoys into the water around the ship. It also has 10 553mm torpedo tubes of its own to respond in kind.
Those latter tubes, however, can also fire the much more obscure RPK-6s, which first entered service in 1981. Unlike in a more conventional missile launcher, compressed air cold-launches what the Russians refer to as a "torpedo-missile" out of the torpedo tube and into the water, after which it sails away from the ship for a distance underwater. Then a rocket motor ignites and sends it flying back into the air and on its way.
The weapon has an inertial navigation guidance system to get it to target areas more than 60 miles away. When it gets there, the missile releases its payload. During the exercises in the Barents Sea, this was a 400mm lightweight homing torpedo.
However, the Soviet Union originally designed the weapon to also be able to carry a nuclear depth charge. That option would make it much more difficult for the target to escape. The stand-off range the RPK-6 would also help shield the launching ship from any adverse effects from the blast.
Russia also has a submarine-launched version of the system, the RPK-7 Veter, or Wind, that works with 650mm torpedo tubes, but otherwise has the same basic characteristics. NATO refers to both systems collectively as the SS-N-16.
The two variants replaced an earlier pair of torpedo tube-fired missile systems for use by surface ships and submarines, known simply as the RPK-2 Vyuga, or Blizzard, which had only half the range. NATO designated applied the designation SS-N-15 Starfish to both of these weapons.
The submarine-launched configurations are roughly analogous to the U.S. Navy’s Cold War-era UUM-44 Submarine Rocket, or SUBROC, which also carried a nuclear depth charge. There was also the surface ship-launched RUR-5 Anti-Submarine Rocket, or ASROC, but this was in no way similar to a torpedo tube-launched system that sends the missile swimming in the water before it blasts off.
The Navy retired SUBROC in 1989. That same year, it stopped deploying ships with nuclear-armed ASROCs and began using the version carrying a conventional lightweight torpedo only. In the 1990s, the service began replacing the RUR-5s with RUM-139 Vertical Launch ASROC, or VL-ASROC, which fits inside standard Mk 41 Vertical Launch System cells.
Though the RPK-6 is odd, it’s really not surprising that Russia still has the weapon in service. It offers a stand-off, fire-and-forget anti-submarine weapon to virtually any ship with 533mm torpedo tubes. This, in turn, offers a major boost in firepower for even small ships without the need to find the space and power necessary to add in complicated vertical launch systems or even bolt-on deck-mounted missile launchers.
There’s also a derivative, the RU-100, also known as the SS-N-16A, which carries a conventional explosive warhead and functions in much the same way as an anti-ship cruise missile. We don't know for sure, but it is likely that this missile has a radar seeker to detect and lock on to its target in the final stages of flight. This adds even more flexibility to the standard 533mm torpedo tubes found on various Russian ships.
The SS-N-16 family is also related to the submarine-launched 91RE1 anti-submarine missile, a member of the Kalibr cruise missile family, which uses a similar booster rocket and carries a lightweight torpedo instead. There is a vertical launch derivative of that missile, the 91RTE2, that is more analogous to the American RUM-139, as well.
The Pyotr Velikiy is due for a major refit in the coming years, which will likely occur after her sister ship, the Admiral Nakhimov, the only other Kirov-class vessel slated to be reactivated, returns to service. Nakhimov’s overhaul has been delayed multiple times and the Russian Navy doesn’t expect to get her back from the Sevmash Shipyard until between 2021 and 2022.
The upgrades include the deletion of the Cold War-era P-700 Granit, or SS-N-19 Shipwreck, anti-ship missiles and the addition of new vertical launch system arrays able to fire the 3M54 Kalibr land-attack cruise missile, supersonic P-800 Oniks anti-ship cruise missile, and 3M22 Zircon hypersonic anti-ship missile. The ships will also get separate launchers for the navalized version of the S-400 long-range surface-to-air missile system.
But there’s no mention of removing any of the torpedo tubes from either of the two ships or public plans to retire the RPK-6. So, unless something changes, it looks like the remaining Kirov-class battlecruisers, along with other ships in the Russian Navy, are set to retain their ability to fire these unique anti-submarine missiles for the foreseeable future.
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