Russia’s Kirov-class nuclear-powered battlecruisers fill their missile launch shafts with seawater prior to firing them. This seems like a weird extra step in the launch sequence – many other ships don’t do that. What is that water for Kirov warships?
The Kirov class ships were built in 1974-1998. The first battlecruisers of this class entered service with the Soviet Navy in 1980. Kirov ships were considered a formidable force in their time. Nuclear-powered, able to sail until the sailors ran out of supplies, armed with powerful anti-ship missiles – Kirov ships still look intimidating today. True, there are not many of them left.
HMS Dragon (background) with the Russian Kirov Class battlecruiser ‘Pyotr Velikiy’. It is armed with P-700 Granit cruise missiles. Image credit: Royal Navy/MOD via Wikimedia (OGL v1.0)
There were a total of four Kirov-class nuclear battlecruisers ever in service. There were supposed to be five, but the construction of the last one was cancelled. The Pyotr Velikiy is now the only Kirov-class battlecruiser in active service, while the Admiral Nakhimov is undergoing reconstruction and should return next year.
By the way, it has not sailed since 1999 and has been in modernization since 2015. With the war in Ukraine taking a significant amount of the Russian military effort and funding, it is foreseeable that Admiral Nakhimov will remain dormant for longer. It won’t be armed with the original P-700 Granit missiles – they’ve been replaced with Zircon hypersonic anti-ship cruise missiles and Kalibr cruise missiles.
The Kirov-class battlecruisers are armed with P-700 Granit anti-ship cruise missiles. No one will be surprised by the fact that this is not an entirely new weapon – the P-700 Granit has been in service since 1983. What is surprising is that the Kirov ships launch these missiles from flooded launchers. Why?
Oscar-class submarines, like the Omsk, were all armed with P-700 Granit missiles. Image credit: Alex omen via Wikimedia (CC BY 3.0)
The P-700 Granit missiles were originally designed for submarines. Submarines fill their missile launch shafts with seawater prior to launch just to be able to open them without surfacing – the P-700 Granit can be launched from a completely submerged submarine. Therefore, the Granit was designed for wet launch.
This gave the developers of this missile the opportunity to not think about possible damage to the launcher, because the water protects the shaft from heat damage.
When the Soviets came up with the idea of arming the Kirov ships with the same Granit missiles, they could have chosen to modify the missile so that it would not damage the ship when launched from a dry shaft. But why modify it when there is a much simpler solution? It is easier to just flood the shaft and not change the P-700 Granit launch technology.
There are ship-launched cruise missiles that are launched from dry shafts, but that’s what they were designed to do without damaging the infrastructure. The P-700 Granit was designed for wet launching, as it had to come from submerged submarines. This is why the Kirov-class nuclear battlecruisers also flood their shafts before missile launches.
Written by Povilas M.
Sources: Kirov-class battlecruiser (Wikipedia), P-700 Granit (Wikipedia)