The New Russian Submarine’s Missing Tiles And Why It’s Completely Normal

The Russian Navy nuclear powered cruise missile submarine Kazan (K-561) alongside in Havana, Cuba during its June 2024 port visit. (Image credit: Russian Ministry of Defence)

The material state of Russia’s brand new Yasen-M class submarine has been called into question after apparent missing pieces were spotted on the hull as it arrived in Havana. But here’s why it’s a completely normal thing to see.

As previously reported by The Aviationist, a fleet of Russian Navy vessels arrived in the Cuban capital Havana on June 12, 2024 for an official port visit. These included the frigate Admiral Gorshkov, two support vessels, and the Yasen-M class submarine Kazan. The visit by this nuclear-powered cruise missile submarine (SSGN) drew the most attention from watchers online as well as international media, with Kazan being among the newest boats in Russia’s large sub-surface fleet.

Particular notice was paid to several images showing what appeared to be missing panels on the side of the submarine’s hull. This led to derision on social media of Russia’s technological capabilities, as well as articles calling the submarine’s state of repair into question. This came alongside reports in British media that a Royal Air Force P-8A Poseidon had detected and sighted the Russian submarine off Scotland on its transit to Cuba, leading to the UK Prime Minister being briefed on the situation.

However, although there are several examples of Russian military’s basic issues of poor maintenance, this is probably not one of them.

In fact, while it is not possible to make any informed estimation with regards to the submarine’s current state of repair, these missing tiles are themselves of little concern.

Anechoic tiles

Known as anechoic tiles, many modern classes of submarine are coated almost all over the hull by thousands of these rubber-like patches.

Their purpose is twofold: first of all they dampen sounds coming from the inside of the submarine, protecting the boat from detection by passive sonar. Secondly, they are able to absorb some of the sound energy emitted by active sonar, reducing the overall sound signature that can be reflected back to anyone who might be listening.

The issue of them coming loose from the hull can be traced back to their very beginning, when they were trialled by the Kriegsmarine’s U-Boats early in the Second World War. After initial tests were burdened by the loss of tiles more development was put into an improved adhesive, but this was not available in large quantities before the war ended in 1945.

Unlike many other technologies where Germany had made significant advancements, anechoic tiles were not widely adopted by other nations immediately after the end of the war. The first post-war design to incorporate the feature operationally was the Soviet Victor class nuclear powered attack submarine. Western intelligence services codenamed the development ‘Cluster Guard’. Anechoic tiles, also known as acoustic tiles, then began appearing on Western submarines in the 1980s with the Royal Navy’s HMS Churchill and U.S. Navy’s USS Batfish, both nuclear-powered attack submarines (SSN).

Subsequent submarine classes often started to include anechoic tiles in their design, and the practice is now also being extended to some anti-submarine warfare (ASW) focused surface vessels like the Royal Navy’s future Type 26 City class frigate.

A Mark 48 torpedo being loaded onto the U.S. Navy Los Angeles class submarine USS Annapolis (SSN 760) at Naval Base Guam. The anechoic tile coating can clearly be seen on the hull above the waterline. (Image credit: U.S. Navy photo/Nikita Custer)

The issue encountered during the Second World War of tiles becoming dislodged during service is, however, one that persists to the present day. The reason for this is simple physics – as the submarine submerges deeper into the water the hull will become colder. As the hull coating will have been applied above surface the tiles are set according to the hull’s exact measurements at an above-water ambient temperature. When the metal hull contracts in the colder water, the tiles will be squeezed closer together. With repeated changes in temperature and multiple cycles of warming and cooling, and aided by the constant friction of moving through the water, eventually the cumulative wear and tear will cause the tiles to simply detach from the hull.

It is therefore common for submarines returning from long deployments to show large patches of missing tiles, ready for a patch-up when the boat goes into a post-deployment maintenance cycle in the same way that a surface vessel would require maintenance following a build-up of rust.

Royal Navy Trafalgar class submarine HMS Triumph (S93) at HMNB Devonport undergoing maintenance following time spent at sea. Note the many cracked and/or missing anechoic tiles from the hull and the sail. (Image credit: author)

In recent years the durability of the anechoic coating on the U.S. Navy’s newest type of SSN, the Virginia class, has been a subject of media scrutiny. Termed officially as Special Hull Treatment, the U.S. Navy’s coating process involves gluing the tiles to a specially painted hull, before precisely filling in gaps between each tile with resin. This results in the very smooth, uniform appearance with the individual tiles only faintly visible. The Virginia class specifically uses a newer, more cost-effective application process, which has been alleged to be a contributing factor to the problem.

With details of the noise signature of submarines being some of the most sensitive information handled by modern military forces, it is difficult to speculate with any certainty how much or how little the missing tiles affect a submarine’s ability to stay undetected. However, it is likely that extensive testing has been conducted by those nations operating submarines with anechoic tiles to determine how differing amounts of tile loss impacts their boats’ operational capabilities. This could then inform how much degradation can be allowed in different operational situations before requiring rectification works.

Modern submarines are so quiet while operating that the development of non-acoustic methods of detecting submarines is a very active process. ASW aircraft often carry magnetic anomaly detectors (MAD) which are designed to detect the magnetic field of an underwater submarine.

To combat this, submarines often pass through specialised degaussing, or magnetic silencing, facilities on a regular basis to reduce their magnetic fields as much as possible. This technique was developed during the Second World War for surface ships as a defence against naval mines that were activated upon detection of a large magnetic field.

Virginia class submarine USS Texas (SSN 775) in the magnetic silencing facility at Joint Base Pearl Harbour-Hickam in Hawaii on Apr. 27, 2012. Note that the hull here is again missing several sections of anechoic tiles. (U.S. Navy photo by Mass Communication Specialist 2nd Class Daniel Barker/Released)

Under the water, Russian and British submarines have been seen fitted with several types of devices believed to be designed for detecting the wake left in the water by other submarines. These devices likely measure for a number of different variables in the water, from temperature and water disturbances to latent radiation potentially left by the passing of a nuclear-powered submarine.

Submarine detection, tracking and engagement remains one of the most difficult aspects of warfare, and these missing tiles are unlikely to be changing that any time soon.

About Kai Greet
Kai is an aviation enthusiast and freelance photographer and writer based in Cornwall, UK. They are a graduate of BA (Hons) Press & Editorial Photography at Falmouth University. Their photographic work has been featured by a number of nationally and internationally recognised organisations and news publications, and in 2022 they self-published a book focused on the history of Cornwall. They are passionate about all aspects of aviation, alongside military operations/history, international relations, politics, intelligence and space.