Akula-class submarine

The Akula class is a series of fourth-generation nuclear-powered attack submarines (SSNs). In the West, they are known by the NATO reporting name Akula, which means "shark" in Russian. The Russians officially designate these vessels as Project 971 Shchuka-B.

These submarines are critical components of naval power because they are designed for stealth and advanced combat capabilities. The first of these vessels was deployed by the Soviet Navy in 1986. This deployment was a major surprise to Western intelligence agencies. Analysts had not expected the Soviet Union to produce such a sophisticated boat for another ten years.

The design of the Akula relies on a sophisticated double hull system. This system consists of an inner pressure hull and an outer "light" hull. The inner hull protects the crew and sensitive equipment from water pressure. The outer hull provides the submarine with more reserve buoyancy than many Western designs. This buoyancy is the capacity of the vessel to float. This dual-layer structure also gives designers more freedom to shape the exterior of the boat. A distinctive feature is a bulb, or "can," located on top of the rudder. This bulb houses a towed sonar array when it is retracted inside.

To remain hidden, these submarines must be extremely quiet. Many Akula units utilize a wake detection system (SOKS) consisting of hydrodynamic sensors. These sensors detect subtle changes in water temperature and salinity. They are placed at specific locations: the leading edge of the sail, the outer hull casing in front of the sail, and the bottom of the hull forward of the sail. The Akula's ability to stay quiet was significantly aided by the Toshiba–Kongsberg scandal. In the 1980s, a Japanese firm named Toshiba sold specialized nine-axis milling equipment to the Soviet Union. This equipment, along with computer controls from the Norwegian firm Kongsberg Vaapenfabrik, allowed for the production of more accurate and quieter propellers. This technology helped the Soviets close the gap in acoustic stealth.

There are four distinct versions, or "flights," of the Shchuka-B series. The first is the original Project 971, known as Akula I. Seven of these boats were commissioned between 1984 and 1990. The second version is the Project 971Is, or Improved Akula I. Six of these boats were commissioned between 1991 and 2009, and they are notably quieter than the originals.

The third version is the Project 971U, or Akula II. Only one boat, the K-157 Vepr, was completed in this class. The final version is the Project 971M, known as Akula III. The K-335 Gepard is the only completed Akula III built for the Russian Navy.

The Akula II and Akula III represent significant engineering leaps in size and quietness. The Akula II is longer than the Akula I. It has a submerged displacement that is approximately 700 tons greater than the original model. This extra space was used specifically for additional quieting measures. The Akula II, K-157 Vepr, was famously quieter than the latest U.S. attack submarines of its time. The Akula III, the K-335 Gepard, is even larger. It features an enlarged sail and a different towed-array dispenser on the vertical fin. The Gepard was the most advanced Russian submarine before the introduction of the Oscar II and Borei classes.

The weaponry of the Akula class is versatile and powerful. Most versions are armed with two rows of four torpedo tubes each. There are four 533 mm tubes used for Type 53 torpedoes or RPK-2 and RPK-6 missiles. There are also four 650 mm tubes used for Type 65 torpedoes or RPK-7 missiles. The 650 mm tubes can be fitted with liners to allow the use of 533 mm weaponry. Additionally, these tubes can be used to deploy naval mines. Some tubes are mounted externally, outside the pressure hull, meaning they can only be reloaded in port or with a submarine tender.

The history of the Akula class includes both significant military operations and tragic accidents. In 1996, the submarine Tigr tracked a U.S. ballistic missile submarine on combat patrol. In 2009, news reported Akula-class submarines operating near the U.S. East Coast and in the Gulf of Mexico. However, the class also faced a serious accident in 2008. During sea trials, the K-152 Nerpa experienced an accidental activation of its halon-based fire-extinguishing system. The gas displaced the breathable air in a compartment, resulting in the deaths of 20 people. Despite these challenges, the Akula remains a central part of naval history and submarine technology.