The Soviet Union produced hot-rod submarines that could swim faster, take more damage, and dive deeper than their American counterparts—but the U.S. Navy remained fairly confident it had the Soviet submarines outmatched because they were all extremely noisy. Should the superpowers clash, the quieter American subs had better odds of detecting their Soviet counterparts first, and greeting them with a homing torpedo. However, that confidence was dented in the mid-1980s, when the Soviet Navy launched its Akula-class nuclear-powered attack submarines. Thirty years later they remain the mainstay of the Russian nuclear attack submarine fleet—and are quieter than the majority of their American counterparts.

Intelligence provided by the spies John Walker and Jerry Whitworth in the 1970s convinced the Soviet Navy that it needed to seriously pursue acoustic stealth in its next attack submarine. After the prolific Victor class and expensive titanium-hulled Sierra class, construction of the first Project 971 submarine, Akula (“Shark”), began in 1983. The new design benefited from advanced milling tools and computer controls imported from Japan and Sweden, respectively, allowing Soviet engineers to fashion quiet seven-bladed propellers.

The large Akula, which displaced nearly thirteen thousand tons submerged, featured a steel double hull typical to Soviet submarines, allowing the vessel to take on more ballast water and survive more damage. The attack submarine’s propulsion plant was rafted to dampen sound, and anechoic tiles coated its outer and inner surface. Even the limber holes which allowed water to pass inside the Akula’s outer hull had retractable covers to minimize acoustic returns. The 111-meter-long vessel was distinguished by its elegant, aquadynamic conning tower and the teardrop-shaped pod atop the tail fin which could deploy a towed passive sonar array. A crew of around seventy could operate the ship for one hundred days at sea.

Powered by a single 190-megawatt pressurized water nuclear reactor with a high-density core, the Akula could swim a fast thirty-three knots (thirty-eight miles per hour) and operate 480 meters deep, two hundred meters deeper than the contemporary Los Angeles–class submarine. More troubling for the U.S. Navy, though, the Akula was nearly as stealthy as the Los Angeles class. American submariners could no longer take their acoustic superiority for granted. On the other hand, the Akula’s own sensors were believed to be inferior.

The Akula I submarines—designated Shchuka (“Pike”) in Russian service—were foremost intended to hunt U.S. Navy submarines, particularly ballistic-missile submarines. Four 533-millimeter torpedo tubes and four large 650-millimeter tubes could deploy up to forty wire-guided torpedoes, mines, or long-range SS-N-15 Starfish and SS-N-16 Stallion antiship missiles. The Akula could also carry up to twelve Granat cruise missiles capable of hitting targets on land up to three thousand kilometers away.

Soviet shipyards pumped out seven Akula Is while the U.S. Navy pressed ahead to build the even stealthier Seawolf-class submarine to compete. However, even as the Soviet Union collapsed, it launched the first of five Project 971U Improved Akula I boats. This was followed by the heavier and slightly longer 971A Akula II class in the form of the Vepr in 1995, which featured a double-layer silencing system for the power train, dampened propulsion systems and a new sonar. Both variants had six additional external tubes that could launch missiles or decoy torpedoes, and a new Strela-3 surface-to-air missile system.

However, the most important improvement was to stealth—the new Akulas were now significantly quieter than even the Improved Los Angeles–class submarines, although some analysts argue that the latter remain stealthier at higher speeds. You can check out an Office of Naval Intelligence comparison chart of submarine acoustic stealth here. The U.S. Navy still operates forty-three Los Angeles–class boats, though fourteen newer Seawolf- and Virginia-class submarines still beat out the Akula in discretion.         

However, Russian shipyards have struggled to complete new Akula IIs, which are not cheap—one figure claims a cost of $1.55 billion each in 1996, or $2.4 billion in today’s dollars. The struggling Russian economy can barely afford to keep the already completed vessels operational. Two Akula IIs were scrapped before finishing construction and three were converted into Borei-class ballistic-missile submarines. As for the Akula II Vepr, it was beset by tragedy in 1998 when a mentally unstable teenage seaman killed eight fellow crewmembers while at dock, and threatened to blow up the torpedo room in a standoff before committing suicide.

After lingering a decade in construction, the Gepard, the only completed Akula III boat, was deployed in 2001, reportedly boasting what was then the pinnacle of Russian stealth technology. Seven years later, Moscow finally pushed through funding to complete the Akula II Nerpa after fifteen years of bungled construction. However, during sea trials in November 2008, a fire alarm was triggered inadvertently, flooding the sub with freon firefighting gas that suffocated twenty onboard, mostly civilians—the most serious recent incident in a long and eventful history of submarine disasters.

After an expensive round of repairs, the Nerpa was ready to go—and promptly transferred on a ten-year lease to India for $950 million. Redubbed the INS Chakra, it served as India’s only nuclear powered submarine for years, armed with the short-range Klub cruise missile due to the restrictions of the Missile Technology Control Regime. In October 2016, Moscow and New Delhi agreed on the leasing of a second Akula-class submarine, although it’s unclear whether it will be the older Akula I Kashalot or never-completed Akula II Iribis—though the steep $2 billion price tag leads some to believe it may be the latter. This year, the Chakra will also be joined by the domestically-produced Arihant class, which is based on the Akula but reoriented to serve as a ballistic-missile sub.

Today the Russian Navy maintains ten to eleven Akulas, according to Jane’s accounting in 2016, but only three or four are in operational condition, while the rest await repairs. Nonetheless, the Russian Navy has kept its boats busy. In 2009, two Akulas were detected off the East Coast of the United States—supposedly the closest Russia submarines had been seen since the end of the Cold War. Three years later, there was an unconfirmed claim (this time denied by the U.S. Navy) that another Akula had spent a month prowling in the Gulf of Mexico without being caught. The older Kashalot even has been honored for “tailing a foreign submarine for fourteen days.” All of these incidents have highlighted concerns that the U.S. Navy needs to refocus on antisubmarine warfare. In the last several years, Russia has also been upgrading the Akula fleet to fire deadly Kalibr cruise missiles, which were launched at targets in Syria in 2015 by the Kilo-class submarine Rostov-on-Don.

Despite the Akula’s poor readiness rate, they continue to make up the larger part of Russia’s nuclear attack submarine force, and will remain in service into the next decade until production of the succeeding Yasen class truly kicks into gear. Until then, the Akula’s strong acoustic stealth characteristics will continue to make it a formidable challenge for antisubmarine warfare specialists.

Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring.

Image: INS Chakra. Wikimedia Commons/Creative Commons/Indian Navy