Russia's Papa-Class Titanium Submarine: Something the Navy Couldn't Match

Summary: The Soviet Project 661 submarine, also known as the Papa-class, exemplifies the Cold War era's exploration of speed in submarine warfare. Conceived in 1959, its design focused on high-speed interception of American carrier task forces, using advanced titanium alloy construction for lightweight and speed enhancement. This innovation allowed the submarine to reach record speeds of up to 44.7 knots, significantly faster than contemporaries. However, the benefits of speed came with drawbacks, including high construction costs, noise levels that compromised stealth, and structural damage at high speeds. Despite these issues, Project 661 paved the way for future advancements in submarine technology but was deemed too costly and problematic to produce in numbers. The only vessel of its class, K-222, served until decommissioned in 1984, marking a bold but isolated chapter in naval engineering.

Meet the Papa-Class Titanium Submarine from Russia 

Speed has often held a mixed appeal in submarine warfare. After all, even very quiet submarines become noisy when they're tearing through the ocean at their maximum speed of 20 to 30 knots. As typically the goal in submarine warfare is to detect an unaware adversary and launch torpedoes without being detected in return, many submarines cruise at little more than a brisk jog to minimize noise.

However, speed also enables more aggressive maneuvers against alert enemies and incoming torpedoes, and the ability to close with or disengage from adversaries as the situation dictates. And sometimes speed is desirable simply to get a submarine where it needs to be to engage a fast-moving enemy.

Such was the thinking behind the Soviet’s Project 661 submarine Anchar that was conceived in 1959: a speedy submarine that could race forth to intercept American carrier task forces cruising at 33 knots, blast them with long-range cruise missiles fired from underwater, and then get the hell out of Dodge.

Project 661, known as the Papa-class by NATO, was developed roughly in parallel with another high speed-design, the Project 705 torpedo attack submarine, which would result in the iconic Alfa-class submarine. Though the two boats diverged in many respects, they had in common hulls made of strong but lightweight titanium alloy instead of steel to save weight, and thereby increase speed.

While U.S. engineers incorporated titanium components into aircraft like the ultra-fast SR-71 Blackbird, doing so on something the scale of a submarine hull was considered unfeasible because the element could only be welded in a de-oxygenated environment. That didn’t stop Soviet engineers, who had workers in pressurized suits weld 60-millimeter thick titanium plates of the Project 661’s pressure hull in the argon gas-flooded Building No. 42 in Severodvinsk.

The cost of this scheme was a (then) considerable 2 billion rubles, leading to titanium submarine being dubbed the “Golden Fish.” Many of the titanium plates subsequently cracked due to manufacturing flaws—particularly in the ballast tanks—requiring lengthy and expensive re-manufacturing of components.

Unlike the relatively small and sleek Alfa and its tiny crew of fifteen to thirty-two, the Project 661 was a large but conventional-looking double-hulled design that displaced a sizeable 7,000 tons submerged, measured 107 meters long and had a complement of eighty-two officers and seamen. Its speed advantage came from the fact that it incorporated two powerful VM-5m pressurized water reactors, each generating 177 megawatts to turn two side-by-side propeller shafts.

The K-222 had four torpedo tubes with just twelve torpedoes for self-defense. Its principal armament was meant to be ten seven-meter-long P-70 Amethyst cruise missiles (NATO codename SS-N-7 Starbright) mounted in flooded, slanted tubes along each side of its bow. These were the first cruise missiles designed for under-water launch (SLCMs) ever deployed.

Project 661’s tactical concept was simple: it would race at maximum speed towards the reported location of carrier task forces. Once it had located prey using its powerful MGK3 Rubin sonar array, the sonar would transmit targeting data to Anchar’s torpedo and missile systems.

The missile submarine would rise to within 30 meters of the surface to launch all its 3.85-ton missiles in two five-shot volleys timed three minutes apart from a distance as great as forty miles away. The Amethyst missiles would pop up to the surface powered by their first-stage rockets, whereupon they would extend wings and a second solid-fuel rocket would hurl them up into the sky. 

Upon attaining an altitude of 200 feet, a third rocket then propelled the P-70s at just under the speed of sound towards the designated target area using inertial guidance systems. In the terminal phase, the missiles switched on active L-Band radars to home in on the largest nearby target. As the missile plunged towards their target, the Project 661 sub would hightail its way back to base for reloading.

The numerous new technologies involved in the Anchar resulted in false starts to the project in 1962 and 1963. Finally, a Project 661 submarine K-162 was laid down in 1965 and launched four years later in 1969. In initial sea trials using 80 percent reactor power, she attained an impressive 42 knots, exceeding the 38 knots stipulated in design documents. By contrast, the American Permit­-class submarines of the era had a maximum speed of 28 knots. But access-hatch fairings, emergency signal buoys and water intakes were torn away during the speed run.

On December 30, Captain Golubkov Filipovich took K-162 on a test run seeking to push the titanium sub to its limits. After overriding engine safety controls, the missile submarine attained a world record of 44.7 knots (51 miles per hour) using 97 percent of reactor power while swimming 100 meters under the surface.

This speed was repeated on a second test on March 30, 1971 using 100 percent power, though the crew had to abort the third leg of the run as the turbines began to fall out of control. That fall the submarine practiced stalking an American carrier task force across the Atlantic, surfacing just once during its eighty-day deployment.

The Project 661’s impressive speed, however, came with major shortcomings—maximum speed resulted in intolerable noise levels of 100 decibels for the crew. In Cold War Submarines, author Norman Polmar shares an account by a Soviet crew member:

“…when 35 knots was exceeded, it was like the noise of a jet aircraft. In the control room was heard not simply the roar of an aircraft, but the thunder of the engine room of a diesel locomotive.”

Obviously, this would have been extremely acoustically conspicuous to adversaries. Furthermore, the submarine was prone to damaging itself when charging ahead at full speed.

This considerable expense involved in the Golden Fish’s construction meant no other boats were built in her class. However, the Papa-class did serve to pioneer technology used in later titanium-hulled submarines, leading to premium hunter-killer designs such as the Alfa and Sierra-class submarines and the deep-diving experimental Mike-class.   \

Re-designated K-222 in 1975, the speedy submarine served the Soviet Northern fleet for fourteen more years, soldiering through a reactor accident in 1980 caused by a wrench dropped into machinery during refueling of the reactor core. The titanium boat was finally decommissioned in December 1984 and left on a pier in Severodvinsk. She remained inactive for twenty-four more years before she finally was scrapped in 2015.

About the Author 

Kyle Mizokami is a writer based in San Francisco who has appeared in The Diplomat, Foreign Policy, War is Boring and The Daily Beast. In 2009 he co-founded the defense and security blog Japan Security Watch.