The Soviet Union was known for fielding extreme machines — from the largest submarines ever built to gargantuan nuclear-powered battle cruisers — unmatched by any other country in history. So it should come as no surprise that during the Cold War, they also built what is believed to be the fastest submarine in history.
Though NATO dubbed the submarine as part of the "Papa" class, it was the only boat of its kind ever built. The Soviet Navy commissioned the vessel the K-162 in late 1969, just around 10 years after the project which led to its creation was initiated.
Using the teardrop-shaped architecture which at the time was new and revolutionary in the submarine world, the K-162 was optimized for speed to the tune of nearly 45 knots (51 miles per hour) underwater during a high-speed dash. It was armed with a complement of 10 cruise missiles and 12 torpedoes with the purpose of attacking and destroying surface formations and flotillas of enemy ships.
At the time, the Soviet Navy sought to deal with the rising threat of American battle groups centered around the "supercarrier." These battle groups, guarded by heavily-armed destroyers, cruisers and submarines, were incredibly powerful projections of American naval force, and were without equal in the USSR.
Instead of building up similar carrier groups, the Soviet Navy decided to task its submarines with inflicting irreparable damage on American groups to render them ineffective. The K-162 became a part of this solution, with its missiles serving as the primary method of attacking enemy surface vessels.
Using a pair of nuclear reactors coupled to steam turbines, the K-162 could achieve blistering speeds which would allow it to surprise a carrier group, launch an attack and then leave the area before the group could respond with a counterattack of its own. In 1971, the submarine demonstrated its ability to dash at high speeds, supposedly achieving 44.85 knots at maximum power.
However, for its incredible speed, the K-162 came with a laundry list of limitations and drawbacks. The costs involved with designing and building the submarine, to begin with, were sky-high, and quickly deemed a poor investment as only one boat would be created, not an entire class.
The K-162's speed proved to be its own undoing, as well. Noise is the primary method of detection for submarines, and the K-162 generated a lot of it, especially during its underwater high-speed runs. Its various engineering components and machinery were not appropriately "noise dampened," making the vessel extremely detectable while at sea.
Further, the K-162 could not perform its high speed dashes without damaging itself. Any protrusions on the surfaces of the sub were buckled or bent out of shape due to the pressure of the water rushing over and around the hull. With poor hydrodynamics, the submarine couldn't achieve the same speeds after, without a return to port for repairs and a refit.
Yet another failing was the fact that K-162 could only fire the opening shots of battle before having to return to port. In combat, a submarine could return to its tender, sailing a safe distance away, to rearm and reload. The K-222 could rearm with torpedoes, but its cruise missiles — its main armament for its primary mission — were only able to be replenished after returning to port.
The K-162 later renamed K-222, and was removed from active service in the early 1980s, though it has since been suspected that it was used to test technologies and practices that would later be used on future Soviet nuclear submarines like the Alfa and Victor class of hunter/killer attack boats.
The Russian Navy completed the K-222's scrapping by 2010, marking the end of the fastest submarine to have ever existed.