Here's What You Need To Remember: The Soviets retired six Alfas by 1990 and the seventh in 1996. The successor Victor III and Akula boats were, like their NATO rivals, balanced—and thus far more fearsome in combat. Even if they were slower and lower-diving than the Alfas.

In 1969, the Soviet navy shocked the U.S. and NATO militaries with a new and incredibly capable submarine—one that could swim faster and dive deeper than anything else under the sea.

But the seven high-tech Alfa-class submarines—able to reach 45 knots and 2,400 feet—were actually inferior where it really mattered. Their speed and depth-resistance came at the cost of noisy internal machinery that made them easy to detect … and destroy.

“The Alfa was a huge step forward in submarine design,” retired Royal Navy sub commander Doug Littlejohns told naval expert Iain Ballantyne. But considering all of the sub’s limitations, “what is the point?” Littlejohns added.

Ballantyne describes the Alfa’s revolutionary features in his new book Hunter Killers—starting with the boat’s streamlined all-titanium hull, which one Soviet officer compared to an expensive work of art or a spaceship. An Alfa was relatively small at 240 feet long and carried a crew of just three dozen.

The CIA was able to determine the new boat’s abilities fairly quickly by studying Soviet metallurgy and recruiting spies along the Soviet waterfront.

The Alfas had powerful new 155-Megawatt nuclear reactors providing 40,000 horsepower, making them like underwater race cars. “The amazing acceleration rate enabled the Alfa to go from six to 42 knots in just 120 seconds,” Ballantyne wrote, “but the use of liquid metal for reactor coolant was extremely radical—and very dangerous.”

Moreover, the high speed “created a lot of noise,” Ballantyne pointed out. In combat with a slower, less-deep-diving American, French or British submarine, an Alfa could speed away from enemy torpedoes and dive so deep that the pressure crushed the munitions.

But the Alfa never stood a chance of hitting back against its attacker. “As soon as the Alfa came back up to actually try and fight NATO boats, it would be nailed due to its noise signature,” Ballantyne asserted.

By contrast, American, French and British subs were more “balanced,” according to Ballantyne. They combined good speed, depth performance and—most importantly—quiet machinery that helped them to sneak and survive in wartime.

The Soviets retired six Alfas by 1990 and the seventh in 1996. The successor Victor III and Akula boats were, like their NATO rivals, balanced—and thus far more fearsome in combat. Even if they were slower and lower-diving than the Alfas.

This article by David Axe originally appeared at War is Boring in 2014.

Image: U.S. National Archives