Summary and key points: The Soviet Union’s Project 705 lira (NATO: Alfa) Submarines produced between 1968 and 1981 were groundbreaking because they used titanium hulls and lead-bismuth cooled fast reactors that allowed for unprecedented speeds and depths. These submarines could reach 41 knots and dive to a depth of 1,148 feet, making them elusive targets.

– However, they suffered from numerous shortcomings, including excessive noise pollution and the high cost and difficulty of processing titanium.

– The lead boat K-64 suffered a reactor failure, which led to its decommissioning.

-Despite their innovative design, the Alfa The AEG class was ultimately too expensive and defective to maintain, and by 1996 all units were decommissioned.

How Soviet Alfa-Class submarines expanded the boundaries of naval warfare

Between 1968 and 1981, the Soviet Union produced a total of seven Project 705 lira (NATO code name Alfa) nuclear-powered attack submarines.

The boats were state-of-the-art at the time of their production and, in addition to the then revolutionary use of titanium for the hull, each of the submarines used a powerful lead and bismuth-cooled fast reactor (OK-550 or BM-40A, 155 MWt) as an energy source.

This significantly reduced the size of the reactor, which in turn reduced the size of the submarine and allowed for high speeds. The submarines displaced 2,300 tons surface and 3,200 tons submerged and were only 267 feet long and had a beam of 31 feet.

Remarkable facts about the 705 Lira or Alfa Class project:

The submarines were considered the fastest and deepest submersibles in the world of their time and could reach a top speed of 41 knots underwater.

The boats could reach their top speed in just about sixty seconds and complete a 180-degree turn at full speed in just forty seconds.

But then came the Alfa-class submarines could only reach about 12 knots. It should be noted that the Soviet experimental nuclear-powered submarine K-222 with cruise missiles reached a submerged speed of 44.7 knots – but it was only a prototype.

Thanks to the use of titanium, which can withstand higher pressures better than steel, the boats reached a test depth of 350 meters, well below the range of NATO anti-submarine weapons at the time. This enabled a Alfa-class allows the submarine to “theoretically” be out of range of NATO ships while firing its own weapons.

In addition, the titanium hull proved to be more corrosion-resistant and made the submarine even harder to detect due to its paramagnetic properties.

The boats, which had a very high degree of automation, required a relatively small crew consisting exclusively of 32 officers and non-commissioned officers. Originally, it was planned that only 16 officers could operate the submarine.

In addition, the tiny crew was housed in the submarine’s mid-section, while the forward section contained the weapons system and electronics. It was only accessible for maintenance, as were the aft reactor and propulsion compartments. Many of the operations were fully automated, such as torpedo loading. This would have increased the crew’s chances of survival in the event of war, as the forward and aft compartments could be sealed off during combat operations.

The Project 705 lira was also the first submarine to be equipped with a rescue capsule; it even allowed the entire crew to safely exit from the greatest depths. Such features became standard on Russian boats.

Faulty: This Alfa-Class subs were loud

Despite its advanced features and capabilities, the Alfa-class boats had some notable Achilles heels – first, they were noisy. The noise generated by the boats was easily noticeable. Another problem was that titanium was not easy to work with at the time. Russia had the advantage of being a major supplier of titanium, but bending and shaping the metal plates proved difficult. Titanium is also very rigid and there was a high risk of imperfections in the metal that could have led to catastrophic failure – especially in a submarine operating under extremely high pressure.

Alfa-Class: Too expensive and too many defects?

At the end the project 705 lira or Alfa-Class was simply too expensive for mass production. In fact, in 1972 – just one year after it was commissioned – the lead boat K-64 was towed back to Severodvinsk after suffering severe reactor damage. However, repairs there proved too expensive. Instead, K-64 was split in half and used to train Soviet submariners.

The remaining six boats remained in service until April 1990, when five were decommissioned and scrapped. The last boat was finally decommissioned and scrapped in July 1996.

You start the Alfa-class submarine in the fictional film “The Hunt for Red October”, in which one of the submarines played an important role.

About the author: Peter Suciu

Peter Suciu is a Michigan-based author who has written for more than four dozen magazines, newspapers and websites. He writes regularly about military gear and is the author of several books on military headwear, including “A Gallery of Military Headdress,” available on Amazon.com. Peter is also a guest writer for Forbes.

All images are Creative Commons.