Prior to commissioning, the two submarines will undergo a comprehensive refit and modernization program that includes replacement of the submarines sonar and navigation systems and refuelling of their nuclear reactors.
The two Project 945 Barrakuda submarines are the only members of its class:
- the K-239 Karp was commissioned in 1984
- the K-276 Kostroma / Karb was commissioned in 1986
There are also two improved Project 945A Kondor / Sierra II class submarines, which are currently in service with the Russian Northern Fleet. They are the Nizhny Novgorod and the Pskov and can be easily distinguished by their larger sail.
The submarines have a releasable escape pod on the sail for the crew. Unlike most steel submarines, the four submarines feature a titanium pressure hull, which is both lighter and stronger than steel.
This enables them to withstand depths of up to 550 meters, while also increasing their survivability and makes them harder to detect with their low magnetic signature.
However, despite their benefits, the titanium hull also made them much more expensive to build, which limited their numbers. The cheaper Project 971 Schuka / Akula class submarines with their steel hull was preferred and build in much greater numbers.