The Soviet Union's Project 661 (Anchar) nuclear-powered attack submarine design is known in the west by its NATO reporting name Papa class. Only one vessel of this class was built: the K-222 (also known as K-162).

The Papa class was designed as an extremely fast attack submarine equipped with anti-shipping cruise missiles. Its design included ten SS-N-9 missiles in individual tubes forward of the sail, between the inner and outer hulls. It is regarded as a predecessor to the Alfa class submarine, and the single submarine of the Papa class may have tested technologies which were later used in the Alfa class.

Specifications

• Displacement
  • 5197 tons surfaced
  • 7000 tons submerged
• Dimensions:
  • Length: 106.9 m
  • Beam: 11.6 m
  • Draft: 8 m
• Estimated maximum depth: 400 m
• Maximum speed: 44.7 knots (82.8 km/h)
• Crew: 82
• Propulsion: Two VM-5m type pressurised water reactors generating 177.4 megawatts. Two steam turbines powering two propellers.
  • Shaft power: 80,000 hp (60 MW).
• Armament: 10 SS-N-9 missiles in individual torpedo tubes.