Known in the West by their NATO reporting name as the Juliett class, the Project 651 diesel-electric submarines were designed in the 1950s to provide the Soviet Navy with a nuclear strike capability against the east coast of the United States. They carried four nuclear cruise missiles, which could be launched while the submarine was surfaced and moving less than four knots (7 km/h). Once surfaced, the first missile could be launched in about five minutes; subsequent missiles would follow within about ten seconds each. Initially, the missiles were the inertially-guided P-5 (NATO reporting name SS-N-3 Shaddock ). When submarine-launched ballistic missiles rendered the P-5s obsolescent, they were replaced with the P-6 (also NATO reporting name SS-N-3 Shaddock , though it is a very different missile) and the P-500 4K-80 "Bazalt" (SS-N-12 Sandbox ) anti-ship cruise missiles designed to attack American aircraft carriers. A special 10m² target guidance radar was built into the forward edge of the sail structure, which opened by rotating. The boats were eventually fitted with the Kasatka satellite downlink for targeting information.

The Juliett class had a low magnetic signature austenitic steel double hull, covered by two inch (50 mm) thick black tiles made of sound-absorbing hard rubber. They had exceptionally high reserve buoyancy, and were divided into eight watertight compartments:

1. the forward torpedo room
2. living accommodations for officers and chiefs and the forward batteries
3. the missile control room and batteries
4. the control room
5. crew berthing and batteries
6. the forward engine room containing the diesels and generators
7. the after engine room with the electric motors
8. the after torpedo room.

Initial plans called for 35 submarines of this class. In fact only 16 were actually built, most by Krasnoye Sormovo shipyard in Gorky. They were commissioned between 1962 and 1968, and served through the 1980s. The last one was decommissioned in 1994.

The nuclear-powered Project 675 Echo II class submarines , with eight missile launchers, were a larger, nuclear-powered version of the Juliett.

General Characteristics

• Displacement
  • Surfaced: 3174 tons (3636 tons with additional fuel)
  • Submerged: 4137 tons
• Speed: 19 knots (35 km/h) surfaced, 14 knots (26 km/h) submerged
• Depth: 250 meters test depth, 400 meters crush depth
• Length: 90 meters (297 feet)
• Beam: 10 meters (33 feet)
• Draft: 7 meters (23 feet)
• Power: two 3500 hp (2,600 kW) diesel generators, silver-zinc Batteries (300 tons)
• Propulsion: two 3000 hp (2,200 kW) electric motors, two 150 hp (110 kW) "silent run" electric motors, two shafts and propellers
• Endurance: 90 days
  • Surfaced: 14,500 kilometers at eight knots (15 km/h) surfaced, 29,000 kilometers at seven knots (13 km/h) with additional fuel
  • Submerged: 1300 kilometers at 2.75 knots (5 km/h), 50 kilometers at 17.5 knots (32 km/h)
• Crew: 12 officers, 16 chiefs, 54 crewmen
• Armament
  • Four P-5 or P-6 or P-500 cruise missiles, fired from vertical launch tubes.
  • Six 533 mm (21 inch) bow torpedo tubes, four 400 mm (16 inch) stern torpedo tubes. Space for six 21-inch torpedoes and twelve 16-inch torpedoes.