Echo-class submarine

Nuclear-powered cruise-missile submarine of Project 675 (Echo II)
Class overview
Builders:	Komsomolsk-on-Amur, shipyard No. 199 Severodvinsk, shipyard No. 402
Operators:	Soviet Navy  Russian Navy
Preceded by:	Whiskey Long Bin
Succeeded by:	Juliett class submarine
In commission:	19 November 1960–15 July 1994
Completed:	Echo I : 5 Echo II : 29
General characteristics
Type:	Nuclear submarine
Displacement:	Echo I : 3,768 long tons (3,828 t) surfaced 4,920 long tons (4,999 t) submerged Echo II : 4,415 long tons (4,486 t) surfaced 5,760 long tons (5,852 t) submerged
Length:	Echo I : 111.2 m (364 ft 10 in) Echo II : 115.4 m (378 ft 7 in)
Beam:	Echo I : 9.2 m (30 ft 2 in) Echo II : 9.3 m (30 ft 6 in)
Draught:	Echo I : 7.1 m (23 ft 4 in) Echo II : 7.4 m (24 ft 3 in)
Propulsion:	Echo I : 2 pressurized water-cooled reactors 44,500 hp (33 MW) each, 2 steam turbines, 2 shafts Echo II : 2 pressurized water-cooled reactors 70,000 hp (52 MW) each, 2 steam turbines, 2 shafts
Speed:	Echo I : 15.1 knots (17.4 mph; 28.0 km/h) surfaced 24.2 knots (27.8 mph; 44.8 km/h) submerged Echo II : 14 knots (16 mph; 26 km/h) surfaced 22 knots (25 mph; 41 km/h) submerged
Range:	18,000–30,000 miles (29,000–48,000 km)
Endurance:	50 days
Test depth:	300 m (984 ft)
Complement:	104-109 men (including 29 officers)
Armament:	Echo I : 6 × P-5 Pyatyorka cruise missiles 4 × 533 mm (21 in) bow torpedo tubes 2 × 400 mm (16 in) bow torpedo tubes 2 × 400 mm (16 in) stern torpedo tubes Echo II : 8 × P-6 cruise missiles 4 × 533 mm (21 in) bow torpedo tubes 2 × 400 mm (16 in) stern torpedo tubes Echo II mod : P-6 replaced with 8 × P-500 or P-1000 (SS-N-12 "Sandbox") missiles

The Echo class were nuclear cruise missile submarines of the Soviet Navy built during the 1960s. Their Soviet designation was Project 659 for the first five vessels, and Project 675 for the following twenty-nine. Their NATO reporting names were Echo I and Echo II. All were decommissioned by 1994.

The Soviet Echo I class (Project 659 class) were completed at Komsomolsk in the Soviet far east in 1960 to 1963. The Echo I class were classed as SSGNs armed with six launchers for the P-5 Pyatyorka (SS-N-3C, "Shaddock") land-attack cruise missile. The Echo I class had to operate in a strategic rather than anti-shipping role because of the lack of fire control and guidance radars.

As the Soviet SSBN force built up, the need for these boats diminished so they were converted to the Project 659T SSN's between 1969 and 1974. The conversion involved the removal of the cruise missiles, the plating over and the streamlining of the hull to reduce underwater noise of the launchers and the modification of the sonar systems to the standard of the November-class SSNs.

All the Echo Is were deployed in the Pacific Fleet although K-122 was damaged by a fire in compartment VII during a patrol mission near Okinawa in August 1980 and had to be towed back to Vladivostok for emergency dry docking (the submarine was removed from active service in October 1985). The last two boats were scrapped in the early 1990s.

The Echo II class (Project 675 class) were built at Severodvinsk (18 vessels) and Komsomolsk (11 vessels) between 1962 and 1967 as anti-carrier missile submarines. The Echo II class carried eight P-6 (SS-N-3a "Shaddock") anti-ship cruise missiles mounted in pairs above the pressure hull.