Alfa class submarine
|
|
The Soviet Union/Russian Navy Project 705 (Lira) were a submarine class of hunter/killer nuclear powered vessels (Podvodnaya Lodka Atomnaya). The class is also known by the NATO reporting name of Alfa. At the time of the first launch they were believed to be the fastest and deepest diving submarines in existence.
| Contents |
Preproduction
The initial design work began in 1957 and was highly innovative. A special titanium alloy hull would be used to create a small, low drag, 1,500 ton, three compartment vessel capable of very high speeds (in excess of 40 knots) and deep diving. The submarine would operate as an interceptor, remaining in harbour and then racing out to reach an approaching fleet. A high-power liquid metal cooled nuclear plant and extensive automation would also greatly reduce the needed crew numbers to just 17 or so. The real-life problems with the design became quickly apparent and in 1963 the design team was replaced and a less radical design was proposed, increasing the vessel weight by 800 tons, increasing all main dimensions and doubling the crew.
A prototype, Project 661 or K-377, was built at the Sudomekh yards in Leningrad and completed in 1972. The long build-time was caused by numerous difficulties in manufacture and design flaws. Extensively tested and reconfigured it was scrapped in 1974 following a reactor accident. It reportedly had a top speed of 44.7 knots and a claimed dive depth of 800 m. This combined with other reports created some alarm in the U.S. Navy and prompted the rapid development of the ADCAP torpedo program and the Sea Lance and W-class submarine projects (both cancelled when more definitive information about the Soviet project was known).
Production
Production started in 1974 as Project 705 with construction at both the Admiralty yard, Leningrad and at Sevmashpredpriyatiye, Severodvinsk. The first vessel was commissioned in 1977. In 1983 with the completion of the seventh vessel production ended. All vessels were assigned to the Northern Fleet. It is believed that the last three boats were for testing purposes only and had only steel hulls.
It appears that the capabilities of the vessels were over-estimated and that they suffered from a number of problems. For a submarine, it was dangerously noisy at high speeds and the 155 MW BM-40 reactors proved to be unreliable—the liquid metal coolant often leaked and could solidify if the system did not run constantly to avoid this. Four vessels were decommissioned due to reactor failures of this type. Certain reliability and efficiency problems were also reported with the weapon and detection systems.
Decommissioning
The first vessel was decommissioned in 1987 and four more before the end of 1992. The final vessel underwent a refit and was loaded with a VM-4 pressurised-water reactor as Project 671, after being used for training she was decommissioned in 1995.
General Characteristics
- Displacement when surfaced: 2,900 tons
- Displacement when submerged: 4,300 tons
- Length: 80 m
- Beam: 9.5 m
- Draft: 7 m
- Max depth: 350 m (safe), 610 m (crush)
- Compartments: 6
- Complement: 43 officers
- Reactor: OK-550 or BM-40, liquid-metal cooled, 155 MW (one or two vessels later received a VM-4 pressurized water reactor)
- Propulsion: Two steam turbines, 45,000 shp, 1 propeller
- Speed (submerged): 43 knots
- Armament: six 533mm torpedo tubes:
- 18-20 torpedoes (or)
- 21 SS-N-15 cruise missiles (or)
- 12 SS-N-16 cruise missiles (or)
- 24 mines