Soviet submarine K-222

The Soviets were well aware of the drawbacks of the large SS-N-3 Shaddock family of missiles, notably its need to be launched from the surface and its complicated target-acquisition process, both of which rendered the submarines launching the missiles vulnerable to the carriers that they were intended to attack. The Council of Ministers issued a resolution on 28 August 1958 calling for a very ambitious submarine development program that called for a doubling of speed, a 50 percent increase in diving depth, smaller nuclear reactors and steam turbines, and a long-range missile system of small dimensions able to be fired while submerged, and new materials, among other objectives. Design bureau TsKB-16 began development of Project 661, an experimental cruise-missile submarine, later that year in response to the resolution. Chief designer N. N. Isanin decided to begin a clean-slate design that would use existing technology as little as possible. By July 1959 a sketch design was ready for a submarine capable of and the State Committee for Shipbuilding had to make decisions about what the submarine's hull would be constructed of and what type of nuclear reactor would be used. Aluminium was quickly rejected as unsuitable because of its poor resistance to corrosion and poor performance under high pressure at high speeds. While new alloys of steel were still under development, titanium had some major advantages. It was much stronger than steel for a given weight, resisted corrosion better and was non-magnetic. This would help protect it against magnetic mines and registering on magnetic anomaly detectors of anti-submarine aircraft. Disregarding the extremely high cost of titanium compared to steel and that titanium could not be welded in an oxygen atmosphere, the committee selected it. Two types of reactor were potentially available at this time, pressurized water or lead-bismuth eutectic. The Soviets had some experience with the former, but none with the latter; this proved to be the deciding factor as the committee was unwilling to wait for the lead-bismuth reactor to be developed even though it promised to be smaller for the same amount of power output. K-222 would be the first submarine built with a titanium hull. ==Description==

K-222 was a double-hulled design that displaced on the surface and submerged. The boat had an overall length of , a beam of and a draft of . The submarine's inner hull had nine watertight compartments and had an unusual configuration at the bow where the first two compartments were narrower than the rest of the hull and were superimposed in a figure 8 shape; the upper compartment housed the torpedo tubes while the lower contained the massive sonar system and some of the batteries. The third compartment was as narrow as the first two () while the rest of the compartments widened to a diameter of . K-222 had a test depth of and a design depth of . The crew numbered 82 officers and enlisted men. One account of the trial wrote: the biggest thing was the noise of the water going by. It increased together with the ship's speed, and when was exceeded, it was like the noise of a jet aircraft. ... In the control room was not heard simply the roar of an aircraft, but the thunder of "the engine room of a diesel locomotive". Those present believed that the noise level was greater than 100 decibels. The torpedoes could be fired down to a depth of . (NATO reporting name: Pert Spring) satellite-communications system. ==Construction and career==

As large-scale fabrication of titanium was unknown anywhere in the world, techniques and equipment had to be developed from scratch by the Soviets at great cost. The Sevmash shipyard had to invest in new equipment capable of shaping plates up to thick and retrain its workers to weld in an argon atmosphere and a cleanroom environment to prevent contamination of the welds. As part of that process two half-scale sections were constructed, one for testing in a pressure chamber and the other to evaluate shock resistance in Lake Ladoga. The collapse of the section under hydraulic pressure and the presence of cracks in the welds of both structures revealed that the welders at the Severodvinsk shipyard failed to follow the strict cool down time requirements. Further consultations with metallurgical experts reached the conclusion that the steel tools used to fabricate the sections were not suitable for use with titanium. Commissioned on 13 December 1969 and assigned to the Soviet Red Banner Northern Fleet, the boat spent most of the next two years conducting sea trials. K-162 made her first operational patrol in the North Atlantic in September–December 1971. During this patrol, the submarine trailed an American battle group centered around the carrier at high speed as it returned to the United States from the Mediterranean. During a lengthy refit that lasted from October 1972 to January 1975, the shipyard discovered a large number of cracks that required repair. Three years later, K-162 was renamed K-222. During this time, the Soviets assessed the possibility of series production of more boats of the class and concluded that the design would have to be modified with longer-range missiles and more torpedoes to improve its combat worthiness. In addition the excessive noise at high speed eliminated the sonar system's ability to acquire targets and needed to be remedied. Coupled with the submarine's high cost, lengthy building time, and the limited resources available, the navy decided not to proceed with any more boats. Thus the design studies for derivatives like the improved Project 661M, the Project 661A armed with P-120 Malakhit (NATO designation: SS-N-9 Siren) missiles and the Project 661B armed with R-29 Vysota (NATO codename: SS-N-8 Sawfly) ballistic missiles were cancelled. Although K-222 was not regarded as a successful design, the technology developed for the build enabled the Soviet Union to construct the titanium-hulled and attack submarines. In 1988, the boat was placed in reserve at the naval base in Belomorsk, not far from Severodvinsk. Having lost the tools to handle the fuel rods, the navy could not find a company or organization willing or able to defuel the submarine. By 2008 cracks started appearing in the hull and the ballast tanks started taking on water. In March 2010 Sevmash began scrapping K-222 with the reactors and nuclear fuel still on board, and this was completed by 4 June. ==Notes==