But only one submarine had the poor luck to sink twice.
The Charlie class (Project 670) was the third class of cruise-missile submarines (SSG) deployed by the Soviet Union, and the second to use nuclear propulsion (SSGN). The Soviet Navy expected to use early SSGs and SSGNs to attack American land targets, primarily cities and naval bases, with conventional and nuclear warheads. The cruise missiles of the time lacked sophisticated guidance mechanisms, making attacks against the interior impossible. Over time, the improvement of radar-homing technology (as well as improvements in ballistic-missile technology) allowed the Soviets to reconceptualize the use of cruise missiles. The Echo II class, the immediate predecessor to the Charlies, were built with an anti-shipping role in mind. Antiship missiles appealed to the Soviets because of the noise of their submarines; the Soviet Navy did not expect that its boats could close within sufficient range to hit American capital ships with torpedoes.
Designed in the early 1960s, the first Charlie entered service in late 1967. Displacing 4900 tons and capable of twenty-four knots, the Project 670 submarines fired the P-70, a subsonic missile which could deliver a conventional warhead or a two-hundred-kiloton nuclear device up to thirty-five miles. This was not a particularly long distance, almost certainly within the anti-submarine warfare (ASW) reach of a carrier battle group or other major NATO asset, but development problems with a new missile forced the design choice. In any case, the ability of the Project 670 boats to fire while underwater gave NATO planners new headaches.
Tenth in its subclass, K-429 entered service in September of 1972. She joined the Pacific Fleet, homeported in Petropavlovsk. In early 1983, she entered port for an extensive refit, with her crew departing on leave. Nuclear-armed cruise missiles and torpedoes remained aboard the boat during refit.
In spring of 1983, tensions between the United States and the USSR ran as high as at any point in the Cold War. In addition to supporting anti-Soviet guerrillas in Afghanistan, the United States had begun aggressively testing Soviet air and sea defenses all along the USSR’s extensive border. In April, the U.S. Navy and several partners began Fleetex ‘83, a major exercise in the North Pacific. The exercise included the USS Midway and USS Coral Sea carrier battle groups, as well as numerous additional surface ships, aircraft, and submarines. At one point, U.S. aircraft overflew islands in dispute between the USSR and Japan.
Possibly in part because of the heightened tensions, the Soviet Pacific Fleet ordered K-429 back to duty before expected, and before the completion of her overhaul. Captain Nikolai Suvorov could not find his crew, and so went to sea (under protest) with an ad hoc crew assembled from several different submarines, including 120 men and two captains. Few of the men onboard K-429 had any direct familiarity with her systems.