The bastion became an important strategy for the ballistic missile submarine fleets of the
Soviet Union during the
Cold War. The
Barents Sea was made a bastion for the
Soviet Red Banner Northern Fleet, and the
Sea of Okhotsk for the
Soviet Pacific Fleet, both of which remain important to the
Russian Northern Fleet and the
Russian Pacific Fleet. The
Soviet Union had (and, even more so,
Russia now has) limited access to the world's oceans: her northern coast is ice-bound at least the majority of the year, and access to the Atlantic requires transiting the
GIUK gap; much of her eastern coast is also ice-bound and requires moderately close approaches to either
Alaska or
Japan; travel from her southern ports involves transiting first the
Bosphorus and
Dardanelles, and then either the
Strait of Gibraltar or the
Suez Canal. The
Soviet Navy originally attempted to directly contest with the navies of
NATO for control of the
blue-water ocean. As the
Cold War progressed, however, it became clear that the Soviets could not win a toe-to-toe fight in the deep water, and the information sold to the Soviets by the
Walker spy ring in the 1980s made it clear that the ballistic missile submarines, in particular, were very unlikely to be able to carry out their nuclear attack missions. Realizing their vulnerability, the Soviets adopted a two-level approach. They armed their older, noisier, and less reliable "second generation" ballistic missile submarines with shorter-range nuclear weapons and deployed them as close as possible to the
United States.
Soviet submarine K-219, which suffered a catastrophic explosion and fire off
Bermuda on 3 October 1986, was one such boat. Meanwhile, they used the information provided by Walker to build both dramatically improved attack boats such as the , as well as more-survivable "boomers" such as the armed with increasingly accurate and long-range missiles. Then they held those "third-generation" boats close to home, patrolling only near and under the Arctic ice cap. To secure the bastions, they also built large numbers of
Sovremennyy- and s, whose primary mission was anti-submarine barrier and picket patrol; furthermore, the Soviet carrier-building projects were dedicated to defense of these bastions as well rather than independent
strike groups, with
Moskva-class limited to anti-submarine
helicopters,
Kiev-class carrying
VTOL fighters as well as helicopters and a sizeable array of weapons (hence the designation
"aircraft-carrying cruiser"), and, finally,
Kuznetsov-class "heavy aircraft-carrying cruiser" fielding
fixed-wing interceptors. The
United States Navy practiced penetrating these bastions; one such attempt resulted in the
20 March 1993 collision between
USS Grayling (SSN-646) and
K-407 Novomoskovsk, a
Delfin-class ballistic missile submarine. The collision was inadvertent and potentially catastrophic, but did demonstrate that US attack submarines were able to get rather near their intended prey. == Chinese naval bastions ==