Topic summary
SSBN
Extracted from the Wikipedia article Ballistic missile submarine.
Poseidon and Trident I
Although the US did not commission any new SSBNs from 1967 through 1981, they did introduce two new SLBMs. Thirty-one of the 41 original US SSBNs were built with larger diameter launch tubes with future missiles in mind. In the early 1970s the Poseidon (C-3) missile entered service, and those 31 SSBNs were backfitted with it. Poseidon offered a massive MIRV capability of up to 14 warheads per missile. Like the Soviets, the US also desired a longer-range missile that would allow SSBNs to be based in CONUS. In the late 1970s the Trident I (C-4) missile was backfitted to 12 of the Poseidon-equipped submarines. The SSBN facilities of the base at Rota, Spain were disestablished and the Naval Submarine Base King's Bay in Georgia was built for the Trident I-equipped force.