Ethan Allen-class (SSBN-608)

The Ethan Allen class was a United States Navy class of five fleet ballistic missile submarines. It was an evolutionary development from the George Washington class and the first class designed from the keel up for the ballistic missile role under project SCB 180. The vessels were built between 1959 and 1963.

The design was more streamlined and longer than the preceding George Washington class. While functionally similar to its predecessors, this class was a purpose-built design rather than a modification of an attack submarine. The vessels were designed for the Polaris missile system. Although the class received missile upgrades in the 1970s, the hull dimensions could not be modified to accommodate the Poseidon missile.

The class served as part of the "41 for Freedom" fleet, which comprised the primary naval nuclear deterrent through the late 1980s. The submarines were commissioned between 1961 and 1963 and remained in active service until the early 1990s.

To comply with the SALT II treaty as Ohio-class submarines entered service, the Ethan Allen class was re-designated as attack submarines in the early 1980s. During this conversion, missile fire control systems were removed and missile tubes were filled with concrete. The USS Sam Houston and USS John Marshall underwent further modifications to support special operations. These changes included the installation of dry deck shelters for SEAL Delivery Vehicles and additional accommodations for special operations personnel. The class was decommissioned between 1983 and 1992. All five vessels were disposed of through the nuclear Ship-Submarine Recycling Program between 1992 and 1999.