SSBN-608 Ethan Allen-Class FBM Submarines
The Ethan Allen class of fleet ballistic missile submarine was an evolutionary development from the George Washington Class. The Ethan Allen, together with the George Washington, Lafayette, James Madison and Benjamin Franklin Classes comprise the "41 for Freedom."
Rather than being designed as Skipjack class attack submarines with a missile compartment added, the Ethan Allens were designed from scratch as Fleet Ballistic Missile (FBM) submarines carrying the Polaris A-2 missile. In the early and mid-1970s, they were upgraded to Polaris A3s. Because they could not be modified to carry the larger diameter Poseiden missile, in the early 1980s they were refitted as SSNs (attack submarines) — fire control systems were removed and the missile tubes were filled with concrete. Two were further converted to carry SEALs, accommodating 67 troops each. The Ethan Allen class submarines were decommissioned between 1983 and 1992. All have now been broken up.
The USS Ethan Allen, (SSBN-608) operating in the Pacific as a unit of Joint Task Force 8 Operation Frigate-Bird," fired the only nuclear-armed POLARIS missile ever launched on 6 May 1962. A POLARIS A1 missile was launched from the USS Ethan Allen (SSBN-608) while submerged in the Pacific, and its nuclear warhead was detonated over the South Pacific at the end of its programmed flight. The shot was made during the 1962 atomic tests and hit "right in the pickle barrel." The captain of the 608 was Paul Lacy, and ADM Levering Smith was aboard. To date, this is the only complete proof test of a U.S. strategic missile. With the ban on atmospheric testing, the chances of another similar test are remote.
The USS John Marshall (SSBN-611) became the last submarine to give up her POLARIS A2's for POLARIS A3 capability when she went into overhaul on 1 November 1974.
Some of these submarines were later reclassified as attack submarines under the Strategic Arms Limitation Treaty (SALT) agreements.
General Dynamics, Electric Boat Division;Power Plant:
Newport News Shipbuilding.
S5W nuclear reactor,Length:
Two geared steam turbines,
410.4 ft (125.1 meters)Beam:
33.1 ft (10.1 meters)Displacement:
7,900 tons submergedSpeed:
16 knots surface,Test Depth:
21 knots submerged.
126 Enlisted (two crews, Blue and Gold).
16 Fleet Ballistic Missiles,
4 x 21 in torpedo tubes.