USS Halibut (SSGN-587)

The USS Halibut (SSGN-587), a United States Navy nuclear-powered submarine, was initially commissioned as an SSGN (guided missile submarine) and later reclassified as an SSN (attack submarine). Halibut was notable for its pioneering role in Cold War espionage and underwater intelligence gathering activities.

Originally designed to carry and launch Regulus cruise missiles, the rapidly evolving nature of ballistic missile technology led to a change in Halibut's mission. In 1965, she entered Mare Island Naval Shipyard for a major conversion. This conversion equipped her with advanced sonar, specialized equipment, and a deep submergence rescue vehicle (DSRV) hangar, transforming her into a highly specialized underwater intelligence platform.

For nearly a decade following her conversion, Halibut undertook clandestine missions to tap Soviet underwater communication cables. She played a crucial role in gathering intelligence about Soviet naval capabilities, submarine deployments, and command and control systems. These operations involved deep-sea diving and sophisticated cable tapping techniques.

In 1976, Halibut entered another overhaul, further enhancing her capabilities for deep-sea operations and intelligence gathering. She continued her clandestine missions until decommissioned in 1994 after nearly 35 years of service. The Halibut's activities were highly classified for many years, and details of her missions have slowly emerged in declassified documents and historical accounts. The ship represents a significant chapter in the history of submarine warfare and Cold War espionage.