 USS Halibut (SSGN-587)

USS Halibut (SSGN-587) was a ballistic missile submarine of the United States Navy, and it was the first submarine to be converted from a Fleet Ballistic Missile (FBM) submarine into a guided missile submarine (SSGN). Commissioned in 1959, the USS Halibut was designed primarily for the purpose of launching Polaris missiles.