MAYPORT, Fla. ? Sailors in blue lined the deck of the aircraft carrier USS John F. Kennedy on Friday as guns boomed to commemorate the decommissioning of "Big John" after nearly 40 years of service. Officers gathered in front of a screen displaying a large American flag, and speakers echoed the words of the carrier's namesake, including the famed line from President Kennedy's 1961 inauguration: "Ask not what your country can do for you, ask what you can do for your country."