USS Marathon (PGM-89/PG-89) was an Asheville-class gunboat acquired by the U.S. Navy for the task of high speed patrolling in shallow waterways. The second ship to be named Marathon by the Navy, PGM-89, a motor gunboat, was laid down 21 June 1966 by Tacoma Boatbuilding Company, Tacoma, Washington; reclassified PG 89 on 28 March 1967; launched 22 April 1967; sponsored by Mrs. Robert W. Copeland; and commissioned 11 May 1968.