USS Elmasada (SP-109) was an armed motorboat that served in the United States Navy as a patrol vessel from 1917 to 1919. Elmasada was built as a civilian motorboat in 1909 by Robert Jacobs at City Island, New York. In mid-May 1917 her owner, C.B. Fox of New Orleans, Louisiana, was ordered to turn her over to the U.S. Navy for use as a patrol boat during World War I. The Navy purchased her from Fox later in May and commissioned her on 4 June 1917 as USS Elmasada (SP-109). Elmasada was attached to the 8th Naval District and employed in patrol and transport duties in the New Orleans area.