USS Sylvia, a 48' 6" patrol craft, was built prior to World War I at Marco, Florida, as a civilian pleasure craft. She was acquired by the Navy in June 1917 and placed in commission early in the following September. Sylvia served in Florida waters during the remainder of the First World War and into the first months of peace. In April 1918 her name was changed to SP-471. While awaiting sale at Key West, Florida, in September 1919, USS Sylvia was destroyed by a hurricane.