Shad was built as a private motorboat of the same name by George Lawley & Son at Neponset, Massachusetts in 1907. On 15 May 1917, the U.S. Navy purchased her from Herbert C. Talbot for use as a section patrol vessel during World War I. She was commissioned as USS Shad (SP-551) on 24 May 1917. Presumably assigned to the 1st Naval District, Shad served on patrol duties in Boston Harbor at Boston, Massachusetts, for the rest of World War I and during the first few months of 1919.