The M.M. Hamilton, originally a sloop, was built in 1869 by Sylvester Stover at Stover’s Cove in Harpswell. Commissioned by John Hamilton of Chebeague Island and named after his wife, Mercy Melissa Hamilton, the ship played an important role in the transportation of large blocks of granite for several notable projects, including the Washington Monument, Chicago Auditorium, and the State War and Navy building at Annapolis.

Measuring 95 feet in length and weighing 111 gross tons, the M.M. Hamilton was constructed from sturdy white oak. In 1916, the vessel was converted from a sloop to a two-masted schooner when it entered general coastwide trade under the ownership of the Bernstein brothers. In 1930, a group of researchers purchased the ship.