Lightship Overfalls is at jct. Pilottown Rd. and Shipcarpenter St. With a 1,000-watt flashing electric lantern, a foghorn with a 5-mile range and a radio beacon capable of transmitting 25 miles, this floating lighthouse served as a navigation aid along the East Coast, first in Long Island Sound, then in Boston Harbor. Built in 1938, it was decommissioned in 1972. A tour includes the interior and exterior of the ship.