Boston Harbor is located on the eastern shore of the Commonwealth of Massachusetts, on Massachusetts Bay. The Corps of Engineers and the Massachusetts Port Authority (Massport) are evaluating a number of improvements to Boston Harbor. These improvements include deepening and widening portions of the Broad Sound North Entrance Channel, Main Ship Channel, and lower Reserved Channel and its turning area for the benefit of larger container vessels calling on Massport's Conley Terminal. To assist in evaluating these improvements, the U.S. Army Engineer Research and Development Center (ERDC) conducted a ship-simulator based navigation study. Data for the simulation models were obtained during a site visit to ride ships in the project area. Currents for both the existing and proposed channels were calculated using the ADCIRC computer model in a joint effort between ERDC and the U.S. Army Engineer District, New England. Harbor pilots traveled from Boston to validate and operate the simulations in September 2005.