Captain John Smith Chesapeake National Historic Watertrail Study Act of 2005 - Amends the National Trails System Act to direct the Secretary of the Interior to carry out a study to determine the feasibility of designating as a national historic trail the Captain John Smith Chesapeake National Historic Watertrail, a series of routes extending along the Chesapeake Bay and its tributaries in Virginia, Maryland, Pennsylvania, Delaware, and the District of Columbia that traces Captain Smith's voyages charting the land waterways of the Chesapeake Bay and it's tributaries.