Gundalow

A gundalow is a type of flat-bottom cargo vessel once common in Maine and New Hampshire rivers. Up to 70 feet (21.34 m) long, they characteristically employed tidal currents for propulsion, with a single lateen sail to harness favorable winds.

Cannon-sporting gunboat style gundalows were built and deployed on Lake Champlain by both British and American forces during the American Revolutionary War, meeting in combat at the Battle of Valcour Island.

A replica gundalow, the Piscataqua, is maintained by a New Hampshire non-profit and employed extensively in grade school educational programs and raising environmental awareness among neighboring New Hampshire and Maine seacoast communities.

...
Wikipedia