Wm. B. Tennison was built in 1899 by Frank Laird at Crab Island near Oriole, Maryland. Her hull was constructed in traditional Chesapeake log canoe fashion from nine large pine logs, hollowed out and fastened together. She was built as a two-masted sailing bugeye designed mainly for oyster dredging. In 1906-1907, she was converted to engine power, her sailing rig was removed, and a pilothouse was added, giving her the form she retains today. From 1907 until 1978, she worked as a buyboat, hauling oysters and dredging on leased oyster beds, and for much of that time was owned by the J. C. Lore and Sons company of Solomons. In 1979, the Calvert Marine Museum acquired her from her last owner, Alton Kersey. She now serves as a floating exhibit and tour boat and has become a symbol of the maritime heritage of Calvert County. She is listed on the National Register of Historic Places and was designated a National Historic Landmark in 1994.