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 bugeye designed mainly for oyster dredging. In 1906-1907, Tennison was converted to engine power, her sailing rig was removed, and a pilothouse was added, giving her the appearance she retains today. From 1907 until 1978, she worked as a buyboat, hauling oysters and dredging on leased oyster beds. For much of that time she was owned by the J. C. Lore and Sons Company of Solomons. She was acquired by the Calvert Marine Museum in 1979 from her last owner, Alton Kersey. Today she 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 in 1994 was designated a National Historic Landmark.