This 1806 naive portrait is attributed to an artist named Nathaniel Wales. The title of the painting is Portrait of Captain Nathan Sage, as are the paintings below.
I think it's interesting that there was a marine artist named George Canning Wales (1868-1940). This is what I was able to find out about him online, along with some of his etchings:
George Canning Wales' passion was for ships and the sea. As a youth, he was around the wharves in Boston before the steam ships replaced the romantic sailing vessels. In his own words, he sketched obsessively the ships that arrived in the Boston area, recording the ships and their riggings. He spent the mid-part of his life as a professional architect before turning to printmaking around his fiftieth birthday. His early love of ships and the sea is present in his etchings and lithographs.
George C. Wales was born in Boston in 1868. He studied architecture at the Massachusetts Institute of Technology from 1885-88. His first job was with the architects, Peabody & Stearns; founded his own architectural firm in Boston 1893-1924; studied etching in 1917 with William M. Paxton; and produced his first etchings that year. He studied and mastered lithography in 1923. His first exhibition was held at Goodspeed's Book Shop in 1921. The venerable, but now closed, Boston gallery and book store published a catalogue raisonne of the artist's prints in 1927. His prints are in the permanent collections of many museums and institutions including The Boston Public Library, Library of Congress, New York Public Library, Peabody Museum, Old Dartmouth Historical Society, The British Museum, Victoria and Albert Museum, and the U. S. Naval Academy.