Capt Thomas II Sumner

Captain Thomas Hubbard Sumner (1807–1876) was an American sea captain best known for developing the Sumner line, a revolutionary celestial navigation method discovered during a 1837 voyage from Charleston, South Carolina, to Greenock, Scotland.[1][2] He published his findings in 1843 in 'A New and Accurate Method of Finding a Ship’s Position at Sea,' which was widely adopted, including by the U.S. Navy.[1][2] A Harvard graduate (A.B. 1826), he became a captain by 1847 but suffered mental illness from 1850 onward, spending his later years in McLean Asylum.[2][5]