 He was promoted to ensign in 1793, served as a lieutenant on the "Ça Ira" in her fight against a superior British force on 14 March 1795, and was taken prisoner when the ship was captured.After his release, Jacob was appointed to the frigate "Bellone".He took part in the Battle of Tory Island and was again taken prisoner when "Bellone" surrendered to "Ethalion".