Marine engineer. Napier began in his father's works at Camlachie and built the boiler for Henry Bell's pioneering Comet in 1812. He took over the Camlachie Foundry from his father in 1814 turning it into a successful engineering firm and establishing his reputation as one of the best builders of marine engines in Scotland. By 1818, he was designing engines for ocean-going ships. In 1821 Napier moved to Lancefield Quay on the north bank of the Clyde and Camlachie was taken over by his better-known cousin (and brother-in-law) Robert Napier (1791 - 1876). At Lancefield, Napier began to construct complete ships, including the Aglaia which, in 1827, was one of the world's first iron steam-ships. Napier is credited with several other innovations during his long career.