Engineer. Born in Leadhills (South Lanarkshire), Symington became a mechanic at the nearby mines at Wanlockhead. He so impressed his superiors that he was sent to attend lectures at the University of Edinburgh. He built several successful steam engines for use in mines and went on to develop the first steam-powered marine engine used to power the world's first paddle steamer - the Dalswinton steam-boat of 1788. Most notably, he built the Charlotte Dundas at Grangemouth, incorporating a novel horizontal steam engine designed by Symington in 1801. The boat was named after the daughter of his patron Lord Dundas (1741 - 1820). It was designed as a canal tug and was demonstrated successfully in 1803. It pulled two 70-ton barges 19½ miles (31 km) along the Forth and Clyde canal in six hours. However, it was never properly used because opponents suggested its wash would damage the canal banks.
Symington retired to London and died a pauper. He is buried at St Botolph's Churchyard (Aldgate, London). Ironically, in the year of his death, a pleasure steamer called the Lord Dundas started excursions through the Forth and Clyde Canal.
