The Cloch Lighthouse is located at the side of the A770 road by Cloch Point, Inverclyde, 2½ miles (4 km) west southwest of Gourock, on the eastern shore of the Firth of Clyde, directly opposite Dunoon. Built in 1797, it was designed by Thomas Smith (1752 - 1815), with the assistance of Robert Stevenson (1772 - 1850). The squat white tower features a single black band and rises 23m (76 feet) above sea level. The light has a range of 14 miles (23 km) and was originally illuminated by an acetylene flame, with the lenses floating on a bath of mercury and rotated by a clockwork mechanism, which had to be wound by the lightkeepers every few hours. A foghorn was added c.1897.