Blackwall is a small town located at Gravelly Beach on the western side of the Tamar River, north of Launceston, Tasmania, Australia. At the 2011 census, Blackwall had a population of 618.Named after Blackwall on the River Thames in England, it was likewise a noted shipbuilding centre. The second-largest ship built in Tasmania during the 19th century, the 547-ton barque Harpley, was launched here in 1847.