First Circumnavigation of Australia. Unveiled by Lord Mayor of Portsmouth Cllr Paula Riches 19th November 2010. On 18th July 1801, HM Sloop Investigator under the command of Commander Matthew Flinders, Royal Navy set sail from Portsmouth's naval anchorage at Spithead. Commander Flinders had been commissioned to carry out a running survey and chart the entire coastline of the then unknown continent of Terra Australis. The circumnavigation was completed between 6th December 1801 and 9th June 1803. On the return passage Flinders was detained on the Ile de France (Mauritius) for six and a half years, returning to Portsmouth on 24th October 1810, giving Terra Australis the name of Australia