Edward Conor Marshall O'Brien (3 November 1880 – 18 April 1952) was an intellectual, Irish aristocrat, republican, nationalist, pioneer in modern maritime theory, owner and captain of one of the first boats to sail under the tri-colour of the Irish Free State, during his circumnavigation in the Saoirse. He was a grandson of the Fenian William Smith O'Brien. Reputedly this was the first small boat to sail around Cape Horn. This is slightly unfair to Joshua Slocum, the Bostonian, who was the first single-handed yachtsman to successfully pass this way (in 1895) although in the end, extreme weather forced him to use some of the inshore routes between the channels and islands and it is believed he may not have actually passed outside the Horn proper. Given the scale of Slocum's achievement it might be considered unfair to deprive him of the honour! Although it was nearly 30 years later, a strict definition of "the first small boat to sail around outside Cape Horn" could indeed cover the 42-foot (13 m) yacht Saoirse, sailed by Conor O'Brien with three hands, who rounded it during a circumnavigation of the world between 1923 and 1925 It was the first boat flying the Irish tri-colour to enter many of the world's ports and harbours. He was a ship builder/designer (notable boats include the Saoirse and AK Ilen ), gun runner for the Irish Volunteers during the war of independence in Ireland, captain of a ship sailing in the merchant navy during WWII.