 On 11 September 1939 , while flying the Irish tricolour , Inverliffey was shelled and sunk . In spite of Captain William Trowsdale 's protestation that they were Irish , Liebe said that they " were sorry " but they would sink Inverliffey as she was carrying contraband petrol to England . The crew took to the lifeboats . Inverliffey burned fiercely , endangering the lifeboats . At risk to herself , the German submarine approached , threw lines to the lifeboats and towed them to safety . As Captain Trowsdale 's lifeboat was damaged , the occupants were allowed to board the U @-@ boat . The captain did not have a lifebelt , so he was given one . U @-@ 38 stopped the American tanker R.G. Stewart and put Inverliffey 's crew on board . Just two days earlier , Inver tankers transferred its ships from the Irish to the British registry . 
