Richard Kempenfelt ( 1718 - 29 August 1782 ) was a British rear-admiral . He joined the navy , was commissioned a lieutenant in January 1741 . He saw service in the West Indies , taking part in the capture of Portobelo during the War of Jenkins ' Ear . In 1746 he returned to England , and from then to 1780 , when he was made rear - admiral , he saw active service in the East Indies with Sir George Pocock and in various quarters of the world . In 1781 he won the Battle of Ushant , with a vastly inferior force , defeating the French fleet under De Guichen and capturing 20 ships . In 1782, Kempenfelt shifted to the ' Royal George ' , 100 guns , as a junior flag officer and he was drowned in her when she sank at anchor at Spithead in August , together with over 800 other people. Kempenfelt was also the inventor of a numeral signal code that helped to revolutionize naval tactics.