Turner was the radio officer on SS Manaar, a 150 metres (490 ft) cargo steamer of 7,000 gross register tons (20,000 m3) built in 1917 and operated by the Brocklebank Line.
When most of the crew abandoned the stricken ship, Turner was accidentally left behind with two wounded crewmates, described in the medal citation as lascars.
While under fire from U-38, Turner tried to launch two lifeboats, but one filled with water and the other was destroyed by enemy action with one of the wounded crew inside.
When a ship on which Turner subsequently sailed was also torpedoed he lost a leg, then spent the remainder of the war in a German prisoner-of-war camp.
A painting of Turner by Bernard Hailstone is in the Government Art Collection, on display at the Ministry of Defence in London.