HMS Douglas was an Admiralty type flotilla leader of the British Royal Navy. Built by Cammell Laird, Douglas commissioned in 1918, just before the end of the First World War. During the Second World War, Douglas served with Force H out of Gibraltar and as a convoy escort. She was sold for scrap in March 1945.

SS California was a British 16,792 GRT steam turbine ocean liner built in Glasgow in 1923 for the Anchor Line. She was a sister ship of Cameronia, Tyrrhenia, Tuscania, Transylvania and Caledonia. In 1939 the Royal Navy requisitioned her. She was bombed and abandoned along with the Duchess of York west of Spain by a Luftwaffe attack in July 1943.