British tanker Lumen visited the Black Sea according to a letter of the German naval attaché at Istanbul dated 30 December 1939

In his letter dated Istanbul, 30 December 1959 B No. 596g. reported the German naval attaché to the Oberkommando der Wehrmacht Abteilung Ausland the ships passing the Dardanelles coming from Romania and loaded with contraband for the enemy. An item mentioned on 28 December the British tanker Lumen loaded with 10,500 ton gasoline bound for England. Armed with 1 gun at the stern and possible 1 flak manned by naval gunners. Dark grey painted, masts, funnel and superstructure light brown.

Source

Bundesarchiv. German Marineattaché for , Greece, Romania and Bulgaria 1939-1941. RM 12-II/459.