British cargo ship King Idwall visited the Black Sea according to a letter of the German naval attaché at Istanbul dated 3 February 1940

In his letter dated Istanbul, Turkey 3 February 1940 No. 712 g. reported the German naval attaché to the Oberkommando der Wehrmacht Abteilung Ausland the neutral ships passing Istanbul coming out of the Black Sea and loaded with contraband for or chartered by the enemy. An item 0n 28 January reported the British cargo ship King Idwall loaded with 7,750 ton wheat underway from Varna, Bulgaria to London, England.

Source

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