The ship's presence in Scapa Flow may have affected the Germans' plans during Operation Rheinübung, the Atlantic sortie of the battleship in May 1941. German aerial reconnaissance spotted "Iron Duke" and two decoy battleships, merchant ships that had been camouflaged with wood and canvas to look like Revenge-class battleships, in the harbour, and erroneously identified them as active units of the Home Fleet. Under the mistaken impression that the heavy units of the Home Fleet were still in port, the German fleet commander, Günther Lütjens, decided to break into the Atlantic via the Denmark Strait, which resulted in the Battle of the Denmark Strait.