The Bismarck and the Prinz Eugen sailed from Gotonhafen in occupied Poland on the 19 May 1941. Operation Rhine had begun. Admiral Lutjens had to sneak through the gap between Denmark and Norway in order to escape into the North Sea. His major concern was to avoid being spotted and allow the Royal Navy time to prepare.

Unfortunately for the Germans the Bismarck was noticed by the Swedish cruiser Gotland. Although the Swedish were officially neutral there were both pro and anti Nazi sympathizers. Fortunately for the British the navy was on their side, and the information was passed on to Captain Henry Denham, Britain's naval attaché in Stockholm.

The threat of the Bismarck breaking out was now a possibility, and the British increased their reconnaissance around occupied Norway. This was done because the German ships would need to refuel in one of the many fjords there, and this might give the Royal Air Force a chance to bomb them.

The Bismarck in port.