'Worked up' and ready for action, on 19 May 1941, the Nazi ships Bismarck and Prinz Eugen set sail from Gotenhafen on the Baltic coast on a mission to cut the British supply route across the Atlantic Ocean from America.
Once out of the Baltic, they headed north. They were spotted during an RAF reconnaissance flight, lying in a Norwegian fjord, but by the time the RAF could strike, Germany's warships had left.
The Home Fleet brought a large number of ships into action to cover all the routes into the Atlantic. But it wasn't until 23 May that the cruiser Norfolk reported that Bismarck had been sighted in the Denmark Strait, where the battle cruiser Hood, the new battleship Prince of Wales, and six destroyers were waiting.
Early the following morning Prince of Wales sighted Bismarck 17 miles away and both ships moved towards the German vessel. At that range, Hood was vulnerable to plunging shell fire. The British ship tried to close up on Bismarck so that any fire would hit her well-protected sides rather than her thinly-protected decks.
Bismarck fires at Hood. (Taken from Prince Eugen)
Hood opened fire first, but her speed and the water spray made accuracy difficult. The Germans, though, shot well using their stereoscopic rangefinders. A shell fromPrinz Eugen hit Hood on the boat deck, causing a fierce fire.
As the two British ships turned round, a salvo from Bismarck hit Hood. There was an enormous explosion and the ship broke in half and then sank within minutes. Only three of the crew of 1,419 survived.
Prince of Wales was damaged but managed to escape.
Bismarck also sustained damage that was serious enough for her to be ordered to St Nazaire in Brittany for repair.
The loss of The Hood sent shockwaves around the Empire and dealt a cruel blow to Britain's confidence in winning the war. Churchill responded by issuing his now famous command, "sink the Bismarck". Her demise was sought, not purely for a military reason, but to secure the revenge and morale of the British people.
For a time the battleship disappeared from view but on the afternoon of 26 May, a patrol aircraft found Bismarck and 14 tiny, fragile Swordfish torpedo bombers from the aircraft carrier Ark Royal hit her three times. One of those hits jammed her twin rudders. The ship could no longer be steered.
Swordfish returns after the strike on 26th May 1941
The Nazi navy knew there was no hope for Bismarck and the U-boats they sent arrived too late to help her. The Home Fleet's Norfolk was the first to make contact with her again, then King George V and Rodney started an attack that lasted two hours.
Despite this pummelling, she still didn't sink until torpedoes from Dorsetshire finally sent Hitler's most fearsome ship to the bottom of the sea - though some people think she was scuttled by her own crew. Her swastika ensign was still flying and her captain standing on the deck, saluting, as she went down.