The 'mighty' Hood was the pride of the British Navy for more than 20 years, revered around the world as the largest and most powerful warship afloat. But when it was sunk by the German battleship Bismarck off the coast of Greenland on 24 May 1941, its end was shockingly swift. For decades, no one has been able to discover why the Hood sank so quickly and two official Boards of Inquiry investigated but failed to explain the tragedy.