Prien's U47 crept into the "protected" harbour at Scapa Flow
and successfully torpedoed and sank the unsuspecting 29,150-ton HMS
Royal Oak with a loss of 833 lives in the early hours of the morning on 14th October 1939.
Following this attack U47 was adorned
with what has become one of the most well-known U-boat conning tower
insignias - the snorting bull, also known as "The Bull of Scapa
Prien went on to become one of Germany's most successful submariners and
was theffirst U-boat commander to
be awarded the Knight's Cross.