Theres alot of Bismark stuff going at the moment particularly a movie by James Cameron. He made the Titanic movie so you will see not someone who lets facts get in the way of a good movie !
He did Lightroller no favours in that move and then gave a token apology payment to his kin !
Basically his claim was that the Bismark was not sunk by the British Navy but that she was scuttled by the German Navy.
I dont suppose it occured to him WHY they scuttled it !
Several groups have been down to it and the reports vary from lots of torpedo holes to no damage apart from the scuttling charges.
Incidentally one of the reports states that she had an Armoured Belt on the water line ( so did the Prince of Wales !!) and that the water and fuel tanks were all aound the outer hull skin as sacrificial compartments. Fuel Tanks
Anyway she was classed as unsinkable ( now where have I heard that before
)