I've read that the Swordfish attack on the Bismarck succeeded because the Germans' up-to-date AA fire control computer couldn't be set for such a slow target. By the time they thought to switch to tracer fire, a torpedo had jammed the battleship's rudder.
You are thinking of the Bismarck I suspect, as Swordfish's were certainly responsible for disabling it. The Graf Spee however was scuttled due to fear that it would fall into British hands shortly the Battle of the River Plate.
I could NOT think of the Bismarck for the LIFE of me..... thanks for setting me straight on my history! Hope all is well with you.... I am happy to report that in July, the Offutt AFB air show is returning to our city. Last year was scuttled due to our "wonderful" government and their budget issues. That will be my next round of aviation photos. A bit of a wait but looking forward to it!!!!!