Was Bismarck the world's most powerful battleship when she entered service?
Short answerNo; her fame rests heavily on the destruction of Hood, while her design contained serious inefficiencies and vulnerabilities.
NotesBismarck did not displace Nelson, Rodney, Hood, or Nagato from the top rank. The German design was inefficient and burdened by committee compromises. The famous hit on Hood transformed Bismarck's reputation, while a similarly fortunate British hit could have ended the German ship's career at Denmark Strait.