At what point did ironclad battleships become obsolete?
Short answerBy the Royal Sovereign era, when their limitations were too serious to be overcome simply by concentrating more ships.
NotesIronclad obsolescence was not a single instant defined by the launch of the first Royal Sovereign. The stage represented by HMS Repulse within the class offers a better marker. By then, the newer battleship's advantages were too large for older ironclads to overcome merely through greater numbers. Obsolescence here is a widening capability gap rather than a ceremonial date.