Carrier escorts had to change once carriers became the main target

The original scouting concept assumed carriers and cruisers would operate at the edge of the decisive battle, strike or observe, and then withdraw. Once carriers became the enemy's primary objective, withdrawal no longer ended the danger because opposing forces would pursue the flattops. A carrier screen then needed something more robust than a lightly protected scout cruiser, including ships able to trade their own survival for time. The destroyers that tried to defend HMS Glorious provide the grim comparison: courage could not make up for insufficient combat power against heavier attackers.