Why Hood was not simply a fast battleship

The Lexington design belongs to a first American battlecruiser generation intended for scouting and economic warfare, making it conceptually closer to the original Invincibles than to Hood. Hood represented a partial reset after Renown and Repulse rather than a simple step toward the fast battleship. Design density provides a way to compare how much protection, armament, and speed were packed into a hull for its period. On that basis, Tiger can make at least as strong a contemporary claim to fast-battleship status as Hood, so calling Hood a fast battleship without the same treatment for Tiger obscures their lineage.