Why a warship refit cannot ignore the hull structure

Warspite-scale reconstruction had to work with the ship's existing frames, subdivision, strong points and load paths. New superstructure weight needed adequate support through the hull. Hood's armor illustrates the same structural constraint: belt thickness alone did not give her the depth and coverage of a contemporary battleship's protection, because the subdivision and supporting framework differed. Carrier design offers another example through the distinction between the hull girder and superstructure. Earlier American flight decks were treated as superstructure, while British arrangements incorporated different parts of the carrier into the hull's strength. The American comparison changes with the Midway class.