What weapons would suit quickly built Vanguard-style battleships?
Short answerProven British 15-inch guns, or possibly Nelson-type 16-inch guns, in a fast capital-ship layout.
NotesA Vanguard-style program works best when a navy already owns guns worth reusing. Britain had unusually capable 15-inch weapons, established facilities, and experience supporting them. Those guns, or possibly Nelson-type 16-inch weapons, could go into a fast hull with a Renown- or Repulse-like arrangement. Reusing a mature gun ecosystem would let shipbuilding concentrate on producing the new hull quickly.