More efficient propellers and more power-dense engines let later ships reach speeds that earlier designers could not obtain from comparable machinery spaces. A simple speed threshold cannot reliably separate battleships, fast battleships, battlecruisers, and related categories across long periods. Comparisons work better within similar technological generations, where propulsion capability and design constraints are genuinely comparable. The end of the naval-treaty system could create a new generation within only a few years, so even ships designed close together may embody different assumptions.
Notable Point · 37:27-39:04
Propulsion generations complicate warship classification
Speed alone cannot define battleships and battlecruisers when propellers, engines, and treaty conditions change rapidly between design generations.