The gas-turbine Librarian-class battlecruiser

The closing study explores what gas turbines make possible in an ahistorical 1940 capital ship. The design starts as a very fast battlecruiser, but low engine efficiency, weight distribution, armour, range, and armament force repeated revisions. Speed is reduced while endurance remains about 24,000 kilometres. The completed design combines 18-inch main guns with a stated range of roughly 52 kilometres, 6-inch and 3-inch secondary batteries, and selective armour reductions to remain within displacement. Once named the Librarian class, ten ships are ordered, turning the exercise into a major procurement commitment rather than a one-off curiosity.