The speculative 18-inch HMS Agincourt

Two readings survive for the British ship originally ordered as HMS Agincourt: the conventional view that she was another Queen Elizabeth and a speculative fast variant with fewer, larger guns and additional machinery. One line of inference connects the cancellation, Portsmouth construction, small-tube-boiler work, later Renown arrangement, and the otherwise unexplained 18-inch '15-inch special' guns. Three twin 18-inch turrets might fit with altered barbette placement and only a modest increase in beam. Combining those turrets with small-tube boilers could produce roughly 30 knots in an exploratory estimate. The evidence remains inconclusive, and the conventional sixth Queen Elizabeth interpretation may still be more likely.