Why equal treaty limits push battleships toward convergence

What design paths would the treaty powers follow with a 40,000-ton battleship limit and a slow replacement cycle?

Their major characteristics would converge, with competition moving into turret layouts, detailed systems, and each navy's willingness to stretch the rules.

Under the same displacement ceiling, the treaty powers would probably converge on broadly similar speed, protection, and main-battery power. National differences would remain in turret arrangement and the willingness to understate displacement rather than in entirely different categories of ship. Britain might begin with four twin turrets while competitors adopted triples, but observing later batches would push designs closer together. The arms race would therefore continue through configuration, machinery, and incremental features even when the treaty constrained the headline characteristics.