The Royal Navy already had 13.5-inch weapons available, while the known 15-inch turrets can be traced to the R-class program rather than to Agincourt. Small-tube boilers and geared turbines do appear where the Agincourt project can plausibly explain their development. An 18-inch gun program also emerges in the right period without another matching battleship project. The case rests on component provenance and timing. It remains an inference rather than a settled reconstruction of the ship.
Notable Point · 39:19-40:59
The component evidence behind an 18-inch Agincourt hypothesis
An 18-inch-gun Agincourt remains a hypothesis based on machinery and gun-program timing.