The Royal Navy force to add in 1939

How many additional Renown-like ships would have most helped the Royal Navy in 1939?

Two more Renowns and a second Hood, all modernized, plus several additional carriers would substantially improve the opening-war fleet.

Fast capital ships could cover distant stations and counter German raiders in ways older battleships could not. The preferred additions would raise the opening fleet toward twenty capital ships. Pairing them with a carrier force closer to ten hulls, including more Ark Royal-like ships, would account for both surface strength and naval aviation. The answer is a compact force-structure exercise built around the Royal Navy's early-war global commitments.