Elswick and competing firms explored 13.5-inch and 14-inch weapons because manageable caliber increases fitted existing industrial and logistical capacity. A navy using existing stores and handling equipment found a one-and-a-half-inch step easier than a wholesale change, while a state building new infrastructure had more freedom. The Royal Navy normally entered after manufacturers had already proved a concept, then paid to adapt it to service requirements. Its 15-inch program departed from that pattern by committing during the proof stage rather than waiting for completed test weapons. Contemporary catalogs nevertheless show that 16- and 16.5-inch concepts were already under consideration, and the wider British-American-Italian-Japanese qualitative race encouraged each navy to seek the next practical advantage.
Chapter · 26:20-32:12
From 12-inch guns to the risky 15-inch program
Gunmakers normally developed larger weapons incrementally before the Royal Navy paid to refine them, making the 15-inch gun's early official backing unusual.