Why Britain chose the 13.5-inch step

The 13.5-inch gun was a deliberately conservative choice rather than a technically inevitable one. A direct move to 14 or 15 inches would have sent a larger political and industrial signal, while the smaller increase was easier to absorb and less likely to provoke a sharp reaction. A later American concern illustrates the logic: a full-inch gap between 16-inch American and 15-inch British guns looked more provocative than the half-inch gap between 14-inch and 13.5-inch weapons. Similar thinking may have influenced Britain's G3 and N3 choice of 16.5-inch guns, which promised an advantage over 16-inch rivals while keeping the difference incremental. Even the limited Orion-era advance forced Germany to weigh matching British quality against sustaining numbers with a smaller budget and maritime industrial base.