Why Royal Navy calibers used decimals

Why did the Royal Navy write gun calibers as decimal inches rather than fractions?

Decimals were easier to calculate, write, and type as the service gradually adopted more decimal practice.

The question contrasts decimal-inch labels such as 13.5 with fractional notation. The Royal Navy moved slowly toward decimal practice because it simplified calculations and written records. Typewriters offered another practical reason to prefer a decimal point over typeset fractions. The convention brought administrative convenience to an otherwise non-decimal measurement system.