United Kingdom
British Royal Navy enlisted man’s cap
Typical flatcap for the Royal Navy with a tally from Her Majesty’s Ship (HMS) Royal Arthur, which is the home of the Navy’s Signalling School, located near Neston. Similar styles are also used by other Commonwealth navies, but usually with a variation on the HMS prefix. For example, Canadian caps will read “HMCS” for “Her Majesty’s Canadian Ship.”