@tty I also wanted to add that some pleasure boaters do carry those flags aboard, esp old school ones :>. The signals flags are used in racing(although they have their own code for them). On special occasions boats fly all of the signal flags at once (referred to as being 'fully dressed')
@rek @tty Old skoolers will also tell you there is a correct order for the flags when dressing a ship/yacht. I'm not sure you'd find anyone who'd know what that order is anymore!