Salutations!

[desperance]

Because I've been reading so much Patrick O'Brian, where ships are constantly firing off salutes to the flag or the governor or an allied fortress - and get quite huffy if their salutes are not returned promptly and appropriately, why aren't you firing back, you bastards? - I did some idle research. As you do.

So, a question for you: without googling or wiki'ing or any other variety of looking it up, what is the maximum number of guns fired in a royal salute, and why is it that number of guns? Make it up, by all means, but I want reasons...