Heh, no need to apologise for it, I dare say it's a useful guide and tool for many purposes. However, it's never going to be a completely authoritative guide to a language as diverse as English, with so many different dialects and colloquial quirks. It's not as simple as "American English vs. British English" - either one of these terms can actually cover a wide variety of dialects (although "British English" is often taken to mean Received Pronunciation, a broad Scottish accent (which is still technically "British English" as Scotland is in Britain) is much further from RP than RP is from most dialects of American English).

I think "she" would probably be just as common to describe a ship amongst American sailors as it is amongst English ones. But of course, this usage is still colloquial, so unlikely to be approved by style guides.