The merchant flags are actually not all that realistic, as far as I can tell. I am mainly concered about the last period, the french and portugese flags are the worst IMO, because they look similar at a distance and they arent realistic.
I think french merchant ships should simply fly the tricolor, and french naval ships the current tricolor ensign (though this is not accurate for the entire last period either, In Napoleon's time the Naval Ensign was replaced with the Tricolor too)
http://en.wikipedia.org/wiki/French_ensigns
Portugal is harder to find information on, and I have found an example of the green and white striped flag ingame, though it seems to be the flag of merchants from the portugese city of Oporto http://www.crwflags.com/fotw/flags/pt~hist.html
I might change it to one of these flags, simply so the nationality of a ship is easier to identify http://en.wikipedia.org/wiki/List_of_Portuguese_flags
The flag currently ingame for British ships is the historical flag of their East India Trading Company http://en.wikipedia.org/wiki/East_India_Company As much as the POTC movies want you to believe that EIC ruled the world, they really didnt, though they rule nearly all of india. However, that is on the other side of the world, they didnt historically have much influence in the caribbean.
I plan to replace it with the Red ensign, which is the current flag of British merchantmen. http://en.wikipedia.org/wiki/Red_Ensign It wasn't their official flag at the time of the game, merchant ships had a choice between several ensigns I think, but this is easily identifiable and it is hard to be mistaken with an american flag. I am considering using a simple Union Jack as well.
As for American Merchants, the current flag with just the stripes was used by merchants during the revolution, but not afterwards, so I will change the period 6 merchant flag to be the same as the Naval one.
I dont know howhistorically accurate spain's merchant flag is, but it is easily identifiable as spanish, looks nice, and I see no reason to change it.
