Hmm, let me make this idea better. Youre right, Mr.Cotton. If you say so, that there wasnt any school like this, just do the same thing, but call it 'naval command', and its bit different, like this:
First trainings remain the same: fencing, firing guns, and maybe 'appropriate official solider talk' like, you need to learn, and choose, what string you need to use, when arrest someone, question someone, etc.
After any beginner training, you need to give 'guard duty' (search given areas near town to kill guys)
and after every guard, you got some miserably little money.
But, If you keep going into the naval command (you only can go in if you wear naval uniform, and your officers too) you get more and more training, and get more and more ranks. hmm.. Let the first be 'footman', then 'corporal' (if there was a rank like this back then) 'sergeant'...
then, if you are became sergeant, a new duty avaliable also, besides 'guard': the 'arrest' duty (find and arrest a guy with given look,and name) Then, If you reach the 'lieutenant' level, you start sea training. Sailing training with a tartane, gunfiring training with a lugger). But you still have to do land duties. But, after you reach the rank: apprentice captain, you got a very strong, but little ship, like a modified brig? yes! mutch faster, and has more guns, but REALLY REALLY few cargo hold. (coastal guardship) and, then you need to do scout duties around the island, and no more land duties. But only with the given brig. And, Then, after some duties, there gonna be a special alert: to find, and eradicate a stronger pirate ship, whats closing to the island. And after that, you reach the rank of true 'captain', and you get the mentioned english frigate..... Then, sometimes you can go to naval command, (in uniform of course) and require duties, to find, and eradicate a ship in deep sea, or harass an enemy port, escort a ship, or something....
I let you work on the next ranks and ships idea, hehe....
Of course, your 'naval career' only exist in the times, when you wear the uniform, go to the command, and later, when you commandeer the given ship. If you loose a given ship, you need to restart the whole careeer.... (hehe, rank loss) so, its not so realistic, to get 'holidays' when you are a naval mariner, But hey, its a game, and I bet, you want your own character look sometimes, and your own, old ship, or fleet. Just for a more great gameplay, you can be a mariner only, when you go there to require duty, and wear the uniform.
I think, this idea both supports (more than the school) historical realism, and greeeat gameplay. If someone teach me about the POTC file and class system, and at least 3-4 guys, who know how to do quests help, we can do this easily. But remain on the idea yet: how you like it?