Hello,
Actually in the we buy our ships with gold, in reality in did not work this way at all !
In reality it did not work so at all. It varies from nation to nation and form period in history. Let me explain. In Great Britain in some periods it was purely a question of family if your family was in the navy you were in the Navy and if your father was a commander you were a commander or you bought your command, nearly like in the game, in another more recent period in the same country the Navy command did understand that commanders had to be chosen only by merits and exams and some time (in rank). In France before the revolution it was a question of family and/or money during and after the revolution only on the merit of the commander how did follow a school education! A little longer after the revolution it was more mixed with professional families how did follow certain schools but the results where more mediocre side. All other nations even the USA follow the same rules with in some variations in time periods.
In the game the XP’s should buy ships, in the Navy of each nation at least, and so also automatically the command going with it. I have never read or heard of a captain buying is ship in the war Navy?! Did you?! In the civil or trade navy you can buy your ship or ships. In some periods, the early one, you could buy your command in gold but never war ships how where the Navy’s propriety how could afford them (in France even the wood to build them was propriety of the nation or King).
So to make it simple I say: at each level of command you should get a choice of new “WAR” ships to command once you are in your port of origin (capital). Equipment: the basic should be provided but all the extras could and should be bought with your own money.