Expansion
A system in which a country can choose to explore deeper into a port, and colonize land. With payments from the treasury, the port can have a higher population due to more land. Expansion sets a new bare minimum of how low a port's population can go.

Captain Modifications
During battles, there is a % chance that while you batting, your men loot a well designed armor that you can give to one of your captains. This armor can boost morale of the ship's captain and as well improve damage dealt in battle.

Destruction
If a port is taken over, these buildings and upgrades will all be burned down by the current owner of the port in 3 days. That being said, the original nation who made these advancements have 3 days to reclaim their port before all their hard work goes into a flame.

Private Shipwright
Members of a nation who hoist their ships in a port containing a Private Shipyard get their ships repaired 10% per hour and free crew.

Art of Taxation
Your port improves its taxation method, per level, your port produces 3% more income per day. Max at level 10.

+1 Archive

i prposed private shipwrights and was quicky turned down. they are too important to the game to mess with.

you may have something different in mind, please reword it than