Ok just a idea to make navy s abit more interesting and realistic. In real life navies are probably one of the most expensive things to up keep. In times off peace throughout history to save money the majority of the ships are laid up or mothballed. In other words put into storage with a skeleton crew to upkeep them. The in times of war instead of building new ships you can just bring out the old ones. So I suggest making navy upkeep a heck of a lot more expensive. But allowing you to mothball some or all of your ships. In this mod they will only cost a fraction of there maintenance BUT you can move them and they have basically no defence and worse can be easily captured by enemy ships or sunk in later eras by bombers. When a war breaks out you can mobilise them again which will take one or two turns (where they will be super vulnerable) and then after they will be ready too use as normal with normal upkeep costs.