Quote Originally Posted by The_Mark
Why hasn't anyone thought of this earlier? With a bit more sophisticated code we could link upkeep to the fleets' distance from nearest docks, at least up to a certain level.
Keep in mind that the AI will never associate naval cost with distance from docks. But there may be a plus/minus for each side:

Human: Knows about the cost/distance link, and so makes an effort to keep fleets as close to home ports as possible. This encourages behaviour that mirrors history, which is good. The AI will not be able to do likewise, so advantage Human.

AI: Unlike the AI, the human player is often prone to send fleets off on great voyages of exploration. In the past there was no reason not to - the cost of maintaining a Pontic fleet off the cost of Norway was the same as being in the Black Sea. Well, no longer. And since the AI typically doesn't launch long range naval explorations, advantage AI.

In sum, this idea would seem to make the game more realistic, and wouldn't unduly penalize one side over the other.