Range effect

[mk4m]

How much range is enough? 5000, 10.000, 20.000?

[HistoricalAccuracyMan]

Assuming you mean operational range, it is really up to you to decide "how much is enough?" And even to that point, it kinda depends on what you want your ships to do.

If you plan on some sort of Global Domination strategy where you want to have ports all over the globe, you're probably gonna need as much operational range as you can squeeze out of your ships...unless you plan to build ships that only operate in certain areas (i.e. these ships will only operate in the Caribbean, and nowhere else), then I guess you wouldn't need a huge operational range since they wouldn't be moving very far.

If you want your Light Cruisers and/or Battlecruisers to be long-range commerce raiders, you generally want to try and maximize your operational range for those ships. If you want a battleship to be more of a costal-defense ship rather than a high-seas powerhouse, you don't need a very large range, since you would generally only operate that ship close to your home territory.

Operational Range also impacts mission generation (I believe that the higher your operational range, the better your chances for "favorable" missions is), your power projection/blockades, and your budget as well--since a ship that has a large operational range may not have to refuel at sea when they sail from San Francisco to Tokyo, thus saving you money in the long run, while a ship that has lower operational range may enter a "low fuel" state and require more money (and time) to reach their destination.

Long story short: it's really up to you and what you want your ships to do. If you are going to be sending ships around the globe, go with longer range. If you are fine with only controlling the waters around your home territory and nearby provinces, shorten your operational range.

[Suribachi]

Personally, I mainly play as Japan with the goal of conquering and controlling the Pacific and Southeast Asia areas.  For me, 15,000 to 20,000 is usually enough for that goal.  If I need to go further, I usually have a few Battlecruisers and Heavy Cruisers specialized for speed and range on hand.  Other classes are then used for defense of "home" waters.