Quite a few naval unit changes, which will be a temporary fix until new units can be added:
-Caravel has 1 defense instead of 2.
-Frigate has 3 attack instead of 2.
-English Man-O-War now has 4/3/4, which it did before all these changes but not in the original game.
-Reminder: The Privateer has 2/1/3 , which is properly weaker than the Frigate's 3/2/4. 1/1/3 was just too weak as a Galley, Caravel, and Galleon had an even chance of killing it by attacking or by defending. I've considered giving it +1 defense or movement, but it should be thoroughly play-tested as-is first.
-Ironclad has 5 attack instead of 4.
-Submarine is available with Combustion instead of Mass Production, has 7 attack instead of 6, and 6 defense instead of 4. While submarines are dead if they are found the game does not properly simulate how difficult it is to actually find them in the first place. Thus Defense stat must be used instead, so it's higher now.
-Nuclear Submarine was 6/4/3, now it's current stats are 10/6/4. While Nuclear subs aren't really better than their non-nuclear counterparts, the changed stats are to show the fact that the nuclear subs are modern subs while the Submarine is pretty much a late version of a U-Boat.
-Destroyer was 12/8/5 and is now 10/7/5, now becomes available with Mass Production instead of Combustion, and can see submarines which it couldn't before. Formerly it seemed to have had an even chance of killing a Battleship if it attacked first, which is stupid, and now it has an even chance of getting killed by a Submarine if attacked first. Though it should manage to kill the sub if it attacks first.
-AEGIS Cruiser can no still Submarines, which it shouldn't, but this is the only way to balance the Nuclear Submarine as I can't add a Modern Destroyer. Also has 15/12/5 now instead of 12/10/5. Just look on the tech tree where the Destroyer and Battleship become available, and then where the AEGIS becomes available. It will be the upgrade for the Cruiser when units are addable, but until then it is a worthy apponent to the Battleship while being cheaper to build.
Many naval units will be changed a LOT when new units can be added, but this should hold us till a patch or until I figure out where the hidden Civilopedia index is which crashes the game upon certain conditions when new technologys (and maybe units) are added.