I'm not sure what you have changed, but is there a way to do any of these: Make ships invisible to units unless in a coastal waters (as opposed to open ocean) except for ships, so fleets are not so unrealistically easy to track. Give carrier ablility to see ships for a little more distance (to represent recon planes). Give destroyers a slightly stackable air defense to represent a destroyer screen to protect against planes (no major ship was without one). Ships immune against collateral damage, since when does a bomber attack a whole fleet. Bombers unrealistically bomb ships, should use torpedo and dive bombers, a new torpedo bomber unit (might get too confusing for AI) for ship attacks and can be carried on carriers.