Cruiser: [15000 Platinum 10,000 metal] /50 Navy power\ Upgrades for the cruiser: Anti Air [100 metal (1 cruiser per 10 must have anti air or the damage modifier won't work)] Submarine: [30000 platinum 12,500 metal] /100 Navy power\ Upgrades for the Submarine: Torpedoes [1500 metal per 10 submarines] Air Craft Carrier: [40000 platinum 15,000 metal] /75 Navy power 75 Air power\ Battleship: [50,000 platinum 25,000 metal] /200 Navy power\
Cruisers at their base take 1.5x damage from Air power due to them not having Anti Air defenses. With Anti Air, the damage goes back down to normal damage. Submarines are strong against other normal ships (meaning cruisers) dealing 1.5x damage if they have torpedoes Air Craft Carriers are used to move your air troops easier Battleships are slower to move, but deal big damage to fortifications.