A battleship is naval unit from the original game that is used primarily for attacking enemy navies. It is the second most powerful out of all the naval units. With Aircraft Carriers being the first
Battleships should generally be used as one's primary naval unit. They can be used to defend valuable aircraft carriers, attack naval shipyards (and construction yards), attack navies, and attack transport ships (especially helpful in preventing the transportation of tanks, as tanks cannot be transported by any other unit). They can also serve as high damage distractions.
To see a small comparison between battleships and destroyers, visit the destroyer page.
It is important to bear in mind that it may take a while for battleships to destroy a transport ship, therefore if a transport ship is close enough to land, one may not have enough time to destroy before it unloads. Always use battleships to attack transport ships as soon as possible, i.e. as soon as a transport ship is created, one should attack it.
Getting a strong navy full of battleships will ensure naval domination - allowing one to prevent enemies from creating plants or invading bases on other islands. This is most important in early to mid game, until players begin to invest in air units. But by then, by dominating the crystals via naval superiority, one will still maintain a massive advantage over other players.