The original game is strictly symmetrical, except for the player moving first having a slight advantage. But in SailCraft the two players don’t have the exact same fleet, nor do they even have the same size of grid. Instead your grid size and your special abilities depend on the ships you choose for your fleet, limited by the level of your mothership. Ships come in common, uncommon, rare and legendary types, and the more of the same ship you find, the higher you can upgrade them in level. Each ship has an active and a passive ability, and stats for how many spaces it adds to your grid and how much “luck” you have going first. Active abilities allow you to do different things than just targeting space D4 and hoping you hit the battleship: For example you can fire a torpedo, send out a bomber, or use a telescope to scout some grid spaces. There are also counter-abilities like a torpedo-net or anti-aircraft guns.
Overall that makes the game a lot more dynamic to play than the original. But obviously the player who has collected more powerful ships has a distinctive advantage, having more powerful active abilities and a larger grid on which to hide his ships. Fortunately there is a matchmaking system that prevents you getting paired against the top players while you are still in the lower leagues. Which makes the game okay playable without paying any money, or just buying the occasional special offer. Having endless amount of time isn’t much help, as you can only grind a certain number of chests full of ships every day.
I don’t think there is any game left that didn’t get this sort of monetization make-over in a mobile version, frequently based around collectible items. I’ve even seen coin dozer games that work like that. SailCraft has the advantage that the underlying game of Battleship is a relatively intelligent one, and you can actually outthink your opponent to a certain degree. I just don’t think I’ll ever make it to the very top, because that appears to require some serious spending, which I am not willing to do.