Marvelous game! For your own sake, you may want some advertisements though.
I absolutely love this game but I don’t understand how you’re even breaking even with it. You’re not charging anything for the game, don’t have any in-app purchases, and have no advertisements! I think that you could maybe add some advertisements after every 3-5 voyages. That way, you make a decent amount of money from them and the players get to enjoy their game without too many ads!